return path - Page 147 - Developer IT

Is it possible to return anything else from controller apart from view?

- by user281180

Is it possible to return a string from controller upon a form submission ?

why does the data property in an jquery ajax call override my return false?

hi, i have the following block of code: $("#contact_container form, #contact_details form").live( "submit", function(event) { $.ajax({ type: this.method, url: this.action, data: this.serialize(), success: function(data) { data = $(data).find("#content"); $("#contact_details").html(data); }, }); return false; } ; when i leave out the data: this.serialize(), it behaves properly and displays the response within the #contact_details div. however, when i leave it in, it submits the form, causing the page to navigate away. why does the presence of the data attribute negates the return false? (probably due to a bug that i can't spot...) also, is the syntax to my find statement correct? it comes back as "undefined" even though i use a debugger to check the ajax response and that id does exists. thanks, steve

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Why does the return statement not print anything to the console?

- by dyoverdx

I Googled it and I didn't hit anything useful, so I decided to ask on here. I can't use System.out.println for the project that I am working on, so I used the return statement. Everything compiles just fine, but my return statement doesn't print anything to the console, the program just terminates. All I have in the code is just an if-else statement that returns true or false. Why don't I see anything on the console? I am using Eclipse Juno's Console by the way.

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gallery2 and nginx with rewrite return file not found for file name with space (or + sign in url)

- by Vangel

I have setup nginx with gallery2 on an internal server. Everything works fine under apache2 which I checked first, it used to be on apache2 Problem is: gallery2 seems to generate url with + sign in it for file names/ images which had spaces in it so a file like "may report.jpg" becomes "may+report.jpg" The URL rewrite works but gallery2 throws an error for file not found. THis does not happen under apache2. Here is my nginx rewrite rule: location / { index main.php index.html; default_type text/html; # If the file exists as a static file serve it # directly without running all # the other rewite tests on it if (-f $request_filename) { break; } } location /v/ { # if ($request_uri !~ /main.php) # { rewrite ^/v/(.*)$ /main.php?g2_view=core.ShowItem&g2_path=$1 last; # } } location /d/ { if ($request_uri !~ /main.php) { rewrite ^/d/([0-9]+)-([0-9]+)/(.*)$ /main.php?g2_view=core.DownloadItem&g2_itemId=$1&g2_serialNumber=$2&g2_fileName=$3 last; } } location ~ \.php$ { fastcgi_pass 127.0.0.1:8889; fastcgi_index main.php; fastcgi_intercept_errors on; # to support 404s for PHP files not found fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; fastcgi_param SERVER_NAME $host; fastcgi_read_timeout 300; } the sit on its own works fine. only the images with spaces in file name do not display in album view and also when clicking the the image for full page view will throw this error Error (ERROR_MISSING_OBJECT) : Parent 103759 path report+april+456.flv in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 98 (GalleryCoreApi::error) in modules/core/classes/GalleryCoreApi.class at line 1853 (GalleryFileSystemEntityHelper_simple::fetchChildIdByPathComponent) in modules/core/classes/helpers/GalleryFileSystemEntityHelper_simple.class at line 53 (GalleryCoreApi::fetchChildIdByPathComponent) in modules/core/classes/GalleryCoreApi.class at line 1804 (GalleryFileSystemEntityHelper_simple::fetchItemIdByPath) in modules/rewrite/classes/RewriteSimpleHelper.class at line 45 (GalleryCoreApi::fetchItemIdByPath) in ??? at line 0 (RewriteSimpleHelper::loadItemIdFromPath) in modules/rewrite/classes/RewriteUrlGenerator.class at line 103 in modules/rewrite/classes/parsers/modrewrite/ModRewriteUrlGenerator.class at line 37 (RewriteUrlGenerator::_onLoad) in init.inc at line 147 (ModRewriteUrlGenerator::initNavigation) in main.php at line 180 in main.php at line 94 in main.php at line 83 System Information Gallery version 2.2.4 PHP version 5.3.6 fpm-fcgi Webserver nginx/0.8.55 Database mysqli 5.0.95 Toolkits ImageMagick, Thumbnail, Gd Operating system Linux CentOS-55-64-minimal 2.6.18-274.18.1.el5 #1 SMP Thu Feb 9 12:45:44 EST 2012 x86_64 Browser Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.52 Safari/536.5 In the report above there is usable system information if that helps. I know the nginx is old but it comes as default in centos repo and I am not sure if upgrading will fix the problem or break something else it seems gallery2 must map the + to space internally but why it's not doing so with nginx I can't tell. EDIT: I just verified that if I change the '+' sign to %20 then gallery2 works. but gallery2 is generating URL as +. I found a (maybe) related problem here for IIS7 and Gallery2 http://forums.asp.net/t/1431951.aspx EDIT2: Accessing the URL without rewrite and having the + sign works. Must be something to do with rewrite. Here is the relevant apache2 rule that might be of help RewriteCond %{THE_REQUEST} /d/([0-9]+)-([0-9]+)/([^/?]+)(\?.|\ .) RewriteCond %{REQUEST_URI} !/main\.php$ RewriteRule . /main.php?g2_view=core.DownloadItem&g2_itemId=%1&g2_serialNumber=%2&g2_fileName=%3 [QSA,L] RewriteCond %{THE_REQUEST} /v/([^?]+)(\?.|\ .) RewriteCond %{REQUEST_URI} !/main\.php$ RewriteRule . /main.php?g2_path=%1 [QSA,L]

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Why is my machine unable to mount my SMB drives ("CIFS VFS: Error connecting to socket. Aborting operation", return code -115)?

- by downbeat

I have a machine running Precise (12.04 x64), and I cannot mount my SMB drives (I have 3, we'll call them public, private and download). It used to work (a week or two ago) and I didn't touch fstab! The machine hosting the shares is a commercial NAS, and I'm not seeing anything that would indicate it's an issue with the NAS. I have an older machine which I updated to Precise at the same time (both fresh installed, not dist-upgrade), so should have a very similar configuration. It is not having any problems. I am not having problems on windows machines/partitions either, only one of my Precise machines. The two machines are using identical entries in fstab and identical /etc/samba/smb.conf files. I don't think I've ever changed smb.conf (has never mattered before). My fstab entries all basically look like this: //10.1.1.111/public /media/public cifs credentials=/home/downbeat/.credentials,iocharset=utf8,uid=downbeat,gid=downbeat,file_mode=0644,dir_mode=0755 0 0 Here's the dmesg output on boot: [ 51.162198] CIFS VFS: Error connecting to socket. Aborting operation [ 51.162369] CIFS VFS: cifs_mount failed w/return code = -115 [ 51.194106] CIFS VFS: Error connecting to socket. Aborting operation [ 51.194250] CIFS VFS: cifs_mount failed w/return code = -115 [ 51.198120] CIFS VFS: Error connecting to socket. Aborting operation [ 51.198243] CIFS VFS: cifs_mount failed w/return code = -115 There are no other errors I see in the dmesg output. Originally when I ran 'testparm -s', the output contained these lines ERROR: lock directory /var/run/samba does not exist ERROR: pid directory /var/run/samba does not exist Here's the samba related programs I have installed: $ dpkg --list|grep -i samba ii libpam-winbind 2:3.6.3-2ubuntu2.3 Samba nameservice and authentication integration plugins ii libwbclient0 2:3.6.3-2ubuntu2.3 Samba winbind client library ii nautilus-share 0.7.3-1ubuntu2 Nautilus extension to share folder using Samba ii python-smbc 1.0.13-0ubuntu1 Python bindings for Samba clients (libsmbclient) ii samba-common 2:3.6.3-2ubuntu2.3 common files used by both the Samba server and client ii samba-common-bin 2:3.6.3-2ubuntu2.3 common files used by both the Samba server and client ii winbind 2:3.6.3-2ubuntu2.3 Samba nameservice integration server $ dpkg --list|grep -i smb ii dmidecode 2.11-4 SMBIOS/DMI table decoder ii libsmbclient 2:3.6.3-2ubuntu2.3 shared library for communication with SMB/CIFS servers ii python-smbc 1.0.13-0ubuntu1 Python bindings for Samba clients (libsmbclient) ii smbclient 2:3.6.3-2ubuntu2.3 command-line SMB/CIFS clients for Unix ii smbfs 2:5.1-1ubuntu1 Common Internet File System utilities - compatibility package $ dpkg --list|grep -i cifs ii cifs-utils 2:5.1-1ubuntu1 Common Internet File System utilities ii libsmbclient 2:3.6.3-2ubuntu2.3 shared library for communication with SMB/CIFS servers ii smbclient 2:3.6.3-2ubuntu2.3 command-line SMB/CIFS clients for Unix I originally noticed that my other machine had "libpam-winbind" and "nautilus-share" installed and the machine with the issue did not. Installing those two packages solved my errors with 'testparm -s', but did not fix my issue. Finally, I tried to purge and reinstall these packages smbclient smbfs cifs-utils samba-common samba-common-bin Still no luck. Again, it used to work; now it doesn't. Very similarly configured machine works (but some packages are out of date on the working machine). The NAS has only one interface/IP address, nmblookup works to find it's IP from it's hostname (from the machine with the issue) and it responds to a ping. Please any help would be great. I've been searching on AskUbuntu, SuperUser, ubuntuforums and plain old search engines for a week now and it's driving me crazy!

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Part 14: Execute a PowerShell script

In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application With PowerShell you can add powerful scripting to your build to for example execute a deployment. If you want more information on PowerShell, please refer to http://technet.microsoft.com/en-us/library/aa973757.aspx For this example we will create a simple PowerShell script that prints “Hello world!”. To create the script, create a new text file and name it “HelloWorld.ps1”. Add to the contents of the script: Write-Host “Hello World!” To test the script do the following: Open the command prompt To run the script you must change the execution policy. To do this execute in the command prompt: powershell set-executionpolicy remotesigned Now go to the directory where you have saved the PowerShell script Execute the following command powershell .\HelloWorld.ps1 In this example I use a relative path, but when the path to the PowerShell script contains spaces, you need to change the syntax to powershell "& '<full path to script>' " for example: powershell "& ‘C:\sources\Build Customization\SolutionToBuild\PowerShell Scripts\HellloWorld.ps1’ " In this blog post, I create a new solution and that solution includes also this PowerShell script. I want to create an argument on the Build Process Template that holds the path to the PowerShell script. In the Build Process Template I will add an InvokeProcess activity to execute the PowerShell command. This InvokeProcess activity needs the location of the script as an argument for the PowerShell command. Since you don’t know the full path at the build server of this script, you can either specify in the argument the relative path of the script, but it is hard to find out what the relative path is. I prefer to specify the location of the script in source control and then convert that server path to a local path. To do this conversion you can use the ConvertWorkspaceItem activity. So to complete the task, open the Build Process Template CustomTemplate.xaml that we created in earlier parts, follow the following steps Add a new argument called “DeploymentScript” and set the appropriate settings in the metadata. See Part 2: Add arguments and variables for more information. Scroll down beneath the TryCatch activity called “Try Compile, Test, and Associate Changesets and Work Items” Add a new If activity and set the condition to "Not String.IsNullOrEmpty(DeploymentScript)" to ensure it will only run when the argument is passed. Add in the Then branch of the If activity a new Sequence activity and rename it to “Start deployment” Click on the activity and add a new variable called DeploymentScriptFilename (scoped to the “Start deployment” Sequence Add a ConvertWorkspaceItem activity on the “Start deployment” Sequence Add a InvokeProcess activity beneath the ConvertWorkspaceItem activity in the “Start deployment” Sequence Click on the ConvertWorkspaceItem activity and change the properties DisplayName = Convert deployment script filename Input = DeploymentScript Result = DeploymentScriptFilename Workspace = Workspace Click on the InvokeProcess activity and change the properties Arguments = String.Format(" ""& '{0}' "" ", DeploymentScriptFilename) DisplayName = Execute deployment script FileName = "PowerShell" To see results from the powershell command drop a WriteBuildMessage activity on the "Handle Standard Output" and pass the stdOutput variable to the Message property. Do the same for a WriteBuildError activity on the "Handle Error Output" To publish it, check in the Build Process Template This leads to the following result We now go to the build definition that depends on the template and set the path of the deployment script to the server path to the HelloWorld.ps1. (If you want to see the result of the PowerShell script, change the Logging verbosity to Detailed or Diagnostic). Save and run the build. A lot of the deployment scripts you have will have some kind of arguments (like username / password or environment variables) that you want to define in the Build Definition. To make the PowerShell configurable, you can follow the following steps. Create a new script and give it the name "HelloWho.ps1". In the contents of the file add the following lines: param ( $person ) $message = [System.String]::Format(“Hello {0}!", $person) Write-Host $message When you now run the script on the command prompt, you will see the following So lets change the Build Process Template to accept one parameter for the deployment script. You can of course make it configurable to add a for-loop that reads through a collection of parameters but that is out of scope of this blog post. Add a new Argument called DeploymentScriptParameter In the InvokeProcess activity where the PowerShell command is executed, modify the Arguments property to String.Format(" ""& '{0}' '{1}' "" ", DeploymentScriptFilename, DeploymentScriptParameter) Check in the Build Process Template Now modify the build definition and set the Parameter of the deployment to any value and run the build. You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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Using Oracle Proxy Authentication with JPA (eclipselink-Style)

- by olaf.heimburger

Security is a very intriguing topic. You will find it everywhere and you need to implement it everywhere. Yes, you need. Unfortunately, one can easily forget it while implementing the last mile. The Last Mile In a multi-tier application it is a common practice to use connection pools between the business layer and the database layer. Connection pools are quite useful to speed database connection creation and to split the load. Another very common practice is to use a specific, often called technical, user to connect to the database. This user has authentication and authorization rules that apply to all application users. Imagine you've put every effort to define roles for different types of users that use your application. These roles are necessary to differentiate between normal users, premium users, and administrators (I bet you will find or already have more roles in your application). While these user roles are pretty well used within your application, once the flow of execution enters the database everything is gone. Each and every user just has one role and is the same database user. Issues? What Issues? As long as things go well, this is not a real issue. However, things do not go well all the time. Once your application becomes famous performance decreases in certain situations or, more importantly, current and upcoming regulations and laws require that your application must be able to apply different security measures on a per user role basis at every stage of your application. If you only have a bunch of users with the same name and role you are not able to find the application usage profile that causes the performance issue, or which user has accessed data that he/she is not allowed to. Another thread to your role concept is that databases tend to be used by different applications and tools. These tools can be developer tools like SQL*Plus, SQL Developer, etc. or end user applications like BI Publisher, Oracle Forms and so on. These tools have no idea of your applications role concept and access the database the way they think is appropriate. A big oversight for your perfect role model and a big nightmare for your Chief Security Officer. Speaking of the CSO, brings up another issue: Password management. Once your technical user account is compromised, every user is able to do things that he/she is not expected to do from the design of your application. Counter Measures In the Oracle world a common counter measure is to use Virtual Private Database (VPD). This restricts the values a database user can see to the allowed minimum. However, it doesn't help in regard of a connection pool user, because this one is still not the real user. Oracle Proxy Authentication Another feature of the Oracle database is Proxy Authentication. First introduced with version 9i it is a quite useful feature for nearly every situation. The main idea behind Proxy Authentication is, to create a crippled database user who has only connect rights. Even if this user is compromised the risks are well understood and fairly limited. This user can be used in every situation in which you need to connect to the database, no matter which tool or application (see above) you use.The proxy user is perfect for multi-tier connection pools. CREATE USER app_user IDENTIFIED BY abcd1234; GRANT CREATE SESSION TO app_user; But what if you need to access real data? Well, this is the primary use case, isn't it? Now is the time to bring the application's role concept into play. You define database roles that define the grants for your identified user groups. Once you have these groups you grant access through the proxy user with the application role to the specific user. CREATE ROLE app_role_a; GRANT app_role_a TO scott; ALTER USER scott GRANT CONNECT THROUGH app_user WITH ROLE app_role_a; Now, hr has permission to connect to the database through the proxy user. Through the role you can restrict the hr's rights the are needed for the application only. If hr connects to the database directly all assigned role and permissions apply. Testing the Setup To test the setup you can use SQL*Plus and connect to your database: $ sqlplus app_user[hr]/abcd1234 Java Persistence API The Java Persistence API (JPA) is a fairly easy means to build applications that retrieve data from the database and put it into Java objects. You use plain old Java objects (POJOs) and mixin some Java annotations that define how the attributes of the object are used for storing data from the database into the Java object. Here is a sample for objects from the HR sample schema EMPLOYEES table. When using Java annotations you only specify what can not be deduced from the code. If your Java class name is Employee but the table name is EMPLOYEES, you need to specify the table name, otherwise it will fail. package demo.proxy.ejb; import java.io.Serializable; import java.sql.Timestamp; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.OneToMany; import javax.persistence.Table; @Entity @NamedQueries({ @NamedQuery(name = "Employee.findAll", query = "select o from Employee o") }) @Table(name = "EMPLOYEES") public class Employee implements Serializable { @Column(name="COMMISSION_PCT") private Double commissionPct; @Column(name="DEPARTMENT_ID") private Long departmentId; @Column(nullable = false, unique = true, length = 25) private String email; @Id @Column(name="EMPLOYEE_ID", nullable = false) private Long employeeId; @Column(name="FIRST_NAME", length = 20) private String firstName; @Column(name="HIRE_DATE", nullable = false) private Timestamp hireDate; @Column(name="JOB_ID", nullable = false, length = 10) private String jobId; @Column(name="LAST_NAME", nullable = false, length = 25) private String lastName; @Column(name="PHONE_NUMBER", length = 20) private String phoneNumber; private Double salary; @ManyToOne @JoinColumn(name = "MANAGER_ID") private Employee employee; @OneToMany(mappedBy = "employee") private List employeeList; public Employee() { } public Employee(Double commissionPct, Long departmentId, String email, Long employeeId, String firstName, Timestamp hireDate, String jobId, String lastName, Employee employee, String phoneNumber, Double salary) { this.commissionPct = commissionPct; this.departmentId = departmentId; this.email = email; this.employeeId = employeeId; this.firstName = firstName; this.hireDate = hireDate; this.jobId = jobId; this.lastName = lastName; this.employee = employee; this.phoneNumber = phoneNumber; this.salary = salary; } public Double getCommissionPct() { return commissionPct; } public void setCommissionPct(Double commissionPct) { this.commissionPct = commissionPct; } public Long getDepartmentId() { return departmentId; } public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Long getEmployeeId() { return employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public Timestamp getHireDate() { return hireDate; } public void setHireDate(Timestamp hireDate) { this.hireDate = hireDate; } public String getJobId() { return jobId; } public void setJobId(String jobId) { this.jobId = jobId; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getPhoneNumber() { return phoneNumber; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public Double getSalary() { return salary; } public void setSalary(Double salary) { this.salary = salary; } public Employee getEmployee() { return employee; } public void setEmployee(Employee employee) { this.employee = employee; } public List getEmployeeList() { return employeeList; } public void setEmployeeList(List employeeList) { this.employeeList = employeeList; } public Employee addEmployee(Employee employee) { getEmployeeList().add(employee); employee.setEmployee(this); return employee; } public Employee removeEmployee(Employee employee) { getEmployeeList().remove(employee); employee.setEmployee(null); return employee; } } JPA could be used in standalone applications and Java EE containers. In both worlds you normally create a Facade to retrieve or store the values of the Entities to or from the database. The Facade does this via an EntityManager which will be injected by the Java EE container. Here is sample Facade Session Bean for a Java EE container. package demo.proxy.ejb; import java.util.HashMap; import java.util.List; import javax.ejb.Local; import javax.ejb.Remote; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query; import javax.interceptor.AroundInvoke; import javax.interceptor.InvocationContext; import oracle.jdbc.driver.OracleConnection; import org.eclipse.persistence.config.EntityManagerProperties; import org.eclipse.persistence.internal.jpa.EntityManagerImpl; @Stateless(name = "DataFacade", mappedName = "ProxyUser-TestEJB-DataFacade") @Remote @Local public class DataFacadeBean implements DataFacade, DataFacadeLocal { @PersistenceContext(unitName = "TestEJB") private EntityManager em; private String username; public Object queryByRange(String jpqlStmt, int firstResult, int maxResults) { // setSessionUser(); Query query = em.createQuery(jpqlStmt); if (firstResult 0) { query = query.setFirstResult(firstResult); } if (maxResults 0) { query = query.setMaxResults(maxResults); } return query.getResultList(); } public Employee persistEmployee(Employee employee) { // setSessionUser(); em.persist(employee); return employee; } public Employee mergeEmployee(Employee employee) { // setSessionUser(); return em.merge(employee); } public void removeEmployee(Employee employee) { // setSessionUser(); employee = em.find(Employee.class, employee.getEmployeeId()); em.remove(employee); } /** select o from Employee o */ public List getEmployeeFindAll() { Query q = em.createNamedQuery("Employee.findAll"); return q.getResultList(); } Putting Both Together To use Proxy Authentication with JPA and within a Java EE container you have to take care of the additional requirements: Use an OCI JDBC driver Provide the user name that connects through the proxy user Use an OCI JDBC driver To use the OCI JDBC driver you need to set up your JDBC data source file to use the correct JDBC URL. hr jdbc:oracle:oci8:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SID=XE))) oracle.jdbc.OracleDriver user app_user 62C32F70E98297522AD97E15439FAC0E SQL SELECT 1 FROM DUAL jdbc/hrDS Application Additionally you need to make sure that the version of the shared libraries of the OCI driver match the version of the JDBC driver in your Java EE container or Java application and are within your PATH (on Windows) or LD_LIBRARY_PATH (on most Unix-based systems). Installing the Oracle Database Instance Client software works perfectly. Provide the user name that connects through the proxy user This part needs some modification of your application software and session facade. Session Facade Changes In the Session Facade we must ensure that every call that goes through the EntityManager must be prepared correctly and uniquely assigned to this session. The second is really important, as the EntityManager works with a connection pool and can not guarantee that we set the proxy user on the connection that will be used for the database activities. To avoid changing every method call of the Session Facade we provide a method to set the username of the user that connects through the proxy user. This method needs to be called by the Facade client bfore doing anything else. public void setUsername(String name) { username = name; } Next we provide a means to instruct the TopLink EntityManager Delegate to use Oracle Proxy Authentication. (I love small helper methods to hide the nitty-gritty details and avoid repeating myself.) private void setSessionUser() { setSessionUser(username); } private void setSessionUser(String user) { if (user != null && !user.isEmpty()) { EntityManagerImpl emDelegate = ((EntityManagerImpl)em.getDelegate()); emDelegate.setProperty(EntityManagerProperties.ORACLE_PROXY_TYPE, OracleConnection.PROXYTYPE_USER_NAME); emDelegate.setProperty(OracleConnection.PROXY_USER_NAME, user); emDelegate.setProperty(EntityManagerProperties.EXCLUSIVE_CONNECTION_MODE, "Always"); } } The final step is use the EJB 3.0 AroundInvoke interceptor. This interceptor will be called around every method invocation. We therefore check whether the Facade methods will be called or not. If so, we set the user for proxy authentication and the normal method flow continues. @AroundInvoke public Object proxyInterceptor(InvocationContext invocationCtx) throws Exception { if (invocationCtx.getTarget() instanceof DataFacadeBean) { setSessionUser(); } return invocationCtx.proceed(); } Benefits Using Oracle Proxy Authentification has a number of additional benefits appart from implementing the role model of your application: Fine grained access control for temporary users of the account, without compromising the original password. Enabling database auditing and logging. Better identification of performance bottlenecks. References Effective Oracle Database 10g Security by Design, David Knox TopLink Developer's Guide, Chapter 98

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A ToDynamic() Extension Method For Fluent Reflection

- by Dixin

Recently I needed to demonstrate some code with reflection, but I felt it inconvenient and tedious. To simplify the reflection coding, I created a ToDynamic() extension method. The source code can be downloaded from here. Problem One example for complex reflection is in LINQ to SQL. The DataContext class has a property Privider, and this Provider has an Execute() method, which executes the query expression and returns the result. Assume this Execute() needs to be invoked to query SQL Server database, then the following code will be expected: using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // Executes the query. Here reflection is required, // because Provider, Execute(), and ReturnValue are not public members. IEnumerable<Product> results = database.Provider.Execute(query.Expression).ReturnValue; // Processes the results. foreach (Product product in results) { Console.WriteLine("{0}, {1}", product.ProductID, product.ProductName); } } Of course, this code cannot compile. And, no one wants to write code like this. Again, this is just an example of complex reflection. using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // database.Provider PropertyInfo providerProperty = database.GetType().GetProperty( "Provider", BindingFlags.NonPublic | BindingFlags.GetProperty | BindingFlags.Instance); object provider = providerProperty.GetValue(database, null); // database.Provider.Execute(query.Expression) // Here GetMethod() cannot be directly used, // because Execute() is a explicitly implemented interface method. Assembly assembly = Assembly.Load("System.Data.Linq"); Type providerType = assembly.GetTypes().SingleOrDefault( type => type.FullName == "System.Data.Linq.Provider.IProvider"); InterfaceMapping mapping = provider.GetType().GetInterfaceMap(providerType); MethodInfo executeMethod = mapping.InterfaceMethods.Single(method => method.Name == "Execute"); IExecuteResult executeResult = executeMethod.Invoke(provider, new object[] { query.Expression }) as IExecuteResult; // database.Provider.Execute(query.Expression).ReturnValue IEnumerable<Product> results = executeResult.ReturnValue as IEnumerable<Product>; // Processes the results. foreach (Product product in results) { Console.WriteLine("{0}, {1}", product.ProductID, product.ProductName); } } This may be not straight forward enough. So here a solution will implement fluent reflection with a ToDynamic() extension method: IEnumerable<Product> results = database.ToDynamic() // Starts fluent reflection. .Provider.Execute(query.Expression).ReturnValue; C# 4.0 dynamic In this kind of scenarios, it is easy to have dynamic in mind, which enables developer to write whatever code after a dot: using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // database.Provider dynamic dynamicDatabase = database; dynamic results = dynamicDatabase.Provider.Execute(query).ReturnValue; } This throws a RuntimeBinderException at runtime: 'System.Data.Linq.DataContext.Provider' is inaccessible due to its protection level. Here dynamic is able find the specified member. So the next thing is just writing some custom code to access the found member. .NET 4.0 DynamicObject, and DynamicWrapper<T> Where to put the custom code for dynamic? The answer is DynamicObject’s derived class. I first heard of DynamicObject from Anders Hejlsberg's video in PDC2008. It is very powerful, providing useful virtual methods to be overridden, like: TryGetMember() TrySetMember() TryInvokeMember() etc. (In 2008 they are called GetMember, SetMember, etc., with different signature.) For example, if dynamicDatabase is a DynamicObject, then the following code: dynamicDatabase.Provider will invoke dynamicDatabase.TryGetMember() to do the actual work, where custom code can be put into. Now create a type to inherit DynamicObject: public class DynamicWrapper<T> : DynamicObject { private readonly bool _isValueType; private readonly Type _type; private T _value; // Not readonly, for value type scenarios. public DynamicWrapper(ref T value) // Uses ref in case of value type. { if (value == null) { throw new ArgumentNullException("value"); } this._value = value; this._type = value.GetType(); this._isValueType = this._type.IsValueType; } public override bool TryGetMember(GetMemberBinder binder, out object result) { // Searches in current type's public and non-public properties. PropertyInfo property = this._type.GetTypeProperty(binder.Name); if (property != null) { result = property.GetValue(this._value, null).ToDynamic(); return true; } // Searches in explicitly implemented properties for interface. MethodInfo method = this._type.GetInterfaceMethod(string.Concat("get_", binder.Name), null); if (method != null) { result = method.Invoke(this._value, null).ToDynamic(); return true; } // Searches in current type's public and non-public fields. FieldInfo field = this._type.GetTypeField(binder.Name); if (field != null) { result = field.GetValue(this._value).ToDynamic(); return true; } // Searches in base type's public and non-public properties. property = this._type.GetBaseProperty(binder.Name); if (property != null) { result = property.GetValue(this._value, null).ToDynamic(); return true; } // Searches in base type's public and non-public fields. field = this._type.GetBaseField(binder.Name); if (field != null) { result = field.GetValue(this._value).ToDynamic(); return true; } // The specified member is not found. result = null; return false; } // Other overridden methods are not listed. } In the above code, GetTypeProperty(), GetInterfaceMethod(), GetTypeField(), GetBaseProperty(), and GetBaseField() are extension methods for Type class. For example: internal static class TypeExtensions { internal static FieldInfo GetBaseField(this Type type, string name) { Type @base = type.BaseType; if (@base == null) { return null; } return @base.GetTypeField(name) ?? @base.GetBaseField(name); } internal static PropertyInfo GetBaseProperty(this Type type, string name) { Type @base = type.BaseType; if (@base == null) { return null; } return @base.GetTypeProperty(name) ?? @base.GetBaseProperty(name); } internal static MethodInfo GetInterfaceMethod(this Type type, string name, params object[] args) { return type.GetInterfaces().Select(type.GetInterfaceMap).SelectMany(mapping => mapping.TargetMethods) .FirstOrDefault( method => method.Name.Split('.').Last().Equals(name, StringComparison.Ordinal) && method.GetParameters().Count() == args.Length && method.GetParameters().Select( (parameter, index) => parameter.ParameterType.IsAssignableFrom(args[index].GetType())).Aggregate( true, (a, b) => a && b)); } internal static FieldInfo GetTypeField(this Type type, string name) { return type.GetFields( BindingFlags.GetField | BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault( field => field.Name.Equals(name, StringComparison.Ordinal)); } internal static PropertyInfo GetTypeProperty(this Type type, string name) { return type.GetProperties( BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault( property => property.Name.Equals(name, StringComparison.Ordinal)); } // Other extension methods are not listed. } So now, when invoked, TryGetMember() searches the specified member and invoke it. The code can be written like this: dynamic dynamicDatabase = new DynamicWrapper<NorthwindDataContext>(ref database); dynamic dynamicReturnValue = dynamicDatabase.Provider.Execute(query.Expression).ReturnValue; This greatly simplified reflection. ToDynamic() and fluent reflection To make it even more straight forward, A ToDynamic() method is provided: public static class DynamicWrapperExtensions { public static dynamic ToDynamic<T>(this T value) { return new DynamicWrapper<T>(ref value); } } and a ToStatic() method is provided to unwrap the value: public class DynamicWrapper<T> : DynamicObject { public T ToStatic() { return this._value; } } In the above TryGetMember() method, please notice it does not output the member’s value, but output a wrapped member value (that is, memberValue.ToDynamic()). This is very important to make the reflection fluent. Now the code becomes: IEnumerable<Product> results = database.ToDynamic() // Here starts fluent reflection. .Provider.Execute(query.Expression).ReturnValue .ToStatic(); // Unwraps to get the static value. With the help of TryConvert(): public class DynamicWrapper<T> : DynamicObject { public override bool TryConvert(ConvertBinder binder, out object result) { result = this._value; return true; } } ToStatic() can be omitted: IEnumerable<Product> results = database.ToDynamic() .Provider.Execute(query.Expression).ReturnValue; // Automatically converts to expected static value. Take a look at the reflection code at the beginning of this post again. Now it is much much simplified! Special scenarios In 90% of the scenarios ToDynamic() is enough. But there are some special scenarios. Access static members Using extension method ToDynamic() for accessing static members does not make sense. Instead, DynamicWrapper<T> has a parameterless constructor to handle these scenarios: public class DynamicWrapper<T> : DynamicObject { public DynamicWrapper() // For static. { this._type = typeof(T); this._isValueType = this._type.IsValueType; } } The reflection code should be like this: dynamic wrapper = new DynamicWrapper<StaticClass>(); int value = wrapper._value; int result = wrapper.PrivateMethod(); So accessing static member is also simple, and fluent of course. Change instances of value types Value type is much more complex. The main problem is, value type is copied when passing to a method as a parameter. This is why ref keyword is used for the constructor. That is, if a value type instance is passed to DynamicWrapper<T>, the instance itself will be stored in this._value of DynamicWrapper<T>. Without the ref keyword, when this._value is changed, the value type instance itself does not change. Consider FieldInfo.SetValue(). In the value type scenarios, invoking FieldInfo.SetValue(this._value, value) does not change this._value, because it changes the copy of this._value. I searched the Web and found a solution for setting the value of field: internal static class FieldInfoExtensions { internal static void SetValue<T>(this FieldInfo field, ref T obj, object value) { if (typeof(T).IsValueType) { field.SetValueDirect(__makeref(obj), value); // For value type. } else { field.SetValue(obj, value); // For reference type. } } } Here __makeref is a undocumented keyword of C#. But method invocation has problem. This is the source code of TryInvokeMember(): public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (binder == null) { throw new ArgumentNullException("binder"); } MethodInfo method = this._type.GetTypeMethod(binder.Name, args) ?? this._type.GetInterfaceMethod(binder.Name, args) ?? this._type.GetBaseMethod(binder.Name, args); if (method != null) { // Oops! // If the returnValue is a struct, it is copied to heap. object resultValue = method.Invoke(this._value, args); // And result is a wrapper of that copied struct. result = new DynamicWrapper<object>(ref resultValue); return true; } result = null; return false; } If the returned value is of value type, it will definitely copied, because MethodInfo.Invoke() does return object. If changing the value of the result, the copied struct is changed instead of the original struct. And so is the property and index accessing. They are both actually method invocation. For less confusion, setting property and index are not allowed on struct. Conclusions The DynamicWrapper<T> provides a simplified solution for reflection programming. It works for normal classes (reference types), accessing both instance and static members. In most of the scenarios, just remember to invoke ToDynamic() method, and access whatever you want: StaticType result = someValue.ToDynamic()._field.Method().Property[index]; In some special scenarios which requires changing the value of a struct (value type), this DynamicWrapper<T> does not work perfectly. Only changing struct’s field value is supported. The source code can be downloaded from here, including a few unit test code.

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JBoss Seam: In ScopeType.PAGE I get: java.lang.IllegalStateException: No conversation context active

- by Markos Fragkakis

Hi all, I have a page-scoped component, which has an instance variable List with data, which I display in a datatable. This datatable has pagination, sorting and filtering. The first time gate into the page, I get this appended in my URL: ?conversationId=97. The page works correctly, and when I change datatable pages no now component is created. After a minute or two, and at seamingly random time, I get an exception saying that there is no context. I have not used @Create in my code or my navigation files. So, I have two questions: Why do I get this suffix in my URL? Why did a conversation start? Why the exception? The component is scoped to PAGE. If I received an exception, it should not be related to a conversation. Right? Or is the conversation the exception is referring a temporary conversation? Cheers! UPDATE: This is the page: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:a4j="http://richfaces.org/a4j" xmlns:rich="http://richfaces.org/rich"> <body> <ui:composition template="/WEB-INF/facelets/templates/template.xhtml"> <ui:define name="content">  <script type="text/javascript"> function submitByEnter(event){ if (event.keyCode == 13) { if (event.preventDefault) { // Firefox event.preventDefault(); } else { // IE event.returnValue = false; } document.getElementById("refreshButton").click(); } } </script> <h:form prependId="false"> <h:commandButton action="Back" value="Back to home page" /> <br /> <p><h:outputText value="Applicants and Products (experimentation page)" class="page_title" /></p> <h:commandButton action="#{applicantProductListBean.showCreateApplicant}" value="Create Applicant" id="createApplicantButton"> </h:commandButton> <a4j:commandButton value="Refresh" id="refreshButton" action="#{applicantProductListBean.refreshData}" image="/images/icons/refresh48x48.gif" reRender="compositeTable, compositeScroller">   </a4j:commandButton> <rich:toolTip for="createApplicantButton" value="Create Applicant" /> <rich:dataTable styleClass="composite2DataTable" id="compositeTable" rows="1" columnClasses="col" value="#{applicantProductListBean.dataModel}" var="pageAppList"> <f:facet name="header"> <rich:columnGroup> <rich:column colspan="3"> <h:outputText styleClass="headerText" value="Applicants" /> </rich:column> <rich:column colspan="3"> <h:outputText styleClass="headerText" value="Products" /> </rich:column> <rich:column breakBefore="true"> <h:outputText styleClass="headerText" value="Applicant Name" /> <a4j:commandButton id="sortingApplicantNameButton" action="#{applicantProductListBean.toggleSorting('applicantName')}" image="/images/icons/sorting/#{sortingFilteringBean.applicantProductListSorting.sortingValues['applicantName']}.gif" reRender="sortingApplicantNameButton, sortingApplicantEmailButton, compositeTable, compositeScroller">   </a4j:commandButton> <br /> <h:inputText value="#{sortingFilteringBean.applicantProductListFiltering.filteringValues['applicantName']}" id="applicantNameFilterValue" onkeypress="return submitByEnter(event)"> </h:inputText> </rich:column> <rich:column> <h:outputText styleClass="headerText" value="Applicant Email" /> <a4j:commandButton id="sortingApplicantEmailButton" action="#{applicantProductListBean.toggleSorting('applicantEmail')}" image="/images/icons/sorting/#{sortingFilteringBean.applicantProductListSorting.sortingValues['applicantEmail']}.gif" reRender="sortingApplicantNameButton, sortingApplicantEmailButton, compositeTable, compositeScroller">   </a4j:commandButton> <br /> <h:inputText value="#{sortingFilteringBean.applicantProductListFiltering.filteringValues['applicantEmail']}" id="applicantEmailFilterValue" onkeypress="return submitByEnter(event)"> </h:inputText> </rich:column> <rich:column> <h:outputText styleClass="headerText" value="Applicant Actions" /> </rich:column> <rich:column> <h:outputText styleClass="headerText" value="Product Name" /> <a4j:commandButton id="sortingProductNameButton" action="#{applicantProductListBean.toggleSorting('productName')}" immediate="true" image="/images/icons/sorting/#{sortingFilteringBean.applicantProductListSorting.sortingValues['productName']}.gif" reRender="sortingProductNameButton, compositeTable, compositeScroller"> </a4j:commandButton> <br /> <h:inputText value="#{sortingFilteringBean.applicantProductListFiltering.filteringValues['productName']}" id="productNameFilterValue" onkeypress="return submitByEnter(event)"> </h:inputText> </rich:column> <rich:column> <h:outputText styleClass="headerText" value="Product Email" /> <br /> <h:inputText value="#{sortingFilteringBean.applicantProductListFiltering.filteringValues['productEmail']}" id="productEmailFilterValue" onkeypress="return submitByEnter(event)"> </h:inputText> </rich:column> <rich:column> <h:outputText styleClass="headerText" value="Product Actions" /> </rich:column> </rich:columnGroup> </f:facet> <rich:subTable rowClasses="odd_applicant_row, even_applicant_row" value="#{pageAppList}" var="app"> <rich:column styleClass=" internal_cell composite2TextContainingColumn" valign="top"> <h:outputText value="#{app.name}" /> </rich:column> <rich:column styleClass="internal_cell composite2TextContainingColumn" valign="top"> <h:outputText value="#{app.receiptEmail}" /> </rich:column> <rich:column valign="top" styleClass="buttonsColumn"> <h:commandButton action="#{applicantProductListBean.showUpdateApplicant(app)}" image="/images/icons/edit.jpg"> </h:commandButton>  <h:commandButton action="#{applicantProductListBean.showDeleteApplicant(app)}" image="/images/icons/delete.png"> </h:commandButton>  </rich:column> <rich:column colspan="3"> <table class="productsTableTable"> <tbody> <tr> <td class="createProductButtonTableCell"><h:commandButton action="#{applicantProductListBean.showCreateProduct(app)}" value="Create Product"> </h:commandButton>  </td> </tr> <tr> <td><rich:dataTable value="#{app.products}" var="prod" rowClasses="odd_product_row, even_product_row"> <rich:column styleClass="internal_cell composite2TextContainingColumn"> <h:outputText value="#{prod.inventedName}" /> </rich:column> <rich:column styleClass="internal_cell composite2TextContainingColumn"> <h:outputText value="#{prod.receiptEmail}" /> </rich:column> <rich:column styleClass="buttonsColumn"> <h:commandButton action="#{applicantProductListBean.showUpdateProduct(prod)}" image="/images/icons/edit.jpg"> </h:commandButton>  <h:commandButton action="#{applicantProductListBean.showDeleteProduct(prod)}" image="/images/icons/delete.png"> <f:setPropertyActionListener target="#{productBean.product}" value="#{prod}" /> </h:commandButton>  </rich:column> </rich:dataTable></td> </tr> </tbody> </table> </rich:column> </rich:subTable> <f:facet name="footer"> <h:panelGrid columns="1" styleClass="applicantProductListFooter"> <h:outputText value="#{msgs.no_results}" rendered="#{(empty applicantProductListBean.dataModel) || (applicantProductListBean.dataModel.rowCount==0)}"/> <rich:datascroller align="center" for="compositeTable" page="#{pageScrollerBean.applicantProductListPage}" id="compositeScroller" reRender="compositeTable" renderIfSinglePage="false" fastControls="hide"> <f:facet name="first"> <h:outputText value="#{msgs.first}" styleClass="scrollerCell" /> </f:facet> <f:facet name="first_disabled"> <h:outputText value="#{msgs.first}" styleClass="scrollerCell" /> </f:facet> <f:facet name="last"> <h:outputText value="#{msgs.last}" styleClass="scrollerCell" /> </f:facet> <f:facet name="last_disabled"> <h:outputText value="#{msgs.last}" styleClass="scrollerCell" /> </f:facet> <f:facet name="next"> <h:outputText value="#{msgs.next}" styleClass="scrollerCell" /> </f:facet> <f:facet name="next_disabled"> <h:outputText value="#{msgs.next}" styleClass="scrollerCell" /> </f:facet> <f:facet name="previous"> <h:outputText value="#{msgs.previous}" styleClass="scrollerCell" /> </f:facet> <f:facet name="previous_disabled"> <h:outputText value="#{msgs.previous}" styleClass="scrollerCell" /> </f:facet> </rich:datascroller> </h:panelGrid> </f:facet> </rich:dataTable> </h:form> </ui:define> This is the backing bean: @Name("applicantProductListBean") @Scope(ScopeType.PAGE) public class ApplicantProductListBean extends BasePagedSortableFilterableListBean { /** * Public field for ad-hoc injection to work. */ @EJB(name = "FacadeService") public ApplicantFacadeService applicantFacadeService; @Logger private static Log logger; private final int pageSize = 10; @Out(scope = ScopeType.CONVERSATION, required = false) Applicant currentApplicant; @Out(scope = ScopeType.CONVERSATION, required = false) Product product; @Create public void onCreate() { System.out.println("Create"); } @Override protected DataModel initDataModel(int pageSize) { // get filtering and sorting from session sorting = getSorting(); filtering = getFiltering(); // System.out.println("Initializing a Composite3DataModel"); // System.out.println("Pagesize: " + pageSize); // System.out.println("Filtering: " + filtering.getFilteringValues()); // System.out.println("Sorting: " + sorting.getSortingValues()); return new Composite3DataModel(1, sorting, filtering); } // Navigation methods /** * Navigation-returning method, returns the action to follow after pressing * the "Create Applicant" button * * @return the action to be taken */ public Navigation.ApplicantProductList showCreateApplicant() { return Navigation.ApplicantProductList.SHOW_CREATE_APPLICANT; } /** * Navigation-returning method, returns the action to follow after pressing * the "Edit Applicant" button * * @return the action to be taken */ public Navigation.ApplicantProductList showUpdateApplicant( Applicant applicant) { this.currentApplicant = applicant; return Navigation.ApplicantProductList.SHOW_UPDATE_APPLICANT; } /** * Navigation-returning method, returns the action to follow after pressing * the "Delete Applicant" button * * @return the action to be taken */ public Navigation.ApplicantProductList showDeleteApplicant( Applicant applicant) { this.currentApplicant = applicant; return Navigation.ApplicantProductList.SHOW_DELETE_APPLICANT; } /** * Navigation-returning method, returns the action to follow after pressing * the "Create Product" button * * @return the action to be taken */ public Navigation.ApplicantProductList showCreateProduct(Applicant app) { this.product = new Product(); this.product.setApplicant(app); return Navigation.ApplicantProductList.SHOW_CREATE_PRODUCT; } /** * Navigation-returning method, returns the action to follow after pressing * the "Edit Product" button * * @return the action to be taken */ public Navigation.ApplicantProductList showUpdateProduct(Product prod) { this.product = prod; return Navigation.ApplicantProductList.SHOW_UPDATE_PRODUCT; } /** * Navigation-returning method, returns the action to follow after pressing * the "Delete Product" button * * @return the action to be taken */ public Navigation.ApplicantProductList showDeleteProduct(Product prod) { this.product = prod; return Navigation.ApplicantProductList.SHOW_DELETE_PRODUCT; } /** * */ @Override public Sorting getSorting() { if (sorting == null) { return (getSortingFilteringBeanFromSession() .getApplicantProductListSorting()); } return sorting; } /** * */ @Override public void setSorting(Sorting sorting) { getSortingFilteringBeanFromSession().setApplicantProductListSorting( sorting); } /** * */ @Override public Filtering getFiltering() { if (filtering == null) { return (getSortingFilteringBeanFromSession() .getApplicantProductListFiltering()); } return filtering; } /** * */ @Override public void setFiltering(Filtering filtering) { getSortingFilteringBeanFromSession().setApplicantProductListFiltering( filtering); } /** * @return the currentApplicant */ public Applicant getCurrentApplicant() { return currentApplicant; } /** * @param currentApplicant * the currentApplicant to set */ public void setCurrentApplicant(Applicant applicant) { this.currentApplicant = applicant; } /** * The model for this page * */ private class Composite3DataModel extends PagedSortableFilterableDataModel<List<Applicant>> { public Composite3DataModel(int pageSize, Sorting sorting, Filtering filtering) { super(pageSize, sorting, filtering); } @Override protected DataPage<List<Applicant>> fetchPage(int fakeStartRow, int fakePageSize) { // if (logger.isTraceEnabled()) { System.out.println("Getting page with fakeStartRow: " + fakeStartRow + " and fakePageSize " + fakePageSize); // } // to find the page size multiply the startRow and the fakePageSize // (which is 1) to the actual page size int startRow = fakeStartRow * ApplicantProductListBean.this.pageSize; int pageSize = fakePageSize * ApplicantProductListBean.this.pageSize; // if (logger.isTraceEnabled()) { System.out.println("Getting page with startRow: " + startRow + " and pageSize " + pageSize); // } List<Applicant> pageApplicants = applicantFacadeService .findPagedWithCriteria(startRow, pageSize, filtering, sorting); // List<Applicant> pageApplicants = applicantFacadeService // .findPagedWithDynamicQuery(startRow, pageSize, filtering, // sorting, true); // if (logger.isTraceEnabled()) { System.out.println("Set of applicants: " + pageApplicants.size()); // } List<List<Applicant>> pageApplicantsListContainer = new ArrayList<List<Applicant>>(); pageApplicantsListContainer.add(pageApplicants); DataPage<List<Applicant>> dataPage = new DataPage<List<Applicant>>( this.getRowCount(), fakeStartRow, pageApplicantsListContainer); return dataPage; } @Override protected int getDatasetSize() { // int size = getServiceFacade().countWithCriteria(filtering, // sorting); // int size = // applicantFacadeService.countWithDynamicQuery(filtering, sorting, // false); int size = (int) Math.ceil((double) applicantFacadeService .countWithCriteria(filtering, sorting, false) / pageSize); if (logger.isTraceEnabled()) { logger.trace("Got Dataset Size: " + size); } return size; } } /** * @return the product */ public Product getProduct() { return product; } /** * @param product * the product to set */ public void setProduct(Product product) { this.product = product; } }

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Why can't I build Deluge?

- by hugemeow

Deluge is a BitTorrent Client. I am trying to build it from source, since I don't have privilege to install it as root. I am using python setup.py build. But, it failed following message, why? copying deluge/ui/web/themes/images/gray/slider/slider-v-thumb.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/gray/slider copying deluge/ui/web/themes/images/gray/slider/slider-thumb.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/gray/slider copying deluge/ui/web/themes/images/gray/panel/top-bottom.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/gray/panel copying deluge/ui/web/themes/images/gray/tabs/tab-strip-bg.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/gray/tabs copying deluge/ui/web/themes/images/yourtheme/window/right-corners.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/window copying deluge/ui/web/themes/images/yourtheme/window/left-corners.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/window copying deluge/ui/web/themes/images/yourtheme/window/left-right.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/window copying deluge/ui/web/themes/images/yourtheme/window/top-bottom.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/window creating build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/slider copying deluge/ui/web/themes/images/yourtheme/slider/slider-v-thumb.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/slider copying deluge/ui/web/themes/images/yourtheme/slider/slider-thumb.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/slider copying deluge/ui/web/themes/images/yourtheme/slider/slider-bg.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/slider copying deluge/ui/web/themes/images/yourtheme/slider/slider-v-bg.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/slider copying deluge/ui/web/themes/images/yourtheme/panel/top-bottom.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/panel copying deluge/ui/web/themes/images/yourtheme/grid/hmenu-lock.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/grid copying deluge/ui/web/themes/images/yourtheme/grid/hmenu-unlock.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/grid copying deluge/ui/web/themes/images/yourtheme/tabs/tab-strip-bg.png -> build/lib.linux-x86_64-2.4/deluge/ui/web/themes/images/yourtheme/tabs running build_ext building 'libtorrent' extension gcc -pthread -shared -L/usr/lib64 -L/opt/local/lib -lboost_filesystem -lboost_date_time -lboost_iostreams -lboost_python -lboost_thread -lpthread -lssl -lz -o build/lib.linux-x86_64-2.4/deluge/libtorrent.so /usr/bin/ld: cannot find -lboost_filesystem collect2: ld returned 1 exit status error: command 'gcc' failed with exit status 1 [mirror@innov deluge-1.3.5]$ echo $? 1 Edit 1: gcc version and os information $(which gcc) --version gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-52) Copyright (C) 2006 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. cat /etc/issue CentOS release 5.7 (Final) Kernel \r on an \m Edit 2: boost is referenced by setup.py in deluge 114 if OS == "linux": 115 if os.path.exists(os.path.join(sysconfig.get_config_vars()['LIBDIR'], \ 116 'libboost_filesystem-mt.so')): 117 boost_filesystem = "boost_filesystem-mt" 118 elif os.path.exists(os.path.join(sysconfig.get_config_vars()['LIBDIR'], \ 119 'libboost_filesystem.so')): 120 boost_filesystem = "boost_filesystem" 121 if os.path.exists(os.path.join(sysconfig.get_config_vars()['LIBDIR'], \ 122 'libboost_date_time-mt.so')): 123 boost_date_time = "boost_date_time-mt" 124 elif os.path.exists(os.path.join(sysconfig.get_config_vars()['LIBDIR'], \ 125 'libboost_date_time.so')): 126 boost_date_time = "boost_date_time" 127 if os.path.exists(os.path.join(sysconfig.get_config_vars()['LIBDIR'], \ 128 'libboost_thread-mt.so')): 129 boost_thread = "boost_thread-mt" 130 elif os.path.exists(os.path.join(sysconfig.get_config_vars()['LIBDIR'], \ 131 'libboost_thread.so')): 132 boost_thread = "boost_thread" 133 134 if 'boost_filesystem' not in vars(): 135 boost_filesystem = "boost_filesystem-mt" 136 if 'boost_date_time' not in vars(): 137 boost_date_time = "boost_date_time-mt" 138 if 'boost_thread' not in vars(): 139 boost_thread = "boost_thread-mt" 140 141 elif OS == "freebsd": 142 boost_filesystem = "boost_filesystem" 143 boost_date_time = "boost_date_time" 144 boost_thread = "boost_thread" 145 else: 146 boost_filesystem = "boost_filesystem-mt" 147 boost_date_time = "boost_date_time-mt" 148 boost_thread = "boost_thread-mt" 149 150 librariestype = [boost_filesystem, boost_date_time, 151 boost_thread, 'z', 'pthread', 'ssl', 'crypto']

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How to load the environment variables at boot time before X11 on Ubuntu Precise?

- by Fnux

Using Ubuntu Precise 64 bit, I'm facing a problem that I'm unable to solve and that I'll try to describe below: I'm using a console mode program (let's say abc) that uses Go, NodeJS, Java and Scala. In order for abc to work with these languages, I've to declare the following statements: a) within /etc/environment: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" CLASSPATH=$CLASSPATH:/usr/share/java/scala-library.jar b) within /etc/login.defs ENV_SUPATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin ENV_PATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin c) a) within /etc/sudoers: `# env_reset Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin"` Then, when I start abc from a terminal, all is fine and I can use any of the 4 languages described above. However, if I put a script within /etc/init.d that starts abc during the boot process (i.e. before to start the GUI), using Java from abc still is fine, but using Go, NodeJS or Scala doesn't work anymore. Then, I guess that during the boot process, the script within /etc/init.d that starts abc is executed before that the different environment variables set within /etc/sudoers, /etc/environment and /etc/login.defs are loaded. So, my question is: how to force the environment variables to be loaded before that my script starting abc is launched? Any help and advice on this topic would be trully appreciated. TIA. Cheers. Thanks again to Mark and Danila. Below is the current "abc" script file that I put within /etc/init.d `#! /bin/sh ### EDIT: ADD THIS VARS DEFINITIONS: PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" CLASSPATH=$CLASSPATH:/usr/share/java/scala-library.jar "ENV_SUPATH PATH"="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" "ENV_PATH PATH"="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" "Defaults secure_path"="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" ##### EXPORT this VARS so they are accessible to children:" export "PATH" "CLASSPATH" "ENV_SUPATH PATH" "ENV_PATH PATH" "Defaults secure_path" `### BEGIN INIT INFO `# Provides: abc `# Required-Start: $remote_fs $syslog `# Required-Stop: $remote_fs $syslog `# Default-Start: 2 3 4 5 `# Default-Stop: 0 1 6 `# Short-Description: abc initscript `# Description: This iniscript starts and stops abc `### END INIT INFO `# Author: Fnux, fnux.fl at gmail dot com `# Version: 1.2 `# Note: (edit ABC_PATH if abc isn't installed in /opt/abc) NAME=abc ABC_PATH=/opt/abc START="-d" STOP="-k" VERSION="-v" SCRIPTNAME=/etc/init.d/$NAME STARTMESG="\nStarting abc in deamon mode." UPMESG="\n$NAME is running." DOWNMESG="\n$NAME is not running." STATUS=`pidof $NAME` `# Exit if abc is not installed [ -x "$ABC_PATH/$NAME" ] || exit 0 case "$1" in start) echo $STARTMESG cd $ABC_PATH ./$NAME $START ;; stop) cd $ABC_PATH ./$NAME $STOP ;; status) if [ "$STATUS" > 0 ] ; then echo $UPMESG else echo $DOWNMESG fi ;; restart) cd $ABC_PATH ./$NAME $STOP echo $STARTMESG ./$NAME $START ;; version) cd $ABC_PATH ./$NAME $VERSION ;; *) echo "Usage: $SCRIPTNAME {start|status|restart|stop|version}" >&2 exit 3 ;; esac : So, where and how should I write the needed environment variables for: a) Go needs the following statements (ie: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin" ENV_SUPATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin ENV_PATH PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin `# env_reset Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/go/bin") b) and Scala needs this one: (ie CLASSPATH=$CLASSPATH:/usr/share/java/scala-library.jar). TIA for an explanation how to do so. Cheers.

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centos6.3 varnish3.03 get the wrong backend

- by Sola.Shawn

I install varnish3.03 with yum! I got a problem with it my varnish config bellow:** # #backend weibo { .host = "192.168.1.178"; .port = "8080"; .connect_timeout=20s; .first_byte_timeout=20s; .between_bytes_timeout=20s; } #backend smth { .host = "192.168.1.115"; .port = "8080"; .connect_timeout=20s; .first_byte_timeout=20s; .between_bytes_timeout=20s; } #sub vcl_recv { if (req.restarts == 0) { if (req.http.x-forwarded-for) { set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip; } else { set req.http.X-Forwarded-For = client.ip; } } if (req.request != "GET" && req.request != "HEAD" && req.request != "PUT" && req.request != "POST" && req.request != "TRACE" && req.request != "OPTIONS" && req.request != "DELETE") { # /* Non-RFC2616 or CONNECT which is weird. */ return(pipe); } if (req.request != "GET" && req.request != "HEAD") { # /* We only deal with GET and HEAD by default */ return(pass); } if (req.http.Authorization || req.http.Cookie) { /* Not cacheable by default */ return(pass); } if (req.http.host ~ "^(hk.)?weibo.com"){ set req.http.host = "hk.weibo.com"; set req.backend = weibo; } elseif (req.http.host ~ "^(www.)?newsmth.net"){ set req.http.host = "www.newsmth.net"; set req.backend = smth; } else { error 404 "Unknown virtual host"; } return(lookup); } ##sub vcl_pipe { return(pipe); } #sub vcl_pass { return(pass); } #sub vcl_hash { hash_data(req.url); if(req.http.host) { hash_data(req.http.host); } else { hash_data(server.ip); } return(hash); } #sub vcl_hit { if(req.http.Cache-Control~"no-cache"||req.http.Cache-Control~"max-age=0"||req.http.Pragma~"no-cache"){ set obj.ttl=0s; return (restart); } return(deliver); } #sub vcl_miss { return(fetch); } #sub vcl_fetch { if (beresp.ttl <= 120s || beresp.http.Set-Cookie || beresp.http.Vary == "*") { /* * Mark as "Hit-For-Pass" for the next 2 minutes */ set beresp.ttl = 10s; return (hit_for_pass); } return(deliver); } #sub vcl_deliver { return(deliver); } #sub vcl_init { return(ok); } #sub vcl_fini { return(ok); } and my Win7's hosts file add bellow: 192.168.1.178 www.newsmth.net 192.168.1.178 hk.weibo.com start varnish varnishd -f /etc/varnish/dd.vcl -s malloc,100M -a 0.0.0.0:8000 -T 0.0.0.0:3500<br> but when I access the "hk.weibo.com:8000" it fine, and got: Hello,I am hk.weibo.com! but when access http://www.newsmth.net:8000/, got: Hello,I am hk.weibo.com! <br> My question is why it isn't "Hello,I am www.newsmth.net!"? varnish fetched the content from the wrong backend. Does anyone know how to fix this?

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Why is my simple recusive method's final return value always off by 1?

- by FrankTheTank

I'm attempting to create a text-based version of this game: http://www.cse.nd.edu/java/SameGame.html Here is the code I have so far: #include <iostream> #include <vector> #include <ctime> class Clickomania { public: Clickomania(); std::vector<std::vector<int> > board; int move(int, int); bool isSolved(); void print(); void pushDown(); bool isValid(); }; Clickomania::Clickomania() : board(12, std::vector<int>(8,0)) { srand((unsigned)time(0)); for(int i = 0; i < 12; i++) { for(int j = 0; j < 8; j++) { int color = (rand() % 3) + 1; board[i][j] = color; } } } void Clickomania::pushDown() { for(int i = 0; i < 8; i++) { for(int j = 0; j < 12; j++) { if (board[j][i] == 0) { for(int k = j; k > 0; k--) { board[k][i] = board[k-1][i]; } board[0][i] = 0; } } } } int Clickomania::move(int row, int col) { bool match = false; int totalMatches = 0; if (row > 12 || row < 0 || col > 8 || col < 0) { return 0; } int currentColor = board[row][col]; board[row][col] = 0; if ((row + 1) < 12) { if (board[row+1][col] == currentColor) { match = true; totalMatches++; totalMatches += move(row+1, col); } } if ((row - 1) >= 0) { if (board[row-1][col] == currentColor) { match = true; totalMatches++; totalMatches += move(row-1, col); } } if ((col + 1) < 8) { if (board[row][col+1] == currentColor) { match = true; totalMatches++; totalMatches += move(row, col+1); } } if ((col - 1) >= 0) { if (board[row][col-1] == currentColor) { match = true; totalMatches++; totalMatches += move(row, col-1); } } return totalMatches; } void Clickomania::print() { for(int i = 0; i < 12; i++) { for(int j = 0; j < 8; j++) { std::cout << board[i][j]; } std::cout << "\n"; } } int main() { Clickomania game; game.print(); int row; int col; std::cout << "Enter row: "; std::cin >> row; std::cout << "Enter col: "; std::cin >> col; int numDestroyed = game.move(row,col); game.print(); std::cout << "Destroyed: " << numDestroyed << "\n"; } The method that is giving me trouble is my "move" method. This method, given a pair of coordinates, should delete all the squares at that coordinate with the same number and likewise with all the squares with the same number connected to it. If you play the link I gave above you'll see how the deletion works on a click. int Clickomania::move(int row, int col) { bool match = false; int totalMatches = 0; if (row > 12 || row < 0 || col > 8 || col < 0) { return 0; } int currentColor = board[row][col]; board[row][col] = 0; if ((row + 1) < 12) { if (board[row+1][col] == currentColor) { match = true; totalMatches++; totalMatches += move(row+1, col); } } if ((row - 1) >= 0) { if (board[row-1][col] == currentColor) { match = true; totalMatches++; totalMatches += move(row-1, col); } } if ((col + 1) < 8) { if (board[row][col+1] == currentColor) { match = true; totalMatches++; totalMatches += move(row, col+1); } } if ((col - 1) >= 0) { if (board[row][col-1] == currentColor) { match = true; totalMatches++; totalMatches += move(row, col-1); } } return totalMatches; } My move() method above works fine, as in, it will delete the appropriate "blocks" and replace them with zeros. However, the number of destroyed (value returned) is always one off (too small). I believe this is because the first call of move() isn't being counted but I don't know how to differentiate between the first call or subsequent calls in that recursive method. How can I modify my move() method so it returns the correct number of destroyed blocks?

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Is this too much code for a header only library?

- by Billy ONeal

It seems like I had to inline quite a bit of code here. I'm wondering if it's bad design practice to leave this entirely in a header file like this: #pragma once #include <string> #include <boost/noncopyable.hpp> #include <boost/make_shared.hpp> #include <boost/iterator/iterator_facade.hpp> #include <Windows.h> #include "../Exception.hpp" namespace WindowsAPI { namespace FileSystem { class FileData; struct AllResults; struct FilesOnly; template <typename Filter_T = AllResults> class DirectoryIterator; namespace detail { class DirectoryIteratorImpl : public boost::noncopyable { WIN32_FIND_DATAW currentData; HANDLE hFind; std::wstring root; public: inline DirectoryIteratorImpl(); inline explicit DirectoryIteratorImpl(const std::wstring& pathSpec); inline void increment(); inline bool equal(const DirectoryIteratorImpl& other) const; inline const std::wstring& GetPathRoot() const; inline const WIN32_FIND_DATAW& GetCurrentFindData() const; inline ~DirectoryIteratorImpl(); }; } class FileData //Serves as a proxy to the WIN32_FIND_DATA struture inside the iterator. { boost::shared_ptr<detail::DirectoryIteratorImpl> iteratorSource; public: FileData(const boost::shared_ptr<detail::DirectoryIteratorImpl>& parent) : iteratorSource(parent) {}; DWORD GetAttributes() const { return iteratorSource->GetCurrentFindData().dwFileAttributes; }; bool IsDirectory() const { return (GetAttributes() | FILE_ATTRIBUTE_DIRECTORY) != 0; }; bool IsFile() const { return !IsDirectory(); }; bool IsArchive() const { return (GetAttributes() | FILE_ATTRIBUTE_ARCHIVE) != 0; }; bool IsReadOnly() const { return (GetAttributes() | FILE_ATTRIBUTE_READONLY) != 0; }; unsigned __int64 GetSize() const { ULARGE_INTEGER intValue; intValue.LowPart = iteratorSource->GetCurrentFindData().nFileSizeLow; intValue.HighPart = iteratorSource->GetCurrentFindData().nFileSizeHigh; return intValue.QuadPart; }; std::wstring GetFolderPath() const { return iteratorSource->GetPathRoot(); }; std::wstring GetFileName() const { return iteratorSource->GetCurrentFindData().cFileName; }; std::wstring GetFullFileName() const { return GetFolderPath() + GetFileName(); }; std::wstring GetShortFileName() const { return iteratorSource->GetCurrentFindData().cAlternateFileName; }; FILETIME GetCreationTime() const { return iteratorSource->GetCurrentFindData().ftCreationTime; }; FILETIME GetLastAccessTime() const { return iteratorSource->GetCurrentFindData().ftLastAccessTime; }; FILETIME GetLastWriteTime() const { return iteratorSource->GetCurrentFindData().ftLastWriteTime; }; }; struct AllResults : public std::unary_function<const FileData&, bool> { bool operator()(const FileData&) { return true; }; }; struct FilesOnly : public std::unary_function<const FileData&, bool> { bool operator()(const FileData& arg) { return arg.IsFile(); }; }; template <typename Filter_T> class DirectoryIterator : public boost::iterator_facade<DirectoryIterator<Filter_T>, const FileData, std::input_iterator_tag> { friend class boost::iterator_core_access; boost::shared_ptr<detail::DirectoryIteratorImpl> impl; FileData current; Filter_T filter; void increment() { do { impl->increment(); } while (! filter(current)); }; bool equal(const DirectoryIterator& other) const { return impl->equal(*other.impl); }; const FileData& dereference() const { return current; }; public: DirectoryIterator(Filter_T functor = Filter_T()) : impl(boost::make_shared<detail::DirectoryIteratorImpl>()), current(impl), filter(functor) { }; explicit DirectoryIterator(const std::wstring& pathSpec, Filter_T functor = Filter_T()) : impl(boost::make_shared<detail::DirectoryIteratorImpl>(pathSpec)), current(impl), filter(functor) { }; }; namespace detail { DirectoryIteratorImpl::DirectoryIteratorImpl() : hFind(INVALID_HANDLE_VALUE) { } DirectoryIteratorImpl::DirectoryIteratorImpl(const std::wstring& pathSpec) { std::wstring::const_iterator lastSlash = std::find(pathSpec.rbegin(), pathSpec.rend(), L'\\').base(); root.assign(pathSpec.begin(), lastSlash); hFind = FindFirstFileW(pathSpec.c_str(), &currentData); if (hFind == INVALID_HANDLE_VALUE) WindowsApiException::ThrowFromLastError(); while (!wcscmp(currentData.cFileName, L".") || !wcscmp(currentData.cFileName, L"..")) { increment(); } } void DirectoryIteratorImpl::increment() { BOOL success = FindNextFile(hFind, &currentData); if (success) return; DWORD error = GetLastError(); if (error == ERROR_NO_MORE_FILES) { FindClose(hFind); hFind = INVALID_HANDLE_VALUE; } else { WindowsApiException::Throw(error); } } DirectoryIteratorImpl::~DirectoryIteratorImpl() { if (hFind != INVALID_HANDLE_VALUE) FindClose(hFind); } bool DirectoryIteratorImpl::equal(const DirectoryIteratorImpl& other) const { if (this == &other) return true; return hFind == other.hFind; } const std::wstring& DirectoryIteratorImpl::GetPathRoot() const { return root; } const WIN32_FIND_DATAW& DirectoryIteratorImpl::GetCurrentFindData() const { return currentData; } } }}

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Problem with boundary collision

- by James Century

The problem: When the player hits the left boundary he stops (this is exactly what I want), when he hits the right boundary. He continues until his rectangle's left boundary meets with the right boundary. Outcome: https://www.youtube.com/watch?v=yuJfIWZ_LL0&feature=youtu.be My Code public class Player extends GameObject{ BufferedImageLoader loader; Texture tex = Game.getInstance(); BufferedImage image; Animation playerWalkLeft; private HealthBarManager healthBar; private String username; private int width; private ManaBarManager manaBar; public Player(float x, float y, ObjectID ID) { super(x, y, ID, null); loader = new BufferedImageLoader(); playerWalkLeft = new Animation(5,tex.player[10],tex.player[11],tex.player[12],tex.player[13],tex.player[14],tex.player[15],tex.player[17],tex.player[18]); } public void tick(LinkedList<GameObject> object) { setX(getX()+velX); setY(getY()+velY); playerWalkLeft.runAnimation(); } public void render(Graphics g) { g.setColor(Color.BLACK); FontMetrics fm = g.getFontMetrics(g.getFont()); if(username != null) width = fm.stringWidth(username); if(username != null){ g.drawString(username,(int) x-width/2+15,(int) y); } if(velX != 0){ playerWalkLeft.drawAnimation(g, (int)x, (int)y); }else{ g.drawImage(tex.player[16], (int)x, (int)y, null); } g.setColor(Color.PINK); g.drawRect((int)x,(int)y,33,48); g.drawRect(0,0,(int)Game.getWalkableBounds().getWidth(), (int)Game.getWalkableBounds().getHeight()); } @SuppressWarnings("unused") private Image getCurrentImage() { return image; } public float getX() { return x; } public float getY() { return y; } public void setX(float x) { Rectangle gameBoundry = Game.getWalkableBounds(); if(x >= gameBoundry.getMinX() && x <= gameBoundry.getMaxX()){ this.x = x; } } public void setY(float y) { //IGNORE THE SetY please. this.y = y; } public float getVelX() { return velX; } public void setHealthBar(HealthBarManager healthBar){ this.healthBar = healthBar; } public HealthBarManager getHealthBar(){ return healthBar; } public float getVelY() { return velY; } public void setVelX(float velX) { this.velX = velX; } public void setVelY(float velY) { this.velY = velY; } public ObjectID getID() { return ID; } public void setUsername(String playerName) { this.username = playerName; } public String getUsername(){ return this.username; } public void setManaBar(ManaBarManager manaBar) { this.manaBar = manaBar; } public ManaBarManager getManaBar(){ return manaBar; } public int getLevel(){ return 1; } public boolean isPlayerInsideBoundry(float x, float y){ Rectangle boundry = Game.getWalkableBounds(); if(boundry.contains(x,y)){ return true; } return false; } } What I've tried: - Using a method that checks if the game boundary contains player boundary rectangle. This gave me the same result as what the check statement in my setX did.

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How to load models in the extended MY_Router class in codeigniter

- by askkirati

I am not able to load models to the extended My_Router class in codeigniter. Below is my code: class MY_Router extends CI_Router { function MY_Router() { parent::CI_Router(); } function _validate_request($segments) { // Does the requested controller exist in the root folder? if (file_exists(APPPATH.'controllers/'.$segments[0].EXT)) { return $segments; } // Is the controller in a sub-folder? if (is_dir(APPPATH.'controllers/'.$segments[0])) { // Set the directory and remove it from the segment array $this->set_directory($segments[0]); $segments = array_slice($segments, 1); if (count($segments) > 0) { // Does the requested controller exist in the sub-folder? if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$segments[0].EXT)) { show_404($this->fetch_directory().$segments[0]); } } else { $this->set_class($this->default_controller); $this->set_method('index'); // Does the default controller exist in the sub-folder? if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$this->default_controller.EXT)) { $this->directory = ''; return array(); } } return $segments; } // Let's check if there are category segments $category_routes = $this->category_routing($segments); if($category_routes !== FALSE) { return $category_routes; } $user_routes = $this->user_routing($segments); if($user_routes != FALSE) { return $user_routes; } show_404($segments[0]); } function category_routing($segments) { $this->load->model('category_model'); if($this->category_model->category_exist($segments[0])) { //if only category if(count($segments)==1) { return array('category', 'category_browse', $segments[0]); } //category pagination if(count($segments)==2 and is_numeric($segments[1])) { return array('category','category_browse', $segments[0], $segments[1]); } //category upcoming if(count($segments)==2 and $segments[1] == 'upcoming') { return array('category','upcoming', $segments[0]); } //category upcoming pagination if(count($segments)==3 and $segments[1] == 'upcoming' and is_numeric($segments[3])) { return array('category','upcoming', $segments[0], $segments[3]); } //category top if(count($segments)==3 and $segments[1] == 'top') { return array('category','top', $segments[0], $segments[2]); } //category top pagination if(count($segments)==4 and $segments[1] == 'top' and is_numeric($segments[3])) { return array('category','top', $segments[0], $segments[3]); } } return FALSE; } function user_routing($segments) { $this->load->model('dx_auth/users', 'user_model'); if($this->user_model->check_username($segments[0])) { //only profile if(count($segments)==1) { return array('user','profile',$segments[0]); } //all friends if(count($segments)==2 and $segment[1]=='allfriends') { return array('user','allfriends',$segments[0]); } //all subscribers if(count($segments)==2 and $segment[1]=='allsubscribers') { return array('user','allsubscribers',$segments[0]); } //all subscription if(count($segments)==2 and $segment[1]=='allsubscriptions') { return array('user','allsubscriptions',$segments[0]); } } return FALSE; } } I have tried loading the models by using get_instance function provided by codeigniter but seems like it doesnot work. All i need is load the models in extended system library.

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Hibernate - strange order of native SQL parameters

- by Xorty

Hello, I am trying to use native MySQL's MD5 crypto func, so I defined custom insert in my mapping file. <hibernate-mapping package="tutorial"> <class name="com.xorty.mailclient.client.domain.User" table="user"> <id name="login" type="string" column="login"></id> <property name="password"> <column name="password" /> </property> <sql-insert>INSERT INTO user (login,password) VALUES ( ?, MD5(?) )</sql-insert> </class> </hibernate-mapping> Then I create User (pretty simple POJO with just 2 Strings - login and password) and try to persist it. session.beginTransaction(); // we have no such user in here yet User junitUser = (User) session.load(User.class, "junit_user"); assert (null == junitUser); // insert new user junitUser = new User(); junitUser.setLogin("junit_user"); junitUser.setPassword("junitpass"); session.save(junitUser); session.getTransaction().commit(); What actually happens? User is created, but with reversed parameters order. He has login "junitpass" and "junit_user" is MD5 encrypted and stored as password. What did I wrong? Thanks EDIT: ADDING POJO class package com.xorty.mailclient.client.domain; import java.io.Serializable; /** * POJO class representing user. * @author MisoV * @version 0.1 */ public class User implements Serializable { /** * Generated UID */ private static final long serialVersionUID = -969127095912324468L; private String login; private String password; /** * @return login */ public String getLogin() { return login; } /** * @return password */ public String getPassword() { return password; } /** * @param login the login to set */ public void setLogin(String login) { this.login = login; } /** * @param password the password to set */ public void setPassword(String password) { this.password = password; } /** * @see java.lang.Object#toString() * @return login */ @Override public String toString() { return login; } /** * Creates new User. * @param login User's login. * @param password User's password. */ public User(String login, String password) { setLogin(login); setPassword(password); } /** * Default constructor */ public User() { } /** * @return hashCode * @see java.lang.Object#hashCode() */ @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((null == login) ? 0 : login.hashCode()); result = prime * result + ((null == password) ? 0 : password.hashCode()); return result; } /** * @param obj Compared object * @return True, if objects are same. Else false. * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null) { return false; } if (!(obj instanceof User)) { return false; } User other = (User) obj; if (login == null) { if (other.login != null) { return false; } } else if (!login.equals(other.login)) { return false; } if (password == null) { if (other.password != null) { return false; } } else if (!password.equals(other.password)) { return false; } return true; } }

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How can I modify my Shunting-Yard Algorithm so it accepts unary operators?

- by KingNestor

I've been working on implementing the Shunting-Yard Algorithm in JavaScript for class. Here is my work so far: var userInput = prompt("Enter in a mathematical expression:"); var postFix = InfixToPostfix(userInput); var result = EvaluateExpression(postFix); document.write("Infix: " + userInput + "<br/>"); document.write("Postfix (RPN): " + postFix + "<br/>"); document.write("Result: " + result + "<br/>"); function EvaluateExpression(expression) { var tokens = expression.split(/([0-9]+|[*+-\/()])/); var evalStack = []; while (tokens.length != 0) { var currentToken = tokens.shift(); if (isNumber(currentToken)) { evalStack.push(currentToken); } else if (isOperator(currentToken)) { var operand1 = evalStack.pop(); var operand2 = evalStack.pop(); var result = PerformOperation(parseInt(operand1), parseInt(operand2), currentToken); evalStack.push(result); } } return evalStack.pop(); } function PerformOperation(operand1, operand2, operator) { switch(operator) { case '+': return operand1 + operand2; case '-': return operand1 - operand2; case '*': return operand1 * operand2; case '/': return operand1 / operand2; default: return; } } function InfixToPostfix(expression) { var tokens = expression.split(/([0-9]+|[*+-\/()])/); var outputQueue = []; var operatorStack = []; while (tokens.length != 0) { var currentToken = tokens.shift(); if (isNumber(currentToken)) { outputQueue.push(currentToken); } else if (isOperator(currentToken)) { while ((getAssociativity(currentToken) == 'left' && getPrecedence(currentToken) <= getPrecedence(operatorStack[operatorStack.length-1])) || (getAssociativity(currentToken) == 'right' && getPrecedence(currentToken) < getPrecedence(operatorStack[operatorStack.length-1]))) { outputQueue.push(operatorStack.pop()) } operatorStack.push(currentToken); } else if (currentToken == '(') { operatorStack.push(currentToken); } else if (currentToken == ')') { while (operatorStack[operatorStack.length-1] != '(') { if (operatorStack.length == 0) throw("Parenthesis balancing error! Shame on you!"); outputQueue.push(operatorStack.pop()); } operatorStack.pop(); } } while (operatorStack.length != 0) { if (!operatorStack[operatorStack.length-1].match(/([()])/)) outputQueue.push(operatorStack.pop()); else throw("Parenthesis balancing error! Shame on you!"); } return outputQueue.join(" "); } function isOperator(token) { if (!token.match(/([*+-\/])/)) return false; else return true; } function isNumber(token) { if (!token.match(/([0-9]+)/)) return false; else return true; } function getPrecedence(token) { switch (token) { case '^': return 9; case '*': case '/': case '%': return 8; case '+': case '-': return 6; default: return -1; } } function getAssociativity(token) { switch(token) { case '+': case '-': case '*': case '/': return 'left'; case '^': return 'right'; } } It works fine so far. If I give it: ((5+3) * 8) It will output: Infix: ((5+3) * 8) Postfix (RPN): 5 3 + 8 * Result: 64 However, I'm struggling with implementing the unary operators so I could do something like: ((-5+3) * 8) What would be the best way to implement unary operators (negation, etc)? Also, does anyone have any suggestions for handling floating point numbers as well? One last thing, if anyone sees me doing anything weird in JavaScript let me know. This is my first JavaScript program and I'm not used to it yet.

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Service Discovery in WCF 4.0 – Part 1

- by Shaun

When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc.. Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN. Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes. Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method. Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7: 8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17: 18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22: 23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27: 28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32: 33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37: 38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42: 43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47: 48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5: 6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6: 7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11: 12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18: 19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12: 13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6: 7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19: 20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26: 27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34: 35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53: 54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61: 62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69: 70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77: 78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85: 86: TAsyncResult asyncResult = result as TAsyncResult; 87: 88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92: 93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97: 98: asyncResult.endCalled = true; 99: 100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104: 105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109: 110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114: 115: return asyncResult; 116: } 117: 118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124: 125: this.completedSynchronously = completedSynchronously; 126: 127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142: 143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148: 149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7: 8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17: 18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22: 23: } 24: 25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32: 33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38: 39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46: 47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52: 53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56: 57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63: 64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13: 14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26: 27: host.Open(); 28: 29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37: 38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message. Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4: 5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11: 12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13: 14: host.Open(); 15: 16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint. On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6: 7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13: 14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16: 17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28: 29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service. Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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Adventures in MVVM – My ViewModel Base

- by Brian Genisio's House Of Bilz

More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it. I have yet to find an MVVM framework that does everything I want it to without doing too much. Don’t get me wrong… there are some good frameworks out there. I just like to pick and choose things that make sense for me. I’d also like to add that some of these features only work in WPF. As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world. I have had several conversations with people about the problems I have solved using this ViewModel base. A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”. What followed from those ideas was a ViewModel base class that I take with me and use in my projects. It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model. Without all three, you don’t have MVVM. But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands. The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method. To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you. The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix. You are left to be expressive with your behavior without the plumbing. If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } } Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface). There have been many attempts to make this more automatic. My base class includes one option. There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field. The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious. Too much plumbing. My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } } Strongly Typed Property Getters/Setters It turns out that we can do better than that. We are using a strongly typed language where the use of “Magic Strings” is often frowned upon. Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } } Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically. This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW) By calling Set(“Foo”, 1), you have now created a dynamic property called Foo. It can be bound against like any static property. The opportunities are endless. One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user. The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already. Why not exploit it? Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" /> Default Property Values The Get() method also allows for default properties to be set. Don’t set them in the constructor. Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} } Derived Properties This is something I blogged about a while back in more detail. This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed. This, to me, is backwards. It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this. What we really want to do is invert the dependency. Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } } Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property. When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } } Command CanExecute Change Notification Back to Commands. One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated. I wanted to wait until we got past a few concepts before explaining this behavior. You can use the same mechanism here to fire off the change. In the CanExecute_ method, declare the property that it depends upon. When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command. The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } } Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer. You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } } What About Silverlight? Some of the features in this base class only work in WPF. As of version 4, Silverlight does not support binding to dynamic properties. This, in my opinion, is a HUGE limitation. Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby. Does this mean that the base class will not work in Silverlight? No. Many of the features outlined in this article WILL work. All of the property abstractions are functional, as long as you refer to them statically in the View. This, of course, means that the automatic command hook-up doesn’t work in Silverlight. You need to plumb it to a static property in order for the Silverlight View to bind to it. Can I has a dynamic property in SL5? Good to go? So, that concludes the feature explanation of my ViewModel base class. Feel free to take it, fork it, whatever. It is hosted on CodePlex. When I find other useful additions, I will add them to the public repository. I use this base class every day. It is mature, and well tested. If, however, you find any problems with it, please let me know! Also, feel free to suggest patches to me via the CodePlex site. :)

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Varnish default.vcl grace period

- by Vladimir

These are my settings for a grace period (/etc/varnish/default.vcl) sub vcl_recv { .... set req.grace = 360000s; ... } sub vcl_fetch { ... set beresp.grace = 360000s; ... } I tested Varnish using localhost and nodejs as a server. I started localhost, the site was up. Then I disconnected server and the site got disconnected in less than 2 min. It says: Error 503 Service Unavailable Service Unavailable Guru Meditation: XID: 1890127100 Varnish cache server Could you tell me what could be the problem? sub vcl_fetch { if (beresp.ttl < 120s) { ##std.log("Adjusting TTL"); set beresp.ttl = 36000s; ##120s; } # Do not cache the object if the backend application does not want us to. if (beresp.http.Cache-Control ~ "(no-cache|no-store|private|must-revalidate)") { return(hit_for_pass); } # Do not cache the object if the status is not in the 200s if (beresp.status >= 300) { # Remove the Set-Cookie header #remove beresp.http.Set-Cookie; return(hit_for_pass); } # # Everything below here should be cached # # Remove the Set-Cookie header ####remove beresp.http.Set-Cookie; # Set the grace time ## set beresp.grace = 1s; //change this to minutes in case of app shutdown set beresp.grace = 360000s; ## 10 hour - reduce if it has negative impact # Static assets - browser caches tpiphem for a long time. if (req.url ~ "\.(css|js|.js|jpg|jpeg|gif|ico|png)\??\d*$") { /* Remove Expires from backend, it's not long enough */ unset beresp.http.expires; /* Set the clients TTL on this object */ set beresp.http.cache-control = "public, max-age=31536000"; /* marker for vcl_deliver to reset Age: */ set beresp.http.magicmarker = "1"; } else { set beresp.http.Cache-Control = "private, max-age=0, must-revalidate"; set beresp.http.Pragma = "no-cache"; } if (req.url ~ "\.(css|js|min|)\??\d*$") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } ##do not duplicate these settings if (req.url ~ ".css") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } if (req.url ~ ".js") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } if (req.url ~ ".min") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } ## If the request to the backend returns a code other than 200, restart the loop ## If the number of restarts reaches the value of the parameter max_restarts, ## the request will be error'ed. max_restarts defaults to 4. This prevents ## an eternal loop in the event that, e.g., the object does not exist at all. if (beresp.status != 200 && beresp.status != 403 && beresp.status != 404) { return(restart); } if (beresp.status == 302) { return(deliver); } # Never cache posts if (req.url ~ "\/post\/" || req.url ~ "\/submit\/" || req.url ~ "\/ask\/" || req.url ~ "\/add\/") { return(hit_for_pass); } ##check this setting to ensure that it does not cause issues for browsers with no gzip if (beresp.http.content-type ~ "text") { set beresp.do_gzip = true; } if (beresp.http.Set-Cookie) { return(deliver); } ##if (req.url == "/index.html") { set beresp.do_esi = true; ##} ## check if this is needed or should be used # return(deliver); the object return(deliver); } sub vcl_recv { ##avoid leeching of images call hot_link; set req.grace = 360000s; ##2m ## if one backend is down - use another if (req.restarts == 0) { set req.backend = cache_director; ##we can specify individual VMs } else if (req.restarts == 1) { set req.backend = cache_director; } ## post calls should not be cached - add cookie for these requests if using micro-caching # Pass requests that are not GET or HEAD if (req.request != "GET" && req.request != "HEAD") { return(pass); ## return(pass) goes to backend - not cache } # Don't cache the result of a redirect if (req.http.Referer ~ "redir" || req.http.Origin ~ "jumpto") { return(pass); } # Don't cache the result of a redirect (asking for logon) if (req.http.Referer ~ "post" || req.http.Referer ~ "submit" || req.http.Referer ~ "add" || req.http.Referer ~ "ask") { return(pass); } # Never cache posts - ensure that we do not use these strings in our URLs' that need to be cached if (req.url ~ "\/post\/" || req.url ~ "\/submit\/" || req.url ~ "\/ask\/" || req.url ~ "\/add\/") { return(pass); } ## if (req.http.Authorization || req.http.Cookie) { if (req.http.Authorization) { /* Not cacheable by default */ return (pass); } # Handle compression correctly. Different browsers send different # "Accept-Encoding" headers, even though they mostly all support the same # compression mechanisms. By consolidating these compression headers into # a consistent format, we can reduce the size of the cache and get more hits. # @see: http:// varnish.projects.linpro.no/wiki/FAQ/Compression if (req.http.Accept-Encoding) { if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|ico)$") { # No point in compressing these remove req.http.Accept-Encoding; } else if (req.http.Accept-Encoding ~ "gzip") { # If the browser supports it, we'll use gzip. set req.http.Accept-Encoding = "gzip"; } else if (req.http.Accept-Encoding ~ "deflate") { # Next, try deflate if it is supported. set req.http.Accept-Encoding = "deflate"; } else { # Unknown algorithm. Remove it and send unencoded. unset req.http.Accept-Encoding; } } # lookup graphics, css, js & ico files in the cache if (req.url ~ "\.(png|gif|jpg|jpeg|css|.js|ico)$") { return(lookup); } ##added on 0918 - check if it causes issues with user specific content if (req.request == "GET" && req.http.cookie) { return(lookup); } # Pipe requests that are non-RFC2616 or CONNECT which is weird. if (req.request != "GET" && req.request != "HEAD" && req.request != "PUT" && req.request != "POST" && req.request != "TRACE" && req.request != "OPTIONS" && req.request != "DELETE") { ##closing connection and calling pipe return(pipe); } ##purge content via localhost only if (req.request == "PURGE") { if (!client.ip ~ purge) { error 405 "Not allowed."; } return(lookup); } ## do we need this? ## return(lookup); }

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Query XML file with PHP to return certain bookmarks...

- by josh brown

I have an XML file full of bookmarks from Google Bookmarks. (File: http://gist.github.com/324844) I want to pull the bookmark based on this path: xml_api_reply-bookmarks-bookmark-labels-label. So, my question is How can I use SimpleXML to grab the bookmarks that have the label Inspiration? Some bookmarks may have more than one bookmark.

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How to make my robot move in a rectangular path along the black tape?

- by Sahat

I am working on a robot, it's part of the summer robotics workshop in our college. We are using C-STAMP micro controllers by A-WIT. I was able to make it move, turn left, turn right, move backward. I have even managed to make it go along the black tape using a contrast sensor. I send the robot at 30-45 degrees toward the black tape on the table and it aligns itself and starts to move along the black tape. It jerks a little, probably due to my programming logic below, it's running a while loop and constantly checking if statements, so it ends up trying to turn left and right every few milliseconds, which explains the jerking part. But it's okay, it works, not as smooth as I want it to work but it works! Problem is that I can't make my robot go into a rectangular path of the black tape. As soon as it reaches the corner it just keeps going straight instead of making a left/right turn. Here's my attempt. The following code is just part of the code. My 2 sensors are located right underneath the robot, next to the front wheel, almost at the floor level. It has "index" value ranging from 0 to 8. I believe it's 8 when you have a lot of light coming into the sensor , and 0 when it's nearly pitch black. So when the robot moves into the black-tape-zone, the index value drops, and based on that I have an if-statement telling my robot to either turn left or right. To avoid confusion I didn't post the entire source code, but only the logical part responsible for the movement of my robot along the black tape. while(1) { // don't worry about these. // 10 and 9 represent Sensor's PIN location on the motherboard V = ANALOGIN(10, 1, 0, 0, 0); V2 = ANALOGIN(9, 1, 0, 0, 0); // i got this "formula" from the example in my Manual. // V stands for voltage of the sensor. // it gives me the index value of the sensor. 0 = darkest, 8 = lightest. index = ((-(V - 5) / 5) * 8 + 0.5); index2 = ((-(V2 - 5) / 5) * 8 + 0.5); // i've tweaked the position of the sensors so index > 7 is just right number. // the robot will move anywhere on the table just fine with index > 7. // as soon as it drops to or below 7 (i.e. finds black tape), the robot will // either turn left or right and then go forward. // lp & rp represent left-wheel pin and right-wheel pin, 1 means run forever. // if i change it from 1 to 100, it will go forward for 100ms. if (index > 7 && index2 > 7) goForward(lp, rp, 1); if (index <= 7) { turnLeft(lp, rp, 1); goForward(lp, rp, 1); // this is the tricky part. i've added this code last minute // trying to make my robot turn, but i didn't work. if (index > 4) { turnLeft(lp, rp, 1); goForward(lp, rp, 1); } } else if (index2 <= 7) { turnRight(lp, rp, 1); goForward(lp, rp, 1); // this is also the last minute addition. it's same code as above // but it's for the 2nd sensor. if (index2 > 4) { turnRight(lp, rp, 1); goForward(lp, rp, 1); } } I've spent the entire day trying to figure it out. I've pretty much exhausted all avenues. Asking for the solution on stackoverflow is my very last option now. Thanks in advance! If you have any questions about the code, let me know, but comments should be self-explanatory.

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In Asp.Net MVC 2 is there a better way to return 401 status codes without getting an auth redirect

- by Greg Roberts

I have a portion of my site that has a lightweight xml/json REST API. Most of my site is behind forms auth but only some of my API actions require authentication. I have a custom AuthorizeAttribute for my API that I use to check for certain permissions and when it fails it results in a 401. All is good, except since I'm using forms auth, Asp.net conveniently converts that into a 302 redirect to my login page. I've seen some previous questions that seem a bit hackish to either return a 403 instead or to put some logic in the global.asax protected void Application_EndRequest() that will essentially convert 302 to 401 where it meets whatever criteria. Previous Question Previous Question 2 What I'm doing now is sort of like one of the questions, but instead of checking the Application_EndRequest() for a 302 I make my authorize attribute return 666 which indicates to me that I need to set this to a 401. Here is my code: protected void Application_EndRequest() { if (Context.Response.StatusCode == MyAuthAttribute.AUTHORIZATION_FAILED_STATUS) { //check for 666 - status code of hidden 401 Context.Response.StatusCode = 401; } } Even though this works, my question is there something in Asp.net MVC 2 that would prevent me from having to do this? Or, in general is there a better way? I would think this would come up a lot for anyone doing REST api's or just people that do ajax requests in their controllers. The last thing you want is to do a request and get the content of a login page instead of json.

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Keyboard navigation for jQuery Tabs

- by Binyamin

How to make Keyboard navigation left/up/right/down (like for photo gallery) feature for jQury Tabs with History? Demo without Keyboard feature in http://dl.dropbox.com/u/6594481/tabs/index.html Needed functions: 1. on keyboardtop/down make select and CSS showactivenested ajax tabs from 1-st to last level 2. on keyboardleft/right changeback/forwardcontent ofactivenested ajax tabs tab 3. an extra option, makeactivenested ajax tab on 'cursor-on' on concrete nested ajax tabs level Read more detailed question with example pictures in http://stackoverflow.com/questions/2975003/jquery-tools-to-make-keyboard-and-cookies-feature-for-ajaxed-tabs-with-history /** * @license * jQuery Tools @VERSION Tabs- The basics of UI design. * * NO COPYRIGHTS OR LICENSES. DO WHAT YOU LIKE. * * http://flowplayer.org/tools/tabs/ * * Since: November 2008 * Date: @DATE */ (function($) { // static constructs $.tools = $.tools || {version: '@VERSION'}; $.tools.tabs = { conf: { tabs: 'a', current: 'current', onBeforeClick: null, onClick: null, effect: 'default', initialIndex: 0, event: 'click', rotate: false, // 1.2 history: false }, addEffect: function(name, fn) { effects[name] = fn; } }; var effects = { // simple "toggle" effect 'default': function(i, done) { this.getPanes().hide().eq(i).show(); done.call(); }, /* configuration: - fadeOutSpeed (positive value does "crossfading") - fadeInSpeed */ fade: function(i, done) { var conf = this.getConf(), speed = conf.fadeOutSpeed, panes = this.getPanes(); if (speed) { panes.fadeOut(speed); } else { panes.hide(); } panes.eq(i).fadeIn(conf.fadeInSpeed, done); }, // for basic accordions slide: function(i, done) { this.getPanes().slideUp(200); this.getPanes().eq(i).slideDown(400, done); }, /** * AJAX effect */ ajax: function(i, done) { this.getPanes().eq(0).load(this.getTabs().eq(i).attr("href"), done); } }; var w; /** * Horizontal accordion * * @deprecated will be replaced with a more robust implementation */ $.tools.tabs.addEffect("horizontal", function(i, done) { // store original width of a pane into memory if (!w) { w = this.getPanes().eq(0).width(); } // set current pane's width to zero this.getCurrentPane().animate({width: 0}, function() { $(this).hide(); }); // grow opened pane to it's original width this.getPanes().eq(i).animate({width: w}, function() { $(this).show(); done.call(); }); }); function Tabs(root, paneSelector, conf) { var self = this, trigger = root.add(this), tabs = root.find(conf.tabs), panes = paneSelector.jquery ? paneSelector : root.children(paneSelector), current; // make sure tabs and panes are found if (!tabs.length) { tabs = root.children(); } if (!panes.length) { panes = root.parent().find(paneSelector); } if (!panes.length) { panes = $(paneSelector); } // public methods $.extend(this, { click: function(i, e) { var tab = tabs.eq(i); if (typeof i == 'string' && i.replace("#", "")) { tab = tabs.filter("[href*=" + i.replace("#", "") + "]"); i = Math.max(tabs.index(tab), 0); } if (conf.rotate) { var last = tabs.length -1; if (i < 0) { return self.click(last, e); } if (i > last) { return self.click(0, e); } } if (!tab.length) { if (current >= 0) { return self; } i = conf.initialIndex; tab = tabs.eq(i); } // current tab is being clicked if (i === current) { return self; } // possibility to cancel click action e = e || $.Event(); e.type = "onBeforeClick"; trigger.trigger(e, [i]); if (e.isDefaultPrevented()) { return; } // call the effect effects[conf.effect].call(self, i, function() { // onClick callback e.type = "onClick"; trigger.trigger(e, [i]); }); // default behaviour current = i; tabs.removeClass(conf.current); tab.addClass(conf.current); return self; }, getConf: function() { return conf; }, getTabs: function() { return tabs; }, getPanes: function() { return panes; }, getCurrentPane: function() { return panes.eq(current); }, getCurrentTab: function() { return tabs.eq(current); }, getIndex: function() { return current; }, next: function() { return self.click(current + 1); }, prev: function() { return self.click(current - 1); } }); // callbacks $.each("onBeforeClick,onClick".split(","), function(i, name) { // configuration if ($.isFunction(conf[name])) { $(self).bind(name, conf[name]); } // API self[name] = function(fn) { $(self).bind(name, fn); return self; }; }); if (conf.history && $.fn.history) { $.tools.history.init(tabs); conf.event = 'history'; } // setup click actions for each tab tabs.each(function(i) { $(this).bind(conf.event, function(e) { self.click(i, e); return e.preventDefault(); }); }); // cross tab anchor link panes.find("a[href^=#]").click(function(e) { self.click($(this).attr("href"), e); }); // open initial tab if (location.hash) { self.click(location.hash); } else { if (conf.initialIndex === 0 || conf.initialIndex > 0) { self.click(conf.initialIndex); } } } // jQuery plugin implementation $.fn.tabs = function(paneSelector, conf) { // return existing instance var el = this.data("tabs"); if (el) { return el; } if ($.isFunction(conf)) { conf = {onBeforeClick: conf}; } // setup conf conf = $.extend({}, $.tools.tabs.conf, conf); this.each(function() { el = new Tabs($(this), paneSelector, conf); $(this).data("tabs", el); }); return conf.api ? el: this; }; }) (jQuery); /** * @license * jQuery Tools @VERSION History "Back button for AJAX apps" * * NO COPYRIGHTS OR LICENSES. DO WHAT YOU LIKE. * * http://flowplayer.org/tools/toolbox/history.html * * Since: Mar 2010 * Date: @DATE */ (function($) { var hash, iframe, links, inited; $.tools = $.tools || {version: '@VERSION'}; $.tools.history = { init: function(els) { if (inited) { return; } // IE if ($.browser.msie && $.browser.version < '8') { // create iframe that is constantly checked for hash changes if (!iframe) { iframe = $("<iframe/>").attr("src", "javascript:false;").hide().get(0); $("body").append(iframe); setInterval(function() { var idoc = iframe.contentWindow.document, h = idoc.location.hash; if (hash !== h) { $.event.trigger("hash", h); } }, 100); setIframeLocation(location.hash || '#'); } // other browsers scans for location.hash changes directly without iframe hack } else { setInterval(function() { var h = location.hash; if (h !== hash) { $.event.trigger("hash", h); } }, 100); } links = !links ? els : links.add(els); els.click(function(e) { var href = $(this).attr("href"); if (iframe) { setIframeLocation(href); } // handle non-anchor links if (href.slice(0, 1) != "#") { location.href = "#" + href; return e.preventDefault(); } }); inited = true; } }; function setIframeLocation(h) { if (h) { var doc = iframe.contentWindow.document; doc.open().close(); doc.location.hash = h; } } // global histroy change listener $(window).bind("hash", function(e, h) { if (h) { links.filter(function() { var href = $(this).attr("href"); return href == h || href == h.replace("#", ""); }).trigger("history", [h]); } else { links.eq(0).trigger("history", [h]); } hash = h; window.location.hash = hash; }); // jQuery plugin implementation $.fn.history = function(fn) { $.tools.history.init(this); // return jQuery return this.bind("history", fn); }; })(jQuery); $(function() { $("#list").tabs("#content > div", {effect: 'ajax', history: true}); });

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