slightly offtopic - Page 78

Why is Java EE 6 better than Spring ?

- by arungupta

Java EE 6 was released over 2 years ago and now there are 14 compliant application servers. In all my talks around the world, a question that is frequently asked is Why should I use Java EE 6 instead of Spring ? There are already several blogs covering that topic: Java EE wins over Spring by Bill Burke Why will I use Java EE instead of Spring in new Enterprise Java projects in 2012 ? by Kai Waehner (more discussion on TSS) Spring to Java EE migration (Part 1 and 2, 3 and 4 coming as well) by David Heffelfinger Spring to Java EE - A Migration Experience by Lincoln Baxter Migrating Spring to Java EE 6 by Bert Ertman and Paul Bakker at NLJUG Moving from Spring to Java EE 6 - The Age of Frameworks is Over at TSS Java EE vs Spring Shootout by Rohit Kelapure and Reza Rehman at JavaOne 2011 Java EE 6 and the Ewoks by Murat Yener Definite excuse to avoid Spring forever - Bert Ertman and Arun Gupta I will try to share my perspective in this blog. First of all, I'd like to start with a note: Thank you Spring framework for filling the interim gap and providing functionality that is now included in the mainstream Java EE 6 application servers. The Java EE platform has evolved over the years learning from frameworks like Spring and provides all the functionality to build an enterprise application. Thank you very much Spring framework! While Spring was revolutionary in its time and is still very popular and quite main stream in the same way Struts was circa 2003, it really is last generation's framework - some people are even calling it legacy. However my theory is "code is king". So my approach is to build/take a simple Hello World CRUD application in Java EE 6 and Spring and compare the deployable artifacts. I started looking at the official tutorial Developing a Spring Framework MVC Application Step-by-Step but it is using the older version 2.5. I wasn't able to find any updated version in the current 3.1 release. Next, I downloaded Spring Tool Suite and thought that would provide some template samples to get started. A least a quick search did not show any handy tutorials - either video or text-based. So I searched and found a link to their SVN repository at src.springframework.org/svn/spring-samples/. I tried the "mvc-basic" sample and the generated WAR file was 4.43 MB. While it was named a "basic" sample it seemed to come with 19 different libraries bundled but it was what I could find: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/joda-time-jsptags-1.0.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar And it is not even using any database! The app deployed fine on GlassFish 3.1.2 but the "@Controller Example" link did not work as it was missing the context root. With a bit of tweaking I could deploy the application and assume that the account got created because no error was displayed in the browser or server log. Next I generated the WAR for "mvc-ajax" and the 5.1 MB WAR had 20 JARs (1 removed, 2 added): ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.6.4.jar./WEB-INF/lib/jackson-mapper-asl-1.6.4.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar 2 more JARs for just doing Ajax. Anyway, deploying this application gave the following error: Caused by: java.lang.NoSuchMethodError: org.codehaus.jackson.map.SerializationConfig.<init>(Lorg/codehaus/jackson/map/ClassIntrospector;Lorg/codehaus/jackson/map/AnnotationIntrospector;Lorg/codehaus/jackson/map/introspect/VisibilityChecker;Lorg/codehaus/jackson/map/jsontype/SubtypeResolver;)V at org.springframework.samples.mvc.ajax.json.ConversionServiceAwareObjectMapper.<init>(ConversionServiceAwareObjectMapper.java:20) at org.springframework.samples.mvc.ajax.json.JacksonConversionServiceConfigurer.postProcessAfterInitialization(JacksonConversionServiceConfigurer.java:40) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) Seems like some incorrect repos in the "pom.xml". Next one is "mvc-showcase" and the 6.49 MB WAR now has 28 JARs as shown below: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/aspectjrt-1.6.10.jar./WEB-INF/lib/commons-fileupload-1.2.2.jar./WEB-INF/lib/commons-io-2.0.1.jar./WEB-INF/lib/el-api-2.2.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.8.1.jar./WEB-INF/lib/jackson-mapper-asl-1.8.1.jar./WEB-INF/lib/javax.inject-1.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/jdom-1.0.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-api-1.2.jar./WEB-INF/lib/jstl-impl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/rome-1.0.0.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.1.0.RELEASE.jar./WEB-INF/lib/spring-asm-3.1.0.RELEASE.jar./WEB-INF/lib/spring-beans-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-support-3.1.0.RELEASE.jar./WEB-INF/lib/spring-core-3.1.0.RELEASE.jar./WEB-INF/lib/spring-expression-3.1.0.RELEASE.jar./WEB-INF/lib/spring-web-3.1.0.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.1.0.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar The app at least deployed and showed results this time. But still no database! Next I tried building "jpetstore" and got the error: [ERROR] Failed to execute goal on project org.springframework.samples.jpetstore:Could not resolve dependencies for project org.springframework.samples:org.springframework.samples.jpetstore:war:1.0.0-SNAPSHOT: Failed to collect dependencies for [commons-fileupload:commons-fileupload:jar:1.2.1 (compile), org.apache.struts:com.springsource.org.apache.struts:jar:1.2.9 (compile), javax.xml.rpc:com.springsource.javax.xml.rpc:jar:1.1.0 (compile), org.apache.commons:com.springsource.org.apache.commons.dbcp:jar:1.2.2.osgi (compile), commons-io:commons-io:jar:1.3.2 (compile), hsqldb:hsqldb:jar:1.8.0.7 (compile), org.apache.tiles:tiles-core:jar:2.2.0 (compile), org.apache.tiles:tiles-jsp:jar:2.2.0 (compile), org.tuckey:urlrewritefilter:jar:3.1.0 (compile), org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-orm:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-context-support:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework.webflow:spring-js:jar:2.0.7.RELEASE (compile), org.apache.ibatis:com.springsource.com.ibatis:jar:2.3.4.726 (runtime), com.caucho:com.springsource.com.caucho:jar:3.2.1 (compile), org.apache.axis:com.springsource.org.apache.axis:jar:1.4.0 (compile), javax.wsdl:com.springsource.javax.wsdl:jar:1.6.1 (compile), javax.servlet:jstl:jar:1.2 (runtime), org.aspectj:aspectjweaver:jar:1.6.5 (compile), javax.servlet:servlet-api:jar:2.5 (provided), javax.servlet.jsp:jsp-api:jar:2.1 (provided), junit:junit:jar:4.6 (test)]: Failed to read artifact descriptor for org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT: Could not transfer artifact org.springframework:spring-webmvc:pom:3.0.0.BUILD-SNAPSHOT from/to JBoss repository (http://repository.jboss.com/maven2): Access denied to: http://repository.jboss.com/maven2/org/springframework/spring-webmvc/3.0.0.BUILD-SNAPSHOT/spring-webmvc-3.0.0.BUILD-SNAPSHOT.pom It appears the sample is broken - maybe I was pulling from the wrong repository - would be great if someone were to point me at a good target to use here. With a 50% hit on samples in this repository, I started searching through numerous blogs, most of which have either outdated information (using XML-heavy Spring 2.5), some piece of configuration (which is a typical "feature" of Spring) is missing, or too much complexity in the sample. I finally found this blog that worked like a charm. This blog creates a trivial Spring MVC 3 application using Hibernate and MySQL. This application performs CRUD operations on a single table in a database using typical Spring technologies. I downloaded the sample code from the blog, deployed it on GlassFish 3.1.2 and could CRUD the "person" entity. The source code for this application can be downloaded here. More details on the application statistics below. And then I built a similar CRUD application in Java EE 6 using NetBeans wizards in a couple of minutes. The source code for the application can be downloaded here and the WAR here. The Spring Source Tool Suite may also offer similar wizard-driven capabilities but this blog focus primarily on comparing the runtimes. The lack of STS tutorials was slightly disappointing as well. NetBeans however has tons of text-based and video tutorials and tons of material even by the community. One more bit on the download size of tools bundle ... NetBeans 7.1.1 "All" is 211 MB (which includes GlassFish and Tomcat) Spring Tool Suite 2.9.0 is 347 MB (~ 65% bigger) This blog is not about the tooling comparison so back to the Java EE 6 version of the application .... In order to run the Java EE version on GlassFish, copy the MySQL Connector/J to glassfish3/glassfish/domains/domain1/lib/ext directory and create a JDBC connection pool and JDBC resource as: ./bin/asadmin create-jdbc-connection-pool --datasourceclassname \\ com.mysql.jdbc.jdbc2.optional.MysqlDataSource --restype \\ javax.sql.DataSource --property \\ portNumber=3306:user=mysql:password=mysql:databaseName=mydatabase \\ myConnectionPool ./bin/asadmin create-jdbc-resource --connectionpoolid myConnectionPool jdbc/myDataSource I generated WARs for the two projects and the table below highlights some differences between them: Java EE 6 Spring WAR File Size 0.021030 MB 10.87 MB (~516x) Number of files 20 53 (> 2.5x) Bundled libraries 0 36 Total size of libraries 0 12.1 MB XML files 3 5 LoC in XML files 50 (11 + 15 + 24) 129 (27 + 46 + 16 + 11 + 19) (~ 2.5x) Total .properties files 1 Bundle.properties 2 spring.properties, log4j.properties Cold Deploy 5,339 ms 11,724 ms Second Deploy 481 ms 6,261 ms Third Deploy 528 ms 5,484 ms Fourth Deploy 484 ms 5,576 ms Runtime memory ~73 MB ~101 MB Some points worth highlighting from the table ... 516x WAR file, 10x deployment time - With 12.1 MB of libraries (for a very basic application) bundled in your application, the WAR file size and the deployment time will naturally go higher. The WAR file for Spring-based application is 516x bigger and the deployment time is double during the first deployment and ~ 10x during subsequent deployments. The Java EE 6 application is fully portable and will run on any Java EE 6 compliant application server. 36 libraries in the WAR - There are 14 Java EE 6 compliant application servers today. Each of those servers provide all the functionality like transactions, dependency injection, security, persistence, etc typically required of an enterprise or web application. There is no need to bundle 36 libraries worth 12.1 MB for a trivial CRUD application. These 14 compliant application servers provide all the functionality baked in. Now you can also deploy these libraries in the container but then you don't get the "portability" offered by Spring in that case. Does your typical Spring deployment actually do that ? 3x LoC in XML - The number of XML files is about 1.6x and the LoC is ~ 2.5x. So much XML seems circa 2003 when the Java language had no annotations. The XML files can be further reduced, e.g. faces-config.xml can be replaced without providing i18n, but I just want to compare stock applications. Memory usage - Both the applications were deployed on default GlassFish 3.1.2 installation and any additional memory consumed as part of deployment/access was attributed to the application. This is by no means scientific but at least provides an initial ballpark. This area definitely needs more investigation. Another table that compares typical Java EE 6 compliant application servers and the custom-stack created for a Spring application ... Java EE 6 Spring Web Container ? 53 MB (tcServer 2.6.3 Developer Edition) Security ? 12 MB (Spring Security 3.1.0) Persistence ? 6.3 MB (Hibernate 4.1.0, required) Dependency Injection ? 5.3 MB (Framework) Web Services ? 796 KB (Spring WS 2.0.4) Messaging ? 3.4 MB (RabbitMQ Server 2.7.1) 936 KB (Java client 936) OSGi ? 1.3 MB (Spring OSGi 1.2.1) GlassFish and WebLogic (starting at 33 MB) 83.3 MB There are differentiating factors on both the stacks. But most of the functionality like security, persistence, and dependency injection is baked in a Java EE 6 compliant application server but needs to be individually managed and patched for a Spring application. This very quickly leads to a "stack explosion". The Java EE 6 servers are tested extensively on a variety of platforms in different combinations whereas a Spring application developer is responsible for testing with different JDKs, Operating Systems, Versions, Patches, etc. Oracle has both the leading OSS lightweight server with GlassFish and the leading enterprise Java server with WebLogic Server, both Java EE 6 and both with lightweight deployment options. The Web Container offered as part of a Java EE 6 application server not only deploys your enterprise Java applications but also provide operational management, diagnostics, and mission-critical capabilities required by your applications. The Java EE 6 platform also introduced the Web Profile which is a subset of the specifications from the entire platform. It is targeted at developers of modern web applications offering a reasonably complete stack, composed of standard APIs, and is capable out-of-the-box of addressing the needs of a large class of Web applications. As your applications grow, the stack can grow to the full Java EE 6 platform. The GlassFish Server Web Profile starting at 33MB (smaller than just the non-standard tcServer) provides most of the functionality typically required by a web application. WebLogic provides battle-tested functionality for a high throughput, low latency, and enterprise grade web application. No individual managing or patching, all tested and commercially supported for you! Note that VMWare does have a server, tcServer, but it is non-standard and not even certified to the level of the standard Web Profile most customers expect these days. Customers who choose this risk proprietary lock-in since VMWare does not seem to want to formally certify with either Java EE 6 Enterprise Platform or with Java EE 6 Web Profile but of course it would be great if they were to join the community and help their customers reduce the risk of deploying on VMWare software. Some more points to help you decide choose between Java EE 6 and Spring ... Freedom to choose container - There are 14 Java EE 6 compliant application servers today, with a variety of open source and commercial offerings. A Java EE 6 application can be deployed on any of those containers. So if you deployed your application on GlassFish today and would like to scale up with your demands then you can deploy the same application to WebLogic. And because of the portability of a Java EE 6 application, you can even take it a different vendor altogether. Spring requires a runtime which could be any of these app servers as well. But why use Spring when all the required functionality is already baked into the application server itself ? Spring also has a different definition of portability where they claim to bundle all the libraries in the WAR file and move to any application server. But we saw earlier how bloated that archive could be. The equivalent features in Spring runtime offerings (mainly tcServer) are not all open source, not as mature, and often require manual assembly. Vendor choice - The Java EE 6 platform is created using the Java Community Process where all the big players like Oracle, IBM, RedHat, and Apache are conritbuting to make the platform successful. Each application server provides the basic Java EE 6 platform compliance and has its own competitive offerings. This allows you to choose an application server for deploying your Java EE 6 applications. If you are not happy with the support or feature of one vendor then you can move your application to a different vendor because of the portability promise offered by the platform. Spring is a set of products from a single company, one price book, one support organization, one sustaining organization, one sales organization, etc. If any of those cause a customer headache, where do you go ? Java EE, backed by multiple vendors, is a safer bet for those that are risk averse. Production support - With Spring, typically you need to get support from two vendors - VMWare and the container provider. With Java EE 6, all of this is typically provided by one vendor. For example, Oracle offers commercial support from systems, operating systems, JDK, application server, and applications on top of them. VMWare certainly offers complete production support but do you really want to put all your eggs in one basket ? Do you really use tcServer ? ;-) Maintainability - With Spring, you are likely building your own distribution with multiple JAR files, integrating, patching, versioning, etc of all those components. Spring's claim is that multiple JAR files allow you to go à la carte and pick the latest versions of different components. But who is responsible for testing whether all these versions work together ? Yep, you got it, its YOU! If something does not work, who patches and maintains the JARs ? Of course, you! Commercial support for such a configuration ? On your own! The Java EE application servers manage all of this for you and provide a well-tested and commercially supported bundle. While it is always good to realize that there is something new and improved that updates and replaces older frameworks like Spring, the good news is not only does a Java EE 6 container offer what is described here, most also will let you deploy and run your Spring applications on them while you go through an upgrade to a more modern architecture. End result, you get the best of both worlds - keeping your legacy investment but moving to a more agile, lightweight world of Java EE 6. A message to the Spring lovers ... The complexity in J2EE 1.2, 1.3, and 1.4 led to the genesis of Spring but that was in 2004. This is 2012 and the name has changed to "Java EE 6" :-) There are tons of improvements in the Java EE platform to make it easy-to-use and powerful. Some examples: Adding @Stateless on a POJO makes it an EJB EJBs can be packaged in a WAR with no special packaging or deployment descriptors "web.xml" and "faces-config.xml" are optional in most of the common cases Typesafe dependency injection is now part of the Java EE platform Add @Path on a POJO allows you to publish it as a RESTful resource EJBs can be used as backing beans for Facelets-driven JSF pages providing full MVC Java EE 6 WARs are known to be kilobytes in size and deployed in milliseconds Tons of other simplifications in the platform and application servers So if you moved away from J2EE to Spring many years ago and have not looked at Java EE 6 (which has been out since Dec 2009) then you should definitely try it out. Just be at least aware of what other alternatives are available instead of restricting yourself to one stack. Here are some workshops and screencasts worth trying: screencast #37 shows how to build an end-to-end application using NetBeans screencast #36 builds the same application using Eclipse javaee-lab-feb2012.pdf is a 3-4 hours self-paced hands-on workshop that guides you to build a comprehensive Java EE 6 application using NetBeans Each city generally has a "spring cleanup" program every year. It allows you to clean up the mess from your house. For your software projects, you don't need to wait for an annual event, just get started and reduce the technical debt now! Move away from your legacy Spring-based applications to a lighter and more modern approach of building enterprise Java applications using Java EE 6. Watch this beautiful presentation that explains how to migrate from Spring -> Java EE 6: List of files in the Java EE 6 project: ./index.xhtml./META-INF./person./person/Create.xhtml./person/Edit.xhtml./person/List.xhtml./person/View.xhtml./resources./resources/css./resources/css/jsfcrud.css./template.xhtml./WEB-INF./WEB-INF/classes./WEB-INF/classes/Bundle.properties./WEB-INF/classes/META-INF./WEB-INF/classes/META-INF/persistence.xml./WEB-INF/classes/org./WEB-INF/classes/org/javaee./WEB-INF/classes/org/javaee/javaeemysql./WEB-INF/classes/org/javaee/javaeemysql/AbstractFacade.class./WEB-INF/classes/org/javaee/javaeemysql/Person.class./WEB-INF/classes/org/javaee/javaeemysql/Person_.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$1.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$PersonControllerConverter.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController.class./WEB-INF/classes/org/javaee/javaeemysql/PersonFacade.class./WEB-INF/classes/org/javaee/javaeemysql/util./WEB-INF/classes/org/javaee/javaeemysql/util/JsfUtil.class./WEB-INF/classes/org/javaee/javaeemysql/util/PaginationHelper.class./WEB-INF/faces-config.xml./WEB-INF/web.xml List of files in the Spring 3.x project: ./META-INF ./META-INF/MANIFEST.MF./WEB-INF./WEB-INF/applicationContext.xml./WEB-INF/classes./WEB-INF/classes/log4j.properties./WEB-INF/classes/org./WEB-INF/classes/org/krams ./WEB-INF/classes/org/krams/tutorial ./WEB-INF/classes/org/krams/tutorial/controller ./WEB-INF/classes/org/krams/tutorial/controller/MainController.class ./WEB-INF/classes/org/krams/tutorial/domain ./WEB-INF/classes/org/krams/tutorial/domain/Person.class ./WEB-INF/classes/org/krams/tutorial/service ./WEB-INF/classes/org/krams/tutorial/service/PersonService.class ./WEB-INF/hibernate-context.xml ./WEB-INF/hibernate.cfg.xml ./WEB-INF/jsp ./WEB-INF/jsp/addedpage.jsp ./WEB-INF/jsp/addpage.jsp ./WEB-INF/jsp/deletedpage.jsp ./WEB-INF/jsp/editedpage.jsp ./WEB-INF/jsp/editpage.jsp ./WEB-INF/jsp/personspage.jsp ./WEB-INF/lib ./WEB-INF/lib/antlr-2.7.6.jar ./WEB-INF/lib/aopalliance-1.0.jar ./WEB-INF/lib/c3p0-0.9.1.2.jar ./WEB-INF/lib/cglib-nodep-2.2.jar ./WEB-INF/lib/commons-beanutils-1.8.3.jar ./WEB-INF/lib/commons-collections-3.2.1.jar ./WEB-INF/lib/commons-digester-2.1.jar ./WEB-INF/lib/commons-logging-1.1.1.jar ./WEB-INF/lib/dom4j-1.6.1.jar ./WEB-INF/lib/ejb3-persistence-1.0.2.GA.jar ./WEB-INF/lib/hibernate-annotations-3.4.0.GA.jar ./WEB-INF/lib/hibernate-commons-annotations-3.1.0.GA.jar ./WEB-INF/lib/hibernate-core-3.3.2.GA.jar ./WEB-INF/lib/javassist-3.7.ga.jar ./WEB-INF/lib/jstl-1.1.2.jar ./WEB-INF/lib/jta-1.1.jar ./WEB-INF/lib/junit-4.8.1.jar ./WEB-INF/lib/log4j-1.2.14.jar ./WEB-INF/lib/mysql-connector-java-5.1.14.jar ./WEB-INF/lib/persistence-api-1.0.jar ./WEB-INF/lib/slf4j-api-1.6.1.jar ./WEB-INF/lib/slf4j-log4j12-1.6.1.jar ./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-jdbc-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-orm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-tx-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar ./WEB-INF/lib/standard-1.1.2.jar ./WEB-INF/lib/xml-apis-1.0.b2.jar ./WEB-INF/spring-servlet.xml ./WEB-INF/spring.properties ./WEB-INF/web.xml So, are you excited about Java EE 6 ? Want to get started now ? Here are some resources: Java EE 6 SDK (including runtime, samples, tutorials etc) GlassFish Server Open Source Edition 3.1.2 (Community) Oracle GlassFish Server 3.1.2 (Commercial) Java EE 6 using WebLogic 12c and NetBeans (Video) Java EE 6 with NetBeans and GlassFish (Video) Java EE with Eclipse and GlassFish (Video)

Read the article

Creating a dynamic proxy generator with c# – Part 3 – Creating the constructors

- by SeanMcAlinden

Creating a dynamic proxy generator with c# – Part 1 – Creating the Assembly builder, Module builder and caching mechanism Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design For the latest code go to http://rapidioc.codeplex.com/ When building our proxy type, the first thing we need to do is build the constructors. There needs to be a corresponding constructor for each constructor on the passed in base type. We also want to create a field to store the interceptors and construct this list within each constructor. So assuming the passed in base type is a User<int, IRepository> class, were looking to generate constructor code like the following: Default Constructor public User`2_RapidDynamicBaseProxy() { this.interceptors = new List<IInterceptor<User<int, IRepository>>>(); DefaultInterceptor<User<int, IRepository>> item = new DefaultInterceptor<User<int, IRepository>>(); this.interceptors.Add(item); } Parameterised Constructor public User`2_RapidDynamicBaseProxy(IRepository repository1) : base(repository1) { this.interceptors = new List<IInterceptor<User<int, IRepository>>>(); DefaultInterceptor<User<int, IRepository>> item = new DefaultInterceptor<User<int, IRepository>>(); this.interceptors.Add(item); } As you can see, we first populate a field on the class with a new list of the passed in base type. Construct our DefaultInterceptor class. Add the DefaultInterceptor instance to our interceptor collection. Although this seems like a relatively small task, there is a fair amount of work require to get this going. Instead of going through every line of code – please download the latest from http://rapidioc.codeplex.com/ and debug through. In this post I’m going to concentrate on explaining how it works. TypeBuilder The TypeBuilder class is the main class used to create the type. You instantiate a new TypeBuilder using the assembly module we created in part 1. /// <summary> /// Creates a type builder. /// </summary> /// <typeparam name="TBase">The type of the base class to be proxied.</typeparam> public static TypeBuilder CreateTypeBuilder<TBase>() where TBase : class { TypeBuilder typeBuilder = DynamicModuleCache.Get.DefineType ( CreateTypeName<TBase>(), TypeAttributes.Class | TypeAttributes.Public, typeof(TBase), new Type[] { typeof(IProxy) } ); if (typeof(TBase).IsGenericType) { GenericsHelper.MakeGenericType(typeof(TBase), typeBuilder); } return typeBuilder; } private static string CreateTypeName<TBase>() where TBase : class { return string.Format("{0}_RapidDynamicBaseProxy", typeof(TBase).Name); } As you can see, I’ve create a new public class derived from TBase which also implements my IProxy interface, this is used later for adding interceptors. If the base type is generic, the following GenericsHelper.MakeGenericType method is called. GenericsHelper using System; using System.Reflection.Emit; namespace Rapid.DynamicProxy.Types.Helpers { /// <summary> /// Helper class for generic types and methods. /// </summary> internal static class GenericsHelper { /// <summary> /// Makes the typeBuilder a generic. /// </summary> /// <param name="concrete">The concrete.</param> /// <param name="typeBuilder">The type builder.</param> public static void MakeGenericType(Type baseType, TypeBuilder typeBuilder) { Type[] genericArguments = baseType.GetGenericArguments(); string[] genericArgumentNames = GetArgumentNames(genericArguments); GenericTypeParameterBuilder[] genericTypeParameterBuilder = typeBuilder.DefineGenericParameters(genericArgumentNames); typeBuilder.MakeGenericType(genericTypeParameterBuilder); } /// <summary> /// Gets the argument names from an array of generic argument types. /// </summary> /// <param name="genericArguments">The generic arguments.</param> public static string[] GetArgumentNames(Type[] genericArguments) { string[] genericArgumentNames = new string[genericArguments.Length]; for (int i = 0; i < genericArguments.Length; i++) { genericArgumentNames[i] = genericArguments[i].Name; } return genericArgumentNames; } } } As you can see, I’m getting all of the generic argument types and names, creating a GenericTypeParameterBuilder and then using the typeBuilder to make the new type generic. InterceptorsField The interceptors field will store a List<IInterceptor<TBase>>. Fields are simple made using the FieldBuilder class. The following code demonstrates how to create the interceptor field. FieldBuilder interceptorsField = typeBuilder.DefineField( "interceptors", typeof(System.Collections.Generic.List<>).MakeGenericType(typeof(IInterceptor<TBase>)), FieldAttributes.Private ); The field will now exist with the new Type although it currently has no data – we’ll deal with this in the constructor. Add method for interceptorsField To enable us to add to the interceptorsField list, we are going to utilise the Add method that already exists within the System.Collections.Generic.List class. We still however have to create the methodInfo necessary to call the add method. This can be done similar to the following: Add Interceptor Field MethodInfo addInterceptor = typeof(List<>) .MakeGenericType(new Type[] { typeof(IInterceptor<>).MakeGenericType(typeof(TBase)) }) .GetMethod ( "Add", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, new Type[] { typeof(IInterceptor<>).MakeGenericType(typeof(TBase)) }, null ); So we’ve create a List<IInterceptor<TBase>> type, then using the type created a method info called Add which accepts an IInterceptor<TBase>. Now in our constructor we can use this to call this.interceptors.Add(// interceptor); Building the Constructors This will be the first hard-core part of the proxy building process so I’m going to show the class and then try to explain what everything is doing. For a clear view, download the source from http://rapidioc.codeplex.com/, go to the test project and debug through the constructor building section. Anyway, here it is: DynamicConstructorBuilder using System; using System.Collections.Generic; using System.Reflection; using System.Reflection.Emit; using Rapid.DynamicProxy.Interception; using Rapid.DynamicProxy.Types.Helpers; namespace Rapid.DynamicProxy.Types.Constructors { /// <summary> /// Class for creating the proxy constructors. /// </summary> internal static class DynamicConstructorBuilder { /// <summary> /// Builds the constructors. /// </summary> /// <typeparam name="TBase">The base type.</typeparam> /// <param name="typeBuilder">The type builder.</param> /// <param name="interceptorsField">The interceptors field.</param> public static void BuildConstructors<TBase> ( TypeBuilder typeBuilder, FieldBuilder interceptorsField, MethodInfo addInterceptor ) where TBase : class { ConstructorInfo interceptorsFieldConstructor = CreateInterceptorsFieldConstructor<TBase>(); ConstructorInfo defaultInterceptorConstructor = CreateDefaultInterceptorConstructor<TBase>(); ConstructorInfo[] constructors = typeof(TBase).GetConstructors(); foreach (ConstructorInfo constructorInfo in constructors) { CreateConstructor<TBase> ( typeBuilder, interceptorsField, interceptorsFieldConstructor, defaultInterceptorConstructor, addInterceptor, constructorInfo ); } } #region Private Methods private static void CreateConstructor<TBase> ( TypeBuilder typeBuilder, FieldBuilder interceptorsField, ConstructorInfo interceptorsFieldConstructor, ConstructorInfo defaultInterceptorConstructor, MethodInfo AddDefaultInterceptor, ConstructorInfo constructorInfo ) where TBase : class { Type[] parameterTypes = GetParameterTypes(constructorInfo); ConstructorBuilder constructorBuilder = CreateConstructorBuilder(typeBuilder, parameterTypes); ILGenerator cIL = constructorBuilder.GetILGenerator(); LocalBuilder defaultInterceptorMethodVariable = cIL.DeclareLocal(typeof(DefaultInterceptor<>).MakeGenericType(typeof(TBase))); ConstructInterceptorsField(interceptorsField, interceptorsFieldConstructor, cIL); ConstructDefaultInterceptor(defaultInterceptorConstructor, cIL, defaultInterceptorMethodVariable); AddDefaultInterceptorToInterceptorsList ( interceptorsField, AddDefaultInterceptor, cIL, defaultInterceptorMethodVariable ); CreateConstructor(constructorInfo, parameterTypes, cIL); } private static void CreateConstructor(ConstructorInfo constructorInfo, Type[] parameterTypes, ILGenerator cIL) { cIL.Emit(OpCodes.Ldarg_0); if (parameterTypes.Length > 0) { LoadParameterTypes(parameterTypes, cIL); } cIL.Emit(OpCodes.Call, constructorInfo); cIL.Emit(OpCodes.Ret); } private static void LoadParameterTypes(Type[] parameterTypes, ILGenerator cIL) { for (int i = 1; i <= parameterTypes.Length; i++) { cIL.Emit(OpCodes.Ldarg_S, i); } } private static void AddDefaultInterceptorToInterceptorsList ( FieldBuilder interceptorsField, MethodInfo AddDefaultInterceptor, ILGenerator cIL, LocalBuilder defaultInterceptorMethodVariable ) { cIL.Emit(OpCodes.Ldarg_0); cIL.Emit(OpCodes.Ldfld, interceptorsField); cIL.Emit(OpCodes.Ldloc, defaultInterceptorMethodVariable); cIL.Emit(OpCodes.Callvirt, AddDefaultInterceptor); } private static void ConstructDefaultInterceptor ( ConstructorInfo defaultInterceptorConstructor, ILGenerator cIL, LocalBuilder defaultInterceptorMethodVariable ) { cIL.Emit(OpCodes.Newobj, defaultInterceptorConstructor); cIL.Emit(OpCodes.Stloc, defaultInterceptorMethodVariable); } private static void ConstructInterceptorsField ( FieldBuilder interceptorsField, ConstructorInfo interceptorsFieldConstructor, ILGenerator cIL ) { cIL.Emit(OpCodes.Ldarg_0); cIL.Emit(OpCodes.Newobj, interceptorsFieldConstructor); cIL.Emit(OpCodes.Stfld, interceptorsField); } private static ConstructorBuilder CreateConstructorBuilder(TypeBuilder typeBuilder, Type[] parameterTypes) { return typeBuilder.DefineConstructor ( MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName | MethodAttributes.HideBySig, CallingConventions.Standard, parameterTypes ); } private static Type[] GetParameterTypes(ConstructorInfo constructorInfo) { ParameterInfo[] parameterInfoArray = constructorInfo.GetParameters(); Type[] parameterTypes = new Type[parameterInfoArray.Length]; for (int p = 0; p < parameterInfoArray.Length; p++) { parameterTypes[p] = parameterInfoArray[p].ParameterType; } return parameterTypes; } private static ConstructorInfo CreateInterceptorsFieldConstructor<TBase>() where TBase : class { return ConstructorHelper.CreateGenericConstructorInfo ( typeof(List<>), new Type[] { typeof(IInterceptor<TBase>) }, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic ); } private static ConstructorInfo CreateDefaultInterceptorConstructor<TBase>() where TBase : class { return ConstructorHelper.CreateGenericConstructorInfo ( typeof(DefaultInterceptor<>), new Type[] { typeof(TBase) }, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic ); } #endregion } } So, the first two tasks within the class should be fairly clear, we are creating a ConstructorInfo for the interceptorField list and a ConstructorInfo for the DefaultConstructor, this is for instantiating them in each contructor. We then using Reflection get an array of all of the constructors in the base class, we then loop through the array and create a corresponding proxy contructor. Hopefully, the code is fairly easy to follow other than some new types and the dreaded Opcodes. ConstructorBuilder This class defines a new constructor on the type. ILGenerator The ILGenerator allows the use of Reflection.Emit to create the method body. LocalBuilder The local builder allows the storage of data in local variables within a method, in this case it’s the constructed DefaultInterceptor. Constructing the interceptors field The first bit of IL you’ll come across as you follow through the code is the following private method used for constructing the field list of interceptors. private static void ConstructInterceptorsField ( FieldBuilder interceptorsField, ConstructorInfo interceptorsFieldConstructor, ILGenerator cIL ) { cIL.Emit(OpCodes.Ldarg_0); cIL.Emit(OpCodes.Newobj, interceptorsFieldConstructor); cIL.Emit(OpCodes.Stfld, interceptorsField); } The first thing to know about generating code using IL is that you are using a stack, if you want to use something, you need to push it up the stack etc. etc. OpCodes.ldArg_0 This opcode is a really interesting one, basically each method has a hidden first argument of the containing class instance (apart from static classes), constructors are no different. This is the reason you can use syntax like this.myField. So back to the method, as we want to instantiate the List in the interceptorsField, first we need to load the class instance onto the stack, we then load the new object (new List<TBase>) and finally we store it in the interceptorsField. Hopefully, that should follow easily enough in the method. In each constructor you would now have this.interceptors = new List<User<int, IRepository>>(); Constructing and storing the DefaultInterceptor The next bit of code we need to create is the constructed DefaultInterceptor. Firstly, we create a local builder to store the constructed type. Create a local builder LocalBuilder defaultInterceptorMethodVariable = cIL.DeclareLocal(typeof(DefaultInterceptor<>).MakeGenericType(typeof(TBase))); Once our local builder is ready, we then need to construct the DefaultInterceptor<TBase> and store it in the variable. Connstruct DefaultInterceptor private static void ConstructDefaultInterceptor ( ConstructorInfo defaultInterceptorConstructor, ILGenerator cIL, LocalBuilder defaultInterceptorMethodVariable ) { cIL.Emit(OpCodes.Newobj, defaultInterceptorConstructor); cIL.Emit(OpCodes.Stloc, defaultInterceptorMethodVariable); } As you can see, using the ConstructorInfo named defaultInterceptorConstructor, we load the new object onto the stack. Then using the store local opcode (OpCodes.Stloc), we store the new object in the local builder named defaultInterceptorMethodVariable. Add the constructed DefaultInterceptor to the interceptors field collection Using the add method created earlier in this post, we are going to add the new DefaultInterceptor object to the interceptors field collection. Add Default Interceptor private static void AddDefaultInterceptorToInterceptorsList ( FieldBuilder interceptorsField, MethodInfo AddDefaultInterceptor, ILGenerator cIL, LocalBuilder defaultInterceptorMethodVariable ) { cIL.Emit(OpCodes.Ldarg_0); cIL.Emit(OpCodes.Ldfld, interceptorsField); cIL.Emit(OpCodes.Ldloc, defaultInterceptorMethodVariable); cIL.Emit(OpCodes.Callvirt, AddDefaultInterceptor); } So, here’s whats going on. The class instance is first loaded onto the stack using the load argument at index 0 opcode (OpCodes.Ldarg_0) (remember the first arg is the hidden class instance). The interceptorsField is then loaded onto the stack using the load field opcode (OpCodes.Ldfld). We then load the DefaultInterceptor object we stored locally using the load local opcode (OpCodes.Ldloc). Then finally we call the AddDefaultInterceptor method using the call virtual opcode (Opcodes.Callvirt). Completing the constructor The last thing we need to do is complete the constructor. Complete the constructor private static void CreateConstructor(ConstructorInfo constructorInfo, Type[] parameterTypes, ILGenerator cIL) { cIL.Emit(OpCodes.Ldarg_0); if (parameterTypes.Length > 0) { LoadParameterTypes(parameterTypes, cIL); } cIL.Emit(OpCodes.Call, constructorInfo); cIL.Emit(OpCodes.Ret); } private static void LoadParameterTypes(Type[] parameterTypes, ILGenerator cIL) { for (int i = 1; i <= parameterTypes.Length; i++) { cIL.Emit(OpCodes.Ldarg_S, i); } } So, the first thing we do again is load the class instance using the load argument at index 0 opcode (OpCodes.Ldarg_0). We then load each parameter using OpCode.Ldarg_S, this opcode allows us to specify an index position for each argument. We then setup calling the base constructor using OpCodes.Call and the base constructors ConstructorInfo. Finally, all methods are required to return, even when they have a void return. As there are no values on the stack after the OpCodes.Call line, we can safely call the OpCode.Ret to give the constructor a void return. If there was a value, we would have to pop the value of the stack before calling return otherwise, the method would try and return a value. Conclusion This was a slightly hardcore post but hopefully it hasn’t been too hard to follow. The main thing is that a number of the really useful opcodes have been used and now the dynamic proxy is capable of being constructed. If you download the code and debug through the tests at http://rapidioc.codeplex.com/, you’ll be able to create proxies at this point, they cannon do anything in terms of interception but you can happily run the tests, call base methods and properties and also take a look at the created assembly in Reflector. Hope this is useful. The next post should be up soon, it will be covering creating the private methods for calling the base class methods and properties. Kind Regards, Sean.

Read the article

Creating STA COM compatible ASP.NET Applications

- by Rick Strahl

When building ASP.NET applications that interface with old school COM objects like those created with VB6 or Visual FoxPro (MTDLL), it's extremely important that the threads that are serving requests use Single Threaded Apartment Threading. STA is a COM built-in technology that allows essentially single threaded components to operate reliably in a multi-threaded environment. STA's guarantee that COM objects instantiated on a specific thread stay on that specific thread and any access to a COM object from another thread automatically marshals that thread to the STA thread. The end effect is that you can have multiple threads, but a COM object instance lives on a fixed never changing thread. ASP.NET by default uses MTA (multi-threaded apartment) threads which are truly free spinning threads that pay no heed to COM object marshaling. This is vastly more efficient than STA threading which has a bit of overhead in determining whether it's OK to run code on a given thread or whether some sort of thread/COM marshaling needs to occur. MTA COM components can be very efficient, but STA COM components in a multi-threaded environment always tend to have a fair amount of overhead. It's amazing how much COM Interop I still see today so while it seems really old school to be talking about this topic, it's actually quite apropos for me as I have many customers using legacy COM systems that need to interface with other .NET applications. In this post I'm consolidating some of the hacks I've used to integrate with various ASP.NET technologies when using STA COM Components. STA in ASP.NET Support for STA threading in the ASP.NET framework is fairly limited. Specifically only the original ASP.NET WebForms technology supports STA threading directly via its STA Page Handler implementation or what you might know as ASPCOMPAT mode. For WebForms running STA components is as easy as specifying the ASPCOMPAT attribute in the @Page tag:<%@ Page Language="C#" AspCompat="true" %> which runs the page in STA mode. Removing it runs in MTA mode. Simple. Unfortunately all other ASP.NET technologies built on top of the core ASP.NET engine do not support STA natively. So if you want to use STA COM components in MVC or with class ASMX Web Services, there's no automatic way like the ASPCOMPAT keyword available. So what happens when you run an STA COM component in an MTA application? In low volume environments - nothing much will happen. The COM objects will appear to work just fine as there are no simultaneous thread interactions and the COM component will happily run on a single thread or multiple single threads one at a time. So for testing running components in MTA environments may appear to work just fine. However as load increases and threads get re-used by ASP.NET COM objects will end up getting created on multiple different threads. This can result in crashes or hangs, or data corruption in the STA components which store their state in thread local storage on the STA thread. If threads overlap this global store can easily get corrupted which in turn causes problems. STA ensures that any COM object instance loaded always stays on the same thread it was instantiated on. What about COM+? COM+ is supposed to address the problem of STA in MTA applications by providing an abstraction with it's own thread pool manager for COM objects. It steps in to the COM instantiation pipeline and hands out COM instances from its own internally maintained STA Thread pool. This guarantees that the COM instantiation threads are STA threads if using STA components. COM+ works, but in my experience the technology is very, very slow for STA components. It adds a ton of overhead and reduces COM performance noticably in load tests in IIS. COM+ can make sense in some situations but for Web apps with STA components it falls short. In addition there's also the need to ensure that COM+ is set up and configured on the target machine and the fact that components have to be registered in COM+. COM+ also keeps components up at all times, so if a component needs to be replaced the COM+ package needs to be unloaded (same is true for IIS hosted components but it's more common to manage that). COM+ is an option for well established components, but native STA support tends to provide better performance and more consistent usability, IMHO. STA for non supporting ASP.NET Technologies As mentioned above only WebForms supports STA natively. However, by utilizing the WebForms ASP.NET Page handler internally it's actually possible to trick various other ASP.NET technologies and let them work with STA components. This is ugly but I've used each of these in various applications and I've had minimal problems making them work with FoxPro STA COM components which is about as dififcult as it gets for COM Interop in .NET. In this post I summarize several STA workarounds that enable you to use STA threading with these ASP.NET Technologies: ASMX Web Services ASP.NET MVC WCF Web Services ASP.NET Web API ASMX Web Services I start with classic ASP.NET ASMX Web Services because it's the easiest mechanism that allows for STA modification. It also clearly demonstrates how the WebForms STA Page Handler is the key technology to enable the various other solutions to create STA components. Essentially the way this works is to override the WebForms Page class and hijack it's init functionality for processing requests. Here's what this looks like for Web Services:namespace FoxProAspNet { public class WebServiceStaHandler : System.Web.UI.Page, IHttpAsyncHandler { protected override void OnInit(EventArgs e) { IHttpHandler handler = new WebServiceHandlerFactory().GetHandler( this.Context, this.Context.Request.HttpMethod, this.Context.Request.FilePath, this.Context.Request.PhysicalPath); handler.ProcessRequest(this.Context); this.Context.ApplicationInstance.CompleteRequest(); } public IAsyncResult BeginProcessRequest( HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } } public class AspCompatWebServiceStaHandlerWithSessionState : WebServiceStaHandler, IRequiresSessionState { } } This class overrides the ASP.NET WebForms Page class which has a little known AspCompatBeginProcessRequest() and AspCompatEndProcessRequest() method that is responsible for providing the WebForms ASPCOMPAT functionality. These methods handle routing requests to STA threads. Note there are two classes - one that includes session state and one that does not. If you plan on using ASP.NET Session state use the latter class, otherwise stick to the former. This maps to the EnableSessionState page setting in WebForms. This class simply hooks into this functionality by overriding the BeginProcessRequest and EndProcessRequest methods and always forcing it into the AspCompat methods. The way this works is that BeginProcessRequest() fires first to set up the threads and starts intializing the handler. As part of that process the OnInit() method is fired which is now already running on an STA thread. The code then creates an instance of the actual WebService handler factory and calls its ProcessRequest method to start executing which generates the Web Service result. Immediately after ProcessRequest the request is stopped with Application.CompletRequest() which ensures that the rest of the Page handler logic doesn't fire. This means that even though the fairly heavy Page class is overridden here, it doesn't end up executing any of its internal processing which makes this code fairly efficient. In a nutshell, we're highjacking the Page HttpHandler and forcing it to process the WebService process handler in the context of the AspCompat handler behavior. Hooking up the Handler Because the above is an HttpHandler implementation you need to hook up the custom handler and replace the standard ASMX handler. To do this you need to modify the web.config file (here for IIS 7 and IIS Express): <configuration> <system.webServer> <handlers> <remove name="WebServiceHandlerFactory-Integrated-4.0" /> <add name="Asmx STA Web Service Handler" path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" precondition="integrated"/> </handlers> </system.webServer> </configuration> (Note: The name for the WebServiceHandlerFactory-Integrated-4.0 might be slightly different depending on your server version. Check the IIS Handler configuration in the IIS Management Console for the exact name or simply remove the handler from the list there which will propagate to your web.config). For IIS 5 & 6 (Windows XP/2003) or the Visual Studio Web Server use:<configuration> <system.web> <httpHandlers> <remove path="*.asmx" verb="*" /> <add path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" /> </httpHandlers> </system.web></configuration> To test, create a new ASMX Web Service and create a method like this: [WebService(Namespace = "http://foxaspnet.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class FoxWebService : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World. Threading mode is: " + System.Threading.Thread.CurrentThread.GetApartmentState(); } } Run this before you put in the web.config configuration changes and you should get: Hello World. Threading mode is: MTA Then put the handler mapping into Web.config and you should see: Hello World. Threading mode is: STA And you're on your way to using STA COM components. It's a hack but it works well! I've used this with several high volume Web Service installations with various customers and it's been fast and reliable. ASP.NET MVC ASP.NET MVC has quickly become the most popular ASP.NET technology, replacing WebForms for creating HTML output. MVC is more complex to get started with, but once you understand the basic structure of how requests flow through the MVC pipeline it's easy to use and amazingly flexible in manipulating HTML requests. In addition, MVC has great support for non-HTML output sources like JSON and XML, making it an excellent choice for AJAX requests without any additional tools. Unlike WebForms ASP.NET MVC doesn't support STA threads natively and so some trickery is needed to make it work with STA threads as well. MVC gets its handler implementation through custom route handlers using ASP.NET's built in routing semantics. To work in an STA handler requires working in the Page Handler as part of the Route Handler implementation. As with the Web Service handler the first step is to create a custom HttpHandler that can instantiate an MVC request pipeline properly:public class MvcStaThreadHttpAsyncHandler : Page, IHttpAsyncHandler, IRequiresSessionState { private RequestContext _requestContext; public MvcStaThreadHttpAsyncHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); _requestContext = requestContext; } public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } protected override void OnInit(EventArgs e) { var controllerName = _requestContext.RouteData.GetRequiredString("controller"); var controllerFactory = ControllerBuilder.Current.GetControllerFactory(); var controller = controllerFactory.CreateController(_requestContext, controllerName); if (controller == null) throw new InvalidOperationException("Could not find controller: " + controllerName); try { controller.Execute(_requestContext); } finally { controllerFactory.ReleaseController(controller); } this.Context.ApplicationInstance.CompleteRequest(); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } public override void ProcessRequest(HttpContext httpContext) { throw new NotSupportedException("STAThreadRouteHandler does not support ProcessRequest called (only BeginProcessRequest)"); } } This handler code figures out which controller to load and then executes the controller. MVC internally provides the information needed to route to the appropriate method and pass the right parameters. Like the Web Service handler the logic occurs in the OnInit() and performs all the processing in that part of the request. Next, we need a RouteHandler that can actually pick up this handler. Unlike the Web Service handler where we simply registered the handler, MVC requires a RouteHandler to pick up the handler. RouteHandlers look at the URL's path and based on that decide on what handler to invoke. The route handler is pretty simple - all it does is load our custom handler: public class MvcStaThreadRouteHandler : IRouteHandler { public IHttpHandler GetHttpHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); return new MvcStaThreadHttpAsyncHandler(requestContext); } } At this point you can instantiate this route handler and force STA requests to MVC by specifying a route. The following sets up the ASP.NET Default Route:Route mvcRoute = new Route("{controller}/{action}/{id}", new RouteValueDictionary( new { controller = "Home", action = "Index", id = UrlParameter.Optional }), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute); To make this code a little easier to work with and mimic the behavior of the routes.MapRoute() functionality extension method that MVC provides, here is an extension method for MapMvcStaRoute(): public static class RouteCollectionExtensions { public static void MapMvcStaRoute(this RouteCollection routeTable, string name, string url, object defaults = null) { Route mvcRoute = new Route(url, new RouteValueDictionary(defaults), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute); } } With this the syntax to add route becomes a little easier and matches the MapRoute() method:RouteTable.Routes.MapMvcStaRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); The nice thing about this route handler, STA Handler and extension method is that it's fully self contained. You can put all three into a single class file and stick it into your Web app, and then simply call MapMvcStaRoute() and it just works. Easy! To see whether this works create an MVC controller like this: public class ThreadTestController : Controller { public string ThreadingMode() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Try this test both with only the MapRoute() hookup in the RouteConfiguration in which case you should get MTA as the value. Then change the MapRoute() call to MapMvcStaRoute() leaving all the parameters the same and re-run the request. You now should see STA as the result. You're on your way using STA COM components reliably in ASP.NET MVC. WCF Web Services running through IIS WCF Web Services provide a more robust and wider range of services for Web Services. You can use WCF over HTTP, TCP, and Pipes, and WCF services support WS* secure services. There are many features in WCF that go way beyond what ASMX can do. But it's also a bit more complex than ASMX. As a basic rule if you need to serve straight SOAP Services over HTTP I 'd recommend sticking with the simpler ASMX services especially if COM is involved. If you need WS* support or want to serve data over non-HTTP protocols then WCF makes more sense. WCF is not my forte but I found a solution from Scott Seely on his blog that describes the progress and that seems to work well. I'm copying his code below so this STA information is all in one place and quickly explain. Scott's code basically works by creating a custom OperationBehavior which can be specified via an [STAOperation] attribute on every method. Using his attribute you end up with a class (or Interface if you separate the contract and class) that looks like this: [ServiceContract] public class WcfService { [OperationContract] public string HelloWorldMta() { return Thread.CurrentThread.GetApartmentState().ToString(); } // Make sure you use this custom STAOperationBehavior // attribute to force STA operation of service methods [STAOperationBehavior] [OperationContract] public string HelloWorldSta() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Pretty straight forward. The latter method returns STA while the former returns MTA. To make STA work every method needs to be marked up. The implementation consists of the attribute and OperationInvoker implementation. Here are the two classes required to make this work from Scott's post:public class STAOperationBehaviorAttribute : Attribute, IOperationBehavior { public void AddBindingParameters(OperationDescription operationDescription, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) { } public void ApplyClientBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.ClientOperation clientOperation) { // If this is applied on the client, well, it just doesn’t make sense. // Don’t throw in case this attribute was applied on the contract // instead of the implementation. } public void ApplyDispatchBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.DispatchOperation dispatchOperation) { // Change the IOperationInvoker for this operation. dispatchOperation.Invoker = new STAOperationInvoker(dispatchOperation.Invoker); } public void Validate(OperationDescription operationDescription) { if (operationDescription.SyncMethod == null) { throw new InvalidOperationException("The STAOperationBehaviorAttribute " + "only works for synchronous method invocations."); } } } public class STAOperationInvoker : IOperationInvoker { IOperationInvoker _innerInvoker; public STAOperationInvoker(IOperationInvoker invoker) { _innerInvoker = invoker; } public object[] AllocateInputs() { return _innerInvoker.AllocateInputs(); } public object Invoke(object instance, object[] inputs, out object[] outputs) { // Create a new, STA thread object[] staOutputs = null; object retval = null; Thread thread = new Thread( delegate() { retval = _innerInvoker.Invoke(instance, inputs, out staOutputs); }); thread.SetApartmentState(ApartmentState.STA); thread.Start(); thread.Join(); outputs = staOutputs; return retval; } public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state) { // We don’t handle async… throw new NotImplementedException(); } public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result) { // We don’t handle async… throw new NotImplementedException(); } public bool IsSynchronous { get { return true; } } } The key in this setup is the Invoker and the Invoke method which creates a new thread and then fires the request on this new thread. Because this approach creates a new thread for every request it's not super efficient. There's a bunch of overhead involved in creating the thread and throwing it away after each thread, but it'll work for low volume requests and insure each thread runs in STA mode. If better performance is required it would be useful to create a custom thread manager that can pool a number of STA threads and hand off threads as needed rather than creating new threads on every request. If your Web Service needs are simple and you need only to serve standard SOAP 1.x requests, I would recommend sticking with ASMX services. It's easier to set up and work with and for STA component use it'll be significantly better performing since ASP.NET manages the STA thread pool for you rather than firing new threads for each request. One nice thing about Scotts code is though that it works in any WCF environment including self hosting. It has no dependency on ASP.NET or WebForms for that matter. STA - If you must STA components are a pain in the ass and thankfully there isn't too much stuff out there anymore that requires it. But when you need it and you need to access STA functionality from .NET at least there are a few options available to make it happen. Each of these solutions is a bit hacky, but they work - I've used all of them in production with good results with FoxPro components. I hope compiling all of these in one place here makes it STA consumption a little bit easier. I feel your pain :-) Resources Download STA Handler Code Examples Scott Seely's original STA WCF OperationBehavior Article© Rick Strahl, West Wind Technologies, 2005-2012Posted in FoxPro ASP.NET .NET COM Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

Read the article

Improving Partitioned Table Join Performance

- by Paul White

The query optimizer does not always choose an optimal strategy when joining partitioned tables. This post looks at an example, showing how a manual rewrite of the query can almost double performance, while reducing the memory grant to almost nothing. Test Data The two tables in this example use a common partitioning partition scheme. The partition function uses 41 equal-size partitions: CREATE PARTITION FUNCTION PFT (integer) AS RANGE RIGHT FOR VALUES ( 125000, 250000, 375000, 500000, 625000, 750000, 875000, 1000000, 1125000, 1250000, 1375000, 1500000, 1625000, 1750000, 1875000, 2000000, 2125000, 2250000, 2375000, 2500000, 2625000, 2750000, 2875000, 3000000, 3125000, 3250000, 3375000, 3500000, 3625000, 3750000, 3875000, 4000000, 4125000, 4250000, 4375000, 4500000, 4625000, 4750000, 4875000, 5000000 ); GO CREATE PARTITION SCHEME PST AS PARTITION PFT ALL TO ([PRIMARY]); There two tables are: CREATE TABLE dbo.T1 ( TID integer NOT NULL IDENTITY(0,1), Column1 integer NOT NULL, Padding binary(100) NOT NULL DEFAULT 0x, CONSTRAINT PK_T1 PRIMARY KEY CLUSTERED (TID) ON PST (TID) ); CREATE TABLE dbo.T2 ( TID integer NOT NULL, Column1 integer NOT NULL, Padding binary(100) NOT NULL DEFAULT 0x, CONSTRAINT PK_T2 PRIMARY KEY CLUSTERED (TID, Column1) ON PST (TID) ); The next script loads 5 million rows into T1 with a pseudo-random value between 1 and 5 for Column1. The table is partitioned on the IDENTITY column TID: INSERT dbo.T1 WITH (TABLOCKX) (Column1) SELECT (ABS(CHECKSUM(NEWID())) % 5) + 1 FROM dbo.Numbers AS N WHERE n BETWEEN 1 AND 5000000; In case you don’t already have an auxiliary table of numbers lying around, here’s a script to create one with 10 million rows: CREATE TABLE dbo.Numbers (n bigint PRIMARY KEY); WITH L0 AS(SELECT 1 AS c UNION ALL SELECT 1), L1 AS(SELECT 1 AS c FROM L0 AS A CROSS JOIN L0 AS B), L2 AS(SELECT 1 AS c FROM L1 AS A CROSS JOIN L1 AS B), L3 AS(SELECT 1 AS c FROM L2 AS A CROSS JOIN L2 AS B), L4 AS(SELECT 1 AS c FROM L3 AS A CROSS JOIN L3 AS B), L5 AS(SELECT 1 AS c FROM L4 AS A CROSS JOIN L4 AS B), Nums AS(SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS n FROM L5) INSERT dbo.Numbers WITH (TABLOCKX) SELECT TOP (10000000) n FROM Nums ORDER BY n OPTION (MAXDOP 1); Table T1 contains data like this: Next we load data into table T2. The relationship between the two tables is that table 2 contains ‘n’ rows for each row in table 1, where ‘n’ is determined by the value in Column1 of table T1. There is nothing particularly special about the data or distribution, by the way. INSERT dbo.T2 WITH (TABLOCKX) (TID, Column1) SELECT T.TID, N.n FROM dbo.T1 AS T JOIN dbo.Numbers AS N ON N.n >= 1 AND N.n <= T.Column1; Table T2 ends up containing about 15 million rows: The primary key for table T2 is a combination of TID and Column1. The data is partitioned according to the value in column TID alone. Partition Distribution The following query shows the number of rows in each partition of table T1: SELECT PartitionID = CA1.P, NumRows = COUNT_BIG(*) FROM dbo.T1 AS T CROSS APPLY (VALUES ($PARTITION.PFT(TID))) AS CA1 (P) GROUP BY CA1.P ORDER BY CA1.P; There are 40 partitions containing 125,000 rows (40 * 125k = 5m rows). The rightmost partition remains empty. The next query shows the distribution for table 2: SELECT PartitionID = CA1.P, NumRows = COUNT_BIG(*) FROM dbo.T2 AS T CROSS APPLY (VALUES ($PARTITION.PFT(TID))) AS CA1 (P) GROUP BY CA1.P ORDER BY CA1.P; There are roughly 375,000 rows in each partition (the rightmost partition is also empty): Ok, that’s the test data done. Test Query and Execution Plan The task is to count the rows resulting from joining tables 1 and 2 on the TID column: SET STATISTICS IO ON; DECLARE @s datetime2 = SYSUTCDATETIME(); SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID; SELECT DATEDIFF(Millisecond, @s, SYSUTCDATETIME()); SET STATISTICS IO OFF; The optimizer chooses a plan using parallel hash join, and partial aggregation: The Plan Explorer plan tree view shows accurate cardinality estimates and an even distribution of rows across threads (click to enlarge the image): With a warm data cache, the STATISTICS IO output shows that no physical I/O was needed, and all 41 partitions were touched: Running the query without actual execution plan or STATISTICS IO information for maximum performance, the query returns in around 2600ms. Execution Plan Analysis The first step toward improving on the execution plan produced by the query optimizer is to understand how it works, at least in outline. The two parallel Clustered Index Scans use multiple threads to read rows from tables T1 and T2. Parallel scan uses a demand-based scheme where threads are given page(s) to scan from the table as needed. This arrangement has certain important advantages, but does result in an unpredictable distribution of rows amongst threads. The point is that multiple threads cooperate to scan the whole table, but it is impossible to predict which rows end up on which threads. For correct results from the parallel hash join, the execution plan has to ensure that rows from T1 and T2 that might join are processed on the same thread. For example, if a row from T1 with join key value ‘1234’ is placed in thread 5’s hash table, the execution plan must guarantee that any rows from T2 that also have join key value ‘1234’ probe thread 5’s hash table for matches. The way this guarantee is enforced in this parallel hash join plan is by repartitioning rows to threads after each parallel scan. The two repartitioning exchanges route rows to threads using a hash function over the hash join keys. The two repartitioning exchanges use the same hash function so rows from T1 and T2 with the same join key must end up on the same hash join thread. Expensive Exchanges This business of repartitioning rows between threads can be very expensive, especially if a large number of rows is involved. The execution plan selected by the optimizer moves 5 million rows through one repartitioning exchange and around 15 million across the other. As a first step toward removing these exchanges, consider the execution plan selected by the optimizer if we join just one partition from each table, disallowing parallelism: SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = 1 AND $PARTITION.PFT(T2.TID) = 1 OPTION (MAXDOP 1); The optimizer has chosen a (one-to-many) merge join instead of a hash join. The single-partition query completes in around 100ms. If everything scaled linearly, we would expect that extending this strategy to all 40 populated partitions would result in an execution time around 4000ms. Using parallelism could reduce that further, perhaps to be competitive with the parallel hash join chosen by the optimizer. This raises a question. If the most efficient way to join one partition from each of the tables is to use a merge join, why does the optimizer not choose a merge join for the full query? Forcing a Merge Join Let’s force the optimizer to use a merge join on the test query using a hint: SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID OPTION (MERGE JOIN); This is the execution plan selected by the optimizer: This plan results in the same number of logical reads reported previously, but instead of 2600ms the query takes 5000ms. The natural explanation for this drop in performance is that the merge join plan is only using a single thread, whereas the parallel hash join plan could use multiple threads. Parallel Merge Join We can get a parallel merge join plan using the same query hint as before, and adding trace flag 8649: SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID OPTION (MERGE JOIN, QUERYTRACEON 8649); The execution plan is: This looks promising. It uses a similar strategy to distribute work across threads as seen for the parallel hash join. In practice though, performance is disappointing. On a typical run, the parallel merge plan runs for around 8400ms; slower than the single-threaded merge join plan (5000ms) and much worse than the 2600ms for the parallel hash join. We seem to be going backwards! The logical reads for the parallel merge are still exactly the same as before, with no physical IOs. The cardinality estimates and thread distribution are also still very good (click to enlarge): A big clue to the reason for the poor performance is shown in the wait statistics (captured by Plan Explorer Pro): CXPACKET waits require careful interpretation, and are most often benign, but in this case excessive waiting occurs at the repartitioning exchanges. Unlike the parallel hash join, the repartitioning exchanges in this plan are order-preserving ‘merging’ exchanges (because merge join requires ordered inputs): Parallelism works best when threads can just grab any available unit of work and get on with processing it. Preserving order introduces inter-thread dependencies that can easily lead to significant waits occurring. In extreme cases, these dependencies can result in an intra-query deadlock, though the details of that will have to wait for another time to explore in detail. The potential for waits and deadlocks leads the query optimizer to cost parallel merge join relatively highly, especially as the degree of parallelism (DOP) increases. This high costing resulted in the optimizer choosing a serial merge join rather than parallel in this case. The test results certainly confirm its reasoning. Collocated Joins In SQL Server 2008 and later, the optimizer has another available strategy when joining tables that share a common partition scheme. This strategy is a collocated join, also known as as a per-partition join. It can be applied in both serial and parallel execution plans, though it is limited to 2-way joins in the current optimizer. Whether the optimizer chooses a collocated join or not depends on cost estimation. The primary benefits of a collocated join are that it eliminates an exchange and requires less memory, as we will see next. Costing and Plan Selection The query optimizer did consider a collocated join for our original query, but it was rejected on cost grounds. The parallel hash join with repartitioning exchanges appeared to be a cheaper option. There is no query hint to force a collocated join, so we have to mess with the costing framework to produce one for our test query. Pretending that IOs cost 50 times more than usual is enough to convince the optimizer to use collocated join with our test query: -- Pretend IOs are 50x cost temporarily DBCC SETIOWEIGHT(50); -- Co-located hash join SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID OPTION (RECOMPILE); -- Reset IO costing DBCC SETIOWEIGHT(1); Collocated Join Plan The estimated execution plan for the collocated join is: The Constant Scan contains one row for each partition of the shared partitioning scheme, from 1 to 41. The hash repartitioning exchanges seen previously are replaced by a single Distribute Streams exchange using Demand partitioning. Demand partitioning means that the next partition id is given to the next parallel thread that asks for one. My test machine has eight logical processors, and all are available for SQL Server to use. As a result, there are eight threads in the single parallel branch in this plan, each processing one partition from each table at a time. Once a thread finishes processing a partition, it grabs a new partition number from the Distribute Streams exchange…and so on until all partitions have been processed. It is important to understand that the parallel scans in this plan are different from the parallel hash join plan. Although the scans have the same parallelism icon, tables T1 and T2 are not being co-operatively scanned by multiple threads in the same way. Each thread reads a single partition of T1 and performs a hash match join with the same partition from table T2. The properties of the two Clustered Index Scans show a Seek Predicate (unusual for a scan!) limiting the rows to a single partition: The crucial point is that the join between T1 and T2 is on TID, and TID is the partitioning column for both tables. A thread that processes partition ‘n’ is guaranteed to see all rows that can possibly join on TID for that partition. In addition, no other thread will see rows from that partition, so this removes the need for repartitioning exchanges. CPU and Memory Efficiency Improvements The collocated join has removed two expensive repartitioning exchanges and added a single exchange processing 41 rows (one for each partition id). Remember, the parallel hash join plan exchanges had to process 5 million and 15 million rows. The amount of processor time spent on exchanges will be much lower in the collocated join plan. In addition, the collocated join plan has a maximum of 8 threads processing single partitions at any one time. The 41 partitions will all be processed eventually, but a new partition is not started until a thread asks for it. Threads can reuse hash table memory for the new partition. The parallel hash join plan also had 8 hash tables, but with all 5,000,000 build rows loaded at the same time. The collocated plan needs memory for only 8 * 125,000 = 1,000,000 rows at any one time. Collocated Hash Join Performance The collated join plan has disappointing performance in this case. The query runs for around 25,300ms despite the same IO statistics as usual. This is much the worst result so far, so what went wrong? It turns out that cardinality estimation for the single partition scans of table T1 is slightly low. The properties of the Clustered Index Scan of T1 (graphic immediately above) show the estimation was for 121,951 rows. This is a small shortfall compared with the 125,000 rows actually encountered, but it was enough to cause the hash join to spill to physical tempdb: A level 1 spill doesn’t sound too bad, until you realize that the spill to tempdb probably occurs for each of the 41 partitions. As a side note, the cardinality estimation error is a little surprising because the system tables accurately show there are 125,000 rows in every partition of T1. Unfortunately, the optimizer uses regular column and index statistics to derive cardinality estimates here rather than system table information (e.g. sys.partitions). Collocated Merge Join We will never know how well the collocated parallel hash join plan might have worked without the cardinality estimation error (and the resulting 41 spills to tempdb) but we do know: Merge join does not require a memory grant; and Merge join was the optimizer’s preferred join option for a single partition join Putting this all together, what we would really like to see is the same collocated join strategy, but using merge join instead of hash join. Unfortunately, the current query optimizer cannot produce a collocated merge join; it only knows how to do collocated hash join. So where does this leave us? CROSS APPLY sys.partitions We can try to write our own collocated join query. We can use sys.partitions to find the partition numbers, and CROSS APPLY to get a count per partition, with a final step to sum the partial counts. The following query implements this idea: SELECT row_count = SUM(Subtotals.cnt) FROM ( -- Partition numbers SELECT p.partition_number FROM sys.partitions AS p WHERE p.[object_id] = OBJECT_ID(N'T1', N'U') AND p.index_id = 1 ) AS P CROSS APPLY ( -- Count per collocated join SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals; The estimated plan is: The cardinality estimates aren’t all that good here, especially the estimate for the scan of the system table underlying the sys.partitions view. Nevertheless, the plan shape is heading toward where we would like to be. Each partition number from the system table results in a per-partition scan of T1 and T2, a one-to-many Merge Join, and a Stream Aggregate to compute the partial counts. The final Stream Aggregate just sums the partial counts. Execution time for this query is around 3,500ms, with the same IO statistics as always. This compares favourably with 5,000ms for the serial plan produced by the optimizer with the OPTION (MERGE JOIN) hint. This is another case of the sum of the parts being less than the whole – summing 41 partial counts from 41 single-partition merge joins is faster than a single merge join and count over all partitions. Even so, this single-threaded collocated merge join is not as quick as the original parallel hash join plan, which executed in 2,600ms. On the positive side, our collocated merge join uses only one logical processor and requires no memory grant. The parallel hash join plan used 16 threads and reserved 569 MB of memory: Using a Temporary Table Our collocated merge join plan should benefit from parallelism. The reason parallelism is not being used is that the query references a system table. We can work around that by writing the partition numbers to a temporary table (or table variable): SET STATISTICS IO ON; DECLARE @s datetime2 = SYSUTCDATETIME(); CREATE TABLE #P ( partition_number integer PRIMARY KEY); INSERT #P (partition_number) SELECT p.partition_number FROM sys.partitions AS p WHERE p.[object_id] = OBJECT_ID(N'T1', N'U') AND p.index_id = 1; SELECT row_count = SUM(Subtotals.cnt) FROM #P AS p CROSS APPLY ( SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals; DROP TABLE #P; SELECT DATEDIFF(Millisecond, @s, SYSUTCDATETIME()); SET STATISTICS IO OFF; Using the temporary table adds a few logical reads, but the overall execution time is still around 3500ms, indistinguishable from the same query without the temporary table. The problem is that the query optimizer still doesn’t choose a parallel plan for this query, though the removal of the system table reference means that it could if it chose to: In fact the optimizer did enter the parallel plan phase of query optimization (running search 1 for a second time): Unfortunately, the parallel plan found seemed to be more expensive than the serial plan. This is a crazy result, caused by the optimizer’s cost model not reducing operator CPU costs on the inner side of a nested loops join. Don’t get me started on that, we’ll be here all night. In this plan, everything expensive happens on the inner side of a nested loops join. Without a CPU cost reduction to compensate for the added cost of exchange operators, candidate parallel plans always look more expensive to the optimizer than the equivalent serial plan. Parallel Collocated Merge Join We can produce the desired parallel plan using trace flag 8649 again: SELECT row_count = SUM(Subtotals.cnt) FROM #P AS p CROSS APPLY ( SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals OPTION (QUERYTRACEON 8649); The actual execution plan is: One difference between this plan and the collocated hash join plan is that a Repartition Streams exchange operator is used instead of Distribute Streams. The effect is similar, though not quite identical. The Repartition uses round-robin partitioning, meaning the next partition id is pushed to the next thread in sequence. The Distribute Streams exchange seen earlier used Demand partitioning, meaning the next partition id is pulled across the exchange by the next thread that is ready for more work. There are subtle performance implications for each partitioning option, but going into that would again take us too far off the main point of this post. Performance The important thing is the performance of this parallel collocated merge join – just 1350ms on a typical run. The list below shows all the alternatives from this post (all timings include creation, population, and deletion of the temporary table where appropriate) from quickest to slowest: Collocated parallel merge join: 1350ms Parallel hash join: 2600ms Collocated serial merge join: 3500ms Serial merge join: 5000ms Parallel merge join: 8400ms Collated parallel hash join: 25,300ms (hash spill per partition) The parallel collocated merge join requires no memory grant (aside from a paltry 1.2MB used for exchange buffers). This plan uses 16 threads at DOP 8; but 8 of those are (rather pointlessly) allocated to the parallel scan of the temporary table. These are minor concerns, but it turns out there is a way to address them if it bothers you. Parallel Collocated Merge Join with Demand Partitioning This final tweak replaces the temporary table with a hard-coded list of partition ids (dynamic SQL could be used to generate this query from sys.partitions): SELECT row_count = SUM(Subtotals.cnt) FROM ( VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9),(10), (11),(12),(13),(14),(15),(16),(17),(18),(19),(20), (21),(22),(23),(24),(25),(26),(27),(28),(29),(30), (31),(32),(33),(34),(35),(36),(37),(38),(39),(40),(41) ) AS P (partition_number) CROSS APPLY ( SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals OPTION (QUERYTRACEON 8649); The actual execution plan is: The parallel collocated hash join plan is reproduced below for comparison: The manual rewrite has another advantage that has not been mentioned so far: the partial counts (per partition) can be computed earlier than the partial counts (per thread) in the optimizer’s collocated join plan. The earlier aggregation is performed by the extra Stream Aggregate under the nested loops join. The performance of the parallel collocated merge join is unchanged at around 1350ms. Final Words It is a shame that the current query optimizer does not consider a collocated merge join (Connect item closed as Won’t Fix). The example used in this post showed an improvement in execution time from 2600ms to 1350ms using a modestly-sized data set and limited parallelism. In addition, the memory requirement for the query was almost completely eliminated – down from 569MB to 1.2MB. The problem with the parallel hash join selected by the optimizer is that it attempts to process the full data set all at once (albeit using eight threads). It requires a large memory grant to hold all 5 million rows from table T1 across the eight hash tables, and does not take advantage of the divide-and-conquer opportunity offered by the common partitioning. The great thing about the collocated join strategies is that each parallel thread works on a single partition from both tables, reading rows, performing the join, and computing a per-partition subtotal, before moving on to a new partition. From a thread’s point of view… If you have trouble visualizing what is happening from just looking at the parallel collocated merge join execution plan, let’s look at it again, but from the point of view of just one thread operating between the two Parallelism (exchange) operators. Our thread picks up a single partition id from the Distribute Streams exchange, and starts a merge join using ordered rows from partition 1 of table T1 and partition 1 of table T2. By definition, this is all happening on a single thread. As rows join, they are added to a (per-partition) count in the Stream Aggregate immediately above the Merge Join. Eventually, either T1 (partition 1) or T2 (partition 1) runs out of rows and the merge join stops. The per-partition count from the aggregate passes on through the Nested Loops join to another Stream Aggregate, which is maintaining a per-thread subtotal. Our same thread now picks up a new partition id from the exchange (say it gets id 9 this time). The count in the per-partition aggregate is reset to zero, and the processing of partition 9 of both tables proceeds just as it did for partition 1, and on the same thread. Each thread picks up a single partition id and processes all the data for that partition, completely independently from other threads working on other partitions. One thread might eventually process partitions (1, 9, 17, 25, 33, 41) while another is concurrently processing partitions (2, 10, 18, 26, 34) and so on for the other six threads at DOP 8. The point is that all 8 threads can execute independently and concurrently, continuing to process new partitions until the wider job (of which the thread has no knowledge!) is done. This divide-and-conquer technique can be much more efficient than simply splitting the entire workload across eight threads all at once. Related Reading Understanding and Using Parallelism in SQL Server Parallel Execution Plans Suck © 2013 Paul White – All Rights Reserved Twitter: @SQL_Kiwi

Read the article

The broken Promise of the Mobile Web

- by Rick Strahl

High end mobile devices have been with us now for almost 7 years and they have utterly transformed the way we access information. Mobile phones and smartphones that have access to the Internet and host smart applications are in the hands of a large percentage of the population of the world. In many places even very remote, cell phones and even smart phones are a common sight. I’ll never forget when I was in India in 2011 I was up in the Southern Indian mountains riding an elephant out of a tiny local village, with an elephant herder in front riding atop of the elephant in front of us. He was dressed in traditional garb with the loin wrap and head cloth/turban as did quite a few of the locals in this small out of the way and not so touristy village. So we’re slowly trundling along in the forest and he’s lazily using his stick to guide the elephant and… 10 minutes in he pulls out his cell phone from his sash and starts texting. In the middle of texting a huge pig jumps out from the side of the trail and he takes a picture running across our path in the jungle! So yeah, mobile technology is very pervasive and it’s reached into even very buried and unexpected parts of this world. Apps are still King Apps currently rule the roost when it comes to mobile devices and the applications that run on them. If there’s something that you need on your mobile device your first step usually is to look for an app, not use your browser. But native app development remains a pain in the butt, with the requirement to have to support 2 or 3 completely separate platforms. There are solutions that try to bridge that gap. Xamarin is on a tear at the moment, providing their cross-device toolkit to build applications using C#. While Xamarin tools are impressive – and also *very* expensive – they only address part of the development madness that is app development. There are still specific device integration isssues, dealing with the different developer programs, security and certificate setups and all that other noise that surrounds app development. There’s also PhoneGap/Cordova which provides a hybrid solution that involves creating local HTML/CSS/JavaScript based applications, and then packaging them to run in a specialized App container that can run on most mobile device platforms using a WebView interface. This allows for using of HTML technology, but it also still requires all the set up, configuration of APIs, security keys and certification and submission and deployment process just like native applications – you actually lose many of the benefits that Web based apps bring. The big selling point of Cordova is that you get to use HTML have the ability to build your UI once for all platforms and run across all of them – but the rest of the app process remains in place. Apps can be a big pain to create and manage especially when we are talking about specialized or vertical business applications that aren’t geared at the mainstream market and that don’t fit the ‘store’ model. If you’re building a small intra department application you don’t want to deal with multiple device platforms and certification etc. for various public or corporate app stores. That model is simply not a good fit both from the development and deployment perspective. Even for commercial, big ticket apps, HTML as a UI platform offers many advantages over native, from write-once run-anywhere, to remote maintenance, single point of management and failure to having full control over the application as opposed to have the app store overloads censor you. In a lot of ways Web based HTML/CSS/JavaScript applications have so much potential for building better solutions based on existing Web technologies for the very same reasons a lot of content years ago moved off the desktop to the Web. To me the Web as a mobile platform makes perfect sense, but the reality of today’s Mobile Web unfortunately looks a little different… Where’s the Love for the Mobile Web? Yet here we are in the middle of 2014, nearly 7 years after the first iPhone was released and brought the promise of rich interactive information at your fingertips, and yet we still don’t really have a solid mobile Web platform. I know what you’re thinking: “But we have lots of HTML/JavaScript/CSS features that allows us to build nice mobile interfaces”. I agree to a point – it’s actually quite possible to build nice looking, rich and capable Web UI today. We have media queries to deal with varied display sizes, CSS transforms for smooth animations and transitions, tons of CSS improvements in CSS 3 that facilitate rich layout, a host of APIs geared towards mobile device features and lately even a number of JavaScript framework choices that facilitate development of multi-screen apps in a consistent manner. Personally I’ve been working a lot with AngularJs and heavily modified Bootstrap themes to build mobile first UIs and that’s been working very well to provide highly usable and attractive UI for typical mobile business applications. From the pure UI perspective things actually look very good. Not just about the UI But it’s not just about the UI - it’s also about integration with the mobile device. When it comes to putting all those pieces together into what amounts to a consolidated platform to build mobile Web applications, I think we still have a ways to go… there are a lot of missing pieces to make it all work together and integrate with the device more smoothly, and more importantly to make it work uniformly across the majority of devices. I think there are a number of reasons for this. Slow Standards Adoption HTML standards implementations and ratification has been dreadfully slow, and browser vendors all seem to pick and choose different pieces of the technology they implement. The end result is that we have a capable UI platform that’s missing some of the infrastructure pieces to make it whole on mobile devices. There’s lots of potential but what is lacking that final 10% to build truly compelling mobile applications that can compete favorably with native applications. Some of it is the fragmentation of browsers and the slow evolution of the mobile specific HTML APIs. A host of mobile standards exist but many of the standards are in the early review stage and they have been there stuck for long periods of time and seem to move at a glacial pace. Browser vendors seem even slower to implement them, and for good reason – non-ratified standards mean that implementations may change and vendor implementations tend to be experimental and likely have to be changed later. Neither Vendors or developers are not keen on changing standards. This is the typical chicken and egg scenario, but without some forward momentum from some party we end up stuck in the mud. It seems that either the standards bodies or the vendors need to carry the torch forward and that doesn’t seem to be happening quickly enough. Mobile Device Integration just isn’t good enough Current standards are not far reaching enough to address a number of the use case scenarios necessary for many mobile applications. While not every application needs to have access to all mobile device features, almost every mobile application could benefit from some integration with other parts of the mobile device platform. Integration with GPS, phone, media, messaging, notifications, linking and contacts system are benefits that are unique to mobile applications and could be widely used, but are mostly (with the exception of GPS) inaccessible for Web based applications today. Unfortunately trying to do most of this today only with a mobile Web browser is a losing battle. Aside from PhoneGap/Cordova’s app centric model with its own custom API accessing mobile device features and the token exception of the GeoLocation API, most device integration features are not widely supported by the current crop of mobile browsers. For example there’s no usable messaging API that allows access to SMS or contacts from HTML. Even obvious components like the Media Capture API are only implemented partially by mobile devices. There are alternatives and workarounds for some of these interfaces by using browser specific code, but that’s might ugly and something that I thought we were trying to leave behind with newer browser standards. But it’s not quite working out that way. It’s utterly perplexing to me that mobile standards like Media Capture and Streams, Media Gallery Access, Responsive Images, Messaging API, Contacts Manager API have only minimal or no traction at all today. Keep in mind we’ve had mobile browsers for nearly 7 years now, and yet we still have to think about how to get access to an image from the image gallery or the camera on some devices? Heck Windows Phone IE Mobile just gained the ability to upload images recently in the Windows 8.1 Update – that’s feature that HTML has had for 20 years! These are simple concepts and common problems that should have been solved a long time ago. It’s extremely frustrating to see build 90% of a mobile Web app with relative ease and then hit a brick wall for the remaining 10%, which often can be show stoppers. The remaining 10% have to do with platform integration, browser differences and working around the limitations that browsers and ‘pinned’ applications impose on HTML applications. The maddening part is that these limitations seem arbitrary as they could easily work on all mobile platforms. For example, SMS has a URL Moniker interface that sort of works on Android, works badly with iOS (only works if the address is already in the contact list) and not at all on Windows Phone. There’s no reason this shouldn’t work universally using the same interface – after all all phones have supported SMS since before the year 2000! But, it doesn’t have to be this way Change can happen very quickly. Take the GeoLocation API for example. Geolocation has taken off at the very beginning of the mobile device era and today it works well, provides the necessary security (a big concern for many mobile APIs), and is supported by just about all major mobile and even desktop browsers today. It handles security concerns via prompts to avoid unwanted access which is a model that would work for most other device APIs in a similar fashion. One time approval and occasional re-approval if code changes or caches expire. Simple and only slightly intrusive. It all works well, even though GeoLocation actually has some physical limitations, such as representing the current location when no GPS device is present. Yet this is a solved problem, where other APIs that are conceptually much simpler to implement have failed to gain any traction at all. Technically none of these APIs should be a problem to implement, but it appears that the momentum is just not there. Inadequate Web Application Linking and Activation Another important piece of the puzzle missing is the integration of HTML based Web applications. Today HTML based applications are not first class citizens on mobile operating systems. When talking about HTML based content there’s a big difference between content and applications. Content is great for search engine discovery and plain browser usage. Content is usually accessed intermittently and permanent linking is not so critical for this type of content. But applications have different needs. Applications need to be started up quickly and must be easily switchable to support a multi-tasking user workflow. Therefore, it’s pretty crucial that mobile Web apps are integrated into the underlying mobile OS and work with the standard task management features. Unfortunately this integration is not as smooth as it should be. It starts with actually trying to find mobile Web applications, to ‘installing’ them onto a phone in an easily accessible manner in a prominent position. The experience of discovering a Mobile Web ‘App’ and making it sticky is by no means as easy or satisfying. Today the way you’d go about this is: Open the browser Search for a Web Site in the browser with your search engine of choice Hope that you find the right site Hope that you actually find a site that works for your mobile device Click on the link and run the app in a fully chrome’d browser instance (read tiny surface area) Pin the app to the home screen (with all the limitations outline above) Hope you pointed at the right URL when you pinned Even for you and me as developers, there are a few steps in there that are painful and annoying, but think about the average user. First figuring out how to search for a specific site or URL? And then pinning the app and hopefully from the right location? You’ve probably lost more than half of your audience at that point. This experience sucks. For developers too this process is painful since app developers can’t control the shortcut creation directly. This problem often gets solved by crazy coding schemes, with annoying pop-ups that try to get people to create shortcuts via fancy animations that are both annoying and add overhead to each and every application that implements this sort of thing differently. And that’s not the end of it - getting the link onto the home screen with an application icon varies quite a bit between browsers. Apple’s non-standard meta tags are prominent and they work with iOS and Android (only more recent versions), but not on Windows Phone. Windows Phone instead requires you to create an actual screen or rather a partial screen be captured for a shortcut in the tile manager. Who had that brilliant idea I wonder? Surprisingly Chrome on recent Android versions seems to actually get it right – icons use pngs, pinning is easy and pinned applications properly behave like standalone apps and retain the browser’s active page state and content. Each of the platforms has a different way to specify icons (WP doesn’t allow you to use an icon image at all), and the most widely used interface in use today is a bunch of Apple specific meta tags that other browsers choose to support. The question is: Why is there no standard implementation for installing shortcuts across mobile platforms using an official format rather than a proprietary one? Then there’s iOS and the crazy way it treats home screen linked URLs using a crazy hybrid format that is neither as capable as a Web app running in Safari nor a WebView hosted application. Moving off the Web ‘app’ link when switching to another app actually causes the browser and preview it to ‘blank out’ the Web application in the Task View (see screenshot on the right). Then, when the ‘app’ is reactivated it ends up completely restarting the browser with the original link. This is crazy behavior that you can’t easily work around. In some situations you might be able to store the application state and restore it using LocalStorage, but for many scenarios that involve complex data sources (like say Google Maps) that’s not a possibility. The only reason for this screwed up behavior I can think of is that it is deliberate to make Web apps a pain in the butt to use and forcing users trough the App Store/PhoneGap/Cordova route. App linking and management is a very basic problem – something that we essentially have solved in every desktop browser – yet on mobile devices where it arguably matters a lot more to have easy access to web content we have to jump through hoops to have even a remotely decent linking/activation experience across browsers. Where’s the Money? It’s not surprising that device home screen integration and Mobile Web support in general is in such dismal shape – the mobile OS vendors benefit financially from App store sales and have little to gain from Web based applications that bypass the App store and the cash cow that it presents. On top of that, platform specific vendor lock-in of both end users and developers who have invested in hardware, apps and consumables is something that mobile platform vendors actually aspire to. Web based interfaces that are cross-platform are the anti-thesis of that and so again it’s no surprise that the mobile Web is on a struggling path. But – that may be changing. More and more we’re seeing operations shifting to services that are subscription based or otherwise collect money for usage, and that may drive more progress into the Web direction in the end . Nothing like the almighty dollar to drive innovation forward. Do we need a Mobile Web App Store? As much as I dislike moderated experiences in today’s massive App Stores, they do at least provide one single place to look for apps for your device. I think we could really use some sort of registry, that could provide something akin to an app store for mobile Web apps, to make it easier to actually find mobile applications. This could take the form of a specialized search engine, or maybe a more formal store/registry like structure. Something like apt-get/chocolatey for Web apps. It could be curated and provide at least some feedback and reviews that might help with the integrity of applications. Coupled to that could be a native application on each platform that would allow searching and browsing of the registry and then also handle installation in the form of providing the home screen linking, plus maybe an initial security configuration that determines what features are allowed access to for the app. I’m not holding my breath. In order for this sort of thing to take off and gain widespread appeal, a lot of coordination would be required. And in order to get enough traction it would have to come from a well known entity – a mobile Web app store from a no name source is unlikely to gain high enough usage numbers to make a difference. In a way this would eliminate some of the freedom of the Web, but of course this would also be an optional search path in addition to the standard open Web search mechanisms to find and access content today. Security Security is a big deal, and one of the perceived reasons why so many IT professionals appear to be willing to go back to the walled garden of deployed apps is that Apps are perceived as safe due to the official review and curation of the App stores. Curated stores are supposed to protect you from malware, illegal and misleading content. It doesn’t always work out that way and all the major vendors have had issues with security and the review process at some time or another. Security is critical, but I also think that Web applications in general pose less of a security threat than native applications, by nature of the sandboxed browser and JavaScript environments. Web applications run externally completely and in the HTML and JavaScript sandboxes, with only a very few controlled APIs allowing access to device specific features. And as discussed earlier – security for any device interaction can be granted the same for mobile applications through a Web browser, as they can for native applications either via explicit policies loaded from the Web, or via prompting as GeoLocation does today. Security is important, but it’s certainly solvable problem for Web applications even those that need to access device hardware. Security shouldn’t be a reason for Web apps to be an equal player in mobile applications. Apps are winning, but haven’t we been here before? So now we’re finding ourselves back in an era of installed app, rather than Web based and managed apps. Only it’s even worse today than with Desktop applications, in that the apps are going through a gatekeeper that charges a toll and censors what you can and can’t do in your apps. Frankly it’s a mystery to me why anybody would buy into this model and why it’s lasted this long when we’ve already been through this process. It’s crazy… It’s really a shame that this regression is happening. We have the technology to make mobile Web apps much more prominent, but yet we’re basically held back by what seems little more than bureaucracy, partisan bickering and self interest of the major parties involved. Back in the day of the desktop it was Internet Explorer’s 98+% market shareholding back the Web from improvements for many years – now it’s the combined mobile OS market in control of the mobile browsers. If mobile Web apps were allowed to be treated the same as native apps with simple ways to install and run them consistently and persistently, that would go a long way to making mobile applications much more usable and seriously viable alternatives to native apps. But as it is mobile apps have a severe disadvantage in placement and operation. There are a few bright spots in all of this. Mozilla’s FireFoxOs is embracing the Web for it’s mobile OS by essentially building every app out of HTML and JavaScript based content. It supports both packaged and certified package modes (that can be put into the app store), and Open Web apps that are loaded and run completely off the Web and can also cache locally for offline operation using a manifest. Open Web apps are treated as full class citizens in FireFoxOS and run using the same mechanism as installed apps. Unfortunately FireFoxOs is getting a slow start with minimal device support and specifically targeting the low end market. We can hope that this approach will change and catch on with other vendors, but that’s also an uphill battle given the conflict of interest with platform lock in that it represents. Recent versions of Android also seem to be working reasonably well with mobile application integration onto the desktop and activation out of the box. Although it still uses the Apple meta tags to find icons and behavior settings, everything at least works as you would expect – icons to the desktop on pinning, WebView based full screen activation, and reliable application persistence as the browser/app is treated like a real application. Hopefully iOS will at some point provide this same level of rudimentary Web app support. What’s also interesting to me is that Microsoft hasn’t picked up on the obvious need for a solid Web App platform. Being a distant third in the mobile OS war, Microsoft certainly has nothing to lose and everything to gain by using fresh ideas and expanding into areas that the other major vendors are neglecting. But instead Microsoft is trying to beat the market leaders at their own game, fighting on their adversary’s terms instead of taking a new tack. Providing a kick ass mobile Web platform that takes the lead on some of the proposed mobile APIs would be something positive that Microsoft could do to improve its miserable position in the mobile device market. Where are we at with Mobile Web? It sure sounds like I’m really down on the Mobile Web, right? I’ve built a number of mobile apps in the last year and while overall result and response has been very positive to what we were able to accomplish in terms of UI, getting that final 10% that required device integration dialed was an absolute nightmare on every single one of them. Big compromises had to be made and some features were left out or had to be modified for some devices. In two cases we opted to go the Cordova route in order to get the integration we needed, along with the extra pain involved in that process. Unless you’re not integrating with device features and you don’t care deeply about a smooth integration with the mobile desktop, mobile Web development is fraught with frustration. So, yes I’m frustrated! But it’s not for lack of wanting the mobile Web to succeed. I am still a firm believer that we will eventually arrive a much more functional mobile Web platform that allows access to the most common device features in a sensible way. It wouldn't be difficult for device platform vendors to make Web based applications first class citizens on mobile devices. But unfortunately it looks like it will still be some time before this happens. So, what’s your experience building mobile Web apps? Are you finding similar issues? Just giving up on raw Web applications and building PhoneGap apps instead? Completely skipping the Web and going native? Leave a comment for discussion. Resources Rick Strahl on DotNet Rocks talking about Mobile Web© Rick Strahl, West Wind Technologies, 2005-2014Posted in HTML5 Mobile Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

Read the article

Setting up a local AI server - easy with Solaris 11

- by Stefan Hinker

Many things are new in Solaris 11, Autoinstall is one of them. If, like me, you've known Jumpstart for the last 2 centuries or so, you'll have to start from scratch. Well, almost, as the concepts are similar, and it's not all that difficult. Just new. I wanted to have an AI server that I could use for demo purposes, on the train if need be. That answers the question of hardware requirements: portable. But let's start at the beginning. First, you need an OS image, of course. In the new world of Solaris 11, it is now called a repository. The original can be downloaded from the Solaris 11 page at Oracle. What you want is the "Oracle Solaris 11 11/11 Repository Image", which comes in two parts that can be combined using cat. MD5 checksums for these (and all other downloads from that page) are available closer to the top of the page. With that, building the repository is quick and simple: # zfs create -o mountpoint=/export/repo rpool/ai/repo # zfs create rpool/ai/repo/s11 # mount -o ro -F hsfs /tmp/sol-11-1111-repo-full.iso /mnt # rsync -aP /mnt/repo /export/repo/s11 # umount /mnt # pkgrepo rebuild -s /export/repo/sol11/repo # zfs snapshot rpool/ai/repo/sol11@fcs # pkgrepo info -s /export/repo/sol11/repo PUBLISHER PACKAGES STATUS UPDATED solaris 4292 online 2012-03-12T20:47:15.378639Z That's all there's to it. Let's make a snapshot, just to be on the safe side. You never know when one will come in handy. To use this repository, you could just add it as a file-based publisher: # pkg set-publisher -g file:///export/repo/sol11/repo solaris In case I'd want to access this repository through a (virtual) network, i'll now quickly activate the repository-service: # svccfg -s application/pkg/server \ setprop pkg/inst_root=/export/repo/sol11/repo # svccfg -s application/pkg/server setprop pkg/readonly=true # svcadm refresh application/pkg/server # svcadm enable application/pkg/server That's all you need - now point your browser to http://localhost/ to view your beautiful repository-server. Step 1 is done. All of this, by the way, is nicely documented in the README file that's contained in the repository image. Of course, we already have updates to the original release. You can find them in MOS in the Oracle Solaris 11 Support Repository Updates (SRU) Index. You can simply add these to your existing repository or create separate repositories for each SRU. The individual SRUs are self-sufficient and incremental - SRU4 includes all updates from SRU2 and SRU3. With ZFS, you can also get both: A full repository with all updates and at the same time incremental ones up to each of the updates: # mount -o ro -F hsfs /tmp/sol-11-1111-sru4-05-incr-repo.iso /mnt # pkgrecv -s /mnt/repo -d /export/repo/sol11/repo '*' # umount /mnt # pkgrepo rebuild -s /export/repo/sol11/repo # zfs snapshot rpool/ai/repo/sol11@sru4 # zfs set snapdir=visible rpool/ai/repo/sol11 # svcadm restart svc:/application/pkg/server:default The normal repository is now updated to SRU4. Thanks to the ZFS snapshots, there is also a valid repository of Solaris 11 11/11 without the update located at /export/repo/sol11/.zfs/snapshot/fcs . If you like, you can also create another repository service for each update, running on a separate port. But now lets continue with the AI server. Just a little bit of reading in the dokumentation makes it clear that we will need to run a DHCP server for this. Since I already have one active (for my SunRay installation) and since it's a good idea to have these kinds of services separate anyway, I decided to create this in a Zone. So, let's create one first: # zfs create -o mountpoint=/export/install rpool/ai/install # zfs create -o mountpoint=/zones rpool/zones # zonecfg -z ai-server zonecfg:ai-server> create create: Using system default template 'SYSdefault' zonecfg:ai-server> set zonepath=/zones/ai-server zonecfg:ai-server> add dataset zonecfg:ai-server:dataset> set name=rpool/ai/install zonecfg:ai-server:dataset> set alias=install zonecfg:ai-server:dataset> end zonecfg:ai-server> commit zonecfg:ai-server> exit # zoneadm -z ai-server install # zoneadm -z ai-server boot ; zlogin -C ai-server Give it a hostname and IP address at first boot, and there's the Zone. For a publisher for Solaris packages, it will be bound to the "System Publisher" from the Global Zone. The /export/install filesystem, of course, is intended to be used by the AI server. Let's configure it now: #zlogin ai-server root@ai-server:~# pkg install install/installadm root@ai-server:~# installadm create-service -n x86-fcs -a i386 \ -s pkg://solaris/install-image/[email protected],5.11-0.175.0.0.0.2.1482 \ -d /export/install/fcs -i 192.168.2.20 -c 3 With that, the core AI server is already done. What happened here? First, I installed the AI server software. IPS makes that nice and easy. If necessary, it'll also pull in the required DHCP-Server and anything else that might be missing. Watch out for that DHCP server software. In Solaris 11, there are two different versions. There's the one you might know from Solaris 10 and earlier, and then there's a new one from ISC. The latter is the one we need for AI. The SMF service names of both are very similar. The "old" one is "svc:/network/dhcp-server:default". The ISC-server comes with several SMF-services. We at least need "svc:/network/dhcp/server:ipv4". The command "installadm create-service" creates the installation-service. It's called "x86-fcs", serves the "i386" architecture and gets its boot image from the repository of the system publisher, using version 5.11,5.11-0.175.0.0.0.2.1482, which is Solaris 11 11/11. (The option "-a i386" in this example is optional, since the installserver itself runs on a x86 machine.) The boot-environment for clients is created in /export/install/fcs and the DHCP-server is configured for 3 IP-addresses starting at 192.168.2.20. This configuration is stored in a very human readable form in /etc/inet/dhcpd4.conf. An AI-service for SPARC systems could be created in the very same way, using "-a sparc" as the architecture option. Now we would be ready to register and install the first client. It would be installed with the default "solaris-large-server" using the publisher "http://pkg.oracle.com/solaris/release" and would query it's configuration interactively at first boot. This makes it very clear that an AI-server is really only a boot-server. The true source of packets to install can be different. Since I don't like these defaults for my demo setup, I did some extra config work for my clients. The configuration of a client is controlled by manifests and profiles. The manifest controls which packets are installed and how the filesystems are layed out. In that, it's very much like the old "rules.ok" file in Jumpstart. Profiles contain additional configuration like root passwords, primary user account, IP addresses, keyboard layout etc. Hence, profiles are very similar to the old sysid.cfg file. The easiest way to get your hands on a manifest is to ask the AI server we just created to give us it's default one. Then modify that to our liking and give it back to the installserver to use: root@ai-server:~# mkdir -p /export/install/configs/manifests root@ai-server:~# cd /export/install/configs/manifests root@ai-server:~# installadm export -n x86-fcs -m orig_default \ -o orig_default.xml root@ai-server:~# cp orig_default.xml s11-fcs.small.local.xml root@ai-server:~# vi s11-fcs.small.local.xml root@ai-server:~# more s11-fcs.small.local.xml <!DOCTYPE auto_install SYSTEM "file:///usr/share/install/ai.dtd.1"> <auto_install> <ai_instance name="S11 Small fcs local"> <target> <logical> <zpool name="rpool" is_root="true"> <filesystem name="export" mountpoint="/export"/> <filesystem name="export/home"/> <be name="solaris"/> </zpool> </logical> </target> <software type="IPS"> <destination> <image>  <facet set="false">facet.locale.*</facet> <facet set="true">facet.locale.de</facet> <facet set="true">facet.locale.de_DE</facet> <facet set="true">facet.locale.en</facet> <facet set="true">facet.locale.en_US</facet> </image> </destination> <source> <publisher name="solaris"> <origin name="http://192.168.2.12/"/> </publisher> </source>  <software_data action="install"> <name>pkg:/[email protected],5.11-0.175.0.0.0.2.0</name> <name>pkg:/group/system/solaris-small-server</name> </software_data> </software> </ai_instance> </auto_install> root@ai-server:~# installadm create-manifest -n x86-fcs -d \ -f ./s11-fcs.small.local.xml root@ai-server:~# installadm list -m -n x86-fcs Manifest Status Criteria -------- ------ -------- S11 Small fcs local Default None orig_default Inactive None The major points in this new manifest are: Install "solaris-small-server" Install a few locales less than the default. I'm not that fluid in French or Japanese... Use my own package service as publisher, running on IP address 192.168.2.12 Install the initial release of Solaris 11: pkg:/[email protected],5.11-0.175.0.0.0.2.0 Using a similar approach, I'll create a default profile interactively and use it as a template for a few customized building blocks, each defining a part of the overall system configuration. The modular approach makes it easy to configure numerous clients later on: root@ai-server:~# mkdir -p /export/install/configs/profiles root@ai-server:~# cd /export/install/configs/profiles root@ai-server:~# sysconfig create-profile -o default.xml root@ai-server:~# cp default.xml general.xml; cp default.xml mars.xml root@ai-server:~# cp default.xml user.xml root@ai-server:~# vi general.xml mars.xml user.xml root@ai-server:~# more general.xml mars.xml user.xml :::::::::::::: general.xml :::::::::::::: <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type="profile" name="sysconfig"> <service version="1" type="service" name="system/timezone"> <instance enabled="true" name="default"> <property_group type="application" name="timezone"> <propval type="astring" name="localtime" value="Europe/Berlin"/> </property_group> </instance> </service> <service version="1" type="service" name="system/environment"> <instance enabled="true" name="init"> <property_group type="application" name="environment"> <propval type="astring" name="LANG" value="C"/> </property_group> </instance> </service> <service version="1" type="service" name="system/keymap"> <instance enabled="true" name="default"> <property_group type="system" name="keymap"> <propval type="astring" name="layout" value="US-English"/> </property_group> </instance> </service> <service version="1" type="service" name="system/console-login"> <instance enabled="true" name="default"> <property_group type="application" name="ttymon"> <propval type="astring" name="terminal_type" value="vt100"/> </property_group> </instance> </service> <service version="1" type="service" name="network/physical"> <instance enabled="true" name="default"> <property_group type="application" name="netcfg"> <propval type="astring" name="active_ncp" value="DefaultFixed"/> </property_group> </instance> </service> <service version="1" type="service" name="system/name-service/switch"> <property_group type="application" name="config"> <propval type="astring" name="default" value="files"/> <propval type="astring" name="host" value="files dns"/> <propval type="astring" name="printer" value="user files"/> </property_group> <instance enabled="true" name="default"/> </service> <service version="1" type="service" name="system/name-service/cache"> <instance enabled="true" name="default"/> </service> <service version="1" type="service" name="network/dns/client"> <property_group type="application" name="config"> <property type="net_address" name="nameserver"> <net_address_list> <value_node value="192.168.2.1"/> </net_address_list> </property> </property_group> <instance enabled="true" name="default"/> </service> </service_bundle> :::::::::::::: mars.xml :::::::::::::: <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type="profile" name="sysconfig"> <service version="1" type="service" name="network/install"> <instance enabled="true" name="default"> <property_group type="application" name="install_ipv4_interface"> <propval type="astring" name="address_type" value="static"/> <propval type="net_address_v4" name="static_address" value="192.168.2.100/24"/> <propval type="astring" name="name" value="net0/v4"/> <propval type="net_address_v4" name="default_route" value="192.168.2.1"/> </property_group> <property_group type="application" name="install_ipv6_interface"> <propval type="astring" name="stateful" value="yes"/> <propval type="astring" name="stateless" value="yes"/> <propval type="astring" name="address_type" value="addrconf"/> <propval type="astring" name="name" value="net0/v6"/> </property_group> </instance> </service> <service version="1" type="service" name="system/identity"> <instance enabled="true" name="node"> <property_group type="application" name="config"> <propval type="astring" name="nodename" value="mars"/> </property_group> </instance> </service> </service_bundle> :::::::::::::: user.xml :::::::::::::: <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type="profile" name="sysconfig"> <service version="1" type="service" name="system/config-user"> <instance enabled="true" name="default"> <property_group type="application" name="root_account"> <propval type="astring" name="login" value="root"/> <propval type="astring" name="password" value="noIWillNotTellYouMyPasswordNotEvenEncrypted"/> <propval type="astring" name="type" value="role"/> </property_group> <property_group type="application" name="user_account"> <propval type="astring" name="login" value="stefan"/> <propval type="astring" name="password" value="noIWillNotTellYouMyPasswordNotEvenEncrypted"/> <propval type="astring" name="type" value="normal"/> <propval type="astring" name="description" value="Stefan Hinker"/> <propval type="count" name="uid" value="12345"/> <propval type="count" name="gid" value="10"/> <propval type="astring" name="shell" value="/usr/bin/bash"/> <propval type="astring" name="roles" value="root"/> <propval type="astring" name="profiles" value="System Administrator"/> <propval type="astring" name="sudoers" value="ALL=(ALL) ALL"/> </property_group> </instance> </service> </service_bundle> root@ai-server:~# installadm create-profile -n x86-fcs -f general.xml root@ai-server:~# installadm create-profile -n x86-fcs -f user.xml root@ai-server:~# installadm create-profile -n x86-fcs -f mars.xml \ -c ipv4=192.168.2.100 root@ai-server:~# installadm list -p Service Name Profile ------------ ------- x86-fcs general.xml mars.xml user.xml root@ai-server:~# installadm list -n x86-fcs -p Profile Criteria ------- -------- general.xml None mars.xml ipv4 = 192.168.2.100 user.xml None Here's the idea behind these files: "general.xml" contains settings valid for all my clients. Stuff like DNS servers, for example, which in my case will always be the same. "user.xml" only contains user definitions. That is, a root password and a primary user.Both of these profiles will be valid for all clients (for now). "mars.xml" defines network settings for an individual client. This profile is associated with an IP-Address. For this to work, I'll have to tweak the DHCP-settings in the next step: root@ai-server:~# installadm create-client -e 08:00:27:AA:3D:B1 -n x86-fcs root@ai-server:~# vi /etc/inet/dhcpd4.conf root@ai-server:~# tail -5 /etc/inet/dhcpd4.conf host 080027AA3DB1 { hardware ethernet 08:00:27:AA:3D:B1; fixed-address 192.168.2.100; filename "01080027AA3DB1"; } This completes the client preparations. I manually added the IP-Address for mars to /etc/inet/dhcpd4.conf. This is needed for the "mars.xml" profile. Disabling arbitrary DHCP-replies will shut up this DHCP server, making my life in a shared environment a lot more peaceful ;-)Now, I of course want this installation to be completely hands-off. For this to work, I'll need to modify the grub boot menu for this client slightly. You can find it in /etc/netboot. "installadm create-client" will create a new boot menu for every client, identified by the client's MAC address. The template for this can be found in a subdirectory with the name of the install service, /etc/netboot/x86-fcs in our case. If you don't want to change this manually for every client, modify that template to your liking instead. root@ai-server:~# cd /etc/netboot root@ai-server:~# cp menu.lst.01080027AA3DB1 menu.lst.01080027AA3DB1.org root@ai-server:~# vi menu.lst.01080027AA3DB1 root@ai-server:~# diff menu.lst.01080027AA3DB1 menu.lst.01080027AA3DB1.org 1,2c1,2 < default=1 < timeout=10 --- > default=0 > timeout=30 root@ai-server:~# more menu.lst.01080027AA3DB1 default=1 timeout=10 min_mem64=0 title Oracle Solaris 11 11/11 Text Installer and command line kernel$ /x86-fcs/platform/i86pc/kernel/$ISADIR/unix -B install_media=htt p://$serverIP:5555//export/install/fcs,install_service=x86-fcs,install_svc_addre ss=$serverIP:5555 module$ /x86-fcs/platform/i86pc/$ISADIR/boot_archive title Oracle Solaris 11 11/11 Automated Install kernel$ /x86-fcs/platform/i86pc/kernel/$ISADIR/unix -B install=true,inst all_media=http://$serverIP:5555//export/install/fcs,install_service=x86-fcs,inst all_svc_address=$serverIP:5555,livemode=text module$ /x86-fcs/platform/i86pc/$ISADIR/boot_archive Now just boot the client off the network using PXE-boot. For my demo purposes, that's a client from VirtualBox, of course. That's all there's to it. And despite the fact that this blog entry is a little longer - that wasn't that hard now, was it?

Read the article

Red Gate Coder interviews: Robin Hellen

- by Michael Williamson

Robin Hellen is a test engineer here at Red Gate, and is also the latest coder I’ve interviewed. We chatted about debugging code, the roles of software engineers and testers, and why Vala is currently his favourite programming language. How did you get started with programming?It started when I was about six. My dad’s a professional programmer, and he gave me and my sister one of his old computers and taught us a bit about programming. It was an old Amiga 500 with a variant of BASIC. I don’t think I ever successfully completed anything! It was just faffing around. I didn’t really get anywhere with it.But then presumably you did get somewhere with it at some point.At some point. The PC emerged as the dominant platform, and I learnt a bit of Visual Basic. I didn’t really do much, just a couple of quick hacky things. A bit of demo animation. Took me a long time to get anywhere with programming, really.When did you feel like you did start to get somewhere?I think it was when I started doing things for someone else, which was my sister’s final year of university project. She called up my dad two days before she was due to submit, saying “We need something to display a graph!”. Dad says, “I’m too busy, go talk to your brother”. So I hacked up this ugly piece of code, sent it off and they won a prize for that project. Apparently, the graph, the bit that I wrote, was the reason they won a prize! That was when I first felt that I’d actually done something that was worthwhile. That was my first real bit of code, and the ugliest code I’ve ever written. It’s basically an array of pre-drawn line elements that I shifted round the screen to draw a very spikey graph.When did you decide that programming might actually be something that you wanted to do as a career?It’s not really a decision I took, I always wanted to do something with computers. And I had to take a gap year for uni, so I was looking for twelve month internships. I applied to Red Gate, and they gave me a job as a tester. And that’s where I really started having to write code well. To a better standard that I had been up to that point.How did you find coming to Red Gate and working with other coders?I thought it was really nice. I learnt so much just from other people around. I think one of the things that’s really great is that people are just willing to help you learn. Instead of “Don’t you know that, you’re so stupid”, it’s “You can just do it this way”.If you could go back to the very start of that internship, is there something that you would tell yourself?Write shorter code. I have a tendency to write massive, many-thousand line files that I break out of right at the end. And then half-way through a project I’m doing something, I think “Where did I write that bit that does that thing?”, and it’s almost impossible to find. I wrote some horrendous code when I started. Just that principle, just keep things short. Even if looks a bit crazy to be jumping around all over the place all of the time, it’s actually a lot more understandable.And how do you hold yourself to that?Generally, if a function’s going off my screen, it’s probably too long. That’s what I tell myself, and within the team here we have code reviews, so the guys I’m with at the moment are pretty good at pulling me up on, “Doesn’t that look like it’s getting a bit long?”. It’s more just the subjective standard of readability than anything.So you’re an advocate of code review?Yes, definitely. Both to spot errors that you might have made, and to improve your knowledge. The person you’re reviewing will say “Oh, you could have done it that way”. That’s how we learn, by talking to others, and also just sharing knowledge of how your project works around the team, or even outside the team. Definitely a very firm advocate of code reviews.Do you think there’s more we could do with them?I don’t know. We’re struggling with how to add them as part of the process without it becoming too cumbersome. We’ve experimented with a few different ways, and we’ve not found anything that just works.To get more into the nitty gritty: how do you like to debug code?The first thing is to do it in my head. I’ll actually think what piece of code is likely to have caused that error, and take a quick look at it, just to see if there’s anything glaringly obvious there. The next thing I’ll probably do is throw in print statements, or throw some exceptions from various points, just to check: is it going through the code path I expect it to? A last resort is to actually debug code using a debugger.Why is the debugger the last resort?Probably because of the environments I learnt programming in. VB and early BASIC didn’t have much of a debugger, the only way to find out what your program was doing was to add print statements. Also, because a lot of the stuff I tend to work with is non-interactive, if it’s something that takes a long time to run, I can throw in the print statements, set a run off, go and do something else, and look at it again later, rather than trying to remember what happened at that point when I was debugging through it. So it also gives me the record of what happens. I hate just sitting there pressing F5, F5, continually. If you’re having to find out what your code is doing at each line, you’ve probably got a very wrong mental model of what your code’s doing, and you can find that out just as easily by inspecting a couple of values through the print statements.If I were on some codebase that you were also working on, what should I do to make it as easy as possible to understand?I’d say short and well-named methods. The one thing I like to do when I’m looking at code is to find out where a value comes from, and the more layers of indirection there are, particularly DI [dependency injection] frameworks, the harder it is to find out where something’s come from. I really hate that. I want to know if the value come from the user here or is a constant here, and if I can’t find that out, that makes code very hard to understand for me.As a tester, where do you think the split should lie between software engineers and testers?I think the split is less on areas of the code you write and more what you’re designing and creating. The developers put a structure on the code, while my major role is to say which tests we should have, whether we should test that, or it’s not worth testing that because it’s a tiny function in code that nobody’s ever actually going to see. So it’s not a split in the code, it’s a split in what you’re thinking about. Saying what code we should write, but alternatively what code we should take out.In your experience, do the software engineers tend to do much testing themselves?They tend to control the lowest layer of tests. And, depending on how the balance of people is in the team, they might write some of the higher levels of test. Or that might go to the testers. I’m the only tester on my team with three other developers, so they’ll be writing quite a lot of the actual test code, with input from me as to whether we should test that functionality, whereas on other teams, where it’s been more equal numbers, the testers have written pretty much all of the high level tests, just because that’s the best use of resource.If you could shuffle resources around however you liked, do you think that the developers should be writing those high-level tests?I think they should be writing them occasionally. It helps when they have an understanding of how testing code works and possibly what assumptions we’ve made in tests, and they can say “actually, it doesn’t work like that under the hood so you’ve missed this whole area”. It’s one of those agile things that everyone on the team should be at least comfortable doing the various jobs. So if the developers can write test code then I think that’s a very good thing.So you think testers should be able to write production code?Yes, although given most testers skills at coding, I wouldn’t advise it too much! I have written a few things, and I did make a few changes that have actually gone into our production code base. They’re not necessarily running every time but they are there. I think having that mix of skill sets is really useful. In some ways we’re using our own product to test itself, so being able to make those changes where it’s not working saves me a round-trip through the developers. It can be really annoying if the developers have no time to make a change, and I can’t touch the code.If the software engineers are consistently writing tests at all levels, what role do you think the role of a tester is?I think on a team like that, those distinctions aren’t quite so useful. There’ll be two cases. There’s either the case where the developers think they’ve written good tests, but you still need someone with a test engineer mind-set to go through the tests and validate that it’s a useful set, or the correct set for that code. Or they won’t actually be pure developers, they’ll have that mix of test ability in there.I think having slightly more distinct roles is useful. When it starts to blur, then you lose that view of the tests as a whole. The tester job is not to create tests, it’s to validate the quality of the product, and you don’t do that just by writing tests. There’s more things you’ve got to keep in your mind. And I think when you blur the roles, you start to lose that end of the tester.So because you’re working on those features, you lose that holistic view of the whole system?Yeah, and anyone who’s worked on the feature shouldn’t be testing it. You always need to have it tested it by someone who didn’t write it. Otherwise you’re a bit too close and you assume “yes, people will only use it that way”, but the tester will come along and go “how do people use this? How would our most idiotic user use this?”. I might not test that because it might be completely irrelevant. But it’s coming in and trying to have a different set of assumptions.Are you a believer that it should all be automated if possible?Not entirely. So an automated test is always better than a manual test for the long-term, but there’s still nothing that beats a human sitting in front of the application and thinking “What could I do at this point?”. The automated test is very good but they follow that strict path, and they never check anything off the path. The human tester will look at things that they weren’t expecting, whereas the automated test can only ever go “Is that value correct?” in many respects, and it won’t notice that on the other side of the screen you’re showing something completely wrong. And that value might have been checked independently, but you always find a few odd interactions when you’re going through something manually, and you always need to go through something manually to start with anyway, otherwise you won’t know where the important bits to write your automation are.When you’re doing that manual testing, do you think it’s important to do that across the entire product, or just the bits that you’ve touched recently?I think it’s important to do it mostly on the bits you’ve touched, but you can’t ignore the rest of the product. Unless you’re dealing with a very, very self-contained bit, you’re almost always encounter other bits of the product along the way. Most testers I know, even if they are looking at just one path, they’ll keep open and move around a bit anyway, just because they want to find something that’s broken. If we find that your path is right, we’ll go out and hunt something else.How do you think this fits into the idea of continuously deploying, so long as the tests pass?With deploying a website it’s a bit different because you can always pull it back. If you’re deploying an application to customers, when you’ve released it, it’s out there, you can’t pull it back. Someone’s going to keep it, no matter how hard you try there will be a few installations that stay around. So I’d always have at least a human element on that path. With websites, you could probably automate straight out, or at least straight out to an internal environment or a single server in a cloud of fifty that will serve some people. But I don’t think you should release to everyone just on automated tests passing.You’ve already mentioned using BASIC and C# — are there any other languages that you’ve used?I’ve used a few. That’s something that has changed more recently, I’ve become familiar with more languages. Before I started at Red Gate I learnt a bit of C. Then last year, I taught myself Python which I actually really enjoyed using. I’ve also come across another language called Vala, which is sort of a C#-like language. It’s basically a pre-processor for C, but it has very nice syntax. I think that’s currently my favourite language.Any particular reason for trying Vala?I have a completely Linux environment at home, and I’ve been looking for a nice language, and C# just doesn’t cut it because I won’t touch Mono. So, I was looking for something like C# but that was useable in an open source environment, and Vala’s what I found. C#’s got a few features that Vala doesn’t, and Vala’s got a few features where I think “It would be awesome if C# had that”.What are some of the features that it’s missing?Extension methods. And I think that’s the only one that really bugs me. I like to use them when I’m writing C# because it makes some things really easy, especially with libraries that you can’t touch the internals of. It doesn’t have method overloading, which is sometimes annoying.Where it does win over C#?Everything is non-nullable by default, you never have to check that something’s unexpectedly null.Also, Vala has code contracts. This is starting to come in C# 4, but the way it works in Vala is that you specify requirements in short phrases as part of your function signature and they stick to the signature, so that when you inherit it, it has exactly the same code contract as the base one, or when you inherit from an interface, you have to match the signature exactly. Just using those makes you think a bit more about how you’re writing your method, it’s not an afterthought when you’ve got contracts from base classes given to you, you can’t change it. Which I think is a lot nicer than the way C# handles it. When are those actually checked?They’re checked both at compile and run-time. The compile-time checking isn’t very strong yet, it’s quite a new feature in the compiler, and because it compiles down to C, you can write C code and interface with your methods, so you can bypass that compile-time check anyway. So there’s an extra runtime check, and if you violate one of the contracts at runtime, it’s game over for your program, there’s no exception to catch, it’s just goodbye!One thing I dislike about C# is the exceptions. You write a bit of code and fifty exceptions could come from any point in your ten lines, and you can’t mentally model how those exceptions are going to come out, and you can’t even predict them based on the functions you’re calling, because if you’ve accidentally got a derived class there instead of a base class, that can throw a completely different set of exceptions. So I’ve got no way of mentally modelling those, whereas in Vala they’re checked like Java, so you know only these exceptions can come out. You know in advance the error conditions.I think Raymond Chen on Old New Thing says “the only thing you know when you throw an exception is that you’re in an invalid state somewhere in your program, so just kill it and be done with it!”You said you’ve also learnt bits of Python. How did you find that compared to Vala and C#?Very different because of the dynamic typing. I’ve been writing a website for my own use. I’m quite into photography, so I take photos off my camera, post-process them, dump them in a file, and I get a webpage with all my thumbnails. So sort of like Picassa, but written by myself because I wanted something to learn Python with. There are some things that are really nice, I just found it really difficult to cope with the fact that I’m not quite sure what this object type that I’m passed is, I might not ever be sure, so it can randomly blow up on me. But once I train myself to ignore that and just say “well, I’m fairly sure it’s going to be something that looks like this, so I’ll use it like this”, then it’s quite nice.Any particular features that you’ve appreciated?I don’t like any particular feature, it’s just very straightforward to work with. It’s very quick to write something in, particularly as you don’t have to worry that you’ve changed something that affects a different part of the program. If you have, then that part blows up, but I can get this part working right now.If you were doing a big project, would you be willing to do it in Python rather than C# or Vala?I think I might be willing to try something bigger or long term with Python. We’re currently doing an ASP.NET MVC project on C#, and I don’t like the amount of reflection. There’s a lot of magic that pulls values out, and it’s all done under the scenes. It’s almost managed to put a dynamic type system on top of C#, which in many ways destroys the language to me, whereas if you’re already in a dynamic language, having things done dynamically is much more natural. In many ways, you get the worst of both worlds. I think for web projects, I would go with Python again, whereas for anything desktop, command-line or GUI-based, I’d probably go for C# or Vala, depending on what environment I’m in.It’s the fact that you can gain from the strong typing in ways that you can’t so much on the web app. Or, in a web app, you have to use dynamic typing at some point, or you have to write a hell of a lot of boilerplate, and I’d rather use the dynamic typing than write the boilerplate.What do you think separates great programmers from everyone else?Probably design choices. Choosing to write it a piece of code one way or another. For any given program you ask me to write, I could probably do it five thousand ways. A programmer who is capable will see four or five of them, and choose one of the better ones. The excellent programmer will see the largest proportion and manage to pick the best one very quickly without having to think too much about it. I think that’s probably what separates, is the speed at which they can see what’s the best path to write the program in. More Red Gater Coder interviews

Read the article

WLS MBeans

- by Jani Rautiainen

WLS provides a set of Managed Beans (MBeans) to configure, monitor and manage WLS resources. We can use the WLS MBeans to automate some of the tasks related to the configuration and maintenance of the WLS instance. The MBeans can be accessed a number of ways; using various UIs and programmatically using Java or WLST Python scripts.For customization development we can use the features to e.g. manage the deployed customization in MDS, control logging levels, automate deployment of dependent libraries etc. This article is an introduction on how to access and use the WLS MBeans. The goal is to illustrate the various access methods in a single article; the details of the features are left to the linked documentation.This article covers Windows based environment, steps for Linux would be similar however there would be some differences e.g. on how the file paths are defined. MBeansThe WLS MBeans can be categorized to runtime and configuration MBeans.The Runtime MBeans can be used to access the runtime information about the server and its resources. The data from runtime beans is only available while the server is running. The runtime beans can be used to e.g. check the state of the server or deployment.The Configuration MBeans contain information about the configuration of servers and resources. The configuration of the domain is stored in the config.xml file and the configuration MBeans can be used to access and modify the configuration data. For more information on the WLS MBeans refer to: Understanding WebLogic Server MBeans WLS MBean reference Java Management Extensions (JMX)We can use JMX APIs to access the WLS MBeans. This allows us to create Java programs to configure, monitor, and manage WLS resources. In order to use the WLS MBeans we need to add the following library into the class-path: WL_HOME\lib\wljmxclient.jar Connecting to a WLS MBean server The WLS MBeans are contained in a Mbean server, depending on the requirement we can connect to (MBean Server / JNDI Name): Domain Runtime MBean Server weblogic.management.mbeanservers.domainruntime Runtime MBean Server weblogic.management.mbeanservers.runtime Edit MBean Server weblogic.management.mbeanservers.edit To connect to the WLS MBean server first we need to create a map containing the credentials; Hashtable<String, String> param = new Hashtable<String, String>(); param.put(Context.SECURITY_PRINCIPAL, "weblogic"); param.put(Context.SECURITY_CREDENTIALS, "weblogic1"); param.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES, "weblogic.management.remote"); These define the user, password and package containing the protocol. Next we create the connection: JMXServiceURL serviceURL = new JMXServiceURL("t3","127.0.0.1",7101, "/jndi/weblogic.management.mbeanservers.domainruntime"); JMXConnector connector = JMXConnectorFactory.connect(serviceURL, param); MBeanServerConnection connection = connector.getMBeanServerConnection(); With the connection we can now access the MBeans for the WLS instance. For a complete example see Appendix A of this post. For more details refer to Accessing WebLogic Server MBeans with JMX Accessing WLS MBeans The WLS MBeans are structured hierarchically; in order to access content we need to know the path to the MBean we are interested in. The MBean is accessed using “MBeanServerConnection. getAttribute” API. WLS provides entry points to the hierarchy allowing us to navigate all the WLS MBeans in the hierarchy (MBean Server / JMX object name): Domain Runtime MBean Server com.bea:Name=DomainRuntimeService,Type=weblogic.management.mbeanservers.domainruntime.DomainRuntimeServiceMBean Runtime MBean Servers com.bea:Name=RuntimeService,Type=weblogic.management.mbeanservers.runtime.RuntimeServiceMBean Edit MBean Server com.bea:Name=EditService,Type=weblogic.management.mbeanservers.edit.EditServiceMBean For example we can access the Domain Runtime MBean using: ObjectName service = new ObjectName( "com.bea:Name=DomainRuntimeService," + "Type=weblogic.management.mbeanservers.domainruntime.DomainRuntimeServiceMBean"); Same syntax works for any “child” WLS MBeans e.g. to find out all application deployments we can: ObjectName domainConfig = (ObjectName)connection.getAttribute(service,"DomainConfiguration"); ObjectName[] appDeployments = (ObjectName[])connection.getAttribute(domainConfig,"AppDeployments"); Alternatively we could access the same MBean using the full syntax: ObjectName domainConfig = new ObjectName("com.bea:Location=DefaultDomain,Name=DefaultDomain,Type=Domain"); ObjectName[] appDeployments = (ObjectName[])connection.getAttribute(domainConfig,"AppDeployments"); For more details refer to Accessing WebLogic Server MBeans with JMX Invoking operations on WLS MBeans The WLS MBean operations can be invoked with MBeanServerConnection. invoke API; in the following example we query the state of “AppsLoggerService” application: ObjectName appRuntimeStateRuntime = new ObjectName("com.bea:Name=AppRuntimeStateRuntime,Type=AppRuntimeStateRuntime"); Object[] parameters = { "AppsLoggerService", "DefaultServer" }; String[] signature = { "java.lang.String", "java.lang.String" }; String result = (String)connection.invoke(appRuntimeStateRuntime,"getCurrentState",parameters, signature); The result returned should be "STATE_ACTIVE" assuming the "AppsLoggerService" application is up and running. WebLogic Scripting Tool (WLST) The WebLogic Scripting Tool (WLST) is a command-line scripting environment that we can access the same WLS MBeans. The tool is located under: $MW_HOME\oracle_common\common\bin\wlst.bat Do note that there are several instances of the wlst script under the $MW_HOME, each of them works, however the commands available vary, so we want to use the one under “oracle_common”. The tool is started in offline mode. In offline mode we can access and manipulate the domain configuration. In online mode we can access the runtime information. We connect to the Administration Server : connect("weblogic","weblogic1", "t3://127.0.0.1:7101") In both online and offline modes we can navigate the WLS MBean using commands like "ls" to print content and "cd" to navigate between objects, for example: All the commands available can be obtained with: help('all') For details of the tool refer to WebLogic Scripting Tool and for the commands available WLST Command and Variable Reference. Also do note that the WLST tool can be invoked from Java code in Embedded Mode. Running Scripts The WLST tool allows us to automate tasks using Python scripts in Script Mode. The script can be manually created or recorded by the WLST tool. Example commands of recording a script: startRecording("c:/temp/recording.py") <commands that we want to record> stopRecording() We can run the script from WLST: execfile("c:/temp/recording.py") We can also run the script from the command line: C:\apps\Oracle\Middleware\oracle_common\common\bin\wlst.cmd c:/temp/recording.py There are various sample scripts are provided with the WLS instance. UI to Access the WLS MBeans There are various UIs through which we can access the WLS MBeans. Oracle Enterprise Manager Fusion Middleware Control Oracle WebLogic Server Administration Console Fusion Middleware Control MBean Browser In the integrated JDeveloper environment only the Oracle WebLogic Server Administration Console is available to us. For more information refer to the documentation, one noteworthy feature in the console is the ability to record WLST scripts based on the navigation. In addition to the UIs above the JConsole included in the JDK can be used to access the WLS MBeans. The JConsole needs to be started with specific parameter to force WLS objects to be used and jar files in the classpath: "C:\apps\Oracle\Middleware\jdk160_24\bin\jconsole" -J-Djava.class.path=C:\apps\Oracle\Middleware\jdk160_24\lib\jconsole.jar;C:\apps\Oracle\Middleware\jdk160_24\lib\tools.jar;C:\apps\Oracle\Middleware\wlserver_10.3\server\lib\wljmxclient.jar -J-Djmx.remote.protocol.provider.pkgs=weblogic.management.remote For more details refer to the Accessing Custom MBeans from JConsole. Summary In this article we have covered various ways we can access and use the WLS MBeans in context of integrated WLS in JDeveloper to be used for Fusion Application customization development. References Developing Custom Management Utilities With JMX for Oracle WebLogic Server Accessing WebLogic Server MBeans with JMX WebLogic Server MBean Reference WebLogic Scripting Tool WLST Command and Variable Reference Appendix A package oracle.apps.test; import java.io.IOException;import java.net.MalformedURLException;import java.util.Hashtable;import javax.management.MBeanServerConnection;import javax.management.MalformedObjectNameException;import javax.management.ObjectName;import javax.management.remote.JMXConnector;import javax.management.remote.JMXConnectorFactory;import javax.management.remote.JMXServiceURL;import javax.naming.Context;/** * This class contains simple examples on how to access WLS MBeans using JMX. */public class BlogExample { /** * Connection to the WLS MBeans */ private MBeanServerConnection connection; /** * Constructor that takes in the connection information for the * domain and obtains the resources from WLS MBeans using JMX. * @param hostName host name to connect to for the WLS server * @param port port to connect to for the WLS server * @param userName user name to connect to for the WLS server * @param password password to connect to for the WLS server */ public BlogExample(String hostName, String port, String userName, String password) { super(); try { initConnection(hostName, port, userName, password); } catch (Exception e) { throw new RuntimeException("Unable to connect to the domain " + hostName + ":" + port); } } /** * Default constructor. * Tries to create connection with default values. Runtime exception will be * thrown if the default values are not used in the local instance. */ public BlogExample() { this("127.0.0.1", "7101", "weblogic", "weblogic1"); } /** * Initializes the JMX connection to the WLS Beans * @param hostName host name to connect to for the WLS server * @param port port to connect to for the WLS server * @param userName user name to connect to for the WLS server * @param password password to connect to for the WLS server * @throws IOException error connecting to the WLS MBeans * @throws MalformedURLException error connecting to the WLS MBeans * @throws MalformedObjectNameException error connecting to the WLS MBeans */ private void initConnection(String hostName, String port, String userName, String password) throws IOException, MalformedURLException, MalformedObjectNameException { String protocol = "t3"; String jndiroot = "/jndi/"; String mserver = "weblogic.management.mbeanservers.domainruntime"; JMXServiceURL serviceURL = new JMXServiceURL(protocol, hostName, Integer.valueOf(port), jndiroot + mserver); Hashtable<String, String> h = new Hashtable<String, String>(); h.put(Context.SECURITY_PRINCIPAL, userName); h.put(Context.SECURITY_CREDENTIALS, password); h.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES, "weblogic.management.remote"); JMXConnector connector = JMXConnectorFactory.connect(serviceURL, h); connection = connector.getMBeanServerConnection(); } /** * Main method used to invoke the logic for testing * @param args arguments passed to the program */ public static void main(String[] args) { BlogExample blogExample = new BlogExample(); blogExample.testEntryPoint(); blogExample.testDirectAccess(); blogExample.testInvokeOperation(); } /** * Example of using an entry point to navigate the WLS MBean hierarchy. */ public void testEntryPoint() { try { System.out.println("testEntryPoint"); ObjectName service = new ObjectName("com.bea:Name=DomainRuntimeService,Type=" +"weblogic.management.mbeanservers.domainruntime.DomainRuntimeServiceMBean"); ObjectName domainConfig = (ObjectName)connection.getAttribute(service, "DomainConfiguration"); ObjectName[] appDeployments = (ObjectName[])connection.getAttribute(domainConfig, "AppDeployments"); for (ObjectName appDeployment : appDeployments) { String resourceIdentifier = (String)connection.getAttribute(appDeployment, "SourcePath"); System.out.println(resourceIdentifier); } } catch (Exception e) { throw new RuntimeException(e); } } /** * Example of accessing WLS MBean directly with a full reference. * This does the same thing as testEntryPoint in slightly difference way. */ public void testDirectAccess() { try { System.out.println("testDirectAccess"); ObjectName appDeployment = new ObjectName("com.bea:Location=DefaultDomain,"+ "Name=AppsLoggerService,Type=AppDeployment"); String resourceIdentifier = (String)connection.getAttribute(appDeployment, "SourcePath"); System.out.println(resourceIdentifier); } catch (Exception e) { throw new RuntimeException(e); } } /** * Example of invoking operation on a WLS MBean. */ public void testInvokeOperation() { try { System.out.println("testInvokeOperation"); ObjectName appRuntimeStateRuntime = new ObjectName("com.bea:Name=AppRuntimeStateRuntime,"+ "Type=AppRuntimeStateRuntime"); String identifier = "AppsLoggerService"; String serverName = "DefaultServer"; Object[] parameters = { identifier, serverName }; String[] signature = { "java.lang.String", "java.lang.String" }; String result = (String)connection.invoke(appRuntimeStateRuntime, "getCurrentState", parameters, signature); System.out.println("State of " + identifier + " = " + result); } catch (Exception e) { throw new RuntimeException(e); } }}

Read the article

Configuring Oracle iPlanet WebServer / Oracle Traffic Director to use crypto accelerators on T4-1 servers

- by mv

Configuring Oracle iPlanet Web Server / Oracle Traffic Director to use crypto accelerators on T4-1 servers Jyri had written a technical article on Configuring Solaris Cryptographic Framework and Sun Java System Web Server 7 on Systems With UltraSPARC T1 Processors. I tried to find out what has changed since then in T4. I have used a T4-1 SPARC system with Solaris 10. Results slightly vary for Solaris 11. For Solaris 11, the T4 optimization was implemented in libsoftcrypto.so while it was in pkcs11_softtoken_extra.so for Solaris 10. Overview of T4 processors is here in this blog. Many thanx to Chi-Chang Lin and Julien for their help. 1. Install Oracle iPlanet Web Server / Oracle Traffic Director. Go to instance/config directory. # cd /opt/oracle/webserver7/https-hostname.fqdn/config 2. List default PKCS#11 Modules # ../../bin/modutil -dbdir . -listListing of PKCS #11 Modules-----------------------------------------------------------1. NSS Internal PKCS #11 Moduleslots: 2 slots attachedstatus: loadedslot: NSS Internal Cryptographic Servicestoken: NSS Generic Crypto Servicesslot: NSS User Private Key and Certificate Servicestoken: NSS Certificate DB2. Root Certslibrary name: libnssckbi.soslots: 1 slot attachedstatus: loadedslot: NSS Builtin Objectstoken: Builtin Object Token----------------------------------------------------------- 3. Initialize the soft token data store in the $HOME/.sunw/pkcs11_softtoken/ directory # pktool setpin keystore=pkcs11Enter token passphrase: olderpasswordCreate new passphrase: passwordRe-enter new passphrase: passwordPassphrase changed. 4. Offload crypto operations to Solaris Crypto Framework on T4 $ ../../bin/modutil -dbdir . -nocertdb -add SCF -libfile /usr/lib/libpkcs11.so -mechanisms RSA:AES:SHA1:MD5 Module "SCF" added to database. Note that -nocertdb means modutil won't try to open the NSS softoken key database. It doesn't even have to be present. PKCS#11 library used is /usr/lib/libpkcs11.so. If the server is running in 64 bit mode, we have to use /usr/lib/64/libpkcs11.so Unlike T1 and T2, in T4 we do not have to disable mechanisms in softtoken provider using cryptoadm. 5. List again to check that a new module SCF is added # ../../bin/modutil -dbdir . -list Listing of PKCS #11 Modules-----------------------------------------------------------1. NSS Internal PKCS #11 Moduleslots: 2 slots attachedstatus: loadedslot: NSS Internal Cryptographic Servicestoken: NSS Generic Crypto Servicesslot: NSS User Private Key and Certificate Servicestoken: NSS Certificate DB2. SCFlibrary name: /usr/lib/libpkcs11.soslots: 2 slots attachedstatus: loadedslot: Sun Metaslottoken: Sun Metaslotslot: n2rng/0 SUNW_N2_Random_Number_Generator token: n2rng/0 SUNW_N2_RNG 3. Root Certs library name: libnssckbi.so slots: 1 slot attached status: loaded slot: NSS Builtin Objects token: Builtin Object Token----------------------------------------------------------- 6. Create certificate in “Sun Metaslot” : I have used certutil, but you must use Admin Server CLI / GUI # ../../bin/certutil -S -x -n "Server-Cert" -t "CT,CT,CT" -s "CN=*.fqdn" -d . -h "Sun Metaslot"Enter Password or Pin for "Sun Metaslot": password 7. Verify that the certificate is created properly in “Sun Metslaot” # ../../bin/certutil -L -d . -h "Sun Metaslot"Certificate Nickname Trust AttributesSSL,S/MIME,JAR/XPIEnter Password or Pin for "Sun Metaslot": passwordSun Metaslot:Server-Cert CTu,Cu,Cu# 8. Associate this newly created certificate to http listener using Admin CLI/GUI. After that server.xml should have <http-listener> ... <ssl> <server-cert-nickname>Sun Metaslot:Server-Cert</server-cert-nicknamer> </ssl> Note the prefix "Sun Metaslot" 9. Disable PKCS#11 bypass To use the accelerated AES algorithm, turn off PKCS#11 bypass, and configure modutil to have the AES mechanism go to the Metaslot. After you disable PKCS#11 bypasss using Admin GUI/CLI, check that server.xml should have <server> .... <pkcs11> <enabled>1</enabled> <allow-bypass>0</allow-bypass> </pkcs11> With PKCS#11 bypass enabled, Oracle iPlanet Web Server will only use the RSA capability of the T4, provided certificate and key are stored in the T4 slot (Metaslot). Actually, the RSA op is never bypassed in NSS, it's always done with PKCS#11 calls. So the bypass settings won't affect the behavior of the probes for RSA at all. The only thing that matters if where the RSA key and certificate live, ie. which PKCS#11 token, and thus which PKCS#11 module gets called to do the work. If your certificate/key are in the NSS certificate/key db, you will see libsoftokn3/libfreebl libraries doing the RSA work. If they are in the Sun Metaslot, it should be the Solaris code. 10. Start the server instance # ../bin/startserv Oracle iPlanet Web Server 7.0.16 B09/14/2012 03:33Please enter the PIN for the "Sun Metaslot" token: password...info: HTTP3072: http-listener-1: https://hostname.fqdn:80 ready to accept requestsinfo: CORE3274: successful server startup 11. Figure out which process to run this DTrace script on # ps -eaf | grep webservd | grep -v dogwebservd 18224 18223 0 13:17:25 ? 0:07 webservd -d /opt/oracle/webserver7/https-hostname.fqdn/config -r /opt/root 18225 18224 0 13:17:25 ? 0:00 webservd -d /opt/oracle/webserver7/https-hostname.fqdn/config -r /opt/ (For Oracle Traffic Director look for process named "trafficd") We see that the child process id is “18225” 12. Clients for testing : You can use any browser. I used NSS tool tstclnt for testing $cat > req.txtGET /index.html HTTP/1.0 For checking both RSA and AES, I used cipher “:0035” which is TLS_RSA_WITH_AES_256_CBC_SHA $./tstclnt -h hostname -p 80 -d . -T -f -o -v -c “:0035” < req.txt 13. How do I make sure that crypto accelerator is being used 13.1 Create DTrace script The following D script should be able to uncover whether T4-specific crypto routine are being called or not. It also displays stats per second. # cat > t4crypto.d#!/usr/sbin/dtrace -spid$target::*rsa*:entry,pid$target::*yf*:entry{ @ops[probemod, probefunc] = count();}tick-1sec{ printa(@ops); trunc(@ops);} Invoke with './t4crypto.d -p <pid> ' 13.2 EXPECTED PROBES FOR Solaris 10 : If offloading to T4 HW are correctly set up, the expected DTrace output would have these probes and libraries library Operations PROBES pkcs11_softtoken_extra.so RSA soft_decrypt_rsa_pkcs_decode, soft_encrypt_rsa_pkcs_encode soft_rsa_crypt_init_common soft_rsa_decrypt, soft_rsa_encrypt soft_rsa_decrypt_common, soft_rsa_encrypt_common AES yf_aes_instructions_present yf_aes_expand256, yf_aes256_cbc_decrypt, yf_aes256_cbc_encrypt, yf_aes256_load_keys_for_decrypt, yf_aes256_load_keys_for_encrypt, Note that these are for 256, same for 128, 192... these are for cbc, same for ecb, ctr, cfb128... DES yf_des_expand, yf_des_instructions_present yf_des_encrypt libmd_psr.so MD5 yf_md5_multiblock, yf_md5_instruction_present SHA1 yf_sha1_instruction_present, yf_sha1_multibloc 13.3 SAMPLE OUTPUT FOR CIPHER TLS_RSA_WITH_AES_256_CBC_SHA (0x0035) ON T4 SPARC SOLARIS 10 WITHOUT PKCS#11 BYPASS # ./t4crypto.d -p 18225 pkcs11_softtoken_extra.so.1 soft_decrypt_rsa_pkcs_decode 1 pkcs11_softtoken_extra.so.1 soft_rsa_crypt_init_common 1 pkcs11_softtoken_extra.so.1 soft_rsa_decrypt 1 pkcs11_softtoken_extra.so.1 big_mp_mul_yf 2 pkcs11_softtoken_extra.so.1 mpm_yf_mpmul 2 pkcs11_softtoken_extra.so.1 mpmul_arr_yf 2 pkcs11_softtoken_extra.so.1 rijndael_key_setup_enc_yf 2 pkcs11_softtoken_extra.so.1 soft_rsa_decrypt_common 2 pkcs11_softtoken_extra.so.1 yf_aes_expand256 2 pkcs11_softtoken_extra.so.1 yf_aes256_cbc_decrypt 3 pkcs11_softtoken_extra.so.1 yf_aes256_load_keys_for_decrypt 3 pkcs11_softtoken_extra.so.1 big_mont_mul_yf 6 pkcs11_softtoken_extra.so.1 mm_yf_montmul 6 pkcs11_softtoken_extra.so.1 yf_des_instructions_present 6 pkcs11_softtoken_extra.so.1 yf_aes256_cbc_encrypt 8 pkcs11_softtoken_extra.so.1 yf_aes256_load_keys_for_encrypt 8 pkcs11_softtoken_extra.so.1 yf_mpmul_present 8 pkcs11_softtoken_extra.so.1 yf_aes_instructions_present 13 pkcs11_softtoken_extra.so.1 yf_des_encrypt 18 libmd_psr.so.1 yf_md5_multiblock 41 libmd_psr.so.1 yf_md5_instruction_present 72 libmd_psr.so.1 yf_sha1_instruction_present 82 libmd_psr.so.1 yf_sha1_multiblock 82 This indicates that both RSA and AES ops are done in Solaris Crypto Framework. 13.4 SAMPLE OUTPUT FOR CIPHER TLS_RSA_WITH_AES_256_CBC_SHA (0x0035) ON T4 SPARC SOLARIS 10 WITH PKCS#11 BYPASS # ./t4crypto.d -p 18225 pkcs11_softtoken_extra.so.1 soft_decrypt_rsa_pkcs_decode 1 pkcs11_softtoken_extra.so.1 soft_rsa_crypt_init_common 1 pkcs11_softtoken_extra.so.1 soft_rsa_decrypt 1 pkcs11_softtoken_extra.so.1 soft_rsa_decrypt_common 1 pkcs11_softtoken_extra.so.1 big_mp_mul_yf 2 pkcs11_softtoken_extra.so.1 mpm_yf_mpmul 2 pkcs11_softtoken_extra.so.1 mpmul_arr_yf 2 pkcs11_softtoken_extra.so.1 big_mont_mul_yf 6 pkcs11_softtoken_extra.so.1 mm_yf_montmul 6 pkcs11_softtoken_extra.so.1 yf_mpmul_present 8 For this cipher, when I enable PKCS#11 bypass, Only RSA probes are being hit AES probes are not being hit. 13.5 ustack() for RSA operations / probefunc == "soft_rsa_decrypt" / Shows that libnss3.so is calling C_* functions of libpkcs11.so which is calling functions of pkcs11_softtoken_extra.so for both cases with and without bypass. When PKCS#11 bypass is disabled (allow-bypass is 0) pkcs11_softtoken_extra.so.1`soft_rsa_decrypt pkcs11_softtoken_extra.so.1`soft_rsa_decrypt_common+0x94 pkcs11_softtoken_extra.so.1`soft_unwrapkey+0x258 pkcs11_softtoken_extra.so.1`C_UnwrapKey+0x1ec libpkcs11.so.1`meta_unwrap_key+0x17c libpkcs11.so.1`meta_UnwrapKey+0xc4 libpkcs11.so.1`C_UnwrapKey+0xfc libnss3.so`pk11_AnyUnwrapKey+0x6b8 libnss3.so`PK11_PubUnwrapSymKey+0x8c libssl3.so`ssl3_HandleRSAClientKeyExchange+0x1a0 libssl3.so`ssl3_HandleClientKeyExchange+0x154 libssl3.so`ssl3_HandleHandshakeMessage+0x440 libssl3.so`ssl3_HandleHandshake+0x11c libssl3.so`ssl3_HandleRecord+0x5e8 libssl3.so`ssl3_GatherCompleteHandshake+0x5c libssl3.so`ssl_GatherRecord1stHandshake+0x30 libssl3.so`ssl_Do1stHandshake+0xec libssl3.so`ssl_SecureRecv+0x1c8 libssl3.so`ssl_Recv+0x9c libns-httpd40.so`__1cNDaemonSessionDrun6M_v_+0x2dc When PKCS#11 bypass is enabled (allow-bypass is 1) pkcs11_softtoken_extra.so.1`soft_rsa_decrypt pkcs11_softtoken_extra.so.1`soft_rsa_decrypt_common+0x94 pkcs11_softtoken_extra.so.1`C_Decrypt+0x164 libpkcs11.so.1`meta_do_operation+0x27c libpkcs11.so.1`meta_Decrypt+0x4c libpkcs11.so.1`C_Decrypt+0xcc libnss3.so`PK11_PrivDecryptPKCS1+0x1ac libssl3.so`ssl3_HandleRSAClientKeyExchange+0xe4 libssl3.so`ssl3_HandleClientKeyExchange+0x154 libssl3.so`ssl3_HandleHandshakeMessage+0x440 libssl3.so`ssl3_HandleHandshake+0x11c libssl3.so`ssl3_HandleRecord+0x5e8 libssl3.so`ssl3_GatherCompleteHandshake+0x5c libssl3.so`ssl_GatherRecord1stHandshake+0x30 libssl3.so`ssl_Do1stHandshake+0xec libssl3.so`ssl_SecureRecv+0x1c8 libssl3.so`ssl_Recv+0x9c libns-httpd40.so`__1cNDaemonSessionDrun6M_v_+0x2dc libnsprwrap.so`ThreadMain+0x1c libnspr4.so`_pt_root+0xe8 13.6 ustack() FOR AES operations / probefunc == "yf_aes256_cbc_encrypt" / When PKCS#11 bypass is disabled (allow-bypass is 0) pkcs11_softtoken_extra.so.1`yf_aes256_cbc_encrypt pkcs11_softtoken_extra.so.1`aes_block_process_contiguous_whole_blocks+0xb4 pkcs11_softtoken_extra.so.1`aes_crypt_contiguous_blocks+0x1cc pkcs11_softtoken_extra.so.1`soft_aes_encrypt_common+0x22c pkcs11_softtoken_extra.so.1`C_EncryptUpdate+0x10c libpkcs11.so.1`meta_do_operation+0x1fc libpkcs11.so.1`meta_EncryptUpdate+0x4c libpkcs11.so.1`C_EncryptUpdate+0xcc libnss3.so`PK11_CipherOp+0x1a0 libssl3.so`ssl3_CompressMACEncryptRecord+0x264 libssl3.so`ssl3_SendRecord+0x300 libssl3.so`ssl3_FlushHandshake+0x54 libssl3.so`ssl3_SendFinished+0x1fc libssl3.so`ssl3_HandleFinished+0x314 libssl3.so`ssl3_HandleHandshakeMessage+0x4ac libssl3.so`ssl3_HandleHandshake+0x11c libssl3.so`ssl3_HandleRecord+0x5e8 libssl3.so`ssl3_GatherCompleteHandshake+0x5c libssl3.so`ssl_GatherRecord1stHandshake+0x30 libssl3.so`ssl_Do1stHandshake+0xec Shows that libnss3.so is calling C_* functions of libpkcs11.so which is calling functions of pkcs11_softtoken_extra.so However when PKCS#11 bypass is disabled (allow-bypass is 1) this stack isn't getting called. 14. LIST OF ALL THE PROBES MATCHED BY D SCRIPT FOR REFERENCE # ./t4crypto.d -p 18225 -l ID PROVIDER MODULE FUNCTION NAME ... 55720 pid18225 libmd_psr.so.1 yf_md5_instruction_present entry 55721 pid18225 libmd_psr.so.1 yf_sha256_instruction_present entry 55722 pid18225 libmd_psr.so.1 yf_sha512_instruction_present entry 55723 pid18225 libmd_psr.so.1 yf_sha1_instruction_present entry 55724 pid18225 libmd_psr.so.1 yf_sha256 entry 55725 pid18225 libmd_psr.so.1 yf_sha256_multiblock entry 55726 pid18225 libmd_psr.so.1 yf_sha512 entry 55727 pid18225 libmd_psr.so.1 yf_sha512_multiblock entry 55728 pid18225 libmd_psr.so.1 yf_sha1 entry 55729 pid18225 libmd_psr.so.1 yf_sha1_multiblock entry 55730 pid18225 libmd_psr.so.1 yf_md5 entry 55731 pid18225 libmd_psr.so.1 yf_md5_multiblock entry 55732 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_instructions_present entry 55733 pid18225 pkcs11_softtoken_extra.so.1 rijndael_key_setup_enc_yf entry 55734 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_expand128 entry 55735 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_encrypt128 entry 55736 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_decrypt128 entry 55737 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_expand192 entry 55738 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_encrypt192 entry 55739 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_decrypt192 entry 55740 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_expand256 entry 55741 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_encrypt256 entry 55742 pid18225 pkcs11_softtoken_extra.so.1 yf_aes_decrypt256 entry 55743 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_load_keys_for_encrypt entry 55744 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_load_keys_for_encrypt entry 55745 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_load_keys_for_encrypt entry 55746 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_ecb_encrypt entry 55747 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_ecb_encrypt entry 55748 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_ecb_encrypt entry 55749 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_cbc_encrypt entry 55750 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_cbc_encrypt entry 55751 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_cbc_encrypt entry 55752 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_ctr_crypt entry 55753 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_ctr_crypt entry 55754 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_ctr_crypt entry 55755 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_cfb128_encrypt entry 55756 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_cfb128_encrypt entry 55757 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_cfb128_encrypt entry 55758 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_load_keys_for_decrypt entry 55759 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_load_keys_for_decrypt entry 55760 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_load_keys_for_decrypt entry 55761 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_ecb_decrypt entry 55762 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_ecb_decrypt entry 55763 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_ecb_decrypt entry 55764 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_cbc_decrypt entry 55765 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_cbc_decrypt entry 55766 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_cbc_decrypt entry 55767 pid18225 pkcs11_softtoken_extra.so.1 yf_aes128_cfb128_decrypt entry 55768 pid18225 pkcs11_softtoken_extra.so.1 yf_aes192_cfb128_decrypt entry 55769 pid18225 pkcs11_softtoken_extra.so.1 yf_aes256_cfb128_decrypt entry 55771 pid18225 pkcs11_softtoken_extra.so.1 yf_des_instructions_present entry 55772 pid18225 pkcs11_softtoken_extra.so.1 yf_des_expand entry 55773 pid18225 pkcs11_softtoken_extra.so.1 yf_des_encrypt entry 55774 pid18225 pkcs11_softtoken_extra.so.1 yf_mpmul_present entry 55775 pid18225 pkcs11_softtoken_extra.so.1 yf_montmul_present entry 55776 pid18225 pkcs11_softtoken_extra.so.1 mm_yf_montmul entry 55777 pid18225 pkcs11_softtoken_extra.so.1 mm_yf_montsqr entry 55778 pid18225 pkcs11_softtoken_extra.so.1 mm_yf_restore_func entry 55779 pid18225 pkcs11_softtoken_extra.so.1 mm_yf_ret_from_mont_func entry 55780 pid18225 pkcs11_softtoken_extra.so.1 mm_yf_execute_slp entry 55781 pid18225 pkcs11_softtoken_extra.so.1 big_modexp_ncp_yf entry 55782 pid18225 pkcs11_softtoken_extra.so.1 big_mont_mul_yf entry 55783 pid18225 pkcs11_softtoken_extra.so.1 mpmul_arr_yf entry 55784 pid18225 pkcs11_softtoken_extra.so.1 big_mp_mul_yf entry 55785 pid18225 pkcs11_softtoken_extra.so.1 mpm_yf_mpmul entry 55786 pid18225 libns-httpd40.so nsapi_rsa_set_priv_fn entry ... 55795 pid18225 libnss3.so prepare_rsa_priv_key_export_for_asn1 entry 55796 pid18225 libresolv.so.2 sunw_dst_rsaref_init entry 55797 pid18225 libnssutil3.so NSS_Get_SEC_UniversalStringTemplate entry ... 55813 pid18225 libsoftokn3.so prepare_low_rsa_priv_key_for_asn1 entry 55814 pid18225 libsoftokn3.so rsa_FormatOneBlock entry 55815 pid18225 libsoftokn3.so rsa_FormatBlock entry 55816 pid18225 libnssdbm3.so lg_prepare_low_rsa_priv_key_for_asn1 entry 55817 pid18225 libfreebl_32fpu_3.so rsa_build_from_primes entry 55818 pid18225 libfreebl_32fpu_3.so rsa_is_prime entry 55819 pid18225 libfreebl_32fpu_3.so rsa_get_primes_from_exponents entry 55820 pid18225 libfreebl_32fpu_3.so rsa_PrivateKeyOpNoCRT entry 55821 pid18225 libfreebl_32fpu_3.so rsa_PrivateKeyOpCRTNoCheck entry 55822 pid18225 libfreebl_32fpu_3.so rsa_PrivateKeyOpCRTCheckedPubKey entry 55823 pid18225 pkcs11_kernel.so.1 key_gen_rsa_by_value entry 55824 pid18225 pkcs11_kernel.so.1 get_rsa_private_key entry 55825 pid18225 pkcs11_kernel.so.1 get_rsa_public_key entry 55826 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_encrypt entry 55827 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_decrypt entry 55828 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_crypt_init_common entry 55829 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_encrypt_common entry 55830 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_decrypt_common entry 55831 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_sign_verify_init_common entry 55832 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_sign_common entry 55833 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_verify_common entry 55834 pid18225 pkcs11_softtoken_extra.so.1 generate_rsa_key entry 55835 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_genkey_pair entry 55836 pid18225 pkcs11_softtoken_extra.so.1 get_rsa_sha1_prefix entry 55837 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_digest_sign_common entry 55838 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_digest_verify_common entry 55839 pid18225 pkcs11_softtoken_extra.so.1 soft_rsa_verify_recover entry 55840 pid18225 pkcs11_softtoken_extra.so.1 rsa_pri_to_asn1 entry 55841 pid18225 pkcs11_softtoken_extra.so.1 asn1_to_rsa_pri entry 55842 pid18225 pkcs11_softtoken_extra.so.1 soft_encrypt_rsa_pkcs_encode entry 55843 pid18225 pkcs11_softtoken_extra.so.1 soft_decrypt_rsa_pkcs_decode entry 55844 pid18225 pkcs11_softtoken_extra.so.1 soft_sign_rsa_pkcs_encode entry 55845 pid18225 pkcs11_softtoken_extra.so.1 soft_verify_rsa_pkcs_decode entry 55770 profile tick-1sec

Read the article

ANTS CLR and Memory Profiler In Depth Review (Part 1 of 2 – CLR Profiler)

- by ToStringTheory

One of the things that people might not know about me, is my obsession to make my code as efficient as possible. Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind… In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve. One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well. In this review, I am going to cover some of the features of the ANTS profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program. I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction The ANTS Profiler pack provided by Red Gate was something that I had not heard of before receiving an email regarding an offer to review it for a license. Since I look to make my code efficient, it was a no brainer for me to try it out! One thing that I have to say took me by surprise is that upon downloading the program and installing it you fill out a form for your usual contact information. Sure enough within 2 hours, I received an email from a sales representative at Red Gate asking if she could help me to achieve the most out of my trial time so it wouldn’t go to waste. After replying to her and explaining that I was looking to review its feature set, she put me in contact with someone that setup a demo session to give me a quick rundown of its features via an online meeting. After having dealt with a massive ordeal with one of my utility companies and their complete lack of customer service, Red Gates friendly and helpful representatives were a breath of fresh air, and something I was thankful for. ANTS CLR Profiler The ANTS CLR profiler is the thing I want to focus on the most in this post, so I am going to dive right in now. Install was simple and took no time at all. It installed both the profiler for the CLR and Memory, but also visual studio extensions to facilitate the usage of the profilers (click any images for full size images): The Visual Studio menu options (under ANTS menu) Starting the CLR Performance Profiler from the start menu yields this window If you follow the instructions after launching the program from the start menu (Click File > New Profiling Session to start a new project), you are given a dialog with plenty of options for profiling: The New Session dialog. Lots of options. One thing I noticed is that the buttons in the lower right were half-covered by the panel of the application. If I had to guess, I would imagine that this is caused by my DPI settings being set to 125%. This is a problem I have seen in other applications as well that don’t scale well to different dpi scales. The profiler options give you the ability to profile: .NET Executable ASP.NET web application (hosted in IIS) ASP.NET web application (hosted in IIS express) ASP.NET web application (hosted in Cassini Web Development Server) SharePoint web application (hosted in IIS) Silverlight 4+ application Windows Service COM+ server XBAP (local XAML browser application) Attach to an already running .NET 4 process Choosing each option provides a varying set of other variables/options that one can set including options such as application arguments, operating path, record I/O performance performance counters to record (43 counters in all!), etc… All in all, they give you the ability to profile many different .Net project types, and make it simple to do so. In most cases of my using this application, I would be using the built in Visual Studio extensions, as they automatically start a new profiling project in ANTS with the options setup, and start your program, however RedGate has made it easy enough to profile outside of Visual Studio as well. On the flip side of this, as someone who lives most of their work life in Visual Studio, one thing I do wish is that instead of opening an entirely separate application/gui to perform profiling after launching, that instead they would provide a Visual Studio panel with the information, and integrate more of the profiling project information into Visual Studio. So, now that we have an idea of what options that the profiler gives us, its time to test its abilities and features. Horrendous Example Code – Prime Number Generator One of my interests besides development, is Physics and Math – what I went to college for. I have especially always been interested in prime numbers, as they are something of a mystery… So, I decided that I would go ahead and to test the abilities of the profiler, I would write a small program, website, and library to generate prime numbers in the quantity that you ask for. I am going to start off with some terrible code, and show how I would see the profiler being used as a development tool. First off, the IPrimes interface (all code is downloadable at the end of the post): interface IPrimes { IEnumerable<int> GetPrimes(int retrieve); } Simple enough, right? Anything that implements the interface will (hopefully) provide an IEnumerable of int, with the quantity specified in the parameter argument. Next, I am going to implement this interface in the most basic way: public class DumbPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _analyzing = 4; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; //start dividing at 2 //divide until number is reached, or determined not prime for (int i = 2; i < _analyzing && isPrime; i++) { //if (i) goes into _analyzing without a remainder, //_analyzing is NOT prime if (_analyzing % i == 0) isPrime = false; } //if it is prime, add to found list if (isPrime) _foundPrimes.Add(_analyzing); //increment number to analyze next _analyzing++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } This is the simplest way to get primes in my opinion. Checking each number by the straight definition of a prime – is it divisible by anything besides 1 and itself. I have included this code in a base class library for my solution, as I am going to use it to demonstrate a couple of features of ANTS. This class library is consumed by a simple non-MVVM WPF application, and a simple MVC4 website. I will not post the WPF code here inline, as it is simply an ObservableCollection<int>, a label, two textbox’s, and a button. Starting a new Profiling Session So, in Visual Studio, I have just completed my first stint developing the GUI and DumbPrimes IPrimes class, so now I want to check my codes efficiency by profiling it. All I have to do is build the solution (surprised initiating a profiling session doesn’t do this, but I suppose I can understand it), and then click the ANTS menu, followed by Profile Performance. I am then greeted by the profiler starting up and already monitoring my program live: You are provided with a realtime graph at the top, and a pane at the bottom giving you information on how to proceed. I am going to start by asking my program to show me the first 15000 primes: After the program finally began responding again (I did all the work on the main UI thread – how bad!), I stopped the profiler, which did kill the process of my program too. One important thing to note, is that the profiler by default wants to give you a lot of detail about the operation – line hit counts, time per line, percent time per line, etc… The important thing to remember is that this itself takes a lot of time. When running my program without the profiler attached, it can generate the 15000 primes in 5.18 seconds, compared to 74.5 seconds – almost a 1500 percent increase. While this may seem like a lot, remember that there is a trade off. It may be WAY more inefficient, however, I am able to drill down and make improvements to specific problem areas, and then decrease execution time all around. Analyzing the Profiling Session After clicking ‘Stop Profiling’, the process running my application stopped, and the entire execution time was automatically selected by ANTS, and the results shown below: Now there are a number of interesting things going on here, I am going to cover each in a section of its own: Real Time Performance Counter Bar (top of screen) At the top of the screen, is the real time performance bar. As your application is running, this will constantly update with the currently selected performance counters status. A couple of cool things to note are the fact that you can drag a selection around specific time periods to drill down the detail views in the lower 2 panels to information pertaining to only that period. After selecting a time period, you can bookmark a section and name it, so that it is easy to find later, or after reloaded at a later time. You can also zoom in, out, or fit the graph to the space provided – useful for drilling down. It may be hard to see, but at the top of the processor time graph below the time ticks, but above the red usage graph, there is a green bar. This bar shows at what times a method that is selected in the ‘Call tree’ panel is called. Very cool to be able to click on a method and see at what times it made an impact. As I said before, ANTS provides 43 different performance counters you can hook into. Click the arrow next to the Performance tab at the top will allow you to change between different counters if you have them selected: Method Call Tree, ADO.Net Database Calls, File IO – Detail Panel Red Gate really hit the mark here I think. When you select a section of the run with the graph, the call tree populates to fill a hierarchical tree of method calls, with information regarding each of the methods. By default, methods are hidden where the source is not provided (framework type code), however, Red Gate has integrated Reflector into ANTS, so even if you don’t have source for something, you can select a method and get the source if you want. Methods are also hidden where the impact is seen as insignificant – methods that are only executed for 1% of the time of the overall calling methods time; in other words, working on making them better is not where your efforts should be focused. – Smart! Source Panel – Detail Panel The source panel is where you can see line level information on your code, showing the code for the currently selected method from the Method Call Tree. If the code is not available, Reflector takes care of it and shows the code anyways! As you can notice, there does seem to be a problem with how ANTS determines what line is the actual line that a call is completed on. I have suspicions that this may be due to some of the inline code optimizations that the CLR applies upon compilation of the assembly. In a method with comments, the problem is much more severe: As you can see here, apparently the most offending code in my base library was a comment – *gasp*! Removing the comments does help quite a bit, however I hope that Red Gate works on their counter algorithm soon to improve the logic on positioning for statistics: I did a small test just to demonstrate the lines are correct without comments. For me, it isn’t a deal breaker, as I can usually determine the correct placements by looking at the application code in the region and determining what makes sense, but it is something that would probably build up some irritation with time. Feature – Suggest Method for Optimization A neat feature to really help those in need of a pointer, is the menu option under tools to automatically suggest methods to optimize/improve: Nice feature – clicking it filters the call tree and stars methods that it thinks are good candidates for optimization. I do wish that they would have made it more visible for those of use who aren’t great on sight: Process Integration I do think that this could have a place in my process. After experimenting with the profiler, I do think it would be a great benefit to do some development, testing, and then after all the bugs are worked out, use the profiler to check on things to make sure nothing seems like it is hogging more than its fair share. For example, with this program, I would have developed it, ran it, tested it – it works, but slowly. After looking at the profiler, and seeing the massive amount of time spent in 1 method, I might go ahead and try to re-implement IPrimes (I actually would probably rewrite the offending code, but so that I can distribute both sets of code easily, I’m just going to make another implementation of IPrimes). Using two pieces of knowledge about prime numbers can make this method MUCH more efficient – prime numbers fall into two buckets 6k+/-1 , and a number is prime if it is not divisible by any other primes before it: public class SmartPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _k = 1; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; int potentialPrime; //analyze 6k-1 //assign the value to potential potentialPrime = 6 * _k - 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); if (_foundPrimes.Count() == retrieve) break; //analyze 6k+1 //assign the value to potential potentialPrime = 6 * _k + 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); //increment k to analyze next _k++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } Now there are definitely more things I can do to help make this more efficient, but for the scope of this example, I think this is fine (but still hideous)! Profiling this now yields a happy surprise 27 seconds to generate the 15000 primes with the profiler attached, and only 1.43 seconds without. One important thing I wanted to call out though was the performance graph now: Notice anything odd? The %Processor time is above 100%. This is because there is now more than 1 core in the operation. A better label for the chart in my mind would have been %Core time, but to each their own. Another odd thing I noticed was that the profiler seemed to be spot on this time in my DumbPrimes class with line details in source, even with comments.. Odd. Profiling Web Applications The last thing that I wanted to cover, that means a lot to me as a web developer, is the great amount of work that Red Gate put into the profiler when profiling web applications. In my solution, I have a simple MVC4 application setup with 1 page, a single input form, that will output prime values as my WPF app did. Launching the profiler from Visual Studio as before, nothing is really different in the profiler window, however I did receive a UAC prompt for a Red Gate helper app to integrate with the web server without notification. After requesting 500, 1000, 2000, and 5000 primes, and looking at the profiler session, things are slightly different from before: As you can see, there are 4 spikes of activity in the processor time graph, but there is also something new in the call tree: That’s right – ANTS will actually group method calls by get/post operations, so it is easier to find out what action/page is giving the largest problems… Pretty cool in my mind! Overview Overall, I think that Red Gate ANTS CLR Profiler has a lot to offer, however I think it also has a long ways to go. 3 Biggest Pros: Ability to easily drill down from time graph, to method calls, to source code Wide variety of counters to choose from when profiling your application Excellent integration/grouping of methods being called from web applications by request – BRILLIANT! 3 Biggest Cons: Issue regarding line details in source view Nit pick – Processor time vs. Core time Nit pick – Lack of full integration with Visual Studio Ratings Ease of Use (7/10) – I marked down here because of the problems with the line level details and the extra work that that entails, and the lack of better integration with Visual Studio. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do. Especially with its large variety of performance counters, a definite plus! Features (9/10) – Besides the real time performance monitoring, and the drill downs that I’ve shown here, ANTS also has great integration with ADO.Net, with the ability to show database queries run by your application in the profiler. This, with the line level details, the web request grouping, reflector integration, and various options to customize your profiling session I think create a great set of features! Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good. their people are friendly, helpful, and happy! UI / UX (8/10) – The interface is very easy to get around, and all of the options are easy to find. With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (8/10) – Overall, I am happy with the Performance Profiler and its features, as well as with the service I received when working with the Red Gate personnel. I WOULD recommend you trying the application and seeing if it would fit into your process, BUT, remember there are still some kinks in it to hopefully be worked out. My next post will definitely be shorter (hopefully), but thank you for reading up to here, or skipping ahead! Please, if you do try the product, drop me a message and let me know what you think! I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

Read the article

Using Stub Objects

- by user9154181

Having told the long and winding tale of where stub objects came from and how we use them to build Solaris, I'd like to focus now on the the nuts and bolts of building and using them. The following new features were added to the Solaris link-editor (ld) to support the production and use of stub objects: -z stub This new command line option informs ld that it is to build a stub object rather than a normal object. In this mode, it accepts the same command line arguments as usual, but will quietly ignore any objects and sharable object dependencies. STUB_OBJECT Mapfile Directive In order to build a stub version of an object, its mapfile must specify the STUB_OBJECT directive. When producing a non-stub object, the presence of STUB_OBJECT causes the link-editor to perform extra validation to ensure that the stub and non-stub objects will be compatible. ASSERT Mapfile Directive All data symbols exported from the object must have an ASSERT symbol directive in the mapfile that declares them as data and supplies the size, binding, bss attributes, and symbol aliasing details. When building the stub objects, the information in these ASSERT directives is used to create the data symbols. When building the real object, these ASSERT directives will ensure that the real object matches the linking interface presented by the stub. Although ASSERT was added to the link-editor in order to support stub objects, they are a general purpose feature that can be used independently of stub objects. For instance you might choose to use an ASSERT directive if you have a symbol that must have a specific address in order for the object to operate properly and you want to automatically ensure that this will always be the case. The material presented here is derived from a document I originally wrote during the development effort, which had the dual goals of providing supplemental materials for the stub object PSARC case, and as a set of edits that were eventually applied to the Oracle Solaris Linker and Libraries Manual (LLM). The Solaris 11 LLM contains this information in a more polished form. Stub Objects A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be used at runtime. However, an application can be built against a stub object, where the stub object provides the real object name to be used at runtime, and then use the real object at runtime. When building a stub object, the link-editor ignores any object or library files specified on the command line, and these files need not exist in order to build a stub. Since the compilation step can be omitted, and because the link-editor has relatively little work to do, stub objects can be built very quickly. Stub objects can be used to solve a variety of build problems: Speed Modern machines, using a version of make with the ability to parallelize operations, are capable of compiling and linking many objects simultaneously, and doing so offers significant speedups. However, it is typical that a given object will depend on other objects, and that there will be a core set of objects that nearly everything else depends on. It is necessary to impose an ordering that builds each object before any other object that requires it. This ordering creates bottlenecks that reduce the amount of parallelization that is possible and limits the overall speed at which the code can be built. Complexity/Correctness In a large body of code, there can be a large number of dependencies between the various objects. The makefiles or other build descriptions for these objects can become very complex and difficult to understand or maintain. The dependencies can change as the system evolves. This can cause a given set of makefiles to become slightly incorrect over time, leading to race conditions and mysterious rare build failures. Dependency Cycles It might be desirable to organize code as cooperating shared objects, each of which draw on the resources provided by the other. Such cycles cannot be supported in an environment where objects must be built before the objects that use them, even though the runtime linker is fully capable of loading and using such objects if they could be built. Stub shared objects offer an alternative method for building code that sidesteps the above issues. Stub objects can be quickly built for all the shared objects produced by the build. Then, all the real shared objects and executables can be built in parallel, in any order, using the stub objects to stand in for the real objects at link-time. Afterwards, the executables and real shared objects are kept, and the stub shared objects are discarded. Stub objects are built from a mapfile, which must satisfy the following requirements. The mapfile must specify the STUB_OBJECT directive. This directive informs the link-editor that the object can be built as a stub object, and as such causes the link-editor to perform validation and sanity checking intended to guarantee that an object and its stub will always provide identical linking interfaces. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data exported from the object must have an ASSERT symbol attribute in the mapfile to specify the symbol type, size, and bss attributes. In the case where there are multiple symbols that reference the same data, the ASSERT for one of these symbols must specify the TYPE and SIZE attributes, while the others must use the ALIAS attribute to reference this primary symbol. Given such a mapfile, the stub and real versions of the shared object can be built using the same command line for each, adding the '-z stub' option to the link for the stub object, and omiting the option from the link for the real object. To demonstrate these ideas, the following code implements a shared object named idx5, which exports data from a 5 element array of integers, with each element initialized to contain its zero-based array index. This data is available as a global array, via an alternative alias data symbol with weak binding, and via a functional interface. % cat idx5.c int _idx5[5] = { 0, 1, 2, 3, 4 }; #pragma weak idx5 = _idx5 int idx5_func(int index) { if ((index 4)) return (-1); return (_idx5[index]); } A mapfile is required to describe the interface provided by this shared object. % cat mapfile $mapfile_version 2 STUB_OBJECT; SYMBOL_SCOPE { _idx5 { ASSERT { TYPE=data; SIZE=4[5] }; }; idx5 { ASSERT { BINDING=weak; ALIAS=_idx5 }; }; idx5_func; local: *; }; The following main program is used to print all the index values available from the idx5 shared object. % cat main.c #include <stdio.h> extern int _idx5[5], idx5[5], idx5_func(int); int main(int argc, char **argv) { int i; for (i = 0; i The following commands create a stub version of this shared object in a subdirectory named stublib. elfdump is used to verify that the resulting object is a stub. The command used to build the stub differs from that of the real object only in the addition of the -z stub option, and the use of a different output file name. This demonstrates the ease with which stub generation can be added to an existing makefile. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o stublib/libidx5.so.1 -zstub % ln -s libidx5.so.1 stublib/libidx5.so % elfdump -d stublib/libidx5.so | grep STUB [11] FLAGS_1 0x4000000 [ STUB ] The main program can now be built, using the stub object to stand in for the real shared object, and setting a runpath that will find the real object at runtime. However, as we have not yet built the real object, this program cannot yet be run. Attempts to cause the system to load the stub object are rejected, as the runtime linker knows that stub objects lack the actual code and data found in the real object, and cannot execute. % cc main.c -L stublib -R '$ORIGIN/lib' -lidx5 -lc % ./a.out ld.so.1: a.out: fatal: libidx5.so.1: open failed: No such file or directory Killed % LD_PRELOAD=stublib/libidx5.so.1 ./a.out ld.so.1: a.out: fatal: stublib/libidx5.so.1: stub shared object cannot be used at runtime Killed We build the real object using the same command as we used to build the stub, omitting the -z stub option, and writing the results to a different file. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o lib/libidx5.so.1 Once the real object has been built in the lib subdirectory, the program can be run. % ./a.out [0] 0 0 0 [1] 1 1 1 [2] 2 2 2 [3] 3 3 3 [4] 4 4 4 Mapfile Changes The version 2 mapfile syntax was extended in a number of places to accommodate stub objects. Conditional Input The version 2 mapfile syntax has the ability conditionalize mapfile input using the $if control directive. As you might imagine, these directives are used frequently with ASSERT directives for data, because a given data symbol will frequently have a different size in 32 or 64-bit code, or on differing hardware such as x86 versus sparc. The link-editor maintains an internal table of names that can be used in the logical expressions evaluated by $if and $elif. At startup, this table is initialized with items that describe the class of object (_ELF32 or _ELF64) and the type of the target machine (_sparc or _x86). We found that there were a small number of cases in the Solaris code base in which we needed to know what kind of object we were producing, so we added the following new predefined items in order to address that need: NameMeaning ...... _ET_DYNshared object _ET_EXECexecutable object _ET_RELrelocatable object ...... STUB_OBJECT Directive The new STUB_OBJECT directive informs the link-editor that the object described by the mapfile can be built as a stub object. STUB_OBJECT; A stub shared object is built entirely from the information in the mapfiles supplied on the command line. When the -z stub option is specified to build a stub object, the presence of the STUB_OBJECT directive in a mapfile is required, and the link-editor uses the information in symbol ASSERT attributes to create global symbols that match those of the real object. When the real object is built, the presence of STUB_OBJECT causes the link-editor to verify that the mapfiles accurately describe the real object interface, and that a stub object built from them will provide the same linking interface as the real object it represents. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data in the object is required to have an ASSERT attribute that specifies the symbol type and size. If the ASSERT BIND attribute is not present, the link-editor provides a default assertion that the symbol must be GLOBAL. If the ASSERT SH_ATTR attribute is not present, or does not specify that the section is one of BITS or NOBITS, the link-editor provides a default assertion that the associated section is BITS. All data symbols that describe the same address and size are required to have ASSERT ALIAS attributes specified in the mapfile. If aliased symbols are discovered that do not have an ASSERT ALIAS specified, the link fails and no object is produced. These rules ensure that the mapfiles contain a description of the real shared object's linking interface that is sufficient to produce a stub object with a completely compatible linking interface. SYMBOL_SCOPE/SYMBOL_VERSION ASSERT Attribute The SYMBOL_SCOPE and SYMBOL_VERSION mapfile directives were extended with a symbol attribute named ASSERT. The syntax for the ASSERT attribute is as follows: ASSERT { ALIAS = symbol_name; BINDING = symbol_binding; TYPE = symbol_type; SH_ATTR = section_attributes; SIZE = size_value; SIZE = size_value[count]; }; The ASSERT attribute is used to specify the expected characteristics of the symbol. The link-editor compares the symbol characteristics that result from the link to those given by ASSERT attributes. If the real and asserted attributes do not agree, a fatal error is issued and the output object is not created. In normal use, the link editor evaluates the ASSERT attribute when present, but does not require them, or provide default values for them. The presence of the STUB_OBJECT directive in a mapfile alters the interpretation of ASSERT to require them under some circumstances, and to supply default assertions if explicit ones are not present. See the definition of the STUB_OBJECT Directive for the details. When the -z stub command line option is specified to build a stub object, the information provided by ASSERT attributes is used to define the attributes of the global symbols provided by the object. ASSERT accepts the following: ALIAS Name of a previously defined symbol that this symbol is an alias for. An alias symbol has the same type, value, and size as the main symbol. The ALIAS attribute is mutually exclusive to the TYPE, SIZE, and SH_ATTR attributes, and cannot be used with them. When ALIAS is specified, the type, size, and section attributes are obtained from the alias symbol. BIND Specifies an ELF symbol binding, which can be any of the STB_ constants defined in <sys/elf.h>, with the STB_ prefix removed (e.g. GLOBAL, WEAK). TYPE Specifies an ELF symbol type, which can be any of the STT_ constants defined in <sys/elf.h>, with the STT_ prefix removed (e.g. OBJECT, COMMON, FUNC). In addition, for compatibility with other mapfile usage, FUNCTION and DATA can be specified, for STT_FUNC and STT_OBJECT, respectively. TYPE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SH_ATTR Specifies attributes of the section associated with the symbol. The section_attributes that can be specified are given in the following table: Section AttributeMeaning BITSSection is not of type SHT_NOBITS NOBITSSection is of type SHT_NOBITS SH_ATTR is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SIZE Specifies the expected symbol size. SIZE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. The syntax for the size_value argument is as described in the discussion of the SIZE attribute below. SIZE The SIZE symbol attribute existed before support for stub objects was introduced. It is used to set the size attribute of a given symbol. This attribute results in the creation of a symbol definition. Prior to the introduction of the ASSERT SIZE attribute, the value of a SIZE attribute was always numeric. While attempting to apply ASSERT SIZE to the objects in the Solaris ON consolidation, I found that many data symbols have a size based on the natural machine wordsize for the class of object being produced. Variables declared as long, or as a pointer, will be 4 bytes in size in a 32-bit object, and 8 bytes in a 64-bit object. Initially, I employed the conditional $if directive to handle these cases as follows: $if _ELF32 foo { ASSERT { TYPE=data; SIZE=4 } }; bar { ASSERT { TYPE=data; SIZE=20 } }; $elif _ELF64 foo { ASSERT { TYPE=data; SIZE=8 } }; bar { ASSERT { TYPE=data; SIZE=40 } }; $else $error UNKNOWN ELFCLASS $endif I found that the situation occurs frequently enough that this is cumbersome. To simplify this case, I introduced the idea of the addrsize symbolic name, and of a repeat count, which together make it simple to specify machine word scalar or array symbols. Both the SIZE, and ASSERT SIZE attributes support this syntax: The size_value argument can be a numeric value, or it can be the symbolic name addrsize. addrsize represents the size of a machine word capable of holding a memory address. The link-editor substitutes the value 4 for addrsize when building 32-bit objects, and the value 8 when building 64-bit objects. addrsize is useful for representing the size of pointer variables and C variables of type long, as it automatically adjusts for 32 and 64-bit objects without requiring the use of conditional input. The size_value argument can be optionally suffixed with a count value, enclosed in square brackets. If count is present, size_value and count are multiplied together to obtain the final size value. Using this feature, the example above can be written more naturally as: foo { ASSERT { TYPE=data; SIZE=addrsize } }; bar { ASSERT { TYPE=data; SIZE=addrsize[5] } }; Exported Global Data Is Still A Bad Idea As you can see, the additional plumbing added to the Solaris link-editor to support stub objects is minimal. Furthermore, about 90% of that plumbing is dedicated to handling global data. We have long advised against global data exported from shared objects. There are many ways in which global data does not fit well with dynamic linking. Stub objects simply provide one more reason to avoid this practice. It is always better to export all data via a functional interface. You should always hide your data, and make it available to your users via a function that they can call to acquire the address of the data item. However, If you do have to support global data for a stub, perhaps because you are working with an already existing object, it is still easilily done, as shown above. Oracle does not like us to discuss hypothetical new features that don't exist in shipping product, so I'll end this section with a speculation. It might be possible to do more in this area to ease the difficulty of dealing with objects that have global data that the users of the library don't need. Perhaps someday... Conclusions It is easy to create stub objects for most objects. If your library only exports function symbols, all you have to do to build a faithful stub object is to add STUB_OBJECT; and then to use the same link command you're currently using, with the addition of the -z stub option. Happy Stubbing!

Read the article

Sniffing out SQL Code Smells: Inconsistent use of Symbolic names and Datatypes

- by Phil Factor

It is an awkward feeling. You’ve just delivered a database application that seems to be working fine in production, and you just run a few checks on it. You discover that there is a potential bug that, out of sheer good chance, hasn’t kicked in to produce an error; but it lurks, like a smoking bomb. Worse, maybe you find that the bug has started its evil work of corrupting the data, but in ways that nobody has, so far detected. You investigate, and find the damage. You are somehow going to have to repair it. Yes, it still very occasionally happens to me. It is not a nice feeling, and I do anything I can to prevent it happening. That’s why I’m interested in SQL code smells. SQL Code Smells aren’t necessarily bad practices, but just show you where to focus your attention when checking an application. Sometimes with databases the bugs can be subtle. SQL is rather like HTML: the language does its best to try to carry out your wishes, rather than to be picky about your bugs. Most of the time, this is a great benefit, but not always. One particular place where this can be detrimental is where you have implicit conversion between different data types. Most of the time it is completely harmless but we’re concerned about the occasional time it isn’t. Let’s give an example: String truncation. Let’s give another even more frightening one, rounding errors on assignment to a number of different precision. Each requires a blog-post to explain in detail and I’m not now going to try. Just remember that it is not always a good idea to assign data to variables, parameters or even columns when they aren’t the same datatype, especially if you are relying on implicit conversion to work its magic.For details of the problem and the consequences, see here: SR0014: Data loss might occur when casting from {Type1} to {Type2} . For any experienced Database Developer, this is a more frightening read than a Vampire Story. This is why one of the SQL Code Smells that makes me edgy, in my own or other peoples’ code, is to see parameters, variables and columns that have the same names and different datatypes. Whereas quite a lot of this is perfectly normal and natural, you need to check in case one of two things have gone wrong. Either sloppy naming, or mixed datatypes. Sure it is hard to remember whether you decided that the length of a log entry was 80 or 100 characters long, or the precision of a number. That is why a little check like this I’m going to show you is excellent for tidying up your code before you check it back into source Control! 1/ Checking Parameters only If you were just going to check parameters, you might just do this. It simply groups all the parameters, either input or output, of all the routines (e.g. stored procedures or functions) by their name and checks to see, in the HAVING clause, whether their data types are all the same. If not, it lists all the examples and their origin (the routine) Even this little check can occasionally be scarily revealing. ;WITH userParameter AS ( SELECT c.NAME AS ParameterName, OBJECT_SCHEMA_NAME(c.object_ID) + '.' + OBJECT_NAME(c.object_ID) AS ObjectName, t.name + ' ' + CASE --we may have to put in the length WHEN t.name IN ('char', 'varchar', 'nchar', 'nvarchar') THEN '(' + CASE WHEN c.max_length = -1 THEN 'MAX' ELSE CONVERT(VARCHAR(4), CASE WHEN t.name IN ('nchar', 'nvarchar') THEN c.max_length / 2 ELSE c.max_length END) END + ')' WHEN t.name IN ('decimal', 'numeric') THEN '(' + CONVERT(VARCHAR(4), c.precision) + ',' + CONVERT(VARCHAR(4), c.Scale) + ')' ELSE '' END --we've done with putting in the length + CASE WHEN XML_collection_ID <> 0 THEN --deal with object schema names '(' + CASE WHEN is_XML_Document = 1 THEN 'DOCUMENT ' ELSE 'CONTENT ' END + COALESCE( (SELECT QUOTENAME(ss.name) + '.' + QUOTENAME(sc.name) FROM sys.xml_schema_collections sc INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID WHERE sc.xml_collection_ID = c.XML_collection_ID),'NULL') + ')' ELSE '' END AS [DataType] FROM sys.parameters c INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys' AND parameter_id>0)SELECT CONVERT(CHAR(80),objectName+'.'+ParameterName),DataType FROM UserParameterWHERE ParameterName IN (SELECT ParameterName FROM UserParameter GROUP BY ParameterName HAVING MIN(Datatype)<>MAX(DataType))ORDER BY ParameterName so, in a very small example here, we have a @ClosingDelimiter variable that is only CHAR(1) when, by the looks of it, it should be up to ten characters long, or even worse, a function that should be a char(1) and seems to let in a string of ten characters. Worth investigating. Then we have a @Comment variable that can't decide whether it is a VARCHAR(2000) or a VARCHAR(MAX) 2/ Columns and Parameters Actually, once we’ve cleared up the mess we’ve made of our parameter-naming in the database we’re inspecting, we’re going to be more interested in listing both columns and parameters. We can do this by modifying the routine to list columns as well as parameters. Because of the slight complexity of creating the string version of the datatypes, we will create a fake table of both columns and parameters so that they can both be processed the same way. After all, we want the datatypes to match Unfortunately, parameters do not expose all the attributes we are interested in, such as whether they are nullable (oh yes, subtle bugs happen if this isn’t consistent for a datatype). We’ll have to leave them out for this check. Voila! A slight modification of the first routine ;WITH userObject AS ( SELECT Name AS DataName,--the actual name of the parameter or column ('@' removed) --and the qualified object name of the routine OBJECT_SCHEMA_NAME(ObjectID) + '.' + OBJECT_NAME(ObjectID) AS ObjectName, --now the harder bit: the definition of the datatype. TypeName + ' ' + CASE --we may have to put in the length. e.g. CHAR (10) WHEN TypeName IN ('char', 'varchar', 'nchar', 'nvarchar') THEN '(' + CASE WHEN MaxLength = -1 THEN 'MAX' ELSE CONVERT(VARCHAR(4), CASE WHEN TypeName IN ('nchar', 'nvarchar') THEN MaxLength / 2 ELSE MaxLength END) END + ')' WHEN TypeName IN ('decimal', 'numeric')--a BCD number! THEN '(' + CONVERT(VARCHAR(4), Precision) + ',' + CONVERT(VARCHAR(4), Scale) + ')' ELSE '' END --we've done with putting in the length + CASE WHEN XML_collection_ID <> 0 --tush tush. XML THEN --deal with object schema names '(' + CASE WHEN is_XML_Document = 1 THEN 'DOCUMENT ' ELSE 'CONTENT ' END + COALESCE( (SELECT TOP 1 QUOTENAME(ss.name) + '.' + QUOTENAME(sc.Name) FROM sys.xml_schema_collections sc INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID WHERE sc.xml_collection_ID = XML_collection_ID),'NULL') + ')' ELSE '' END AS [DataType], DataObjectType FROM (Select t.name AS TypeName, REPLACE(c.name,'@','') AS Name, c.max_length AS MaxLength, c.precision AS [Precision], c.scale AS [Scale], c.[Object_id] AS ObjectID, XML_collection_ID, is_XML_Document,'P' AS DataobjectType FROM sys.parameters c INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID AND parameter_id>0 UNION all Select t.name AS TypeName, c.name AS Name, c.max_length AS MaxLength, c.precision AS [Precision], c.scale AS [Scale], c.[Object_id] AS ObjectID, XML_collection_ID,is_XML_Document, 'C' AS DataobjectType FROM sys.columns c INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys' )f)SELECT CONVERT(CHAR(80),objectName+'.' + CASE WHEN DataobjectType ='P' THEN '@' ELSE '' END + DataName),DataType FROM UserObjectWHERE DataName IN (SELECT DataName FROM UserObject GROUP BY DataName HAVING MIN(Datatype)<>MAX(DataType))ORDER BY DataName Hmm. I can tell you I found quite a few minor issues with the various tabases I tested this on, and found some potential bugs that really leap out at you from the results. Here is the start of the result for AdventureWorks. Yes, AccountNumber is, for some reason, a Varchar(10) in the Customer table. Hmm. odd. Why is a city fifty characters long in that view? The idea of the description of a colour being 256 characters long seems over-ambitious. Go down the list and you'll spot other mistakes. There are no bugs, but just mess. We started out with a listing to examine parameters, then we mixed parameters and columns. Our last listing is for a slightly more in-depth look at table columns. You’ll notice that we’ve delibarately removed the indication of whether a column is persisted, or is an identity column because that gives us false positives for our code smells. If you just want to browse your metadata for other reasons (and it can quite help in some circumstances) then uncomment them! ;WITH userColumns AS ( SELECT c.NAME AS columnName, OBJECT_SCHEMA_NAME(c.object_ID) + '.' + OBJECT_NAME(c.object_ID) AS ObjectName, REPLACE(t.name + ' ' + CASE WHEN is_computed = 1 THEN ' AS ' + --do DDL for a computed column (SELECT definition FROM sys.computed_columns cc WHERE cc.object_id = c.object_id AND cc.column_ID = c.column_ID) --we may have to put in the length WHEN t.Name IN ('char', 'varchar', 'nchar', 'nvarchar') THEN '(' + CASE WHEN c.Max_Length = -1 THEN 'MAX' ELSE CONVERT(VARCHAR(4), CASE WHEN t.Name IN ('nchar', 'nvarchar') THEN c.Max_Length / 2 ELSE c.Max_Length END) END + ')' WHEN t.name IN ('decimal', 'numeric') THEN '(' + CONVERT(VARCHAR(4), c.precision) + ',' + CONVERT(VARCHAR(4), c.Scale) + ')' ELSE '' END + CASE WHEN c.is_rowguidcol = 1 THEN ' ROWGUIDCOL' ELSE '' END + CASE WHEN XML_collection_ID <> 0 THEN --deal with object schema names '(' + CASE WHEN is_XML_Document = 1 THEN 'DOCUMENT ' ELSE 'CONTENT ' END + COALESCE((SELECT QUOTENAME(ss.name) + '.' + QUOTENAME(sc.name) FROM sys.xml_schema_collections sc INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID WHERE sc.xml_collection_ID = c.XML_collection_ID), 'NULL') + ')' ELSE '' END + CASE WHEN is_identity = 1 THEN CASE WHEN OBJECTPROPERTY(object_id, 'IsUserTable') = 1 AND COLUMNPROPERTY(object_id, c.name, 'IsIDNotForRepl') = 0 AND OBJECTPROPERTY(object_id, 'IsMSShipped') = 0 THEN '' ELSE ' NOT FOR REPLICATION ' END ELSE '' END + CASE WHEN c.is_nullable = 0 THEN ' NOT NULL' ELSE ' NULL' END + CASE WHEN c.default_object_id <> 0 THEN ' DEFAULT ' + object_Definition(c.default_object_id) ELSE '' END + CASE WHEN c.collation_name IS NULL THEN '' WHEN c.collation_name <> (SELECT collation_name FROM sys.databases WHERE name = DB_NAME()) COLLATE Latin1_General_CI_AS THEN COALESCE(' COLLATE ' + c.collation_name, '') ELSE '' END,' ',' ') AS [DataType]FROM sys.columns c INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys')SELECT CONVERT(CHAR(80),objectName+'.'+columnName),DataType FROM UserColumnsWHERE columnName IN (SELECT columnName FROM UserColumns GROUP BY columnName HAVING MIN(Datatype)<>MAX(DataType))ORDER BY columnName If you take a look down the results against Adventureworks, you'll see once again that there are things to investigate, mostly, in the illustration, discrepancies between null and non-null datatypes So I here you ask, what about temporary variables within routines? If ever there was a source of elusive bugs, you'll find it there. Sadly, these temporary variables are not stored in the metadata so we'll have to find a more subtle way of flushing these out, and that will, I'm afraid, have to wait!

Read the article

How to display a JSON error message?

- by Tiny Giant Studios

I'm currently developing a tumblr theme and have built a jQuery JSON thingamabob that uses the Tumblr API to do the following: The user would click on the "post type" link (e.g. Video Posts), at which stage jQuery would use JSON to grab all the posts that's related to that type and then dynamically display them in a designated area. Now everything works absolutely peachy, except that with Tumblr being Tumblr and their servers taking a knock every now and then, the Tumblr API thingy is sometimes offline. Now I can't foresee when this function will be down, which is why I want to display some generic error message if JSON (for whatever reason) was unable to load the post. You'll see I've already written some code to show an error message when jQuery can't find any posts related to that post type BUT it doesn't cover any server errors. Note: I sometimes get this error: Failed to load resource: the server responded with a status of 503 (Service Temporarily Unavailable) It is for this 503 Error message that I need to write some code, but I'm slightly clueless :) Here's the jQuery JSON code: $('ul.right li').find('a').click(function() { var postType = this.className; var count = 0; byCategory(postType); return false; function byCategory(postType, callback) { $.getJSON('{URL}/api/read/json?type=' + postType + '&callback=?', function(data) { var article = []; $.each(data.posts, function(i, item) { // i = index // item = data for a particular post switch(item.type) { case 'photo': article[i] = '<div class="post_wrap"><div class="photo" style="padding-bottom:5px;">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/XSTldh6ds/photo_icon.png" alt="type_icon"/></a>' + '<a href="' + item.url + '" title="{Title}"><img src="' + item['photo-url-500'] + '"alt="image" /></a></div></div>'; count = 1; break; case 'video': article[i] = '<div class="post_wrap"><div class="video" style="padding-bottom:5px;">' + '<a href="' + item.url + '" title="{Title}" class="type_icon">' + '<img src="http://static.tumblr.com/ewjv7ap/nuSldhclv/video_icon.png" alt="type_icon"/></a>' + '<span style="margin: auto;">' + item['video-player'] + '</span>' + '</div></div>'; count = 1; break; case 'audio': if (use_IE == true) { article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/R50ldh5uj/audio_icon.png" alt="type_icon"/></a>' + '<h3><a href="' + item.url + '">' + item['id3-artist'] +' - ' + item['id3-title'] + '</a></h3>' + '</div></div>'; } else { article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/R50ldh5uj/audio_icon.png" alt="type_icon"/></a>' + '<h3><a href="' + item.url + '">' + item['id3-artist'] +' - ' + item['id3-title'] + '</a></h3><div class="player">' + item['audio-player'] + '</div>' + '</div></div>'; }; count = 1; break; case 'regular': article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/dwxldhck1/regular_icon.png" alt="type_icon"/></a><h3><a href="' + item.url + '">' + item['regular-title'] + '</a></h3><div class="description_container">' + item['regular-body'] + '</div></div></div>'; count = 1; break; case 'quote': article[i] = '<div class="post_wrap"><div class="quote">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/loEldhcpr/quote_icon.png" alt="type_icon"/></a><blockquote><h3><a href="' + item.url + '" title="{Title}">' + item['quote-text'] + '</a></h3></blockquote><cite>- ' + item['quote-source'] + '</cite></div></div>'; count = 1; break; case 'conversation': article[i] = '<div class="post_wrap"><div class="chat">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/MVuldhcth/conversation_icon.png" alt="type_icon"/></a><h3><a href="' + item.url + '">' + item['conversation-title'] + '</a></h3></div></div>'; count = 1; break; case 'link': article[i] = '<div class="post_wrap"><div class="link">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/EQGldhc30/link_icon.png" alt="type_icon"/></a><h3><a href="' + item['link-url'] + '" target="_blank">' + item['link-text'] + '</a></h3></div></div>'; count = 1; break; default: alert('No Entries Found.'); }; }) // end each if (!(count == 0)) { $('#content_right') .hide('fast') .html('<div class="first_div"><span class="left_corner"></span><span class="right_corner"></span><h2>Displaying ' + postType + ' Posts Only</h2></div>' + article.join('')) .slideDown('fast') } else { $('#content_right') .hide('fast') .html('<div class="first_div"><span class="left_corner"></span><span class="right_corner"></span><h2>Hmmm, currently there are no ' + postType + ' posts to display</h2></div>') .slideDown('fast') } // end getJSON }); // end byCategory } }); If you'd like to see the demo in action, check out Elegantem but do note that everything might work absolutely fine for you (or not), depending on Tumblr's temperament.

Read the article

XSL Template outputting massive chunk of text, rather than HTML. But only on one section

- by Throlkim

I'm having a slightly odd situation with an XSL template. Most of it outputs fine, but a certain for-each loop is causing me problems. Here's the XML: <area> <feature type="Hall"> <Heading><![CDATA[Hall]]></Heading> <Para><![CDATA[Communal gardens, pathway leading to PVCu double glazed communal front door to]]></Para> </feature> <feature type="Entrance Hall"> <Heading><![CDATA[Communal Entrance Hall]]></Heading> <Para><![CDATA[Plain ceiling, centre light fitting, fire door through to inner hallway, wood and glazed panelled front door to]]></Para> </feature> <feature type="Inner Hall"> <Heading><![CDATA[Inner Hall]]></Heading> <Para><![CDATA[Plain ceiling with pendant light fitting and covings, security telephone, airing cupboard housing gas boiler serving domestic hot water and central heating, telephone point, storage cupboard housing gas and electric meters, wooden panelled doors off to all rooms.]]></Para> </feature> <feature type="Lounge (Reception)" width="3.05" length="4.57" units="metre"> <Heading><![CDATA[Lounge (Reception)]]></Heading> <Para><![CDATA[15' 6" x 10' 7" (4.72m x 3.23m) Window to the side and rear elevation, papered ceiling with pendant light fitting and covings, two double panelled radiators, power points, wall mounted security entry phone, TV aerial point.]]></Para> </feature> <feature type="Kitchen" width="3.05" length="3.66" units="metre"> <Heading><![CDATA[Kitchen]]></Heading> <Para><![CDATA[12' x 10' (3.66m x 3.05m) Double glazed window to the rear elevation, textured ceiling with strip lighting, range of base and wall units in Beech with brushed aluminium handles, co-ordinated working surfaces with inset stainless steel sink with mixer taps over, co-ordinated tiled splashbacks, gas and electric cooker points, large storage cupboard with shelving, power points.]]></Para> </feature> <feature type="Entrance Porch"> <Heading><![CDATA[Balcony]]></Heading> <Para><![CDATA[Views across the communal South facing garden, wrought iron balustrade.]]></Para> </feature> <feature type="Bedroom" width="3.35" length="3.96" units="metre"> <Heading><![CDATA[Bedroom One]]></Heading> <Para><![CDATA[13' 6" x 11' 5" (4.11m x 3.48m) Double glazed windows to the front and side elevations, papered ceiling with pendant light fittings and covings, single panelled radiator, power points, telephone point, security entry phone.]]></Para> </feature> <feature type="Bedroom" width="3.05" length="3.35" units="metre"> <Heading><![CDATA[Bedroom Two]]></Heading> <Para><![CDATA[11' 4" x 10' 1" (3.45m x 3.07m) Double glazed window to the front elevation, plain ceiling with centre light fitting and covings, power points.]]></Para> </feature> <feature type="bathroom"> <Heading><![CDATA[Bathroom]]></Heading> <Para><![CDATA[Obscure double glazed window to the rear elevation, textured ceiling with centre light fitting and extractor fan, suite in white comprising of low level WC, wall mounted wash hand basin and walk in shower housing 'Triton T80' electric shower, co-ordinated tiled splashbacks.]]></Para> </feature> </area> And here's the section of my template that processes it: <xsl:for-each select="area"> <li> <xsl:for-each select="feature"> <li> <h5> <xsl:value-of select="Heading"/> </h5> <xsl:value-of select="Para"/> </li> </xsl:for-each> </li> </xsl:for-each> And here's the output: Hall Communal gardens, pathway leading to PVCu double glazed communal front door to Communal Entrance Hall Plain ceiling, centre light fitting, fire door through to inner hallway, wood and glazed panelled front door to Inner Hall Plain ceiling with pendant light fitting and covings, security telephone, airing cupboard housing gas boiler serving domestic hot water and central heating, telephone point, storage cupboard housing gas and electric meters, wooden panelled doors off to all rooms. Lounge (Reception) 15' 6" x 10' 7" (4.72m x 3.23m) Window to the side and rear elevation, papered ceiling with pendant light fitting and covings, two double panelled radiators, power points, wall mounted security entry phone, TV aerial point. Kitchen 12' x 10' (3.66m x 3.05m) Double glazed window to the rear elevation, textured ceiling with strip lighting, range of base and wall units in Beech with brushed aluminium handles, co-ordinated working surfaces with inset stainless steel sink with mixer taps over, co-ordinated tiled splashbacks, gas and electric cooker points, large storage cupboard with shelving, power points. Balcony Views across the communal South facing garden, wrought iron balustrade. Bedroom One 13' 6" x 11' 5" (4.11m x 3.48m) Double glazed windows to the front and side elevations, papered ceiling with pendant light fittings and covings, single panelled radiator, power points, telephone point, security entry phone. Bedroom Two 11' 4" x 10' 1" (3.45m x 3.07m) Double glazed window to the front elevation, plain ceiling with centre light fitting and covings, power points. Bathroom Obscure double glazed window to the rear elevation, textured ceiling with centre light fitting and extractor fan, suite in white comprising of low level WC, wall mounted wash hand basin and walk in shower housing 'Triton T80' electric shower, co-ordinated tiled splashbacks. For reference, here's the entire XSLT: http://pastie.org/private/eq4gjvqoc1amg9ynyf6wzg The rest of it all outputs fine - what am I missing from the above section?

Read the article

Failure with LogonUser in MC++

- by Alikar

After fighting with this for a week I have not really gotten anywhere in why it constantly fails in my code, but not in other examples. My code, which while it compiles, will not log into a user that I know has the correct login information. Where it fails is the following line: wi = gcnew WindowsIdentity(token); It fails here because the token is zero, meaning that it was never set to a user token. Here is my full code: #ifndef UNCAPI_H #define UNCAPI_H #include <windows.h> #pragma once using namespace System; using namespace System::Runtime::InteropServices; using namespace System::Security::Principal; using namespace System::Security::Permissions; namespace UNCAPI { public ref class UNCAccess { public: //bool Logon(String ^_srUsername, String ^_srDomain, String ^_srPassword); [PermissionSetAttribute(SecurityAction::Demand, Name = "FullTrust")] bool Logon(String ^_srUsername, String ^_srDomain, String ^_srPassword) { bool bSuccess = false; token = IntPtr(0); bSuccess = LogonUser(_srUsername, _srDomain, _srPassword, 8, 0, &tokenHandle); if(bSuccess) { wi = gcnew WindowsIdentity(token); wic = wi->Impersonate(); } return bSuccess; } void UNCAccess::Logoff() { if (wic != nullptr ) { wic->Undo(); } CloseHandle((int*)token.ToPointer()); } private: [DllImport("advapi32.dll", SetLastError=true)]//[DllImport("advapi32.DLL", EntryPoint="LogonUserW", SetLastError=true, CharSet=CharSet::Unicode, ExactSpelling=true, CallingConvention=CallingConvention::StdCall)] bool static LogonUser(String ^lpszUsername, String ^lpszDomain, String ^lpszPassword, int dwLogonType, int dwLogonProvider, IntPtr *phToken); [DllImport("KERNEL32.DLL", EntryPoint="CloseHandle", SetLastError=true, CharSet=CharSet::Unicode, ExactSpelling=true, CallingConvention=CallingConvention::StdCall)] bool static CloseHandle(int *handle); IntPtr token; WindowsIdentity ^wi; WindowsImpersonationContext ^wic; };// End of Class UNCAccess }// End of Name Space #endif UNCAPI_H Now using this slightly modified example from Microsoft I was able to get a login and a token: #using <mscorlib.dll> #using <System.dll> using namespace System; using namespace System::Runtime::InteropServices; using namespace System::Security::Principal; using namespace System::Security::Permissions; [assembly:SecurityPermissionAttribute(SecurityAction::RequestMinimum, UnmanagedCode=true)] [assembly:PermissionSetAttribute(SecurityAction::RequestMinimum, Name = "FullTrust")]; [DllImport("advapi32.dll", SetLastError=true)] bool LogonUser(String^ lpszUsername, String^ lpszDomain, String^ lpszPassword, int dwLogonType, int dwLogonProvider, IntPtr* phToken); [DllImport("kernel32.dll", CharSet=System::Runtime::InteropServices::CharSet::Auto)] int FormatMessage(int dwFlags, IntPtr* lpSource, int dwMessageId, int dwLanguageId, String^ lpBuffer, int nSize, IntPtr *Arguments); [DllImport("kernel32.dll", CharSet=CharSet::Auto)] bool CloseHandle(IntPtr handle); [DllImport("advapi32.dll", CharSet=CharSet::Auto, SetLastError=true)] bool DuplicateToken(IntPtr ExistingTokenHandle, int SECURITY_IMPERSONATION_LEVEL, IntPtr* DuplicateTokenHandle); // GetErrorMessage formats and returns an error message // corresponding to the input errorCode. String^ GetErrorMessage(int errorCode) { int FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100; int FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200; int FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000; //int errorCode = 0x5; //ERROR_ACCESS_DENIED //throw new System.ComponentModel.Win32Exception(errorCode); int messageSize = 255; String^ lpMsgBuf = ""; int dwFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS; IntPtr ptrlpSource = IntPtr::Zero; IntPtr prtArguments = IntPtr::Zero; int retVal = FormatMessage(dwFlags, &ptrlpSource, errorCode, 0, lpMsgBuf, messageSize, &prtArguments); if (0 == retVal) { throw gcnew Exception(String::Format( "Failed to format message for error code {0}. ", errorCode)); } return lpMsgBuf; } // Test harness. // If you incorporate this code into a DLL, be sure to demand FullTrust. [PermissionSetAttribute(SecurityAction::Demand, Name = "FullTrust")] int main() { IntPtr tokenHandle = IntPtr(0); IntPtr dupeTokenHandle = IntPtr(0); try { String^ userName; String^ domainName; // Get the user token for the specified user, domain, and password using the // unmanaged LogonUser method. // The local machine name can be used for the domain name to impersonate a user on this machine. Console::Write("Enter the name of the domain on which to log on: "); domainName = Console::ReadLine(); Console::Write("Enter the login of a user on {0} that you wish to impersonate: ", domainName); userName = Console::ReadLine(); Console::Write("Enter the password for {0}: ", userName); const int LOGON32_PROVIDER_DEFAULT = 0; //This parameter causes LogonUser to create a primary token. const int LOGON32_LOGON_INTERACTIVE = 2; const int SecurityImpersonation = 2; tokenHandle = IntPtr::Zero; dupeTokenHandle = IntPtr::Zero; // Call LogonUser to obtain a handle to an access token. bool returnValue = LogonUser(userName, domainName, Console::ReadLine(), LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, &tokenHandle); Console::WriteLine("LogonUser called."); if (false == returnValue) { int ret = Marshal::GetLastWin32Error(); Console::WriteLine("LogonUser failed with error code : {0}", ret); Console::WriteLine("\nError: [{0}] {1}\n", ret, GetErrorMessage(ret)); int errorCode = 0x5; //ERROR_ACCESS_DENIED throw gcnew System::ComponentModel::Win32Exception(errorCode); } Console::WriteLine("Did LogonUser Succeed? {0}", (returnValue?"Yes":"No")); Console::WriteLine("Value of Windows NT token: {0}", tokenHandle); // Check the identity. Console::WriteLine("Before impersonation: {0}", WindowsIdentity::GetCurrent()->Name); bool retVal = DuplicateToken(tokenHandle, SecurityImpersonation, &dupeTokenHandle); if (false == retVal) { CloseHandle(tokenHandle); Console::WriteLine("Exception thrown in trying to duplicate token."); return -1; } // The token that is passed to the following constructor must // be a primary token in order to use it for impersonation. WindowsIdentity^ newId = gcnew WindowsIdentity(dupeTokenHandle); WindowsImpersonationContext^ impersonatedUser = newId->Impersonate(); // Check the identity. Console::WriteLine("After impersonation: {0}", WindowsIdentity::GetCurrent()->Name); // Stop impersonating the user. impersonatedUser->Undo(); // Check the identity. Console::WriteLine("After Undo: {0}", WindowsIdentity::GetCurrent()->Name); // Free the tokens. if (tokenHandle != IntPtr::Zero) CloseHandle(tokenHandle); if (dupeTokenHandle != IntPtr::Zero) CloseHandle(dupeTokenHandle); } catch(Exception^ ex) { Console::WriteLine("Exception occurred. {0}", ex->Message); } Console::ReadLine(); }// end of function Why should Microsoft's code succeed, where mine fails?

Read the article

rotating bitmaps. In code.

- by Marco van de Voort

Is there a faster way to rotate a large bitmap by 90 or 270 degrees than simply doing a nested loop with inverted coordinates? The bitmaps are 8bpp and typically 2048*2400*8bpp Currently I do this by simply copying with argument inversion, roughly (pseudo code: for x = 0 to 2048-1 for y = 0 to 2048-1 dest[x][y]=src[y][x]; (In reality I do it with pointers, for a bit more speed, but that is roughly the same magnitude) GDI is quite slow with large images, and GPU load/store times for textures (GF7 cards) are in the same magnitude as the current CPU time. Any tips, pointers? An in-place algorithm would even be better, but speed is more important than being in-place. Target is Delphi, but it is more an algorithmic question. SSE(2) vectorization no problem, it is a big enough problem for me to code it in assembler Duplicates How do you rotate a two dimensional array?. Follow up to Nils' answer Image 2048x2700 - 2700x2048 Compiler Turbo Explorer 2006 with optimization on. Windows: Power scheme set to "Always on". (important!!!!) Machine: Core2 6600 (2.4 GHz) time with old routine: 32ms (step 1) time with stepsize 8 : 12ms time with stepsize 16 : 10ms time with stepsize 32+ : 9ms Meanwhile I also tested on a Athlon 64 X2 (5200+ iirc), and the speed up there was slightly more than a factor four (80 to 19 ms). The speed up is well worth it, thanks. Maybe that during the summer months I'll torture myself with a SSE(2) version. However I already thought about how to tackle that, and I think I'll run out of SSE2 registers for an straight implementation: for n:=0 to 7 do begin load r0, <source+n*rowsize> shift byte from r0 into r1 shift byte from r0 into r2 .. shift byte from r0 into r8 end; store r1, <target> store r2, <target+1*<rowsize> .. store r8, <target+7*<rowsize> So 8x8 needs 9 registers, but 32-bits SSE only has 8. Anyway that is something for the summer months :-) Note that the pointer thing is something that I do out of instinct, but it could be there is actually something to it, if your dimensions are not hardcoded, the compiler can't turn the mul into a shift. While muls an sich are cheap nowadays, they also generate more register pressure afaik. The code (validated by subtracting result from the "naieve" rotate1 implementation): const stepsize = 32; procedure rotatealign(Source: tbw8image; Target:tbw8image); var stepsx,stepsy,restx,resty : Integer; RowPitchSource, RowPitchTarget : Integer; pSource, pTarget,ps1,ps2 : pchar; x,y,i,j: integer; rpstep : integer; begin RowPitchSource := source.RowPitch; // bytes to jump to next line. Can be negative (includes alignment) RowPitchTarget := target.RowPitch; rpstep:=RowPitchTarget*stepsize; stepsx:=source.ImageWidth div stepsize; stepsy:=source.ImageHeight div stepsize; // check if mod 16=0 here for both dimensions, if so -> SSE2. for y := 0 to stepsy - 1 do begin psource:=source.GetImagePointer(0,y*stepsize); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(target.imagewidth-(y+1)*stepsize,0); for x := 0 to stepsx - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; // 3 more areas to do, with dimensions // - stepsy*stepsize * restx // right most column of restx width // - stepsx*stepsize * resty // bottom row with resty height // - restx*resty // bottom-right rectangle. restx:=source.ImageWidth mod stepsize; // typically zero because width is // typically 1024 or 2048 resty:=source.Imageheight mod stepsize; if restx>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(source.ImageWidth-restx,0); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(Target.imagewidth-stepsize,Target.imageheight-restx); for y := 0 to stepsy - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize*RowPitchSource); dec(ptarget,stepsize); end; end; if resty>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(0,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,0); for x := 0 to stepsx - 1 do begin for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; if (resty>0) and (restx>0) then begin // another loop less, since only one block psource:=source.GetImagePointer(source.ImageWidth-restx,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,target.ImageHeight-restx); for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; end; end;

Read the article

Assignment operator that calls a constructor is broken

- by Delan Azabani

I've implemented some of the changes suggested in this question, and (thanks very much) it works quite well, however... in the process I've seemed to break the post-declaration assignment operator. With the following code: #include <cstdio> #include "ucpp" main() { ustring a = "test"; ustring b = "ing"; ustring c = "- -"; ustring d = "cafe\xcc\x81"; printf("%s\n", (a + b + c[1] + d).encode()); } I get a nice "testing cafe´" message. However, if I modify the code slightly so that the const char * conversion is done separately, post-declaration: #include <cstdio> #include "ucpp" main() { ustring a = "test"; ustring b = "ing"; ustring c = "- -"; ustring d; d = "cafe\xcc\x81"; printf("%s\n", (a + b + c[1] + d).encode()); } the ustring named d becomes blank, and all that is output is "testing ". My new code has three constructors, one void (which is probably the one being incorrectly used, and is used in the operator+ function), one that takes a const ustring &, and one that takes a const char *. The following is my new library code: #include <cstdlib> #include <cstring> class ustring { int * values; long len; public: long length() { return len; } ustring() { len = 0; values = (int *) malloc(0); } ustring(const ustring &input) { len = input.len; values = (int *) malloc(sizeof(int) * len); for (long i = 0; i < len; i++) values[i] = input.values[i]; } ustring operator=(ustring input) { ustring result(input); return result; } ustring(const char * input) { values = (int *) malloc(0); long s = 0; // s = number of parsed chars int a, b, c, d, contNeed = 0, cont = 0; for (long i = 0; input[i]; i++) if (input[i] < 0x80) { // ASCII, direct copy (00-7f) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = input[i]; } else if (input[i] < 0xc0) { // this is a continuation (80-bf) if (cont == contNeed) { // no need for continuation, use U+fffd values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } cont = cont + 1; values[s - 1] = values[s - 1] | ((input[i] & 0x3f) << ((contNeed - cont) * 6)); if (cont == contNeed) cont = contNeed = 0; } else if (input[i] < 0xc2) { // invalid byte, use U+fffd (c0-c1) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } else if (input[i] < 0xe0) { // start of 2-byte sequence (c2-df) contNeed = 1; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x1f) << 6; } else if (input[i] < 0xf0) { // start of 3-byte sequence (e0-ef) contNeed = 2; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x0f) << 12; } else if (input[i] < 0xf5) { // start of 4-byte sequence (f0-f4) contNeed = 3; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x07) << 18; } else { // restricted or invalid (f5-ff) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } len = s; } ustring operator=(const char * input) { ustring result(input); return result; } ustring operator+(ustring input) { ustring result; result.len = len + input.len; result.values = (int *) malloc(sizeof(int) * result.len); for (long i = 0; i < len; i++) result.values[i] = values[i]; for (long i = 0; i < input.len; i++) result.values[i + len] = input.values[i]; return result; } ustring operator[](long index) { ustring result; result.len = 1; result.values = (int *) malloc(sizeof(int)); result.values[0] = values[index]; return result; } char * encode() { char * r = (char *) malloc(0); long s = 0; for (long i = 0; i < len; i++) { if (values[i] < 0x80) r = (char *) realloc(r, s + 1), r[s + 0] = char(values[i]), s += 1; else if (values[i] < 0x800) r = (char *) realloc(r, s + 2), r[s + 0] = char(values[i] >> 6 | 0x60), r[s + 1] = char(values[i] & 0x3f | 0x80), s += 2; else if (values[i] < 0x10000) r = (char *) realloc(r, s + 3), r[s + 0] = char(values[i] >> 12 | 0xe0), r[s + 1] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 2] = char(values[i] & 0x3f | 0x80), s += 3; else r = (char *) realloc(r, s + 4), r[s + 0] = char(values[i] >> 18 | 0xf0), r[s + 1] = char(values[i] >> 12 & 0x3f | 0x80), r[s + 2] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 3] = char(values[i] & 0x3f | 0x80), s += 4; } return r; } };

Read the article

Flash and Google Maps - Only Last Icon showing

- by Peter

I have a simple Map and geocoding sample in Flash using CS4 The problem is simple - I can retrieve a short list from the google search api, but when I try to generate the icons on the map using a loop, only the last icon is displayed. (ignore the house icon, it is generated earlier) I feel I am missing something or made a stupid AS3 mistake (like treating it as if it was c#) - or even a stupid wood-for-the-trees mistake. The problem is in the last line of the code. I have added all my code just in case somebody else can find a use for it - lord knows it took me a great while to figure this out :) It runs here (also, if anybody has an idea why the icon is slightly in the wrong place on render, but corrects if you move the map - please let me know) Any help would be great. Thanks. P import com.google.maps.services.ClientGeocoder; import com.google.maps.services.GeocodingEvent; import com.google.maps.LatLng; import com.google.maps.Map; import com.google.maps.MapEvent; import com.google.maps.MapType; import com.google.maps.overlays.Marker; import com.google.maps.overlays.MarkerOptions; import com.google.maps.styles.FillStyle; import com.google.maps.styles.StrokeStyle; import com.google.maps.controls.* import com.google.maps.overlays.* import flash.display.Bitmap; import flash.display.BitmapData; import com.adobe.utils.StringUtil; import be.boulevart.google.ajaxapi.search.GoogleSearchResult; import be.boulevart.google.events.GoogleApiEvent; import be.boulevart.google.ajaxapi.search.local.GoogleLocalSearch; import be.boulevart.google.ajaxapi.search.local.data.GoogleLocalSearchItem; var strZip:String = new String(); strZip="60661"; var strAddress:String = new String(); strAddress ="100 W. Jackson Blvd, chicago, IL 60661"; var IconArray:Array = new Array; var SearchArray:Array = new Array; /*-------------------------------------------------------------- // The returned search data gets placed into this array ---------------------------------------------------------------*/ var LocalInfo:Array = new Array(); var intCount:int = new int; var intMapReady:int=0; /*=================================================================================== We load the map first and then get the search criteria - this will keep the order of operation clean. The ====================================================================================*/ var map:Map = new Map(); map.key = "ABQIAAAAHwSPp7Lhew456ffD6qa2WmxT_VwdLJEfmcCgytxKjcH1jLKkiihQtfC- TbcwryvBQYhRwHWa8F_Gp9Q"; map.setSize(new Point(600, 550)); map.addEventListener(MapEvent.MAP_READY, onMapReady); //Places the map on the page this.addChild(map); map.x=5; map.y=5; function onMapReady(event:Event):void { //Center the map and place the house marker doGeocode(); } /*========================================================================== Goecode to return the LAT and LONG for the specific address, center the map and add the house icon ===========================================================================*/ function doGeocode() { var geocoder:ClientGeocoder = new ClientGeocoder(); geocoder.addEventListener(GeocodingEvent.GEOCODING_SUCCESS, function(event:GeocodingEvent):void { var objPlacemarks:Array = event.response.placemarks; if (objPlacemarks.length > 0) { map.setCenter(objPlacemarks[0].point, 14, MapType.NORMAL_MAP_TYPE); var request:URLRequest = new URLRequest("house.png"); var imageLoader:Loader = new Loader(); imageLoader.load(request); var objMarkerOptions:MarkerOptions = new MarkerOptions(); objMarkerOptions.icon=imageLoader; objMarkerOptions.icon.scaleX=.15; objMarkerOptions.icon.scaleY=.15; objMarkerOptions.iconAlignment = MarkerOptions.ALIGN_HORIZONTAL_CENTER + MarkerOptions.ALIGN_VERTICAL_CENTER; var objMarker:Marker = new Marker(objPlacemarks[0].point, objMarkerOptions); map.addOverlay(objMarker); doLoadSearch() } }); //Failure code - good practice, really geocoder.addEventListener(GeocodingEvent.GEOCODING_FAILURE, function(event:GeocodingEvent):void { txtResult.appendText("Geocoding failed"); }); // generate geocode geocoder.geocode(strAddress); } /*=============================================================== XML Loader - loads icon file and search text pair from xml file =================================================================*/ function doLoadSearch() { var xmlLoader:URLLoader = new URLLoader(); var xmlData:XML = new XML(); xmlLoader.addEventListener(Event.COMPLETE, LoadXML); xmlLoader.load(new URLRequest("config.xml")); function LoadXML(e:Event):void { xmlData = new XML(e.target.data); RetrieveSearch(); } function RetrieveSearch() { //extract the MapData subset var xmlSearch = xmlData.MapData; // push this to an xml list object var xmlChildren:XMLList = xmlSearch.children(); //loop the list and extract the data into an //array of formatted search criteria for each (var Search:XML in xmlChildren) { txtResult.appendText("Searching For: "+Search.Criteria+" Icon=" + Search.Icon+ "Zip=" + strZip +"\r\n\r\n"); //retrieve search criteria loadLocalInfo(Search.Criteria,Search.Icon,strZip); } } } /*================================================================================== Search Functionality - does a google API search and loads the lats and longs required to place the icons on the map - THIS WILL NOT RUN LOCALLY ===================================================================================*/ function loadLocalInfo(strSearch,strIcon,strZip) { var objLocal:GoogleLocalSearch=new GoogleLocalSearch() objLocal.search(strSearch+" "+strZip,0,"0,0","","") objLocal.addEventListener(GoogleApiEvent.LOCAL_SEARCH_RESULT,onSearchComplete) function onSearchComplete(e:GoogleApiEvent):void { var resulta:GoogleSearchResult=e.data as GoogleSearchResult; //------------------------------------------------ // Load the icon for this particular search //------------------------------------------------ var request:URLRequest = new URLRequest(strIcon); var imageLoader:Loader = new Loader(); imageLoader.load(request); //------------------------------------------------------------- // For test purposes txtResult.appendText("Result Count for "+strSearch+" = "+e.data.results.length+"\r\n\r\n"); for each (var result:GoogleLocalSearchItem in e.data.results as Array) { LocalInfo[intCount]=[String(result.title),strIcon,String(result.latitude),String(result.longitude)]; //--------------------------------------- // Pop the icon onto the map //--------------------------------------- var objLatLng:LatLng = new LatLng(parseFloat(result.latitude), parseFloat(result.longitude)); var objMarkerOptions:MarkerOptions = new MarkerOptions(); objMarkerOptions.icon=imageLoader; objMarkerOptions.hasShadow=false; objMarkerOptions.iconAlignment = MarkerOptions.ALIGN_HORIZONTAL_CENTER + MarkerOptions.ALIGN_VERTICAL_CENTER; var objMarker:Marker = new Marker(objLatLng, objMarkerOptions); /********************************************************** *Everything* works to here - I have traced out execution and all variables. It only works on the last item in the array :( ***********************************************************/ map.addOverlay(objMarker); } } }

Read the article

posting multiple radio button values to mysql using "foreach"

- by jeansymolanza

i have adjusted my code slightly but i am still having difficulty posting it to the table. could someone please provide me with an example of the foreach array? form page <div style="padding: 15px;"> <span class="loginfail" style="font-size:24px; font-weight: bold">Notifications</span><p> <?php include("progress_insertcomment.php"); ?> <?php // Make a MySQL Connection mysql_select_db("speedycm_data") or die(mysql_error()); $query_comment = "select * from tbl_alert order by id desc limit 1"; $comment = mysql_query($query_comment, $speedycms) or die(mysql_error()); $row_comment = mysql_fetch_assoc($comment); $totalRows_comment = mysql_num_rows($comment); ?>  <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <span id="sprytextarea1"> <textarea id='comment' name="comment" style="height: 75px; width:330px;"><?php echo $row_comment['comment']; ?></textarea> </span> <p> <button type="submit">Add</button> <input type="hidden" name="notc" value="1"/> </form>  <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"> <table border="0" cellspacing="2" cellpadding="2"> <?php if ( $row_comment == 0 ) { echo "<span style='font-size: 11px;'>No current alerts.</span>"; } else { // Get all the data from the "example" table $result = mysql_query("SELECT * FROM tbl_alert ORDER BY id DESC") or die(mysql_error()); while($rows=mysql_fetch_array($result)){ ?> <tr> <td> <?php echo "<div class='bubble'><div class='pimped'> <blockquote>" . $rows['comment'] . " </blockquote></div> <cite><strong>" . $rows['user'] . "</strong> @ " . $rows['date'] . "</cite> <span style='font-size: 10px;'> <p> <a href='editalert.php?id=". $rows['id'] ."' class='form' >Edit</a> • <a href='deletealert.php?id=". $rows['id'] ."' class='form'>Delete</a> </span> </div> "; ?> </td> <td valign="top" align="center"><div style="padding-left: 30px;"><span style="font-size: 10px;">Completed?</span> <p class="field switch">  <?php $status = $rows['status']; ?> <input type="radio" name="selstatus" value="no" <?php if($status == 'yes') {echo 'checked';} else {echo '';} ?>/> <input type="radio" name="selstatus" value="yes" <?php if($status == 'yes') {echo 'checked';} else {echo '';} ?>/> <input type="hidden" name="statusid" value="<?php echo $rows['id']; ?>"/> <label for="radio1" class="cb-enable <?php if($status == 'yes') {echo 'selected';} else {echo '';} ?>"><span>Yes</span></label> <label for="radio2" class="cb-disable <?php if($status == 'no') {echo 'selected';} else {echo '';} ?>"><span>No</span></label> </p> </div></td> </tr> <tr> <td></td> <?php } } ?> <td align="center"><div style="padding-left: 30px;"> <button type="submit">Update</button> <input type="hidden" name="notc2" value="1"/> </div></td> </tr> </table> </form> </div> </body> processing <?php // 6) update notifications if (array_key_exists('notc2',$_POST)) { echo "<p style='font-size: 12px;'>Thank you. The notifications have been updated successfully.<p>"; echo "<p><span style='font-size: 12px;'> <a onClick=\"history.go(-1)\" class='form'>Return</a></p> <p></span> "; exit; }; ?> after doing some research i learnt that the only way to insert multiple radio values into the MYSQL table is to use arrays. there was a similar question raised somewhere on this site: http://stackoverflow.com/questions/1656260/php-multiple-radio-buttons that recommended using a foreach loop. use a foreach loop <?php foreach ( $_POST as $key => $val ) echo "$key -> $val\n"; ?> $key will be the name of the selected option and $val, well, the value. how would this apply to my situation as i am struggling to find any help on the internet. i understand that i would use this on the processing page to pull out any radio values from the previous page and then loop the INSERT MYSQL code within the process until it was all done. any advice would be appreciated! GOD BLESS.

Read the article

F# - Facebook Hacker Cup - Double Squares

- by Jacob

I'm working on strengthening my F#-fu and decided to tackle the Facebook Hacker Cup Double Squares problem. I'm having some problems with the run-time and was wondering if anyone could help me figure out why it is so much slower than my C# equivalent. There's a good description from another post; Source: Facebook Hacker Cup Qualification Round 2011 A double-square number is an integer X which can be expressed as the sum of two perfect squares. For example, 10 is a double-square because 10 = 3^2 + 1^2. Given X, how can we determine the number of ways in which it can be written as the sum of two squares? For example, 10 can only be written as 3^2 + 1^2 (we don't count 1^2 + 3^2 as being different). On the other hand, 25 can be written as 5^2 + 0^2 or as 4^2 + 3^2. You need to solve this problem for 0 = X = 2,147,483,647. Examples: 10 = 1 25 = 2 3 = 0 0 = 1 1 = 1 My basic strategy (which I'm open to critique on) is to; Create a dictionary (for memoize) of the input numbers initialzed to 0 Get the largest number (LN) and pass it to count/memo function Get the LN square root as int Calculate squares for all numbers 0 to LN and store in dict Sum squares for non repeat combinations of numbers from 0 to LN If sum is in memo dict, add 1 to memo Finally, output the counts of the original numbers. Here is the F# code (See code changes at bottom) I've written that I believe corresponds to this strategy (Runtime: ~8:10); open System open System.Collections.Generic open System.IO /// Get a sequence of values let rec range min max = seq { for num in [min .. max] do yield num } /// Get a sequence starting from 0 and going to max let rec zeroRange max = range 0 max /// Find the maximum number in a list with a starting accumulator (acc) let rec maxNum acc = function | [] -> acc | p::tail when p > acc -> maxNum p tail | p::tail -> maxNum acc tail /// A helper for finding max that sets the accumulator to 0 let rec findMax nums = maxNum 0 nums /// Build a collection of combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) let rec combos range = seq { let count = ref 0 for inner in range do for outer in Seq.skip !count range do yield (inner, outer) count := !count + 1 } let rec squares nums = let dict = new Dictionary<int, int>() for s in nums do dict.[s] <- (s * s) dict /// Counts the number of possible double squares for a given number and keeps track of other counts that are provided in the memo dict. let rec countDoubleSquares (num: int) (memo: Dictionary<int, int>) = // The highest relevent square is the square root because it squared plus 0 squared is the top most possibility let maxSquare = System.Math.Sqrt((float)num) // Our relevant squares are 0 to the highest possible square; note the cast to int which shouldn't hurt. let relSquares = range 0 ((int)maxSquare) // calculate the squares up front; let calcSquares = squares relSquares // Build up our square combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) for (sq1, sq2) in combos relSquares do let v = calcSquares.[sq1] + calcSquares.[sq2] // Memoize our relevant results if memo.ContainsKey(v) then memo.[v] <- memo.[v] + 1 // return our count for the num passed in memo.[num] // Read our numbers from file. //let lines = File.ReadAllLines("test2.txt") //let nums = [ for line in Seq.skip 1 lines -> Int32.Parse(line) ] // Optionally, read them from straight array let nums = [1740798996; 1257431873; 2147483643; 602519112; 858320077; 1048039120; 415485223; 874566596; 1022907856; 65; 421330820; 1041493518; 5; 1328649093; 1941554117; 4225; 2082925; 0; 1; 3] // Initialize our memoize dictionary let memo = new Dictionary<int, int>() for num in nums do memo.[num] <- 0 // Get the largest number in our set, all other numbers will be memoized along the way let maxN = findMax nums // Do the memoize let maxCount = countDoubleSquares maxN memo // Output our results. for num in nums do printfn "%i" memo.[num] // Have a little pause for when we debug let line = Console.Read() And here is my version in C# (Runtime: ~1:40: using System; using System.Collections.Generic; using System.Diagnostics; using System.IO; using System.Linq; using System.Text; namespace FBHack_DoubleSquares { public class TestInput { public int NumCases { get; set; } public List<int> Nums { get; set; } public TestInput() { Nums = new List<int>(); } public int MaxNum() { return Nums.Max(); } } class Program { static void Main(string[] args) { // Read input from file. //TestInput input = ReadTestInput("live.txt"); // As example, load straight. TestInput input = new TestInput { NumCases = 20, Nums = new List<int> { 1740798996, 1257431873, 2147483643, 602519112, 858320077, 1048039120, 415485223, 874566596, 1022907856, 65, 421330820, 1041493518, 5, 1328649093, 1941554117, 4225, 2082925, 0, 1, 3, } }; var maxNum = input.MaxNum(); Dictionary<int, int> memo = new Dictionary<int, int>(); foreach (var num in input.Nums) { if (!memo.ContainsKey(num)) memo.Add(num, 0); } DoMemoize(maxNum, memo); StringBuilder sb = new StringBuilder(); foreach (var num in input.Nums) { //Console.WriteLine(memo[num]); sb.AppendLine(memo[num].ToString()); } Console.Write(sb.ToString()); var blah = Console.Read(); //File.WriteAllText("out.txt", sb.ToString()); } private static int DoMemoize(int num, Dictionary<int, int> memo) { var highSquare = (int)Math.Floor(Math.Sqrt(num)); var squares = CreateSquareLookup(highSquare); var relSquares = squares.Keys.ToList(); Debug.WriteLine("Starting - " + num.ToString()); Debug.WriteLine("RelSquares.Count = {0}", relSquares.Count); int sum = 0; var index = 0; foreach (var square in relSquares) { foreach (var inner in relSquares.Skip(index)) { sum = squares[square] + squares[inner]; if (memo.ContainsKey(sum)) memo[sum]++; } index++; } if (memo.ContainsKey(num)) return memo[num]; return 0; } private static TestInput ReadTestInput(string fileName) { var lines = File.ReadAllLines(fileName); var input = new TestInput(); input.NumCases = int.Parse(lines[0]); foreach (var lin in lines.Skip(1)) { input.Nums.Add(int.Parse(lin)); } return input; } public static Dictionary<int, int> CreateSquareLookup(int maxNum) { var dict = new Dictionary<int, int>(); int square; foreach (var num in Enumerable.Range(0, maxNum)) { square = num * num; dict[num] = square; } return dict; } } } Thanks for taking a look. UPDATE Changing the combos function slightly will result in a pretty big performance boost (from 8 min to 3:45): /// Old and Busted... let rec combosOld range = seq { let rangeCache = Seq.cache range let count = ref 0 for inner in rangeCache do for outer in Seq.skip !count rangeCache do yield (inner, outer) count := !count + 1 } /// The New Hotness... let rec combos maxNum = seq { for i in 0..maxNum do for j in i..maxNum do yield i,j }

Read the article

Capturing and Transforming ASP.NET Output with Response.Filter

- by Rick Strahl

During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT: ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if(IsGZipSupported()) { stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if(AcceptEncoding.Contains("deflate")) { Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "deflate"); } else { Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "gzip"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a> and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a> without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET

Read the article

Custom ASP.NET Routing to an HttpHandler

- by Rick Strahl

As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){ RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}", new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) ); routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}", new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){ string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes): which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies. (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET AJAX HTTP

Read the article

Red Gate Coder interviews: Alex Davies

- by Michael Williamson

Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

Read the article

Silverlight for Windows Embedded tutorial (step 4)

- by Valter Minute

I’m back with my Silverlight for Windows Embedded tutorial. Sorry for the long delay between step 3 and step 4, the MVP summit and some work related issue prevented me from working on the tutorial during the last weeks. In our first, second and third tutorial steps we implemented some very simple applications, just to understand the basic structure of a Silverlight for Windows Embedded application, learn how to handle events and how to operate on images. In this third step our sample application will be slightly more complicated, to introduce two new topics: list boxes and custom control. We will also learn how to create controls at runtime. I choose to explain those topics together and provide a sample a bit more complicated than usual just to start to give the feeling of how a “real” Silverlight for Windows Embedded application is organized. As usual we can start using Expression Blend to define our main page. In this case we will have a listbox and a textblock. Here’s the XAML code: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="ListDemo.Page" Width="640" Height="480" x:Name="ListPage" xmlns:ListDemo="clr-namespace:ListDemo"> <Grid x:Name="LayoutRoot" Background="White"> <ListBox Margin="19,57,19,66" x:Name="FileList" SelectionChanged="Filelist_SelectionChanged"/> <TextBlock Height="35" Margin="19,8,19,0" VerticalAlignment="Top" TextWrapping="Wrap" x:Name="CurrentDir" Text="TextBlock" FontSize="20"/> </Grid> </UserControl> In our listbox we will load a list of directories, starting from the filesystem root (there are no drives in Windows CE, the filesystem has a single root named “\”). When the user clicks on an item inside the list, the corresponding directory path will be displayed in the TextBlock object and the subdirectories of the selected branch will be shown inside the list. As you can see we declared an event handler for the SelectionChanged event of our listbox. We also used a different font size for the TextBlock, to make it more readable. XAML and Expression Blend allow you to customize your UI pretty heavily, experiment with the tools and discover how you can completely change the aspect of your application without changing a single line of code! Inside our ListBox we want to insert the directory presenting a nice icon and their name, just like you are used to see them inside Windows 7 file explorer, for example. To get this we will define a user control. This is a custom object that will behave like “regular” Silverlight for Windows Embedded objects inside our application. First of all we have to define the look of our custom control, named DirectoryItem, using XAML: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" x:Class="ListDemo.DirectoryItem" Width="500" Height="80"> <StackPanel x:Name="LayoutRoot" Orientation="Horizontal"> <Canvas Width="31.6667" Height="45.9583" Margin="10,10,10,10" RenderTransformOrigin="0.5,0.5"> <Canvas.RenderTransform> <TransformGroup> <ScaleTransform/> <SkewTransform/> <RotateTransform Angle="-31.27"/> <TranslateTransform/> </TransformGroup> </Canvas.RenderTransform> <Rectangle Width="31.6667" Height="45.8414" Canvas.Left="0" Canvas.Top="0.116943" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FF7B6802" Offset="0"/> <GradientStop Color="#FFF3D42C" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.569519" Canvas.Top="1.05249" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142632,0.753441" EndPoint="1.01886,0.753441"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142632" CenterY="0.753441" AngleX="19.3127" AngleY="0"/> <RotateTransform CenterX="0.142632" CenterY="0.753441" Angle="-35.3437"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.455627" Canvas.Top="2.28036" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.455627" Canvas.Top="1.34485" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="26.4269" Height="45.8414" Canvas.Left="0.227798" Canvas.Top="0" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3127" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FF7B6802" Offset="0"/> <GradientStop Color="#FFF3D42C" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="1.25301" Height="45.8414" Canvas.Left="1.70862" Canvas.Top="0.116943" Stretch="Fill" Fill="#FFEBFF07"/> </Canvas> <TextBlock Height="80" x:Name="Name" Width="448" TextWrapping="Wrap" VerticalAlignment="Center" FontSize="24" Text="Directory"/> </StackPanel> </UserControl> As you can see, this XAML contains many graphic elements. Those elements are used to design the folder icon. The original drawing has been designed in Expression Design and then exported as XAML. In Silverlight for Windows Embedded you can use vector images. This means that your images will look good even when scaled or rotated. In our DirectoryItem custom control we have a TextBlock named Name, that will be used to display….(suspense)…. the directory name (I’m too lazy to invent fancy names for controls, and using “boring” intuitive names will make code more readable, I hope!). Now that we have some XAML code, we may execute XAML2CPP to generate part of the aplication code for us. We should then add references to our XAML2CPP generated resource file and include in our code and add a reference to the XAML runtime library to our sources file (you can follow the instruction of the first tutorial step to do that), To generate the code used in this tutorial you need XAML2CPP ver 1.0.1.0, that is downloadable here: http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2010/03/08/xaml2cpp-1.0.1.0.aspx We can now create our usual simple Win32 application inside Platform Builder, using the same step described in the first chapter of this tutorial (http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2009/10/01/silverlight-for-embedded-tutorial.aspx). We can declare a class for our main page, deriving it from the template that XAML2CPP generated for us: class ListPage : public TListPage<ListPage> { ... } We will see the ListPage class code in a short time, but before we will see the code of our DirectoryItem user control. This object will be used to populate our list, one item for each directory. To declare a user control things are a bit more complicated (but also in this case XAML2CPP will write most of the “boilerplate” code for use. To interact with a user control you should declare an interface. An interface defines the functions of a user control that can be called inside the application code. Our custom control is currently quite simple and we just need some member functions to store and retrieve a full pathname inside our control. The control will display just the last part of the path inside the control. An interface is declared as a C++ class that has only abstract virtual members. It should also have an UUID associated with it. UUID means Universal Unique IDentifier and it’s a 128 bit number that will identify our interface without the need of specifying its fully qualified name. UUIDs are used to identify COM interfaces and, as we discovered in chapter one, Silverlight for Windows Embedded is based on COM or, at least, provides a COM-like Application Programming Interface (API). Here’s the declaration of the DirectoryItem interface: class __declspec(novtable,uuid("{D38C66E5-2725-4111-B422-D75B32AA8702}")) IDirectoryItem : public IXRCustomUserControl { public: virtual HRESULT SetFullPath(BSTR fullpath) = 0; virtual HRESULT GetFullPath(BSTR* retval) = 0; }; The interface is derived from IXRCustomControl, this will allow us to add our object to a XAML tree. It declares the two functions needed to set and get the full path, but don’t implement them. Implementation will be done inside the control class. The interface only defines the functions of our control class that are accessible from the outside. It’s a sort of “contract” between our control and the applications that will use it. We must support what’s inside the contract and the application code should know nothing else about our own control. To reference our interface we will use the UUID, to make code more readable we can declare a #define in this way: #define IID_IDirectoryItem __uuidof(IDirectoryItem) Silverlight for Windows Embedded objects (like COM objects) use a reference counting mechanism to handle object destruction. Every time you store a pointer to an object you should call its AddRef function and every time you no longer need that pointer you should call Release. The object keeps an internal counter, incremented for each AddRef and decremented on Release. When the counter reaches 0, the object is destroyed. Managing reference counting in our code can be quite complicated and, since we are lazy (I am, at least!), we will use a great feature of Silverlight for Windows Embedded: smart pointers.A smart pointer can be connected to a Silverlight for Windows Embedded object and manages its reference counting. To declare a smart pointer we must use the XRPtr template: typedef XRPtr<IDirectoryItem> IDirectoryItemPtr; Now that we have defined our interface, it’s time to implement our user control class. XAML2CPP has implemented a class for us, and we have only to derive our class from it, defining the main class and interface of our new custom control: class DirectoryItem : public DirectoryItemUserControlRegister<DirectoryItem,IDirectoryItem> { ... } XAML2CPP has generated some code for us to support the user control, we don’t have to mind too much about that code, since it will be generated (or written by hand, if you like) always in the same way, for every user control. But knowing how does this works “under the hood” is still useful to understand the architecture of Silverlight for Windows Embedded. Our base class declaration is a bit more complex than the one we used for a simple page in the previous chapters: template <class A,class B> class DirectoryItemUserControlRegister : public XRCustomUserControlImpl<A,B>,public TDirectoryItem<A,XAML2CPPUserControl> { ... } This class derives from the XAML2CPP generated template class, like the ListPage class, but it uses XAML2CPPUserControl for the implementation of some features. This class shares the same ancestor of XAML2CPPPage (base class for “regular” XAML pages), XAML2CPPBase, implements binding of member variables and event handlers but, instead of loading and creating its own XAML tree, it attaches to an existing one. The XAML tree (and UI) of our custom control is created and loaded by the XRCustomUserControlImpl class. This class is part of the Silverlight for Windows Embedded framework and implements most of the functions needed to build-up a custom control in Silverlight (the guys that developed Silverlight for Windows Embedded seem to care about lazy programmers!). We have just to initialize it, providing our class (DirectoryItem) and interface (IDirectoryItem). Our user control class has also a static member: protected: static HINSTANCE hInstance; This is used to store the HINSTANCE of the modules that contain our user control class. I don’t like this implementation, but I can’t find a better one, so if somebody has good ideas about how to handle the HINSTANCE object, I’ll be happy to hear suggestions! It also implements two static members required by XRCustomUserControlImpl. The first one is used to load the XAML UI of our custom control: static HRESULT GetXamlSource(XRXamlSource* pXamlSource) { pXamlSource->SetResource(hInstance,TEXT("XAML"),IDR_XAML_DirectoryItem); return S_OK; } It initializes a XRXamlSource object, connecting it to the XAML resource that XAML2CPP has included in our resource script. The other method is used to register our custom control, allowing Silverlight for Windows Embedded to create it when it load some XAML or when an application creates a new control at runtime (more about this later): static HRESULT Register() { return XRCustomUserControlImpl<A,B>::Register(__uuidof(B), L"DirectoryItem", L"clr-namespace:DirectoryItemNamespace"); } To register our control we should provide its interface UUID, the name of the corresponding element in the XAML tree and its current namespace (namespaces compatible with Silverlight must use the “clr-namespace” prefix. We may also register additional properties for our objects, allowing them to be loaded and saved inside XAML. In this case we have no permanent properties and the Register method will just register our control. An additional static method is implemented to allow easy registration of our custom control inside our application WinMain function: static HRESULT RegisterUserControl(HINSTANCE hInstance) { DirectoryItemUserControlRegister::hInstance=hInstance; return DirectoryItemUserControlRegister<A,B>::Register(); } Now our control is registered and we will be able to create it using the Silverlight for Windows Embedded runtime functions. But we need to bind our members and event handlers to have them available like we are used to do for other XAML2CPP generated objects. To bind events and members we need to implement the On_Loaded function: virtual HRESULT OnLoaded(__in IXRDependencyObject* pRoot) { HRESULT retcode; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode; return ((A*)this)->Init(pRoot,hInstance,app); } This function will call the XAML2CPPUserControl::Init member that will connect the “root” member with the XAML sub tree that has been created for our control and then calls BindObjects and BindEvents to bind members and events to our code. Now we can go back to our application code (the code that you’ll have to actually write) to see the contents of our DirectoryItem class: class DirectoryItem : public DirectoryItemUserControlRegister<DirectoryItem,IDirectoryItem> { protected: WCHAR fullpath[_MAX_PATH+1]; public: DirectoryItem() { *fullpath=0; } virtual HRESULT SetFullPath(BSTR fullpath) { wcscpy_s(this->fullpath,fullpath); WCHAR* p=fullpath; for(WCHAR*q=wcsstr(p,L"\\");q;p=q+1,q=wcsstr(p,L"\\")) ; Name->SetText(p); return S_OK; } virtual HRESULT GetFullPath(BSTR* retval) { *retval=SysAllocString(fullpath); return S_OK; } }; It’s pretty easy and contains a fullpath member (used to store that path of the directory connected with the user control) and the implementation of the two interface members that can be used to set and retrieve the path. The SetFullPath member parses the full path and displays just the last branch directory name inside the “Name” TextBlock object. As you can see, implementing a user control in Silverlight for Windows Embedded is not too complex and using XAML also for the UI of the control allows us to re-use the same mechanisms that we learnt and used in the previous steps of our tutorial. Now let’s see how the main page is managed by the ListPage class. class ListPage : public TListPage<ListPage> { protected: // current path TCHAR curpath[_MAX_PATH+1]; It has a member named “curpath” that is used to store the current directory. It’s initialized inside the constructor: ListPage() { *curpath=0; } And it’s value is displayed inside the “CurrentDir” TextBlock inside the initialization function: virtual HRESULT Init(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode; if (FAILED(retcode=TListPage<ListPage>::Init(hInstance,app))) return retcode; CurrentDir->SetText(L"\\"); return S_OK; } The FillFileList function is used to enumerate subdirectories of the current dir and add entries for each one inside the list box that fills most of the client area of our main page: HRESULT FillFileList() { HRESULT retcode; IXRItemCollectionPtr items; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode; // retrieves the items contained in the listbox if (FAILED(retcode=FileList->GetItems(&items))) return retcode; // clears the list if (FAILED(retcode=items->Clear())) return retcode; // enumerates files and directory in the current path WCHAR filemask[_MAX_PATH+1]; wcscpy_s(filemask,curpath); wcscat_s(filemask,L"\\*.*"); WIN32_FIND_DATA finddata; HANDLE findhandle; findhandle=FindFirstFile(filemask,&finddata); // the directory is empty? if (findhandle==INVALID_HANDLE_VALUE) return S_OK; do { if (finddata.dwFileAttributes&=FILE_ATTRIBUTE_DIRECTORY) { IXRListBoxItemPtr listboxitem; // add a new item to the listbox if (FAILED(retcode=app->CreateObject(IID_IXRListBoxItem,&listboxitem))) { FindClose(findhandle); return retcode; } if (FAILED(retcode=items->Add(listboxitem,NULL))) { FindClose(findhandle); return retcode; } IDirectoryItemPtr directoryitem; if (FAILED(retcode=app->CreateObject(IID_IDirectoryItem,&directoryitem))) { FindClose(findhandle); return retcode; } WCHAR fullpath[_MAX_PATH+1]; wcscpy_s(fullpath,curpath); wcscat_s(fullpath,L"\\"); wcscat_s(fullpath,finddata.cFileName); if (FAILED(retcode=directoryitem->SetFullPath(fullpath))) { FindClose(findhandle); return retcode; } XAML2CPPXRValue value((IXRDependencyObject*)directoryitem); if (FAILED(retcode=listboxitem->SetContent(&value))) { FindClose(findhandle); return retcode; } } } while (FindNextFile(findhandle,&finddata)); FindClose(findhandle); return S_OK; } This functions retrieve a pointer to the collection of the items contained in the directory listbox. The IXRItemCollection interface is used by listboxes and comboboxes and allow you to clear the list (using Clear(), as our function does at the beginning) and change its contents by adding and removing elements. This function uses the FindFirstFile/FindNextFile functions to enumerate all the objects inside our current directory and for each subdirectory creates a IXRListBoxItem object. You can insert any kind of control inside a list box, you don’t need a IXRListBoxItem, but using it will allow you to handle the selected state of an item, highlighting it inside the list. The function creates a list box item using the CreateObject function of XRApplication. The same function is then used to create an instance of our custom control. The function returns a pointer to the control IDirectoryItem interface and we can use it to store the directory full path inside the object and add it as content of the IXRListBox item object, adding it to the listbox contents. The listbox generates an event (SelectionChanged) each time the user clicks on one of the items contained in the listbox. We implement an event handler for that event and use it to change our current directory and repopulate the listbox. The current directory full path will be displayed in the TextBlock: HRESULT Filelist_SelectionChanged(IXRDependencyObject* source,XRSelectionChangedEventArgs* args) { HRESULT retcode; IXRListBoxItemPtr listboxitem; if (!args->pAddedItem) return S_OK; if (FAILED(retcode=args->pAddedItem->QueryInterface(IID_IXRListBoxItem,(void**)&listboxitem))) return retcode; XRValue content; if (FAILED(retcode=listboxitem->GetContent(&content))) return retcode; if (content.vType!=VTYPE_OBJECT) return E_FAIL; IDirectoryItemPtr directoryitem; if (FAILED(retcode=content.pObjectVal->QueryInterface(IID_IDirectoryItem,(void**)&directoryitem))) return retcode; content.pObjectVal->Release(); content.pObjectVal=NULL; BSTR fullpath=NULL; if (FAILED(retcode=directoryitem->GetFullPath(&fullpath))) return retcode; CurrentDir->SetText(fullpath); wcscpy_s(curpath,fullpath); FillFileList(); SysFreeString(fullpath); return S_OK; } }; The function uses the pAddedItem member of the XRSelectionChangedEventArgs object to retrieve the currently selected item, converts it to a IXRListBoxItem interface using QueryInterface, and then retrives its contents (IDirectoryItem object). Using the GetFullPath method we can get the full path of our selected directory and assing it to the curdir member. A call to FillFileList will update the listbox contents, displaying the list of subdirectories of the selected folder. To build our sample we just need to add code to our WinMain function: int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { if (!XamlRuntimeInitialize()) return -1; HRESULT retcode; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return -1; if (FAILED(retcode=DirectoryItem::RegisterUserControl(hInstance))) return retcode; ListPage page; if (FAILED(page.Init(hInstance,app))) return -1; page.FillFileList(); UINT exitcode; if (FAILED(page.GetVisualHost()->StartDialog(&exitcode))) return -1; return 0; } This code is very similar to the one of the WinMains of our previous samples. The main differences are that we register our custom control (you should do that as soon as you have initialized the XAML runtime) and call FillFileList after the initialization of our ListPage object to load the contents of the root folder of our device inside the listbox. As usual you can download the full sample source code from here: http://cid-9b7b0aefe3514dc5.skydrive.live.com/self.aspx/.Public/ListBoxTest.zip

Read the article

Silverlight Recruiting Application Part 5 - Jobs Module / View

Now we starting getting into a more code-heavy portion of this series, thankfully though this means the groundwork is all set for the most part and after adding the modules we will have a complete application that can be provided with full source. The Jobs module will have two concerns- adding and maintaining jobs that can then be broadcast out to the website. How they are displayed on the site will be handled by our admin system (which will just poll from this common database), so we aren't too concerned with that, but rather with getting the information into the system and allowing the backend administration/HR users to keep things up to date. Since there is a fair bit of information that we want to display, we're going to move editing to a separate view so we can get all that information in an easy-to-use spot. With all the files created for this module, the project looks something like this: And now... on to the code. XAML for the Job Posting View All we really need for the Job Posting View is a RadGridView and a few buttons. This will let us both show off records and perform operations on the records without much hassle. That XAML is going to look something like this: 01.<Grid x:Name="LayoutRoot" 02.Background="White"> 03.<Grid.RowDefinitions> 04.<RowDefinition Height="30" /> 05.<RowDefinition /> 06.</Grid.RowDefinitions> 07.<StackPanel Orientation="Horizontal"> 08.<Button x:Name="xAddRecordButton" 09.Content="Add Job" 10.Width="120" 11.cal:Click.Command="{Binding AddRecord}" 12.telerik:StyleManager.Theme="Windows7" /> 13.<Button x:Name="xEditRecordButton" 14.Content="Edit Job" 15.Width="120" 16.cal:Click.Command="{Binding EditRecord}" 17.telerik:StyleManager.Theme="Windows7" /> 18.</StackPanel> 19.<telerikGrid:RadGridView x:Name="xJobsGrid" 20.Grid.Row="1" 21.IsReadOnly="True" 22.AutoGenerateColumns="False" 23.ColumnWidth="*" 24.RowDetailsVisibilityMode="VisibleWhenSelected" 25.ItemsSource="{Binding MyJobs}" 26.SelectedItem="{Binding SelectedJob, Mode=TwoWay}" 27.command:SelectedItemChangedEventClass.Command="{Binding SelectedItemChanged}"> 28.<telerikGrid:RadGridView.Columns> 29.<telerikGrid:GridViewDataColumn Header="Job Title" 30.DataMemberBinding="{Binding JobTitle}" 31.UniqueName="JobTitle" /> 32.<telerikGrid:GridViewDataColumn Header="Location" 33.DataMemberBinding="{Binding Location}" 34.UniqueName="Location" /> 35.<telerikGrid:GridViewDataColumn Header="Resume Required" 36.DataMemberBinding="{Binding NeedsResume}" 37.UniqueName="NeedsResume" /> 38.<telerikGrid:GridViewDataColumn Header="CV Required" 39.DataMemberBinding="{Binding NeedsCV}" 40.UniqueName="NeedsCV" /> 41.<telerikGrid:GridViewDataColumn Header="Overview Required" 42.DataMemberBinding="{Binding NeedsOverview}" 43.UniqueName="NeedsOverview" /> 44.<telerikGrid:GridViewDataColumn Header="Active" 45.DataMemberBinding="{Binding IsActive}" 46.UniqueName="IsActive" /> 47.</telerikGrid:RadGridView.Columns> 48.</telerikGrid:RadGridView> 49.</Grid> I'll explain what's happening here by line numbers: Lines 11 and 16: Using the same type of click commands as we saw in the Menu module, we tie the button clicks to delegate commands in the viewmodel. Line 25: The source for the jobs will be a collection in the viewmodel. Line 26: We also bind the selected item to a public property from the viewmodel for use in code. Line 27: We've turned the event into a command so we can handle it via code in the viewmodel. So those first three probably make sense to you as far as Silverlight/WPF binding magic is concerned, but for line 27... This actually comes from something I read onDamien Schenkelman's blog back in the day for creating an attached behavior from any event. So, any time you see me using command:Whatever.Command, the backing for it is actually something like this: SelectedItemChangedEventBehavior.cs: 01.public class SelectedItemChangedEventBehavior : CommandBehaviorBase<Telerik.Windows.Controls.DataControl> 02.{ 03.public SelectedItemChangedEventBehavior(DataControl element) 04.: base(element) 05.{ 06.element.SelectionChanged += new EventHandler<SelectionChangeEventArgs>(element_SelectionChanged); 07.} 08.void element_SelectionChanged(object sender, SelectionChangeEventArgs e) 09.{ 10.// We'll only ever allow single selection, so will only need item index 0 11.base.CommandParameter = e.AddedItems[0]; 12.base.ExecuteCommand(); 13.} 14.} SelectedItemChangedEventClass.cs: 01.public class SelectedItemChangedEventClass 02.{ 03.#region The Command Stuff 04.public static ICommand GetCommand(DependencyObject obj) 05.{ 06.return (ICommand)obj.GetValue(CommandProperty); 07.} 08.public static void SetCommand(DependencyObject obj, ICommand value) 09.{ 10.obj.SetValue(CommandProperty, value); 11.} 12.public static readonly DependencyProperty CommandProperty = 13.DependencyProperty.RegisterAttached("Command", typeof(ICommand), 14.typeof(SelectedItemChangedEventClass), new PropertyMetadata(OnSetCommandCallback)); 15.public static void OnSetCommandCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) 16.{ 17.DataControl element = dependencyObject as DataControl; 18.if (element != null) 19.{ 20.SelectedItemChangedEventBehavior behavior = GetOrCreateBehavior(element); 21.behavior.Command = e.NewValue as ICommand; 22.} 23.} 24.#endregion 25.public static SelectedItemChangedEventBehavior GetOrCreateBehavior(DataControl element) 26.{ 27.SelectedItemChangedEventBehavior behavior = element.GetValue(SelectedItemChangedEventBehaviorProperty) as SelectedItemChangedEventBehavior; 28.if (behavior == null) 29.{ 30.behavior = new SelectedItemChangedEventBehavior(element); 31.element.SetValue(SelectedItemChangedEventBehaviorProperty, behavior); 32.} 33.return behavior; 34.} 35.public static SelectedItemChangedEventBehavior GetSelectedItemChangedEventBehavior(DependencyObject obj) 36.{ 37.return (SelectedItemChangedEventBehavior)obj.GetValue(SelectedItemChangedEventBehaviorProperty); 38.} 39.public static void SetSelectedItemChangedEventBehavior(DependencyObject obj, SelectedItemChangedEventBehavior value) 40.{ 41.obj.SetValue(SelectedItemChangedEventBehaviorProperty, value); 42.} 43.public static readonly DependencyProperty SelectedItemChangedEventBehaviorProperty = 44.DependencyProperty.RegisterAttached("SelectedItemChangedEventBehavior", 45.typeof(SelectedItemChangedEventBehavior), typeof(SelectedItemChangedEventClass), null); 46.} These end up looking very similar from command to command, but in a nutshell you create a command based on any event, determine what the parameter for it will be, then execute. It attaches via XAML and ties to a DelegateCommand in the viewmodel, so you get the full event experience (since some controls get a bit event-rich for added functionality). Simple enough, right? Viewmodel for the Job Posting View The Viewmodel is going to need to handle all events going back and forth, maintaining interactions with the data we are using, and both publishing and subscribing to events. Rather than breaking this into tons of little pieces, I'll give you a nice view of the entire viewmodel and then hit up the important points line-by-line: 001.public class JobPostingViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005.public DelegateCommand<object> AddRecord { get; set; } 006.public DelegateCommand<object> EditRecord { get; set; } 007.public DelegateCommand<object> SelectedItemChanged { get; set; } 008.public RecruitingContext context; 009.private QueryableCollectionView _myJobs; 010.public QueryableCollectionView MyJobs 011.{ 012.get { return _myJobs; } 013.} 014.private QueryableCollectionView _selectionJobActionHistory; 015.public QueryableCollectionView SelectedJobActionHistory 016.{ 017.get { return _selectionJobActionHistory; } 018.} 019.private JobPosting _selectedJob; 020.public JobPosting SelectedJob 021.{ 022.get { return _selectedJob; } 023.set 024.{ 025.if (value != _selectedJob) 026.{ 027._selectedJob = value; 028.NotifyChanged("SelectedJob"); 029.} 030.} 031.} 032.public SubscriptionToken editToken = new SubscriptionToken(); 033.public SubscriptionToken addToken = new SubscriptionToken(); 034.public JobPostingViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 035.{ 036.// set Unity items 037.this.eventAggregator = eventAgg; 038.this.regionManager = regionmanager; 039.// load our context 040.context = new RecruitingContext(); 041.this._myJobs = new QueryableCollectionView(context.JobPostings); 042.context.Load(context.GetJobPostingsQuery()); 043.// set command events 044.this.AddRecord = new DelegateCommand<object>(this.AddNewRecord); 045.this.EditRecord = new DelegateCommand<object>(this.EditExistingRecord); 046.this.SelectedItemChanged = new DelegateCommand<object>(this.SelectedRecordChanged); 047.SetSubscriptions(); 048.} 049.#region DelegateCommands from View 050.public void AddNewRecord(object obj) 051.{ 052.this.eventAggregator.GetEvent<AddJobEvent>().Publish(true); 053.} 054.public void EditExistingRecord(object obj) 055.{ 056.if (_selectedJob == null) 057.{ 058.this.eventAggregator.GetEvent<NotifyUserEvent>().Publish("No job selected."); 059.} 060.else 061.{ 062.this._myJobs.EditItem(this._selectedJob); 063.this.eventAggregator.GetEvent<EditJobEvent>().Publish(this._selectedJob); 064.} 065.} 066.public void SelectedRecordChanged(object obj) 067.{ 068.if (obj.GetType() == typeof(ActionHistory)) 069.{ 070.// event bubbles up so we don't catch items from the ActionHistory grid 071.} 072.else 073.{ 074.JobPosting job = obj as JobPosting; 075.GrabHistory(job.PostingID); 076.} 077.} 078.#endregion 079.#region Subscription Declaration and Events 080.public void SetSubscriptions() 081.{ 082.EditJobCompleteEvent editComplete = eventAggregator.GetEvent<EditJobCompleteEvent>(); 083.if (editToken != null) 084.editComplete.Unsubscribe(editToken); 085.editToken = editComplete.Subscribe(this.EditCompleteEventHandler); 086.AddJobCompleteEvent addComplete = eventAggregator.GetEvent<AddJobCompleteEvent>(); 087.if (addToken != null) 088.addComplete.Unsubscribe(addToken); 089.addToken = addComplete.Subscribe(this.AddCompleteEventHandler); 090.} 091.public void EditCompleteEventHandler(bool complete) 092.{ 093.if (complete) 094.{ 095.JobPosting thisJob = _myJobs.CurrentEditItem as JobPosting; 096.this._myJobs.CommitEdit(); 097.this.context.SubmitChanges((s) => 098.{ 099.ActionHistory myAction = new ActionHistory(); 100.myAction.PostingID = thisJob.PostingID; 101.myAction.Description = String.Format("Job '{0}' has been edited by {1}", thisJob.JobTitle, "default user"); 102.myAction.TimeStamp = DateTime.Now; 103.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 104.} 105., null); 106.} 107.else 108.{ 109.this._myJobs.CancelEdit(); 110.} 111.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 112.} 113.public void AddCompleteEventHandler(JobPosting job) 114.{ 115.if (job == null) 116.{ 117.// do nothing, new job add cancelled 118.} 119.else 120.{ 121.this.context.JobPostings.Add(job); 122.this.context.SubmitChanges((s) => 123.{ 124.ActionHistory myAction = new ActionHistory(); 125.myAction.PostingID = job.PostingID; 126.myAction.Description = String.Format("Job '{0}' has been added by {1}", job.JobTitle, "default user"); 127.myAction.TimeStamp = DateTime.Now; 128.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 129.} 130., null); 131.} 132.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 133.} 134.#endregion 135.public void GrabHistory(int postID) 136.{ 137.context.ActionHistories.Clear(); 138._selectionJobActionHistory = new QueryableCollectionView(context.ActionHistories); 139.context.Load(context.GetHistoryForJobQuery(postID)); 140.} Taking it from the top, we're injecting an Event Aggregator and Region Manager for use down the road and also have the public DelegateCommands (just like in the Menu module). We also grab a reference to our context, which we'll obviously need for data, then set up a few fields with public properties tied to them. We're also setting subscription tokens, which we have not yet seen but I will get into below. The AddNewRecord (50) and EditExistingRecord (54) methods should speak for themselves for functionality, the one thing of note is we're sending events off to the Event Aggregator which some module, somewhere will take care of. Since these aren't entirely relying on one another, the Jobs View doesn't care if anyone is listening, but it will publish AddJobEvent (52), NotifyUserEvent (58) and EditJobEvent (63)regardless. Don't mind the GrabHistory() method so much, that is just grabbing history items (visibly being created in the SubmitChanges callbacks), and adding them to the database. Every action will trigger a history event, so we'll know who modified what and when, just in case. ;) So where are we at? Well, if we click to Add a job, we publish an event, if we edit a job, we publish an event with the selected record (attained through the magic of binding). Where is this all going though? To the Viewmodel, of course! XAML for the AddEditJobView This is pretty straightforward except for one thing, noted below: 001.<Grid x:Name="LayoutRoot" 002.Background="White"> 003.<Grid x:Name="xEditGrid" 004.Margin="10" 005.validationHelper:ValidationScope.Errors="{Binding Errors}"> 006.<Grid.Background> 007.<LinearGradientBrush EndPoint="0.5,1" 008.StartPoint="0.5,0"> 009.<GradientStop Color="#FFC7C7C7" 010.Offset="0" /> 011.<GradientStop Color="#FFF6F3F3" 012.Offset="1" /> 013.</LinearGradientBrush> 014.</Grid.Background> 015.<Grid.RowDefinitions> 016.<RowDefinition Height="40" /> 017.<RowDefinition Height="40" /> 018.<RowDefinition Height="40" /> 019.<RowDefinition Height="100" /> 020.<RowDefinition Height="100" /> 021.<RowDefinition Height="100" /> 022.<RowDefinition Height="40" /> 023.<RowDefinition Height="40" /> 024.<RowDefinition Height="40" /> 025.</Grid.RowDefinitions> 026.<Grid.ColumnDefinitions> 027.<ColumnDefinition Width="150" /> 028.<ColumnDefinition Width="150" /> 029.<ColumnDefinition Width="300" /> 030.<ColumnDefinition Width="100" /> 031.</Grid.ColumnDefinitions> 032. 033.<TextBlock Margin="8" 034.Text="{Binding AddEditString}" 035.TextWrapping="Wrap" 036.Grid.Column="1" 037.Grid.ColumnSpan="2" 038.FontSize="16" /> 039. 040. 041.<TextBlock Margin="8,0,0,0" 042.Style="{StaticResource LabelTxb}" 043.Grid.Row="1" 044.Text="Job Title" 045.VerticalAlignment="Center" /> 046.<TextBox x:Name="xJobTitleTB" 047.Margin="0,8" 048.Grid.Column="1" 049.Grid.Row="1" 050.Text="{Binding activeJob.JobTitle, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 051.Grid.ColumnSpan="2" /> 052.<TextBlock Margin="8,0,0,0" 053.Grid.Row="2" 054.Text="Location" 055.d:LayoutOverrides="Height" 056.VerticalAlignment="Center" /> 057.<TextBox x:Name="xLocationTB" 058.Margin="0,8" 059.Grid.Column="1" 060.Grid.Row="2" 061.Text="{Binding activeJob.Location, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 062.Grid.ColumnSpan="2" /> 063. 064.<TextBlock Margin="8,11,8,0" 065.Grid.Row="3" 066.Text="Description" 067.TextWrapping="Wrap" 068.VerticalAlignment="Top" /> 069. 070.<TextBox x:Name="xDescriptionTB" 071.Height="84" 072.TextWrapping="Wrap" 073.ScrollViewer.VerticalScrollBarVisibility="Auto" 074.Grid.Column="1" 075.Grid.Row="3" 076.Text="{Binding activeJob.Description, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 077.Grid.ColumnSpan="2" /> 078.<TextBlock Margin="8,11,8,0" 079.Grid.Row="4" 080.Text="Requirements" 081.TextWrapping="Wrap" 082.VerticalAlignment="Top" /> 083. 084.<TextBox x:Name="xRequirementsTB" 085.Height="84" 086.TextWrapping="Wrap" 087.ScrollViewer.VerticalScrollBarVisibility="Auto" 088.Grid.Column="1" 089.Grid.Row="4" 090.Text="{Binding activeJob.Requirements, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 091.Grid.ColumnSpan="2" /> 092.<TextBlock Margin="8,11,8,0" 093.Grid.Row="5" 094.Text="Qualifications" 095.TextWrapping="Wrap" 096.VerticalAlignment="Top" /> 097. 098.<TextBox x:Name="xQualificationsTB" 099.Height="84" 100.TextWrapping="Wrap" 101.ScrollViewer.VerticalScrollBarVisibility="Auto" 102.Grid.Column="1" 103.Grid.Row="5" 104.Text="{Binding activeJob.Qualifications, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 105.Grid.ColumnSpan="2" /> 106. 107. 108.<CheckBox x:Name="xResumeRequiredCB" Margin="8,8,8,15" 109.Content="Resume Required" 110.Grid.Row="6" 111.Grid.ColumnSpan="2" 112.IsChecked="{Binding activeJob.NeedsResume, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 113. 114.<CheckBox x:Name="xCoverletterRequiredCB" Margin="8,8,8,15" 115.Content="Cover Letter Required" 116.Grid.Column="2" 117.Grid.Row="6" 118.IsChecked="{Binding activeJob.NeedsCV, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 119. 120.<CheckBox x:Name="xOverviewRequiredCB" Margin="8,8,8,15" 121.Content="Overview Required" 122.Grid.Row="7" 123.Grid.ColumnSpan="2" 124.IsChecked="{Binding activeJob.NeedsOverview, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 125. 126.<CheckBox x:Name="xJobActiveCB" Margin="8,8,8,15" 127.Content="Job is Active" 128.Grid.Column="2" 129.Grid.Row="7" 130.IsChecked="{Binding activeJob.IsActive, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 131. 132. 133. 134.<Button x:Name="xAddEditButton" Margin="8,8,0,10" 135.Content="{Binding AddEditButtonString}" 136.cal:Click.Command="{Binding AddEditCommand}" 137.Grid.Column="2" 138.Grid.Row="8" 139.HorizontalAlignment="Left" 140.Width="125" 141.telerik:StyleManager.Theme="Windows7" /> 142. 143.<Button x:Name="xCancelButton" HorizontalAlignment="Right" 144.Content="Cancel" 145.cal:Click.Command="{Binding CancelCommand}" 146.Margin="0,8,8,10" 147.Width="125" 148.Grid.Column="2" 149.Grid.Row="8" 150.telerik:StyleManager.Theme="Windows7" /> 151.</Grid> 152.</Grid> The 'validationHelper:ValidationScope' line may seem odd. This is a handy little trick for catching current and would-be validation errors when working in this whole setup. This all comes from an approach found on theJoy Of Code blog, although it looks like the story for this will be changing slightly with new advances in SL4/WCF RIA Services, so this section can definitely get an overhaul a little down the road. The code is the fun part of all this, so let us see what's happening under the hood. Viewmodel for the AddEditJobView We are going to see some of the same things happening here, so I'll skip over the repeat info and get right to the good stuff: 001.public class AddEditJobViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005. 006.public RecruitingContext context; 007. 008.private JobPosting _activeJob; 009.public JobPosting activeJob 010.{ 011.get { return _activeJob; } 012.set 013.{ 014.if (_activeJob != value) 015.{ 016._activeJob = value; 017.NotifyChanged("activeJob"); 018.} 019.} 020.} 021. 022.public bool isNewJob; 023. 024.private string _addEditString; 025.public string AddEditString 026.{ 027.get { return _addEditString; } 028.set 029.{ 030.if (_addEditString != value) 031.{ 032._addEditString = value; 033.NotifyChanged("AddEditString"); 034.} 035.} 036.} 037. 038.private string _addEditButtonString; 039.public string AddEditButtonString 040.{ 041.get { return _addEditButtonString; } 042.set 043.{ 044.if (_addEditButtonString != value) 045.{ 046._addEditButtonString = value; 047.NotifyChanged("AddEditButtonString"); 048.} 049.} 050.} 051. 052.public SubscriptionToken addJobToken = new SubscriptionToken(); 053.public SubscriptionToken editJobToken = new SubscriptionToken(); 054. 055.public DelegateCommand<object> AddEditCommand { get; set; } 056.public DelegateCommand<object> CancelCommand { get; set; } 057. 058.private ObservableCollection<ValidationError> _errors = new ObservableCollection<ValidationError>(); 059.public ObservableCollection<ValidationError> Errors 060.{ 061.get { return _errors; } 062.} 063. 064.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 065.public ObservableCollection<ValidationResult> ValResults 066.{ 067.get { return this._valResults; } 068.} 069. 070.public AddEditJobViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 071.{ 072.// set Unity items 073.this.eventAggregator = eventAgg; 074.this.regionManager = regionmanager; 075. 076.context = new RecruitingContext(); 077. 078.AddEditCommand = new DelegateCommand<object>(this.AddEditJobCommand); 079.CancelCommand = new DelegateCommand<object>(this.CancelAddEditCommand); 080. 081.SetSubscriptions(); 082.} 083. 084.#region Subscription Declaration and Events 085. 086.public void SetSubscriptions() 087.{ 088.AddJobEvent addJob = this.eventAggregator.GetEvent<AddJobEvent>(); 089. 090.if (addJobToken != null) 091.addJob.Unsubscribe(addJobToken); 092. 093.addJobToken = addJob.Subscribe(this.AddJobEventHandler); 094. 095.EditJobEvent editJob = this.eventAggregator.GetEvent<EditJobEvent>(); 096. 097.if (editJobToken != null) 098.editJob.Unsubscribe(editJobToken); 099. 100.editJobToken = editJob.Subscribe(this.EditJobEventHandler); 101.} 102. 103.public void AddJobEventHandler(bool isNew) 104.{ 105.this.activeJob = null; 106.this.activeJob = new JobPosting(); 107.this.activeJob.IsActive = true; // We assume that we want a new job to go up immediately 108.this.isNewJob = true; 109.this.AddEditString = "Add New Job Posting"; 110.this.AddEditButtonString = "Add Job"; 111. 112.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 113.} 114. 115.public void EditJobEventHandler(JobPosting editJob) 116.{ 117.this.activeJob = null; 118.this.activeJob = editJob; 119.this.isNewJob = false; 120.this.AddEditString = "Edit Job Posting"; 121.this.AddEditButtonString = "Edit Job"; 122. 123.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 124.} 125. 126.#endregion 127. 128.#region DelegateCommands from View 129. 130.public void AddEditJobCommand(object obj) 131.{ 132.if (this.Errors.Count > 0) 133.{ 134.List<string> errorMessages = new List<string>(); 135. 136.foreach (var valR in this.Errors) 137.{ 138.errorMessages.Add(valR.Exception.Message); 139.} 140. 141.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 142. 143.} 144.else if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 145.{ 146.List<string> errorMessages = new List<string>(); 147. 148.foreach (var valR in this._valResults) 149.{ 150.errorMessages.Add(valR.ErrorMessage); 151.} 152. 153.this._valResults.Clear(); 154. 155.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 156.} 157.else 158.{ 159.if (this.isNewJob) 160.{ 161.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(this.activeJob); 162.} 163.else 164.{ 165.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(true); 166.} 167.} 168.} 169. 170.public void CancelAddEditCommand(object obj) 171.{ 172.if (this.isNewJob) 173.{ 174.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(null); 175.} 176.else 177.{ 178.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(false); 179.} 180.} 181. 182.#endregion 183.} 184.} We start seeing something new on line 103- the AddJobEventHandler will create a new job and set that to the activeJob item on the ViewModel. When this is all set, the view calls that familiar MakeMeActive method to activate itself. I made a bit of a management call on making views self-activate like this, but I figured it works for one reason. As I create this application, views may not exist that I have in mind, so after a view receives its 'ping' from being subscribed to an event, it prepares whatever it needs to do and then goes active. This way if I don't have 'edit' hooked up, I can click as the day is long on the main view and won't get lost in an empty region. Total personal preference here. :) Everything else should again be pretty straightforward, although I do a bit of validation checking in the AddEditJobCommand, which can either fire off an event back to the main view/viewmodel if everything is a success or sent a list of errors to our notification module, which pops open a RadWindow with the alerts if any exist. As a bonus side note, here's what my WCF RIA Services metadata looks like for handling all of the validation: private JobPostingMetadata() { } [StringLength(2500, ErrorMessage = "Description should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage = "Description is required.")] public string Description; [Required(ErrorMessage="Active Status is Required")] public bool IsActive; [StringLength(100, ErrorMessage = "Posting title must be more than 3 but less than 100 characters.", MinimumLength = 3)] [Required(ErrorMessage = "Job Title is required.")] public bool JobTitle; [Required] public string Location; public bool NeedsCV; public bool NeedsOverview; public bool NeedsResume; public int PostingID; [Required(ErrorMessage="Qualifications are required.")] [StringLength(2500, ErrorMessage="Qualifications should be more than one and less than 2500 characters.", MinimumLength=1)] public string Qualifications; [StringLength(2500, ErrorMessage = "Requirements should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage="Requirements are required.")] public string Requirements; The RecruitCB Alternative See all that Xaml I pasted above? Those are now two pieces sitting in the JobsView.xaml file now. The only real difference is that the xEditGrid now sits in the same place as xJobsGrid, with visibility swapping out between the two for a quick switch. I also took out all the cal: and command: command references and replaced Button events with clicks and the Grid selection command replaced with a SelectedItemChanged event. Also, at the bottom of the xEditGrid after the last button, I add a ValidationSummary (with Visibility=Collapsed) to catch any errors that are popping up. Simple as can be, and leads to this being the single code-behind file: 001.public partial class JobsView : UserControl 002.{ 003.public RecruitingContext context; 004.public JobPosting activeJob; 005.public bool isNew; 006.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 007.public ObservableCollection<ValidationResult> ValResults 008.{ 009.get { return this._valResults; } 010.} 011.public JobsView() 012.{ 013.InitializeComponent(); 014.this.Loaded += new RoutedEventHandler(JobsView_Loaded); 015.} 016.void JobsView_Loaded(object sender, RoutedEventArgs e) 017.{ 018.context = new RecruitingContext(); 019.xJobsGrid.ItemsSource = context.JobPostings; 020.context.Load(context.GetJobPostingsQuery()); 021.} 022.private void xAddRecordButton_Click(object sender, RoutedEventArgs e) 023.{ 024.activeJob = new JobPosting(); 025.isNew = true; 026.xAddEditTitle.Text = "Add a Job Posting"; 027.xAddEditButton.Content = "Add"; 028.xEditGrid.DataContext = activeJob; 029.HideJobsGrid(); 030.} 031.private void xEditRecordButton_Click(object sender, RoutedEventArgs e) 032.{ 033.activeJob = xJobsGrid.SelectedItem as JobPosting; 034.isNew = false; 035.xAddEditTitle.Text = "Edit a Job Posting"; 036.xAddEditButton.Content = "Edit"; 037.xEditGrid.DataContext = activeJob; 038.HideJobsGrid(); 039.} 040.private void xAddEditButton_Click(object sender, RoutedEventArgs e) 041.{ 042.if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 043.{ 044.List<string> errorMessages = new List<string>(); 045.foreach (var valR in this._valResults) 046.{ 047.errorMessages.Add(valR.ErrorMessage); 048.} 049.this._valResults.Clear(); 050.ShowErrors(errorMessages); 051.} 052.else if (xSummary.Errors.Count > 0) 053.{ 054.List<string> errorMessages = new List<string>(); 055.foreach (var err in xSummary.Errors) 056.{ 057.errorMessages.Add(err.Message); 058.} 059.ShowErrors(errorMessages); 060.} 061.else 062.{ 063.if (this.isNew) 064.{ 065.context.JobPostings.Add(activeJob); 066.context.SubmitChanges((s) => 067.{ 068.ActionHistory thisAction = new ActionHistory(); 069.thisAction.PostingID = activeJob.PostingID; 070.thisAction.Description = String.Format("Job '{0}' has been edited by {1}", activeJob.JobTitle, "default user"); 071.thisAction.TimeStamp = DateTime.Now; 072.context.ActionHistories.Add(thisAction); 073.context.SubmitChanges(); 074.}, null); 075.} 076.else 077.{ 078.context.SubmitChanges((s) => 079.{ 080.ActionHistory thisAction = new ActionHistory(); 081.thisAction.PostingID = activeJob.PostingID; 082.thisAction.Description = String.Format("Job '{0}' has been added by {1}", activeJob.JobTitle, "default user"); 083.thisAction.TimeStamp = DateTime.Now; 084.context.ActionHistories.Add(thisAction); 085.context.SubmitChanges(); 086.}, null); 087.} 088.ShowJobsGrid(); 089.} 090.} 091.private void xCancelButton_Click(object sender, RoutedEventArgs e) 092.{ 093.ShowJobsGrid(); 094.} 095.private void ShowJobsGrid() 096.{ 097.xAddEditRecordButtonPanel.Visibility = Visibility.Visible; 098.xEditGrid.Visibility = Visibility.Collapsed; 099.xJobsGrid.Visibility = Visibility.Visible; 100.} 101.private void HideJobsGrid() 102.{ 103.xAddEditRecordButtonPanel.Visibility = Visibility.Collapsed; 104.xJobsGrid.Visibility = Visibility.Collapsed; 105.xEditGrid.Visibility = Visibility.Visible; 106.} 107.private void ShowErrors(List<string> errorList) 108.{ 109.string nm = "Errors received: \n"; 110.foreach (string anerror in errorList) 111.nm += anerror + "\n"; 112.RadWindow.Alert(nm); 113.} 114.} The first 39 lines should be pretty familiar, not doing anything too unorthodox to get this up and running. Once we hit the xAddEditButton_Click on line 40, we're still doing pretty much the same things except instead of checking the ValidationHelper errors, we both run a check on the current activeJob object as well as check the ValidationSummary errors list. Once that is set, we again use the callback of context.SubmitChanges (lines 68 and 78) to create an ActionHistory which we will use to track these items down the line. That's all? Essentially... yes. If you look back through this post, most of the code and adventures we have taken were just to get things working in the MVVM/Prism setup. Since I have the whole 'module' self-contained in a single JobView+code-behind setup, I don't have to worry about things like sending events off into space for someone to pick up, communicating through an Infrastructure project, or even re-inventing events to be used with attached behaviors. Everything just kinda works, and again with much less code. Here's a picture of the MVVM and Code-behind versions on the Jobs and AddEdit views, but since the functionality is the same in both apps you still cannot tell them apart (for two-strike): Looking ahead, the Applicants module is effectively the same thing as the Jobs module, so most of the code is being cut-and-pasted back and forth with minor tweaks here and there. So that one is being taken care of by me behind the scenes. Next time, we get into a new world of fun- the interview scheduling module, which will pull from available jobs and applicants for each interview being scheduled, tying everything together with RadScheduler to the rescue. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

Search Results

Search found 1962 results on 79 pages for 'slightly offtopic'.

Page 78/79 | < Previous Page | 74 75 76 77 78 79 | Next Page >

- by arungupta

- by SeanMcAlinden

- by Rick Strahl

- by Paul White

- by Rick Strahl

- by Stefan Hinker

- by Michael Williamson

- by Jani Rautiainen

- by mv

- by ToStringTheory

- by user9154181

- by Phil Factor

- by Tiny Giant Studios

- by Throlkim

- by Alikar

- by Marco van de Voort

- by Delan Azabani

- by Peter

- by jeansymolanza

- by Jacob

- by Rick Strahl

- by Rick Strahl

- by Michael Williamson

- by Valter Minute

< Previous Page | 74 75 76 77 78 79 | Next Page >