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Differences Between NHibernate and Entity Framework

- by Ricardo Peres

Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one you know less. Mind you, this is a personal selection of features to compare, it is by no way an exhaustive list. History First, a bit of history. NHibernate is an open-source project that was first ported from Java’s venerable Hibernate framework, one of the first O/RM frameworks, but nowadays it is not tied to it, for example, it has .NET specific features, and has evolved in different ways from those of its Java counterpart. Current version is 3.3, with 3.4 on the horizon. It currently targets .NET 3.5, but can be used as well in .NET 4, it only makes no use of any of its specific functionality. You can find its home page at NHForge. Entity Framework 1 came out with .NET 3.5 and is now on its second major version, despite being version 4. Code First sits on top of it and but came separately and will also continue to be released out of line with major .NET distributions. It is currently on version 4.3.1 and version 5 will be released together with .NET Framework 4.5. All versions will target the current version of .NET, at the time of their release. Its home location is located at MSDN. Architecture In NHibernate, there is a separation between the Unit of Work and the configuration and model instances. You start off by creating a Configuration object, where you specify all global NHibernate settings such as the database and dialect to use, the batch sizes, the mappings, etc, then you build an ISessionFactory from it. The ISessionFactory holds model and metadata that is tied to a particular database and to the settings that came from the Configuration object, and, there will typically be only one instance of each in a process. Finally, you create instances of ISession from the ISessionFactory, which is the NHibernate representation of the Unit of Work and Identity Map. This is a lightweight object, it basically opens and closes a database connection as required and keeps track of the entities associated with it. ISession objects are cheap to create and dispose, because all of the model complexity is stored in the ISessionFactory and Configuration objects. As for Entity Framework, the ObjectContext/DbContext holds the configuration, model and acts as the Unit of Work, holding references to all of the known entity instances. This class is therefore not lightweight as its NHibernate counterpart and it is not uncommon to see examples where an instance is cached on a field. Mappings Both NHibernate and Entity Framework (Code First) support the use of POCOs to represent entities, no base classes are required (or even possible, in the case of NHibernate). As for mapping to and from the database, NHibernate supports three types of mappings: XML-based, which have the advantage of not tying the entity classes to a particular O/RM; the XML files can be deployed as files on the file system or as embedded resources in an assembly; Attribute-based, for keeping both the entities and database details on the same place at the expense of polluting the entity classes with NHibernate-specific attributes; Strongly-typed code-based, which allows dynamic creation of the model and strongly typing it, so that if, for example, a property name changes, the mapping will also be updated. Entity Framework can use: Attribute-based (although attributes cannot express all of the available possibilities – for example, cascading); Strongly-typed code mappings. Database Support With NHibernate you can use mostly any database you want, including: SQL Server; SQL Server Compact; SQL Server Azure; Oracle; DB2; PostgreSQL; MySQL; Sybase Adaptive Server/SQL Anywhere; Firebird; SQLLite; Informix; Any through OLE DB; Any through ODBC. Out of the box, Entity Framework only supports SQL Server, but a number of providers exist, both free and commercial, for some of the most used databases, such as Oracle and MySQL. See a list here. Inheritance Strategies Both NHibernate and Entity Framework support the three canonical inheritance strategies: Table Per Type Hierarchy (Single Table Inheritance), Table Per Type (Class Table Inheritance) and Table Per Concrete Type (Concrete Table Inheritance). Associations Regarding associations, both support one to one, one to many and many to many. However, NHibernate offers far more collection types: Bags of entities or values: unordered, possibly with duplicates; Lists of entities or values: ordered, indexed by a number column; Maps of entities or values: indexed by either an entity or any value; Sets of entities or values: unordered, no duplicates; Arrays of entities or values: indexed, immutable. Querying NHibernate exposes several querying APIs: LINQ is probably the most used nowadays, and really does not need to be introduced; Hibernate Query Language (HQL) is a database-agnostic, object-oriented SQL-alike language that exists since NHibernate’s creation and still offers the most advanced querying possibilities; well suited for dynamic queries, even if using string concatenation; Criteria API is an implementation of the Query Object pattern where you create a semi-abstract conceptual representation of the query you wish to execute by means of a class model; also a good choice for dynamic querying; Query Over offers a similar API to Criteria, but using strongly-typed LINQ expressions instead of strings; for this, although more refactor-friendlier that Criteria, it is also less suited for dynamic queries; SQL, including stored procedures, can also be used; Integration with Lucene.NET indexer is available. As for Entity Framework: LINQ to Entities is fully supported, and its implementation is considered very complete; it is the API of choice for most developers; Entity-SQL, HQL’s counterpart, is also an object-oriented, database-independent querying language that can be used for dynamic queries; SQL, of course, is also supported. Caching Both NHibernate and Entity Framework, of course, feature first-level cache. NHibernate also supports a second-level cache, that can be used among multiple ISessionFactorys, even in different processes/machines: Hashtable (in-memory); SysCache (uses ASP.NET as the cache provider); SysCache2 (same as above but with support for SQL Server SQL Dependencies); Prevalence; SharedCache; Memcached; Redis; NCache; Appfabric Caching. Out of the box, Entity Framework does not have any second-level cache mechanism, however, there are some public samples that show how we can add this. ID Generators NHibernate supports different ID generation strategies, coming from the database and otherwise: Identity (for SQL Server, MySQL, and databases who support identity columns); Sequence (for Oracle, PostgreSQL, and others who support sequences); Trigger-based; HiLo; Sequence HiLo (for databases that support sequences); Several GUID flavors, both in GUID as well as in string format; Increment (for single-user uses); Assigned (must know what you’re doing); Sequence-style (either uses an actual sequence or a single-column table); Table of ids; Pooled (similar to HiLo but stores high values in a table); Native (uses whatever mechanism the current database supports, identity or sequence). Entity Framework only supports: Identity generation; GUIDs; Assigned values. Properties NHibernate supports properties of entity types (one to one or many to one), collections (one to many or many to many) as well as scalars and enumerations. It offers a mechanism for having complex property types generated from the database, which even include support for querying. It also supports properties originated from SQL formulas. Entity Framework only supports scalars, entity types and collections. Enumerations support will come in the next version. Events and Interception NHibernate has a very rich event model, that exposes more than 20 events, either for synchronous pre-execution or asynchronous post-execution, including: Pre/Post-Load; Pre/Post-Delete; Pre/Post-Insert; Pre/Post-Update; Pre/Post-Flush. It also features interception of class instancing and SQL generation. As for Entity Framework, only two events exist: ObjectMaterialized (after loading an entity from the database); SavingChanges (before saving changes, which include deleting, inserting and updating). Tracking Changes For NHibernate as well as Entity Framework, all changes are tracked by their respective Unit of Work implementation. Entities can be attached and detached to it, Entity Framework does, however, also support self-tracking entities. Optimistic Concurrency Control NHibernate supports all of the imaginable scenarios: SQL Server’s ROWVERSION; Oracle’s ORA_ROWSCN; A column containing date and time; A column containing a version number; All/dirty columns comparison. Entity Framework is more focused on Entity Framework, so it only supports: SQL Server’s ROWVERSION; Comparing all/some columns. Batching NHibernate has full support for insertion batching, but only if the ID generator in use is not database-based (for example, it cannot be used with Identity), whereas Entity Framework has no batching at all. Cascading Both support cascading for collections and associations: when an entity is deleted, their conceptual children are also deleted. NHibernate also offers the possibility to set the foreign key column on children to NULL instead of removing them. Flushing Changes NHibernate’s ISession has a FlushMode property that can have the following values: Auto: changes are sent to the database when necessary, for example, if there are dirty instances of an entity type, and a query is performed against this entity type, or if the ISession is being disposed; Commit: changes are sent when committing the current transaction; Never: changes are only sent when explicitly calling Flush(). As for Entity Framework, changes have to be explicitly sent through a call to AcceptAllChanges()/SaveChanges(). Lazy Loading NHibernate supports lazy loading for Associated entities (one to one, many to one); Collections (one to many, many to many); Scalar properties (thing of BLOBs or CLOBs). Entity Framework only supports lazy loading for: Associated entities; Collections. Generating and Updating the Database Both NHibernate and Entity Framework Code First (with the Migrations API) allow creating the database model from the mapping and updating it if the mapping changes. Extensibility As you can guess, NHibernate is far more extensible than Entity Framework. Basically, everything can be extended, from ID generation, to LINQ to SQL transformation, HQL native SQL support, custom column types, custom association collections, SQL generation, supported databases, etc. With Entity Framework your options are more limited, at least, because practically no information exists as to what can be extended/changed. It features a provider model that can be extended to support any database. Integration With Other Microsoft APIs and Tools When it comes to integration with Microsoft technologies, it will come as no surprise that Entity Framework offers the best support. For example, the following technologies are fully supported: ASP.NET (through the EntityDataSource); ASP.NET Dynamic Data; WCF Data Services; WCF RIA Services; Visual Studio (through the integrated designer). Documentation This is another point where Entity Framework is superior: NHibernate lacks, for starters, an up to date API reference synchronized with its current version. It does have a community mailing list, blogs and wikis, although not much used. Entity Framework has a number of resources on MSDN and, of course, several forums and discussion groups exist. Conclusion Like I said, this is a personal list. I may come as a surprise to some that Entity Framework is so behind NHibernate in so many aspects, but it is true that NHibernate is much older and, due to its open-source nature, is not tied to product-specific timeframes and can thus evolve much more rapidly. I do like both, and I chose whichever is best for the job I have at hands. I am looking forward to the changes in EF5 which will add significant value to an already interesting product. So, what do you think? Did I forget anything important or is there anything else worth talking about? Looking forward for your comments!

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Tip/Trick: Fix Common SEO Problems Using the URL Rewrite Extension

- by ScottGu

Search engine optimization (SEO) is important for any publically facing web-site. A large % of traffic to sites now comes directly from search engines, and improving your site’s search relevancy will lead to more users visiting your site from search engine queries. This can directly or indirectly increase the money you make through your site. This blog post covers how you can use the free Microsoft URL Rewrite Extension to fix a bunch of common SEO problems that your site might have. It takes less than 15 minutes (and no code changes) to apply 4 simple URL Rewrite rules to your site, and in doing so cause search engines to drive more visitors and traffic to your site. The techniques below work equally well with both ASP.NET Web Forms and ASP.NET MVC based sites. They also works with all versions of ASP.NET (and even work with non-ASP.NET content). [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Measuring the SEO of your website with the Microsoft SEO Toolkit A few months ago I blogged about the free SEO Toolkit that we’ve shipped. This useful tool enables you to automatically crawl/scan your site for SEO correctness, and it then flags any SEO issues it finds. I highly recommend downloading and using the tool against any public site you work on. It makes it easy to spot SEO issues you might have in your site, and pinpoint ways to optimize it further. Below is a simple example of a report I ran against one of my sites (www.scottgu.com) prior to applying the URL Rewrite rules I’ll cover later in this blog post: Search Relevancy and URL Splitting Two of the important things that search engines evaluate when assessing your site’s “search relevancy” are: How many other sites link to your content. Search engines assume that if a lot of people around the web are linking to your content, then it is likely useful and so weight it higher in relevancy. The uniqueness of the content it finds on your site. If search engines find that the content is duplicated in multiple places around the Internet (or on multiple URLs on your site) then it is likely to drop the relevancy of the content. One of the things you want to be very careful to avoid when building public facing sites is to not allow different URLs to retrieve the same content within your site. Doing so will hurt with both of the situations above. In particular, allowing external sites to link to the same content with multiple URLs will cause your link-count and page-ranking to be split up across those different URLs (and so give you a smaller page rank than what it would otherwise be if it was just one URL). Not allowing external sites to link to you in different ways sounds easy in theory – but you might wonder what exactly this means in practice and how you avoid it. 4 Really Common SEO Problems Your Sites Might Have Below are 4 really common scenarios that can cause your site to inadvertently expose multiple URLs for the same content. When this happens external sites linking to yours will end up splitting their page links across multiple URLs - and as a result cause you to have a lower page ranking with search engines than you deserve. SEO Problem #1: Default Document IIS (and other web servers) supports the concept of a “default document”. This allows you to avoid having to explicitly specify the page you want to serve at either the root of the web-site/application, or within a sub-directory. This is convenient – but means that by default this content is available via two different publically exposed URLs (which is bad). For example: http://scottgu.com/ http://scottgu.com/default.aspx SEO Problem #2: Different URL Casings Web developers often don’t realize URLs are case sensitive to search engines on the web. This means that search engines will treat the following links as two completely different URLs: http://scottgu.com/Albums.aspx http://scottgu.com/albums.aspx SEO Problem #3: Trailing Slashes Consider the below two URLs – they might look the same at first, but they are subtly different. The trailing slash creates yet another situation that causes search engines to treat the URLs as different and so split search rankings: http://scottgu.com http://scottgu.com/ SEO Problem #4: Canonical Host Names Sometimes sites support scenarios where they support a web-site with both a leading “www” hostname prefix as well as just the hostname itself. This causes search engines to treat the URLs as different and split search rankling: http://scottgu.com/albums.aspx/ http://www.scottgu.com/albums.aspx/ How to Easily Fix these SEO Problems in 10 minutes (or less) using IIS Rewrite If you haven’t been careful when coding your sites, chances are you are suffering from one (or more) of the above SEO problems. Addressing these issues will improve your search engine relevancy ranking and drive more traffic to your site. The “good news” is that fixing the above 4 issues is really easy using the URL Rewrite Extension. This is a completely free Microsoft extension available for IIS 7.x (on Windows Server 2008, Windows Server 2008 R2, Windows 7 and Windows Vista). The great thing about using the IIS Rewrite extension is that it allows you to fix the above problems *without* having to change any code within your applications. You can easily install the URL Rewrite Extension in under 3 minutes using the Microsoft Web Platform Installer (a free tool we ship that automates setting up web servers and development machines). Just click the green “Install Now” button on the URL Rewrite Spotlight page to install it on your Windows Server 2008, Windows 7 or Windows Vista machine: Once installed you’ll find that a new “URL Rewrite” icon is available within the IIS 7 Admin Tool: Double-clicking the icon will open up the URL Rewrite admin panel – which will display the list of URL Rewrite rules configured for a particular application or site: Notice that our rewrite rule list above is currently empty (which is the default when you first install the extension). We can click the “Add Rule…” link button in the top-right of the panel to add and enable new URL Rewriting logic for our site. Scenario 1: Handling Default Document Scenarios One of the SEO problems I discussed earlier in this post was the scenario where the “default document” feature of IIS causes you to inadvertently expose two URLs for the same content on your site. For example: http://scottgu.com/ http://scottgu.com/default.aspx We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the second URL to instead go to the first one. We will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve. Let’s look at how we can create such a rule. We’ll begin by clicking the “Add Rule” link in the screenshot above. This will cause the below dialog to display: We’ll select the “Blank Rule” template within the “Inbound rules” section to create a new custom URL Rewriting rule. This will display an empty pane like below: Don’t worry – setting up the above rule is easy. The following 4 steps explain how to do so: Step 1: Name the Rule Our first step will be to name the rule we are creating. Naming it with a descriptive name will make it easier to find and understand later. Let’s name this rule our “Default Document URL Rewrite” rule: Step 2: Setup the Regular Expression that Matches this Rule Our second step will be to specify a regular expression filter that will cause this rule to execute when an incoming URL matches the regex pattern. Don’t worry if you aren’t good with regular expressions - I suck at them too. The trick is to know someone who is good at them or copy/paste them from a web-site. Below we are going to specify the following regular expression as our pattern rule: (.*?)/?Default\.aspx$ This pattern will match any URL string that ends with Default.aspx. The "(.*?)" matches any preceding character zero or more times. The "/?" part says to match the slash symbol zero or one times. The "$" symbol at the end will ensure that the pattern will only match strings that end with Default.aspx. Combining all these regex elements allows this rule to work not only for the root of your web site (e.g. http://scottgu.com/default.aspx) but also for any application or subdirectory within the site (e.g. http://scottgu.com/photos/default.aspx. Because the “ignore case” checkbox is selected it will match both “Default.aspx” as well as “default.aspx” within the URL. One nice feature built-into the rule editor is a “Test pattern” button that you can click to bring up a dialog that allows you to test out a few URLs with the rule you are configuring: Above I've added a “products/default.aspx” URL and clicked the “Test” button. This will give me immediate feedback on whether the rule will execute for it. Step 3: Setup a Permanent Redirect Action We’ll then setup an action to occur when our regular expression pattern matches the incoming URL: In the dialog above I’ve changed the “Action Type” drop down to be a “Redirect” action. The “Redirect Type” will be a HTTP 301 Permanent redirect – which means search engines will follow it. I’ve also set the “Redirect URL” property to be: {R:1}/ This indicates that we want to redirect the web client requesting the original URL to a new URL that has the originally requested URL path - minus the "Default.aspx" in it. For example, requests for http://scottgu.com/default.aspx will be redirected to http://scottgu.com/, and requests for http://scottgu.com/photos/default.aspx will be redirected to http://scottgu.com/photos/ The "{R:N}" regex construct, where N >= 0, is called a back-reference and N is the back-reference index. In the case of our pattern "(.*?)/?Default\.aspx$", if the input URL is "products/Default.aspx" then {R:0} will contain "products/Default.aspx" and {R:1} will contain "products". We are going to use this {R:1}/ value to be the URL we redirect users to. Step 4: Apply and Save the Rule Our final step is to click the “Apply” button in the top right hand of the IIS admin tool – which will cause the tool to persist the URL Rewrite rule into our application’s root web.config file (under a <system.webServer/rewrite> configuration section): <configuration> <system.webServer> <rewrite> <rules> <rule name="Default Document" stopProcessing="true"> <match url="(.*?)/?Default\.aspx$" /> <action type="Redirect" url="{R:1}/" /> </rule> </rules> </rewrite> </system.webServer> </configuration> Because IIS 7.x and ASP.NET share the same web.config files, you can actually just copy/paste the above code into your web.config files using Visual Studio and skip the need to run the admin tool entirely. This also makes adding/deploying URL Rewrite rules with your ASP.NET applications really easy. Step 5: Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site. Try the following two URLs on my site: http://scottgu.com/ http://scottgu.com/default.aspx Notice that the second URL automatically redirects to the first one. Because it is a permanent redirect, search engines will follow the URL and should update the page ranking of http://scottgu.com to include links to http://scottgu.com/default.aspx as well. Scenario 2: Different URL Casing Another common SEO problem I discussed earlier in this post is that URLs are case sensitive to search engines on the web. This means that search engines will treat the following links as two completely different URLs: http://scottgu.com/Albums.aspx http://scottgu.com/albums.aspx We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the first URL to instead go to the second (all lower-case) one. Like before, we will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve. To create such a rule we’ll click the “Add Rule” link in the URL Rewrite admin tool again. This will cause the “Add Rule” dialog to appear again: Unlike the previous scenario (where we created a “Blank Rule”), with this scenario we can take advantage of a built-in “Enforce lowercase URLs” rule template. When we click the “ok” button we’ll see the following dialog which asks us if we want to create a rule that enforces the use of lowercase letters in URLs: When we click the “Yes” button we’ll get a pre-written rule that automatically performs a permanent redirect if an incoming URL has upper-case characters in it – and automatically send users to a lower-case version of the URL: We can click the “Apply” button to use this rule “as-is” and have it apply to all incoming URLs to our site. Because my www.scottgu.com site uses ASP.NET Web Forms, I’m going to make one small change to the rule we generated above – which is to add a condition that will ensure that URLs to ASP.NET’s built-in “WebResource.axd” handler are excluded from our case-sensitivity URL Rewrite logic. URLs to the WebResource.axd handler will only come from server-controls emitted from my pages – and will never be linked to from external sites. While my site will continue to function fine if we redirect these URLs to automatically be lower-case – doing so isn’t necessary and will add an extra HTTP redirect to many of my pages. The good news is that adding a condition that prevents my URL Rewriting rule from happening with certain URLs is easy. We simply need to expand the “Conditions” section of the form above We can then click the “Add” button to add a condition clause. This will bring up the “Add Condition” dialog: Above I’ve entered {URL} as the Condition input – and said that this rule should only execute if the URL does not match a regex pattern which contains the string “WebResource.axd”. This will ensure that WebResource.axd URLs to my site will be allowed to execute just fine without having the URL be re-written to be all lower-case. Note: If you have static resources (like references to .jpg, .css, and .js files) within your site that currently use upper-case characters you’ll probably want to add additional condition filter clauses so that URLs to them also don’t get redirected to be lower-case (just add rules for patterns like .jpg, .gif, .js, etc). Your site will continue to work fine if these URLs get redirected to be lower case (meaning the site won’t break) – but it will cause an extra HTTP redirect to happen on your site for URLs that don’t need to be redirected for SEO reasons. So setting up a condition clause makes sense to add. When I click the “ok” button above and apply our lower-case rewriting rule the admin tool will save the following additional rule to our web.config file: <configuration> <system.webServer> <rewrite> <rules> <rule name="Default Document" stopProcessing="true"> <match url="(.*?)/?Default\.aspx$" /> <action type="Redirect" url="{R:1}/" /> </rule> <rule name="Lower Case URLs" stopProcessing="true"> <match url="[A-Z]" ignoreCase="false" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{URL}" pattern="WebResource.axd" negate="true" /> </conditions> <action type="Redirect" url="{ToLower:{URL}}" /> </rule> </rules> </rewrite> </system.webServer> </configuration> Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site. Try the following two URLs on my site: http://scottgu.com/Albums.aspx http://scottgu.com/albums.aspx Notice that the first URL (which has a capital “A”) automatically does a redirect to a lower-case version of the URL. Scenario 3: Trailing Slashes Another common SEO problem I discussed earlier in this post is the scenario of trailing slashes within URLs. The trailing slash creates yet another situation that causes search engines to treat the URLs as different and so split search rankings: http://scottgu.com http://scottgu.com/ We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the first URL (that does not have a trailing slash) to instead go to the second one that does. Like before, we will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve. To create such a rule we’ll click the “Add Rule” link in the URL Rewrite admin tool again. This will cause the “Add Rule” dialog to appear again: The URL Rewrite admin tool has a built-in “Append or remove the trailing slash symbol” rule template. When we select it and click the “ok” button we’ll see the following dialog which asks us if we want to create a rule that automatically redirects users to a URL with a trailing slash if one isn’t present: Like within our previous lower-casing rewrite rule we’ll add one additional condition clause that will exclude WebResource.axd URLs from being processed by this rule. This will avoid an unnecessary redirect for happening for those URLs. When we click the “OK” button we’ll get a pre-written rule that automatically performs a permanent redirect if the URL doesn’t have a trailing slash – and if the URL is not processed by either a directory or a file. This will save the following additional rule to our web.config file: <configuration> <system.webServer> <rewrite> <rules> <rule name="Default Document" stopProcessing="true"> <match url="(.*?)/?Default\.aspx$" /> <action type="Redirect" url="{R:1}/" /> </rule> <rule name="Lower Case URLs" stopProcessing="true"> <match url="[A-Z]" ignoreCase="false" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{URL}" pattern="WebResource.axd" negate="true" /> </conditions> <action type="Redirect" url="{ToLower:{URL}}" /> </rule> <rule name="Trailing Slash" stopProcessing="true"> <match url="(.*[^/])$" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" /> <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" /> <add input="{URL}" pattern="WebResource.axd" negate="true" /> </conditions> <action type="Redirect" url="{R:1}/" /> </rule> </rules> </rewrite> </system.webServer> </configuration> Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site. Try the following two URLs on my site: http://scottgu.com http://scottgu.com/ Notice that the first URL (which has no trailing slash) automatically does a redirect to a URL with the trailing slash. Because it is a permanent redirect, search engines will follow the URL and update the page ranking. Scenario 4: Canonical Host Names The final SEO problem I discussed earlier are scenarios where a site works with both a leading “www” hostname prefix as well as just the hostname itself. This causes search engines to treat the URLs as different and split search rankling: http://www.scottgu.com/albums.aspx http://scottgu.com/albums.aspx We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the first URL (that has a www prefix) to instead go to the second URL. Like before, we will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve. To create such a rule we’ll click the “Add Rule” link in the URL Rewrite admin tool again. This will cause the “Add Rule” dialog to appear again: The URL Rewrite admin tool has a built-in “Canonical domain name” rule template. When we select it and click the “ok” button we’ll see the following dialog which asks us if we want to create a redirect rule that automatically redirects users to a primary host name URL: Above I’m entering the primary URL address I want to expose to the web: scottgu.com. When we click the “OK” button we’ll get a pre-written rule that automatically performs a permanent redirect if the URL has another leading domain name prefix. This will save the following additional rule to our web.config file: <configuration> <system.webServer> <rewrite> <rules> <rule name="Cannonical Hostname"> <match url="(.*)" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{HTTP_HOST}" pattern="^scottgu\.com$" negate="true" /> </conditions> <action type="Redirect" url="http://scottgu.com/{R:1}" /> </rule> <rule name="Default Document" stopProcessing="true"> <match url="(.*?)/?Default\.aspx$" /> <action type="Redirect" url="{R:1}/" /> </rule> <rule name="Lower Case URLs" stopProcessing="true"> <match url="[A-Z]" ignoreCase="false" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{URL}" pattern="WebResource.axd" negate="true" /> </conditions> <action type="Redirect" url="{ToLower:{URL}}" /> </rule> <rule name="Trailing Slash" stopProcessing="true"> <match url="(.*[^/])$" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false"> <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" /> <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" /> <add input="{URL}" pattern="WebResource.axd" negate="true" /> </conditions> <action type="Redirect" url="{R:1}/" /> </rule> </rules> </rewrite> </system.webServer> </configuration> Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site. Try the following two URLs on my site: http://www.scottgu.com/albums.aspx http://scottgu.com/albums.aspx Notice that the first URL (which has the “www” prefix) now automatically does a redirect to the second URL which does not have the www prefix. Because it is a permanent redirect, search engines will follow the URL and update the page ranking. 4 Simple Rules for Improved SEO The above 4 rules are pretty easy to setup and should take less than 15 minutes to configure on existing sites you already have. The beauty of using a solution like the URL Rewrite Extension is that you can take advantage of it without having to change code within your web-site – and without having to break any existing links already pointing at your site. Users who follow existing links will be automatically redirected to the new URLs you wish to publish. And search engines will start to give your site a higher search relevancy ranking – which will list your site higher in search results and drive more traffic to it. Customizing your URL Rewriting rules further is easy to-do either by editing the web.config file directly, or alternatively, just double click the URL Rewrite icon within the IIS 7.x admin tool and it will list all the active rules for your web-site or application: Clicking any of the rules above will open the rules editor back up and allow you to tweak/customize/save them further. Summary Measuring and improving SEO is something every developer building a public-facing web-site needs to think about and focus on. If you haven’t already, download and use the SEO Toolkit to analyze the SEO of your sites today. New URL Routing features in ASP.NET MVC and ASP.NET Web Forms 4 make it much easier to build applications that have more control over the URLs that are published. Tools like the URL Rewrite Extension that I’ve talked about in this blog post make it much easier to improve the URLs that are published from sites you already have built today – without requiring you to change a lot of code. The URL Rewrite Extension provides a bunch of additional great capabilities – far beyond just SEO - as well. I’ll be covering these additional capabilities more in future blog posts. Hope this helps, Scott

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Social Network Updates: While You Were Busy Marketing 2

- by Mike Stiles

Since social moves at the speed of data, it’s already time for another update, as we did back in April, on the changes the various social networks have made or gone through while you were busy marketing. Facebook There’s a lot of talk Facebook’s developing a mobile product to act like Flipboard and surface news, from both users and media outlets. The biggest news was Facebook/Instagram’s introduction of 15-second videos, enhanced with with filters, to take some of Vine’s candy. You can also delete parts of videos and rerecord them, and there’s image stabilization. Facebook’s ad revenue is coming along just fine, thank you very much. 35% quarter-to-quarter growth in Q2. And it looks like new formats like Mobile App Install Ads and Unpublished Page Posts are adding to the mix. If you don’t already, you’ll soon see a little camera in comment boxes letting you insert photos right into the comments you make. The drive toward “more visual” continues. The other big news is Facebook’s adoption of our Twitter friend, the hashtag. Adding # sets apart the post topic so it can be easily found or discovered. It’s also being added to Google Plus, Tumblr, and Pinterest. Twitter Want to send someone a promoted tweet when they’re in range of your store? That could be happening by the end of this year. Some users have been seeing automatic in-stream previews of images on Twitter.com. Right now it’s images in your own tweets, but we can assume all tweets are next. Get your followers organized! Twitter raised the limit on the number of lists you can create from 20 to 1,000. They also raised the number of accounts you can have in a list from 500 to 5,000. Twitter started notifying you when someone favorites a tweet you’re mentioned in or re-tweets a tweet you re-tweeted. Anyway, it’s the first time Twitter’s notified you about indirect interactions like that. Who’s afraid of Instagram? A study shows 6-second Vine videos are being posted to Twitter at the rate of 9/second, up from 5/second 2 months ago. Vine has over 13 million users and branded Vines are 4x more likely to be shared than video ads. Google Plus Now featuring a 3-column redesigned stream, and images that take up a whole column. And photo filters Auto Highlight and Auto Awesome work to turn your photos into a real show. Google Hangouts is the workhorse for all Google messaging now, it’s not just an online chat with 9 people anymore. Google Plus Dashboard improves the connection between your company’s Google Plus business page and your Google Plus Local. Updates go out across all Google properties and you can do your managing from the dashboard. With Google Plus’ authorship system, you can build “Author Rank” based on what you write and put on the web. If your stuff is +1’ed and shared a lot, you’re the real deal and there are search result benefits. LinkedIn "Who's Viewed Your Updates" shows you what you’ve shared recently, who saw it and what they did about it in real-time. “Influencers” is, well, influential. Traffic to all LI news products has gone up 8x since it was introduced. LinkedIn is quickly figuring out how to get users to stick around awhile. You and your brand can post images and documents in status updates now. In fact, that whole “document posting” thing is making some analysts wonder if LinkedIn will drift on over to the Dropboxes and YouSendIts of the world. C’mon, admit it. Your favorite part of LinkedIn is being able to see who’s viewed your profile. Now you’ve got even more info and can see what/who you have in common. Premium users get even deeper insights about how people are finding them. If you’re a big fan of security, you’ll love that LinkedIn started offering two-factor authentication (2FA). It’s optional, but step 2 is a one-time code texted to your registered mobile. Pinterest A study showed pins have a looong shelf life compared to other social net posts. “Clicks kept coming for 30 days and beyond.” Most pins are timeless, and the infinite scroll causes people to see older pins. Is it a keeper? Pinterest jumped 82% to 54 million users in the past year. It’s valued at $2.5 billion and is one of the biggest sources of referral traffic there is. That said, CEO Ben Silbermann adds, "Right now, we don't make money." A new search feature stops you from having to endlessly scroll through your own pins looking for that waterfall picture you posted. Simply select “just my pins” in the search bar. New "Rich Pins" lets brands add info like price and availability to pins that can be updated daily via a data feed from your merchant site. Not so fast, you have to apply to Pinterest for it first. Like other social nets, Pinterest does not allow sexual content, nudity, or even partial nudity. However…some art contains nudity, and Pinterest wants to allow art. What constitutes “art” will be judged by…what we have to assume are Pinterest employees who love their job. @mikestilesPhoto: stock.xchng, Tim Marmon

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Issuing Current Time Increments in StreamInsight (A Practical Example)

The issuing of a Current Time Increment, Cti, in StreamInsight is very definitely one of the most important concepts to learn if you want your Streams to be responsive. A full discussion of how to issue Ctis is beyond the scope of this article but a very good explanation in addition to Books Online can be found in these three articles by a member of the StreamInsight team at Microsoft, Ciprian Gerea. Time in StreamInsight Series http://blogs.msdn.com/b/streaminsight/archive/2010/07/23/time-in-streaminsight-i.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/07/30/time-in-streaminsight-ii.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/08/03/time-in-streaminsight-iii.aspx A lot of the problems I see with unresponsive or stuck streams on the MSDN Forums are to do with how Ctis are enqueued or in a lot of cases not enqueued. If you enqueue events and never enqueue a Cti then StreamInsight will be perfectly happy. You, on the other hand, will never see data on the output as you have not told StreamInsight to flush the stream. This article deals with a specific implementation problem I had recently whilst working on a StreamInsight project. I look at some possible options and discuss why they would not work before showing the way I solved the problem. The stream of data I was dealing with on this project was very bursty that is to say when events were flowing they came through very quickly and in large numbers (1000 events/sec), but when the stream calmed down it could be a few seconds between each event. When enqueuing events into the StreamInsight engne it is best practice to do so with a StartTime that is given to you by the system producing the event . StreamInsight processes events and it doesn't matter whether those events are being pushed into the engine by a source system or the events are being read from something like a flat file in a directory somewhere. You can apply the same logic and temporal algebra to both situations. Reading from a file is an excellent example of where the time of the event on the source itself is very important. We could be reading that file a long time after it was written. Being able to read the StartTime from the events allows us to define windows that will hold the correct sets of events. I was able to do this with my stream but this is where my problems started. Below is a very simple script to create a SQL Server table and populate it with sample data that will show exactly the problem I had. CREATE TABLE [dbo].[t] ( [c1] [int] PRIMARY KEY, [c2] [datetime] NULL ) INSERT t VALUES (1,'20100810'),(2,'20100810'),(3,'20100810') Column c2 defines the StartTime of the event on the source and as you can see the values in all 3 rows of data is the same. If we read Ciprian’s articles we know that we can define how Ctis get injected into the stream in 3 different places The Stream Definition The Input Factory The Input Adapter I personally have always been a fan of enqueing Ctis through the factory. Below is code typical of what I would use to do this On the class itself I do some inheriting public class SimpleInputFactory : ITypedInputAdapterFactory<SimpleInputConfig>, ITypedDeclareAdvanceTimeProperties<SimpleInputConfig> And then I implement the following function public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.FromTicks(-1)), AdvanceTimePolicy.Adjust); } The configInfo .CtiFrequency property is a value I pass through to define after how many events I want a Cti to be injected and this in turn will flush through the stream of data. I usually pass a value of 1 for this setting. The second parameter determines the CTI timestamp in terms of a delay relative to the events. -1 ticks in the past results in 1 tick in the future, i.e., ahead of the event. The problem with this method though is that if consecutive events have the same StartTime then only one of those events will be enqueued. In this example I use the following to define how I assign the StartTime of my events currEvent.StartTime = (DateTimeOffset)dt.c2; If I go ahead and run my StreamInsight process with this configuration i can see on the output adapter that two events have been removed To see this in a little more depth I can use the StreamInsight Debugger and see what happens internally. What is happening here is that the first event arrives and a Cti is injected with a time of 1 tick after the StartTime of that event (Also the EndTime of the event). The second event arrives and it has a StartTime of before the Cti and even though we specified AdvanceTimePolicy.Adjust on the factory we know that a point event can never be adjusted like this and the event is dropped. The same happens for the third event as well (The second and third events get trumped by the Cti). For a more detailed discussion of why this happens look here http://www.sqlis.com/sqlis/post/AdvanceTimePolicy-and-Point-Event-Streams-In-StreamInsight.aspx We end up with a single event being pushed into the output adapter and our result now makes sense. The next way I tried to solve this problem by changing the value of the second parameter to TimeSpan.Zero Here is how my factory code now looks public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.Zero), AdvanceTimePolicy.Adjust); } What I am doing here is declaring a policy that says inject a Cti together with every event and stamp it with a StartTime that is equal to the start time of the event itself (TimeSpan.Zero). This method has plus points as well as a downside. The upside is that no events will be lost by having the same StartTime as previous events. The Downside is that because the Cti is declared with the StartTime of the event itself then it does not actually flush that particular event because in the StreamInsight algebra, a Cti commits only those events that occurred strictly before them. To flush the events we need a Cti to be enqueued with a greater StartTime than the events themselves. Here is what happened when I ran this configuration As you can see all we got through was the Cti and none of the events. The debugger output shows the stamps on the Cti and the events themselves. Because the Cti issued has the same timestamp (StartTime) as the events then none of the events get flushed. I was nearly there but not quite. Because my stream was bursty it was possible that the next event would not come along for a few seconds and this was far too long for an event to be enqueued and not be flushed to the output adapter. I needed another solution. Two possible solutions crossed my mind although only one of them made sense when I explored it some more. Where multiple events have the same StartTime I could add 1 tick to the first event, two to the second, three to third etc thereby giving them unique StartTime values. Add a timer to manually inject Ctis The problem with the first implementation is that I would be giving the events a new StartTime. This would cause me the following problems If I want to define windows over the stream then some events may not be captured in the right windows and therefore any calculations on those windows I did would be wrong What would happen if we had 10,000 events with the same StartTime? I would enqueue them with StartTime + n ticks. Along comes a genuine event with a StartTime of the very first event + 1 tick. It is now too far in the past as far as my stream is concerned and it would be dropped. Not what I would want to do at all. I decided then to look at the Timer based solution I created a timer on my input adapter that elapsed every 200ms. private Timer tmr; public SimpleInputAdapter(SimpleInputConfig configInfo) { ctx = new SimpleTimeExtractDataContext(configInfo.ConnectionString); this.configInfo = configInfo; tmr = new Timer(200); tmr.Elapsed += new ElapsedEventHandler(t_Elapsed); tmr.Enabled = true; } void t_Elapsed(object sender, ElapsedEventArgs e) { ts = DateTime.Now - dtCtiIssued; if (ts.TotalMilliseconds >= 200 && TimerIssuedCti == false) { EnqueueCtiEvent(System.DateTime.Now.AddTicks(-100)); TimerIssuedCti = true; } } In the t_Elapsed event handler I find out the difference in time between now and when the last event was processed (dtCtiIssued). I then check to see if that is greater than or equal to 200ms and if the last issuing of a Cti was done by the timer or by a genuine event (TimerIssuedCti). If I didn’t do this check then I would enqueue a Cti every time the timer elapsed which is not something I wanted. If the difference between the two times is greater than or equal to 500ms and the last event enqueued was by a real event then I issue a Cti through the timer to flush the event Queue, otherwise I do nothing. When I enqueue the Ctis into my stream in my ProduceEvents method I also set the values of dtCtiIssued and TimerIssuedCti currEvent = CreateInsertEvent(); currEvent.StartTime = (DateTimeOffset)dt.c2; TimerIssuedCti = false; dtCtiIssued = currEvent.StartTime; If I go ahead and run this configuration I see the following in my output. As we can see the first Cti gets enqueued as before but then another is enqueued by the timer and because this has a later timestamp it flushes the enqueued events through the engine. Conclusion Hopefully this has shown how the enqueuing of Ctis can have a dramatic effect on the responsiveness of your output in StreamInsight. Understanding the temporal nature of the product is for me one of the most important things you can learn. I have attached my solution for the demos. It is all in one project and testing each variation is a simple matter of commenting and un-commenting the parts in the code we have been dealing with here.

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Nginx and PHP Fundamentals

- by Elton Stoneman

Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2013/08/01/nginx-and-php-fundamentals.aspxHot on the heels of my .NET caching course, I’ve had my first “fundamentals” course released on Pluralsight: Nginx and PHP Fundamentals. It’s a practical look at two of the biggest technologies on the web – Nginx, which is the fastest growing HTTP server around (currently hosting 100+ million sites), and PHP, which powers more websites than any other server-side framework (currently 240+ million sites). The two technologies work well together, both are open-source and cross-platform and both are lightweight and easy to get started with - you just need to download and unzip the runtimes, and with a text editor you can create and host dynamic websites. I’ve used PHP as a second (sometimes third) language since 2005 when I was brought cold into an established codebase to help improve performance, and Nginx to host tier 2 apps for the last couple of years. As with any training course, you learn new things as you produce it, and it was good to focus on a different stack from my commercial .NET world. In the course I start with a website in two parts – one which is just static content, and one which processes a user registration form using ASP.NET MVC, both running in IIS. Over four modules I migrate the app to Nginx and PHP: Hosting Static Content in Nginx – how to deploy and configure Nginx for a basic website; PHP Part 1: Basic Web Forms – installing PHP and an IDE, and building a simple form with server-side validation; PHP Part 2: Packages and Integration – using PECL and Composer for packages to connect to Azure, AWS, Mongo and reCAPTCHA; Hosting PHP in Nginx – configuring Nginx to host our PHP site. Along the way I run some performance stats with JMeter, and the headlines are that Nginx running on Linux outperforms IIS on Windows for static content,by 800 requests per second over 1000 concurrent requests; and Linux+Ngnix+PHP outperforms Windows+IIS+ASP.NET MVC by 700 request per second with the same load. Of course, the headline stats don’t tell the whole story, and when you add OpCode caching for PHP and the ASP.NET Output Cache, the results are very different. As Web architecture moves away from heavy server-side processing, to Single Page Apps with client-side frameworks like AngularJS and Knockout, I think there’s an increasing need for high-performance, low-cost server technologies, and the combination of Nginx and PHP makes a compelling case.

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Fed Authentication Methods in OIF / IdP

- by Damien Carru

This article is a continuation of my previous entry where I explained how OIF/IdP leverages OAM to authenticate users at runtime: OIF/IdP internally forwards the user to OAM and indicates which Authentication Scheme should be used to challenge the user if needed OAM determine if the user should be challenged (user already authenticated, session timed out or not, session authentication level equal or higher than the level of the authentication scheme specified by OIF/IdP…) After identifying the user, OAM internally forwards the user back to OIF/IdP OIF/IdP can resume its operation In this article, I will discuss how OIF/IdP can be configured to map Federation Authentication Methods to OAM Authentication Schemes: When processing an Authn Request, where the SP requests a specific Federation Authentication Method with which the user should be challenged When sending an Assertion, where OIF/IdP sets the Federation Authentication Method in the Assertion Enjoy the reading! Overview The various Federation protocols support mechanisms allowing the partners to exchange information on: How the user should be challenged, when the SP/RP makes a request How the user was challenged, when the IdP/OP issues an SSO response When a remote SP partner redirects the user to OIF/IdP for Federation SSO, the message might contain data requesting how the user should be challenged by the IdP: this is treated as the Requested Federation Authentication Method. OIF/IdP will need to map that Requested Federation Authentication Method to a local Authentication Scheme, and then invoke OAM for user authentication/challenge with the mapped Authentication Scheme. OAM would authenticate the user if necessary with the scheme specified by OIF/IdP. Similarly, when an IdP issues an SSO response, most of the time it will need to include an identifier representing how the user was challenged: this is treated as the Federation Authentication Method. When OIF/IdP issues an Assertion, it will evaluate the Authentication Scheme with which OAM identified the user: If the Authentication Scheme can be mapped to a Federation Authentication Method, then OIF/IdP will use the result of that mapping in the outgoing SSO response: AuthenticationStatement in the SAML Assertion OpenID Response, if PAPE is enabled If the Authentication Scheme cannot be mapped, then OIF/IdP will set the Federation Authentication Method as the Authentication Scheme name in the outgoing SSO response: AuthenticationStatement in the SAML Assertion OpenID Response, if PAPE is enabled Mappings In OIF/IdP, the mapping between Federation Authentication Methods and Authentication Schemes has the following rules: One Federation Authentication Method can be mapped to several Authentication Schemes In a Federation Authentication Method <-> Authentication Schemes mapping, a single Authentication Scheme is marked as the default scheme that will be used to authenticate a user, if the SP/RP partner requests the user to be authenticated via a specific Federation Authentication Method An Authentication Scheme can be mapped to a single Federation Authentication Method Let’s examine the following example and the various use cases, based on the SAML 2.0 protocol: Mappings defined as: urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport mapped to LDAPScheme, marked as the default scheme used for authentication BasicScheme urn:oasis:names:tc:SAML:2.0:ac:classes:X509 mapped to X509Scheme, marked as the default scheme used for authentication Use cases: SP sends an AuthnRequest specifying urn:oasis:names:tc:SAML:2.0:ac:classes:X509 as the RequestedAuthnContext: OIF/IdP will authenticate the use with X509Scheme since it is the default scheme mapped for that method. SP sends an AuthnRequest specifying urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport as the RequestedAuthnContext: OIF/IdP will authenticate the use with LDAPScheme since it is the default scheme mapped for that method, not the BasicScheme SP did not request any specific methods, and user was authenticated with BasisScheme: OIF/IdP will issue an Assertion with urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport as the FederationAuthenticationMethod SP did not request any specific methods, and user was authenticated with LDAPScheme: OIF/IdP will issue an Assertion with urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport as the FederationAuthenticationMethod SP did not request any specific methods, and user was authenticated with BasisSessionlessScheme: OIF/IdP will issue an Assertion with BasisSessionlessScheme as the FederationAuthenticationMethod, since that scheme could not be mapped to any Federation Authentication Method (in this case, the administrator would need to correct that and create a mapping) Configuration Mapping Federation Authentication Methods to OAM Authentication Schemes is protocol dependent, since the methods are defined in the various protocols (SAML 2.0, SAML 1.1, OpenID 2.0). As such, the WLST commands to set those mappings will involve: Either the SP Partner Profile and affect all Partners referencing that profile, which do not override the Federation Authentication Method to OAM Authentication Scheme mappings Or the SP Partner entry, which will only affect the SP Partner It is important to note that if an SP Partner is configured to define one or more Federation Authentication Method to OAM Authentication Scheme mappings, then all the mappings defined in the SP Partner Profile will be ignored. Authentication Schemes As discussed in the previous article, during Federation SSO, OIF/IdP will internally forward the user to OAM for authentication/verification and specify which Authentication Scheme to use. OAM will determine if a user needs to be challenged: If the user is not authenticated yet If the user is authenticated but the session timed out If the user is authenticated, but the authentication scheme level of the original authentication is lower than the level of the authentication scheme requested by OIF/IdP So even though an SP requests a specific Federation Authentication Method to be used to challenge the user, if that method is mapped to an Authentication Scheme and that at runtime OAM deems that the user does not need to be challenged with that scheme (because the user is already authenticated, session did not time out, and the session authn level is equal or higher than the one for the specified Authentication Scheme), the flow won’t result in a challenge operation. Protocols SAML 2.0 The SAML 2.0 specifications define the following Federation Authentication Methods for SAML 2.0 flows: urn:oasis:names:tc:SAML:2.0:ac:classes:unspecified urn:oasis:names:tc:SAML:2.0:ac:classes:InternetProtocol urn:oasis:names:tc:SAML:2.0:ac:classes:Telephony urn:oasis:names:tc:SAML:2.0:ac:classes:MobileOneFactorUnregistered urn:oasis:names:tc:SAML:2.0:ac:classes:PersonalTelephony urn:oasis:names:tc:SAML:2.0:ac:classes:PreviousSession urn:oasis:names:tc:SAML:2.0:ac:classes:MobileOneFactorContract urn:oasis:names:tc:SAML:2.0:ac:classes:Smartcard urn:oasis:names:tc:SAML:2.0:ac:classes:Password urn:oasis:names:tc:SAML:2.0:ac:classes:InternetProtocolPassword urn:oasis:names:tc:SAML:2.0:ac:classes:X509 urn:oasis:names:tc:SAML:2.0:ac:classes:TLSClient urn:oasis:names:tc:SAML:2.0:ac:classes:PGP urn:oasis:names:tc:SAML:2.0:ac:classes:SPKI urn:oasis:names:tc:SAML:2.0:ac:classes:XMLDSig urn:oasis:names:tc:SAML:2.0:ac:classes:SoftwarePKI urn:oasis:names:tc:SAML:2.0:ac:classes:Kerberos urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport urn:oasis:names:tc:SAML:2.0:ac:classes:SecureRemotePassword urn:oasis:names:tc:SAML:2.0:ac:classes:NomadTelephony urn:oasis:names:tc:SAML:2.0:ac:classes:AuthenticatedTelephony urn:oasis:names:tc:SAML:2.0:ac:classes:MobileTwoFactorUnregistered urn:oasis:names:tc:SAML:2.0:ac:classes:MobileTwoFactorContract urn:oasis:names:tc:SAML:2.0:ac:classes:SmartcardPKI urn:oasis:names:tc:SAML:2.0:ac:classes:TimeSyncToken Out of the box, OIF/IdP has the following mappings for the SAML 2.0 protocol: Only urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport is defined This Federation Authentication Method is mapped to: LDAPScheme, marked as the default scheme used for authentication FAAuthScheme BasicScheme BasicFAScheme This mapping is defined in the saml20-sp-partner-profile SP Partner Profile which is the default OOTB SP Partner Profile for SAML 2.0 An example of an AuthnRequest message sent by an SP to an IdP with the SP requesting a specific Federation Authentication Method to be used to challenge the user would be: <samlp:AuthnRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" Destination="https://idp.com/oamfed/idp/samlv20" ID="id-8bWn-A9o4aoMl3Nhx1DuPOOjawc-" IssueInstant="2014-03-21T20:51:11Z" Version="2.0"> <saml:Issuer ...>https://acme.com/sp</saml:Issuer> <samlp:NameIDPolicy AllowCreate="false" Format="urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified"/> <samlp:RequestedAuthnContext Comparison="minimum"> <saml:AuthnContextClassRef xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"> urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport </saml:AuthnContextClassRef> </samlp:RequestedAuthnContext></samlp:AuthnRequest> An example of an Assertion issued by an IdP would be: <samlp:Response ...> <saml:Issuer ...>https://idp.com/oam/fed</saml:Issuer> <samlp:Status> <samlp:StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/> </samlp:Status> <saml:Assertion ...> <saml:Issuer ...>https://idp.com/oam/fed</saml:Issuer> <dsig:Signature> ... </dsig:Signature> <saml:Subject> <saml:NameID ...>[email protected]</saml:NameID> <saml:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer"> <saml:SubjectConfirmationData .../> </saml:SubjectConfirmation> </saml:Subject> <saml:Conditions ...> <saml:AudienceRestriction> <saml:Audience>https://acme.com/sp</saml:Audience> </saml:AudienceRestriction> </saml:Conditions> <saml:AuthnStatement AuthnInstant="2014-03-21T20:53:55Z" SessionIndex="id-6i-Dm0yB-HekG6cejktwcKIFMzYE8Yrmqwfd0azz" SessionNotOnOrAfter="2014-03-21T21:53:55Z"> <saml:AuthnContext> <saml:AuthnContextClassRef> urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport </saml:AuthnContextClassRef> </saml:AuthnContext> </saml:AuthnStatement> </saml:Assertion></samlp:Response> An administrator would be able to specify a mapping between a SAML 2.0 Federation Authentication Method and one or more OAM Authentication Schemes SAML 1.1 The SAML 1.1 specifications define the following Federation Authentication Methods for SAML 1.1 flows: urn:oasis:names:tc:SAML:1.0:am:unspecified urn:oasis:names:tc:SAML:1.0:am:HardwareToken urn:oasis:names:tc:SAML:1.0:am:password urn:oasis:names:tc:SAML:1.0:am:X509-PKI urn:ietf:rfc:2246 urn:oasis:names:tc:SAML:1.0:am:PGP urn:oasis:names:tc:SAML:1.0:am:SPKI urn:ietf:rfc:3075 urn:oasis:names:tc:SAML:1.0:am:XKMS urn:ietf:rfc:1510 urn:ietf:rfc:2945 Out of the box, OIF/IdP has the following mappings for the SAML 1.1 protocol: Only urn:oasis:names:tc:SAML:1.0:am:password is defined This Federation Authentication Method is mapped to: LDAPScheme, marked as the default scheme used for authentication FAAuthScheme BasicScheme BasicFAScheme This mapping is defined in the saml11-sp-partner-profile SP Partner Profile which is the default OOTB SP Partner Profile for SAML 1.1 An example of an Assertion issued by an IdP would be: <samlp:Response ...> <samlp:Status> <samlp:StatusCode Value="samlp:Success"/> </samlp:Status> <saml:Assertion Issuer="https://idp.com/oam/fed" ...> <saml:Conditions ...> <saml:AudienceRestriction> <saml:Audience>https://acme.com/sp/ssov11</saml:Audience> </saml:AudienceRestriction> </saml:Conditions> <saml:AuthnStatement AuthenticationInstant="2014-03-21T20:53:55Z" AuthenticationMethod="urn:oasis:names:tc:SAML:1.0:am:password"> <saml:Subject> <saml:NameID ...>[email protected]</saml:NameID> <saml:SubjectConfirmation> <saml:ConfirmationMethod> urn:oasis:names:tc:SAML:1.0:cm:bearer </saml:ConfirmationMethod> </saml:SubjectConfirmation> </saml:Subject> </saml:AuthnStatement> <dsig:Signature> ... </dsig:Signature> </saml:Assertion></samlp:Response> Note: SAML 1.1 does not define an AuthnRequest message. An administrator would be able to specify a mapping between a SAML 1.1 Federation Authentication Method and one or more OAM Authentication Schemes OpenID 2.0 The OpenID 2.0 PAPE specifications define the following Federation Authentication Methods for OpenID 2.0 flows: http://schemas.openid.net/pape/policies/2007/06/phishing-resistant http://schemas.openid.net/pape/policies/2007/06/multi-factor http://schemas.openid.net/pape/policies/2007/06/multi-factor-physical Out of the box, OIF/IdP does not define any mappings for the OpenID 2.0 Federation Authentication Methods. For OpenID 2.0, the configuration will involve mapping a list of OpenID 2.0 policies to a list of Authentication Schemes. An example of an OpenID 2.0 Request message sent by an SP/RP to an IdP/OP would be: https://idp.com/openid?openid.ns=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0&openid.mode=checkid_setup&openid.claimed_id=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0%2Fidentifier_select&openid.identity=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0%2Fidentifier_select&openid.assoc_handle=id-6a5S6zhAKaRwQNUnjTKROREdAGSjWodG1el4xyz3&openid.return_to=https%3A%2F%2Facme.com%2Fopenid%3Frefid%3Did-9PKVXZmRxAeDYcgLqPm36ClzOMA-&openid.realm=https%3A%2F%2Facme.com%2Fopenid&openid.ns.ax=http%3A%2F%2Fopenid.net%2Fsrv%2Fax%2F1.0&openid.ax.mode=fetch_request&openid.ax.type.attr0=http%3A%2F%2Faxschema.org%2Fcontact%2Femail&openid.ax.if_available=attr0&openid.ns.pape=http%3A%2F%2Fspecs.openid.net%2Fextensions%2Fpape%2F1.0&openid.pape.max_auth_age=0 An example of an Open ID 2.0 SSO Response issued by an IdP/OP would be: https://acme.com/openid?refid=id-9PKVXZmRxAeDYcgLqPm36ClzOMA-&openid.ns=http%3A%2F%2Fspecs.openid.net%2Fauth%2F2.0&openid.mode=id_res&openid.op_endpoint=https%3A%2F%2Fidp.com%2Fopenid&openid.claimed_id=https%3A%2F%2Fidp.com%2Fopenid%3Fid%3Did-38iCmmlAVEXPsFjnFVKArfn5RIiF75D5doorhEgqqPM%3D&openid.identity=https%3A%2F%2Fidp.com%2Fopenid%3Fid%3Did-38iCmmlAVEXPsFjnFVKArfn5RIiF75D5doorhEgqqPM%3D&openid.return_to=https%3A%2F%2Facme.com%2Fopenid%3Frefid%3Did-9PKVXZmRxAeDYcgLqPm36ClzOMA-&openid.response_nonce=2014-03-24T19%3A20%3A06Zid-YPa2kTNNFftZkgBb460jxJGblk2g--iNwPpDI7M1&openid.assoc_handle=id-6a5S6zhAKaRwQNUnjTKROREdAGSjWodG1el4xyz3&openid.ns.ax=http%3A%2F%2Fopenid.net%2Fsrv%2Fax%2F1.0&openid.ax.mode=fetch_response&openid.ax.type.attr0=http%3A%2F%2Fsession%2Fcount&openid.ax.value.attr0=1&openid.ax.type.attr1=http%3A%2F%2Fopenid.net%2Fschema%2FnamePerson%2Ffriendly&openid.ax.value.attr1=My+name+is+Bobby+Smith&openid.ax.type.attr2=http%3A%2F%2Fschemas.openid.net%2Fax%2Fapi%2Fuser_id&openid.ax.value.attr2=bob&openid.ax.type.attr3=http%3A%2F%2Faxschema.org%2Fcontact%2Femail&openid.ax.value.attr3=bob%40oracle.com&openid.ax.type.attr4=http%3A%2F%2Fsession%2Fipaddress&openid.ax.value.attr4=10.145.120.253&openid.ns.pape=http%3A%2F%2Fspecs.openid.net%2Fextensions%2Fpape%2F1.0&openid.pape.auth_time=2014-03-24T19%3A20%3A05Z&openid.pape.auth_policies=http%3A%2F%2Fschemas.openid.net%2Fpape%2Fpolicies%2F2007%2F06%2Fphishing-resistant&openid.signed=op_endpoint%2Cclaimed_id%2Cidentity%2Creturn_to%2Cresponse_nonce%2Cassoc_handle%2Cns.ax%2Cax.mode%2Cax.type.attr0%2Cax.value.attr0%2Cax.type.attr1%2Cax.value.attr1%2Cax.type.attr2%2Cax.value.attr2%2Cax.type.attr3%2Cax.value.attr3%2Cax.type.attr4%2Cax.value.attr4%2Cns.pape%2Cpape.auth_time%2Cpape.auth_policies&openid.sig=mYMgbGYSs22l8e%2FDom9NRPw15u8%3D In the next article, I will provide examples on how to configure OIF/IdP for the various protocols, to map OAM Authentication Schemes to Federation Authentication Methods.Cheers,Damien Carru

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String Format for DateTime in C#

- by SAMIR BHOGAYTA

String Format for DateTime [C#] This example shows how to format DateTime using String.Format method. All formatting can be done also using DateTime.ToString method. Custom DateTime Formatting There are following custom format specifiers y (year), M (month), d (day), h (hour 12), H (hour 24), m (minute), s (second), f (second fraction), F (second fraction, trailing zeroes are trimmed), t (P.M or A.M) and z (time zone). Following examples demonstrate how are the format specifiers rewritten to the output. [C#] // create date time 2008-03-09 16:05:07.123 DateTime dt = new DateTime(2008, 3, 9, 16, 5, 7, 123); String.Format("{0:y yy yyy yyyy}", dt); // "8 08 008 2008" year String.Format("{0:M MM MMM MMMM}", dt); // "3 03 Mar March" month String.Format("{0:d dd ddd dddd}", dt); // "9 09 Sun Sunday" day String.Format("{0:h hh H HH}", dt); // "4 04 16 16" hour 12/24 String.Format("{0:m mm}", dt); // "5 05" minute String.Format("{0:s ss}", dt); // "7 07" second String.Format("{0:f ff fff ffff}", dt); // "1 12 123 1230" sec.fraction String.Format("{0:F FF FFF FFFF}", dt); // "1 12 123 123" without zeroes String.Format("{0:t tt}", dt); // "P PM" A.M. or P.M. String.Format("{0:z zz zzz}", dt); // "-6 -06 -06:00" time zone You can use also date separator / (slash) and time sepatator : (colon). These characters will be rewritten to characters defined in the current DateTimeFormatInfo.DateSeparator and DateTimeFormatInfo.TimeSeparator. [C#] // date separator in german culture is "." (so "/" changes to ".") String.Format("{0:d/M/yyyy HH:mm:ss}", dt); // "9/3/2008 16:05:07" - english (en-US) String.Format("{0:d/M/yyyy HH:mm:ss}", dt); // "9.3.2008 16:05:07" - german (de-DE) Here are some examples of custom date and time formatting: [C#] // month/day numbers without/with leading zeroes String.Format("{0:M/d/yyyy}", dt); // "3/9/2008" String.Format("{0:MM/dd/yyyy}", dt); // "03/09/2008" // day/month names String.Format("{0:ddd, MMM d, yyyy}", dt); // "Sun, Mar 9, 2008" String.Format("{0:dddd, MMMM d, yyyy}", dt); // "Sunday, March 9, 2008" // two/four digit year String.Format("{0:MM/dd/yy}", dt); // "03/09/08" String.Format("{0:MM/dd/yyyy}", dt); // "03/09/2008" Standard DateTime Formatting In DateTimeFormatInfo there are defined standard patterns for the current culture. For example property ShortTimePattern is string that contains value h:mm tt for en-US culture and value HH:mm for de-DE culture. Following table shows patterns defined in DateTimeFormatInfo and their values for en-US culture. First column contains format specifiers for the String.Format method. Specifier DateTimeFormatInfo property Pattern value (for en-US culture) t ShortTimePattern h:mm tt d ShortDatePattern M/d/yyyy T LongTimePattern h:mm:ss tt D LongDatePattern dddd, MMMM dd, yyyy f (combination of D and t) dddd, MMMM dd, yyyy h:mm tt F FullDateTimePattern dddd, MMMM dd, yyyy h:mm:ss tt g (combination of d and t) M/d/yyyy h:mm tt G (combination of d and T) M/d/yyyy h:mm:ss tt m, M MonthDayPattern MMMM dd y, Y YearMonthPattern MMMM, yyyy r, R RFC1123Pattern ddd, dd MMM yyyy HH':'mm':'ss 'GMT' (*) s SortableDateTimePattern yyyy'-'MM'-'dd'T'HH':'mm':'ss (*) u UniversalSortableDateTimePattern yyyy'-'MM'-'dd HH':'mm':'ss'Z' (*) (*) = culture independent Following examples show usage of standard format specifiers in String.Format method and the resulting output. [C#] String.Format("{0:t}", dt); // "4:05 PM" ShortTime String.Format("{0:d}", dt); // "3/9/2008" ShortDate String.Format("{0:T}", dt); // "4:05:07 PM" LongTime String.Format("{0:D}", dt); // "Sunday, March 09, 2008" LongDate String.Format("{0:f}", dt); // "Sunday, March 09, 2008 4:05 PM" LongDate+ShortTime String.Format("{0:F}", dt); // "Sunday, March 09, 2008 4:05:07 PM" FullDateTime String.Format("{0:g}", dt); // "3/9/2008 4:05 PM" ShortDate+ShortTime String.Format("{0:G}", dt); // "3/9/2008 4:05:07 PM" ShortDate+LongTime String.Format("{0:m}", dt); // "March 09" MonthDay String.Format("{0:y}", dt); // "March, 2008" YearMonth String.Format("{0:r}", dt); // "Sun, 09 Mar 2008 16:05:07 GMT" RFC1123 String.Format("{0:s}", dt); // "2008-03-09T16:05:07" SortableDateTime String.Format("{0:u}", dt); // "2008-03-09 16:05:07Z" UniversalSortableDateTime

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Increase Security by Enabling Two-Factor Authentication on Your Google Account

- by Jason Fitzpatrick

You can easily increase the security of your Google account by enabling two-factor authentication; flip it on today for a free security boost. It’s not a new feature but it’s a feature worth giving a second look. Watch the above video for a quick overview of Google’s two-factor authentication system. Essentially your mobile phone becomes the second authentication tool–you use your password + a code sent to your phone to log into your account. It’s a great way to easily increase the security of your Google account, it’s free, and you can set it so that you only have to validate your home computer once every 30 days. Google Two-Step Verification [via Google+] HTG Explains: When Do You Need to Update Your Drivers? How to Make the Kindle Fire Silk Browser *Actually* Fast! Amazon’s New Kindle Fire Tablet: the How-To Geek Review

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xgamma -display parameter for dual monitor setup

- by Shiplu

I want to change gamma for my first monitor. Every time I invoke xgamma with different -display parameters it somehow points to my second monitor. But I want to modify first one. I tried these commands. The parameters I have used for -display are :0, :0.0, :0.1, :1.0, :1.1, :1. Only the first 2 works. But it points to my second monitor. Not the first one. Here is a shell script to test it. shiplu@KubuntuD:~$ xgamma -display :0 -> Red 1.000, Green 1.000, Blue 1.000 shiplu@KubuntuD:~$ xgamma -display :0.0 -> Red 1.000, Green 1.000, Blue 1.000 shiplu@KubuntuD:~$ xgamma -display :0.1 xgamma: unable to open display ':0.1' shiplu@KubuntuD:~$ xgamma -display :1.0 xgamma: unable to open display ':1.0' shiplu@KubuntuD:~$ xgamma -display :1.1 xgamma: unable to open display ':1.1' shiplu@KubuntuD:~$ xgamma -display :1 xgamma: unable to open display ':1' How can I change the gamma for the first/primary monitor?

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Language Club – Battle of the Dynamic Languages

- by Ben Griswold

After dedicating the last eight weeks to learning Ruby, it’s time to move onto another language. I really dig Ruby. I really enjoy its dynamism and expressiveness and always-openness and it’s been the highlight of our coding club for me so far. But that’s just my take on the language. I know a lot of coders who’s stomachs turn with the mere thought of Ruby. They say it’s Ruby’s openness which has them feeling uneasy. I’d say “write a bunch of tests and get over it,” but I figure there must be more to it than always open classes and possible method collisions. Yes, there’s something else to it alright. The folks who didn’t fall head over heals for Ruby are already in love with Python. You might remember that Python was the first language we tackled in our coding club. My time with Python was okay but it didn’t feel as natural to me as Ruby. But let’s say we started with Ruby and then moved onto Python. Would I see Python in a different light right now. Might I even prefer Python over Ruby? I suppose it’s possible but it’s pretty tough to test that theory – unless we visit Python for a second time. That’s right. The language club is going to focus on Python again and in my attempt to learn Python – yet again – in the open, I’ll be posting my solutions here just as I did for Ruby. We don’t always have second chances so I going about this relearning with two primary goals in mind: First, I’m going to use IronPython and the IronPython tools which provide a Python code editor, a file-based project system, and an interactive Python interpreter, all inside Visual Studio 2010. As a note, the IronPython tools are now part of the main IronPython installer which is Version 2.7 Alpha 1 (not the latest stable version, 2.6.1) and I’d be crazy not to use them. Second, I’d like to make sure I’m still learning Python without a complete MS skew so I’m going to run my code through Eclipse using the PyDev plugin as well. Heck, I might use IDLE too. I already have this setup on my machine so it’s no big deal. Okay, that’s it for now. I worked on the first ten Euler problems last night and the solutions will be posted shortly. Wish me luck.

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Silverlight Cream for May 17, 2010 -- #863

- by Dave Campbell

In this Issue: Christian Schormann, Vladimir Bodurov, Pete Brown, Justin Angel, John Papa(-2-), Fons Sonnemans, Miroslav Miroslavov, and Jeremy Likness. Shoutouts: Jeff Brand has been doing WP7 presentations and posted Windows Phone 7 Presentation and Sample Code Mark Tucker posted about his Windows Phone 7 Presentation at Desert Code Camp 2010 John Allwright discusses 4 New case Studies on Silverlight at the Winter Olympics From SilverlightCream.com: New Video by Jon Harris: Blend 4 for Windows Phone in 90 Seconds Christian Schormann is discussing a second 90-second Expression Blend video tutorial by Jon Harris... this second one is about Blend 4 for WP7. XmlCodeEditor – Silverlight 4 control for editing XML and HTML on the browser Vladimir Bodurov has a post up extending the RichTextBox control to add coloring for HTML and XAML ... it colors as you type, and he plans on adding Intellisense! Creating a Simple Report Writer in Silverlight 4 While working on his book, Pete Brown decided to share some Silverlight 'Report Writer' work with us... check out that list of goals near the top that are all met... looks great to me! Windows Phone 7 - Unlocked ROMs Justin Angel has a good long post about a subject I've stayed away from until now that someone of Justin's level of knowledge has approached it: WP7 ROMs. Silverlight 4 Tools for Visual Studio 2010 Launch: New Designer Capabilities (Silverlight TV 27) John Papa has Silverlight TV 27 up today and is talking about the Silverlight 4 Tools for VS2010 launch with Mark Wilson-Thomas ... the video would be a great place to pick up some of the new features (hint, hint) WCF RIA Services v1.0 Launch! (Silverlight TV 28) John Papa also has Silverlight TV 28 up, talking with Nikhil Kothari and Dinesh Kulkarni about the v 1.0 release of WCF RIA Services. RightMouseTrigger Fons Sonnemans updated his MineSweeper game and has it posted at Silver Arcade, this version supports right mouse click via RightMouseTrigger code that he is sharing. Smoke effect The 'Smoke Effect' menus at the CompleteIT site are awesome, and this time out, Miroslav Miroslavov discusses how that was done and gives up the code...! WebClient and DeploymentCatalog gotchas in Silverlight OOB Jeremy Likness has a post up to give you some relief if you hit the same MEF/Silverlight gotcha he did when running OOB... like not running in OOB for instance. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight Silverlight 3 Silverlight 4 Windows Phone MIX10

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Metro: Promises

- by Stephen.Walther

The goal of this blog entry is to describe the Promise class in the WinJS library. You can use promises whenever you need to perform an asynchronous operation such as retrieving data from a remote website or a file from the file system. Promises are used extensively in the WinJS library. Asynchronous Programming Some code executes immediately, some code requires time to complete or might never complete at all. For example, retrieving the value of a local variable is an immediate operation. Retrieving data from a remote website takes longer or might not complete at all. When an operation might take a long time to complete, you should write your code so that it executes asynchronously. Instead of waiting for an operation to complete, you should start the operation and then do something else until you receive a signal that the operation is complete. An analogy. Some telephone customer service lines require you to wait on hold – listening to really bad music – until a customer service representative is available. This is synchronous programming and very wasteful of your time. Some newer customer service lines enable you to enter your telephone number so the customer service representative can call you back when a customer representative becomes available. This approach is much less wasteful of your time because you can do useful things while waiting for the callback. There are several patterns that you can use to write code which executes asynchronously. The most popular pattern in JavaScript is the callback pattern. When you call a function which might take a long time to return a result, you pass a callback function to the function. For example, the following code (which uses jQuery) includes a function named getFlickrPhotos which returns photos from the Flickr website which match a set of tags (such as “dog” and “funny”): function getFlickrPhotos(tags, callback) { $.getJSON( "http://api.flickr.com/services/feeds/photos_public.gne?jsoncallback=?", { tags: tags, tagmode: "all", format: "json" }, function (data) { if (callback) { callback(data.items); } } ); } getFlickrPhotos("funny, dogs", function(data) { $.each(data, function(index, item) { console.log(item); }); }); The getFlickr() function includes a callback parameter. When you call the getFlickr() function, you pass a function to the callback parameter which gets executed when the getFlicker() function finishes retrieving the list of photos from the Flickr web service. In the code above, the callback function simply iterates through the results and writes each result to the console. Using callbacks is a natural way to perform asynchronous programming with JavaScript. Instead of waiting for an operation to complete, sitting there and listening to really bad music, you can get a callback when the operation is complete. Using Promises The CommonJS website defines a promise like this (http://wiki.commonjs.org/wiki/Promises): “Promises provide a well-defined interface for interacting with an object that represents the result of an action that is performed asynchronously, and may or may not be finished at any given point in time. By utilizing a standard interface, different components can return promises for asynchronous actions and consumers can utilize the promises in a predictable manner.” A promise provides a standard pattern for specifying callbacks. In the WinJS library, when you create a promise, you can specify three callbacks: a complete callback, a failure callback, and a progress callback. Promises are used extensively in the WinJS library. The methods in the animation library, the control library, and the binding library all use promises. For example, the xhr() method included in the WinJS base library returns a promise. The xhr() method wraps calls to the standard XmlHttpRequest object in a promise. The following code illustrates how you can use the xhr() method to perform an Ajax request which retrieves a file named Photos.txt: var options = { url: "/data/photos.txt" }; WinJS.xhr(options).then( function (xmlHttpRequest) { console.log("success"); var data = JSON.parse(xmlHttpRequest.responseText); console.log(data); }, function(xmlHttpRequest) { console.log("fail"); }, function(xmlHttpRequest) { console.log("progress"); } ) The WinJS.xhr() method returns a promise. The Promise class includes a then() method which accepts three callback functions: a complete callback, an error callback, and a progress callback: Promise.then(completeCallback, errorCallback, progressCallback) In the code above, three anonymous functions are passed to the then() method. The three callbacks simply write a message to the JavaScript Console. The complete callback also dumps all of the data retrieved from the photos.txt file. Creating Promises You can create your own promises by creating a new instance of the Promise class. The constructor for the Promise class requires a function which accepts three parameters: a complete, error, and progress function parameter. For example, the code below illustrates how you can create a method named wait10Seconds() which returns a promise. The progress function is called every second and the complete function is not called until 10 seconds have passed: (function () { "use strict"; var app = WinJS.Application; function wait10Seconds() { return new WinJS.Promise(function (complete, error, progress) { var seconds = 0; var intervalId = window.setInterval(function () { seconds++; progress(seconds); if (seconds > 9) { window.clearInterval(intervalId); complete(); } }, 1000); }); } app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { wait10Seconds().then( function () { console.log("complete") }, function () { console.log("error") }, function (seconds) { console.log("progress:" + seconds) } ); } } app.start(); })(); All of the work happens in the constructor function for the promise. The window.setInterval() method is used to execute code every second. Every second, the progress() callback method is called. If more than 10 seconds have passed then the complete() callback method is called and the clearInterval() method is called. When you execute the code above, you can see the output in the Visual Studio JavaScript Console. Creating a Timeout Promise In the previous section, we created a custom Promise which uses the window.setInterval() method to complete the promise after 10 seconds. We really did not need to create a custom promise because the Promise class already includes a static method for returning promises which complete after a certain interval. The code below illustrates how you can use the timeout() method. The timeout() method returns a promise which completes after a certain number of milliseconds. WinJS.Promise.timeout(3000).then( function(){console.log("complete")}, function(){console.log("error")}, function(){console.log("progress")} ); In the code above, the Promise completes after 3 seconds (3000 milliseconds). The Promise returned by the timeout() method does not support progress events. Therefore, the only message written to the console is the message “complete” after 10 seconds. Canceling Promises Some promises, but not all, support cancellation. When you cancel a promise, the promise’s error callback is executed. For example, the following code uses the WinJS.xhr() method to perform an Ajax request. However, immediately after the Ajax request is made, the request is cancelled. // Specify Ajax request options var options = { url: "/data/photos.txt" }; // Make the Ajax request var request = WinJS.xhr(options).then( function (xmlHttpRequest) { console.log("success"); }, function (xmlHttpRequest) { console.log("fail"); }, function (xmlHttpRequest) { console.log("progress"); } ); // Cancel the Ajax request request.cancel(); When you run the code above, the message “fail” is written to the Visual Studio JavaScript Console. Composing Promises You can build promises out of other promises. In other words, you can compose promises. There are two static methods of the Promise class which you can use to compose promises: the join() method and the any() method. When you join promises, a promise is complete when all of the joined promises are complete. When you use the any() method, a promise is complete when any of the promises complete. The following code illustrates how to use the join() method. A new promise is created out of two timeout promises. The new promise does not complete until both of the timeout promises complete: WinJS.Promise.join([WinJS.Promise.timeout(1000), WinJS.Promise.timeout(5000)]) .then(function () { console.log("complete"); }); The message “complete” will not be written to the JavaScript Console until both promises passed to the join() method completes. The message won’t be written for 5 seconds (5,000 milliseconds). The any() method completes when any promise passed to the any() method completes: WinJS.Promise.any([WinJS.Promise.timeout(1000), WinJS.Promise.timeout(5000)]) .then(function () { console.log("complete"); }); The code above writes the message “complete” to the JavaScript Console after 1 second (1,000 milliseconds). The message is written to the JavaScript console immediately after the first promise completes and before the second promise completes. Summary The goal of this blog entry was to describe WinJS promises. First, we discussed how promises enable you to easily write code which performs asynchronous actions. You learned how to use a promise when performing an Ajax request. Next, we discussed how you can create your own promises. You learned how to create a new promise by creating a constructor function with complete, error, and progress parameters. Finally, you learned about several advanced methods of promises. You learned how to use the timeout() method to create promises which complete after an interval of time. You also learned how to cancel promises and compose promises from other promises.

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C#/.NET Little Wonders: The EventHandler and EventHandler<TEventArgs> delegates

- by James Michael Hare

Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last two weeks, we examined the Action family of delegates (and delegates in general), and the Func family of delegates and how they can be used to support generic, reusable algorithms and classes. So this week, we are going to look at a handy pair of delegates that can be used to eliminate the need for defining custom delegates when creating events: the EventHandler and EventHandler<TEventArgs> delegates. Events and delegates Before we begin, let’s quickly consider events in .NET. According to the MSDN: An event in C# is a way for a class to provide notifications to clients of that class when some interesting thing happens to an object. So, basically, you can create an event in a type so that users of that type can subscribe to notifications of things of interest. How is this different than some of the delegate programming that we talked about in the last two weeks? Well, you can think of an event as a special access modifier on a delegate. Some differences between the two are: Events are a special access case of delegates They behave much like delegates instances inside the type they are declared in, but outside of that type they can only be (un)subscribed to. Events can specify add/remove behavior explicitly If you want to do additional work when someone subscribes or unsubscribes to an event, you can specify the add and remove actions explicitly. Events have access modifiers, but these only specify the access level of those who can (un)subscribe A public event, for example, means anyone can (un)subscribe, but it does not mean that anyone can raise (invoke) the event directly. Events can only be raised by the type that contains them In contrast, if a delegate is visible, it can be invoked outside of the object (not even in a sub-class!). Events tend to be for notifications only, and should be treated as optional Semantically speaking, events typically don’t perform work on the the class directly, but tend to just notify subscribers when something of note occurs. My basic rule-of-thumb is that if you are just wanting to notify any listeners (who may or may not care) that something has happened, use an event. However, if you want the caller to provide some function to perform to direct the class about how it should perform work, make it a delegate. Declaring events using custom delegates To declare an event in a type, we simply use the event keyword and specify its delegate type. For example, let’s say you wanted to create a new TimeOfDayTimer that triggers at a given time of the day (as opposed to on an interval). We could write something like this: 1: public delegate void TimeOfDayHandler(object source, ElapsedEventArgs e); 2: 3: // A timer that will fire at time of day each day. 4: public class TimeOfDayTimer : IDisposable 5: { 6: // Event that is triggered at time of day. 7: public event TimeOfDayHandler Elapsed; 8: 9: // ... 10: } The first thing to note is that the event is a delegate type, which tells us what types of methods may subscribe to it. The second thing to note is the signature of the event handler delegate, according to the MSDN: The standard signature of an event handler delegate defines a method that does not return a value, whose first parameter is of type Object and refers to the instance that raises the event, and whose second parameter is derived from type EventArgs and holds the event data. If the event does not generate event data, the second parameter is simply an instance of EventArgs. Otherwise, the second parameter is a custom type derived from EventArgs and supplies any fields or properties needed to hold the event data. So, in a nutshell, the event handler delegates should return void and take two parameters: An object reference to the object that raised the event. An EventArgs (or a subclass of EventArgs) reference to event specific information. Even if your event has no additional information to provide, you are still expected to provide an EventArgs instance. In this case, feel free to pass the EventArgs.Empty singleton instead of creating new instances of EventArgs (to avoid generating unneeded memory garbage). The EventHandler delegate Because many events have no additional information to pass, and thus do not require custom EventArgs, the signature of the delegates for subscribing to these events is typically: 1: // always takes an object and an EventArgs reference 2: public delegate void EventHandler(object sender, EventArgs e) It would be insane to recreate this delegate for every class that had a basic event with no additional event data, so there already exists a delegate for you called EventHandler that has this very definition! Feel free to use it to define any events which supply no additional event information: 1: public class Cache 2: { 3: // event that is raised whenever the cache performs a cleanup 4: public event EventHandler OnCleanup; 5: 6: // ... 7: } This will handle any event with the standard EventArgs (no additional information). But what of events that do need to supply additional information? Does that mean we’re out of luck for subclasses of EventArgs? That’s where the generic for of EventHandler comes into play… The generic EventHandler<TEventArgs> delegate Starting with the introduction of generics in .NET 2.0, we have a generic delegate called EventHandler<TEventArgs>. Its signature is as follows: 1: public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e) 2: where TEventArgs : EventArgs This is similar to EventHandler except it has been made generic to support the more general case. Thus, it will work for any delegate where the first argument is an object (the sender) and the second argument is a class derived from EventArgs (the event data). For example, let’s say we wanted to create a message receiver, and we wanted it to have a few events such as OnConnected that will tell us when a connection is established (probably with no additional information) and OnMessageReceived that will tell us when a new message arrives (probably with a string for the new message text). So for OnMessageReceived, our MessageReceivedEventArgs might look like this: 1: public sealed class MessageReceivedEventArgs : EventArgs 2: { 3: public string Message { get; set; } 4: } And since OnConnected needs no event argument type defined, our class might look something like this: 1: public class MessageReceiver 2: { 3: // event that is called when the receiver connects with sender 4: public event EventHandler OnConnected; 5: 6: // event that is called when a new message is received. 7: public event EventHandler<MessageReceivedEventArgs> OnMessageReceived; 8: 9: // ... 10: } Notice, nowhere did we have to define a delegate to fit our event definition, the EventHandler and generic EventHandler<TEventArgs> delegates fit almost anything we’d need to do with events. Sidebar: Thread-safety and raising an event When the time comes to raise an event, we should always check to make sure there are subscribers, and then only raise the event if anyone is subscribed. This is important because if no one is subscribed to the event, then the instance will be null and we will get a NullReferenceException if we attempt to raise the event. 1: // This protects against NullReferenceException... or does it? 2: if (OnMessageReceived != null) 3: { 4: OnMessageReceived(this, new MessageReceivedEventArgs(aMessage)); 5: } The above code seems to handle the null reference if no one is subscribed, but there’s a problem if this is being used in multi-threaded environments. For example, assume we have thread A which is about to raise the event, and it checks and clears the null check and is about to raise the event. However, before it can do that thread B unsubscribes to the event, which sets the delegate to null. Now, when thread A attempts to raise the event, this causes the NullReferenceException that we were hoping to avoid! To counter this, the simplest best-practice method is to copy the event (just a multicast delegate) to a temporary local variable just before we raise it. Since we are inside the class where this event is being raised, we can copy it to a local variable like this, and it will protect us from multi-threading since multicast delegates are immutable and assignments are atomic: 1: // always make copy of the event multi-cast delegate before checking 2: // for null to avoid race-condition between the null-check and raising it. 3: var handler = OnMessageReceived; 4: 5: if (handler != null) 6: { 7: handler(this, new MessageReceivedEventArgs(aMessage)); 8: } The very slight trade-off is that it’s possible a class may get an event after it unsubscribes in a multi-threaded environment, but this is a small risk and classes should be prepared for this possibility anyway. For a more detailed discussion on this, check out this excellent Eric Lippert blog post on Events and Races. Summary Generic delegates give us a lot of power to make generic algorithms and classes, and the EventHandler delegate family gives us the flexibility to create events easily, without needing to redefine delegates over and over. Use them whenever you need to define events with or without specialized EventArgs. Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Delegates, EventHandler

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Predicting Your Firm's Future with Least Squares, Part II

The second part of this two-part article explains how you can use advanced math -- polynomial least squares -- to analyze your company's data.

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Predicting Your Firm's Future with Least Squares, Part II

The second part of this two-part article explains how you can use advanced math -- polynomial least squares -- to analyze your company's data.

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Google Now is One Step Closer to Becoming Active in Google Chrome

- by Akemi Iwaya

Many people have been eager to have Google Now working in their Chrome browsers and this week that dream got one step closer to reality. The first teasers that the new feature is becoming active have started to appear, so now is a good time to activate the switch for it and be ready for its arrival. You will need to be running the Dev Channel on your computer and enable the Google Now switch via Chrome Flags (chrome://flags/) if you have not already done so. The switch will be towards the bottom of the list. Once that is done restart your browser. After the browser has restarted you will see a notification window pop up as seen in the first screenshot above. Click Yes and a second small pop up message window will appear letting you know more about the freshly enabled feature. Unfortunately we were not able to catch a screenshot of the second message window before it disappeared.

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C# 4.0: Covariance And Contravariance In Generics

- by Paulo Morgado

C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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Programming Pearls (2nd Edition) vs More Programming Pearls: Confessions of a Coder [closed]

- by Geek

I have been reading very good reviews of the books by Jon Bentley : Programming Pearls (2nd Edition) More Programming Pearls: Confessions of a Coder. I know that these books have been out there for a long time and I feel bad that I haven't read either one . But it is always better late than never . I understand that the second one was written after the first one . So are these two books complementary to each other ? Do the second one assume that the reader has read the first one ? For some one who haven't read either which one would you propose to read up first ?

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What's up with OCFS2?

- by wcoekaer

On Linux there are many filesystem choices and even from Oracle we provide a number of filesystems, all with their own advantages and use cases. Customers often confuse ACFS with OCFS or OCFS2 which then causes assumptions to be made such as one replacing the other etc... I thought it would be good to write up a summary of how OCFS2 got to where it is, what we're up to still, how it is different from other options and how this really is a cool native Linux cluster filesystem that we worked on for many years and is still widely used. Work on a cluster filesystem at Oracle started many years ago, in the early 2000's when the Oracle Database Cluster development team wrote a cluster filesystem for Windows that was primarily focused on providing an alternative to raw disk devices and help customers with the deployment of Oracle Real Application Cluster (RAC). Oracle RAC is a cluster technology that lets us make a cluster of Oracle Database servers look like one big database. The RDBMS runs on many nodes and they all work on the same data. It's a Shared Disk database design. There are many advantages doing this but I will not go into detail as that is not the purpose of my write up. Suffice it to say that Oracle RAC expects all the database data to be visible in a consistent, coherent way, across all the nodes in the cluster. To do that, there were/are a few options : 1) use raw disk devices that are shared, through SCSI, FC, or iSCSI 2) use a network filesystem (NFS) 3) use a cluster filesystem(CFS) which basically gives you a filesystem that's coherent across all nodes using shared disks. It is sort of (but not quite) combining option 1 and 2 except that you don't do network access to the files, the files are effectively locally visible as if it was a local filesystem. So OCFS (Oracle Cluster FileSystem) on Windows was born. Since Linux was becoming a very important and popular platform, we decided that we would also make this available on Linux and thus the porting of OCFS/Windows started. The first version of OCFS was really primarily focused on replacing the use of Raw devices with a simple filesystem that lets you create files and provide direct IO to these files to get basically native raw disk performance. The filesystem was not designed to be fully POSIX compliant and it did not have any where near good/decent performance for regular file create/delete/access operations. Cache coherency was easy since it was basically always direct IO down to the disk device and this ensured that any time one issues a write() command it would go directly down to the disk, and not return until the write() was completed. Same for read() any sort of read from a datafile would be a read() operation that went all the way to disk and return. We did not cache any data when it came down to Oracle data files. So while OCFS worked well for that, since it did not have much of a normal filesystem feel, it was not something that could be submitted to the kernel mail list for inclusion into Linux as another native linux filesystem (setting aside the Windows porting code ...) it did its job well, it was very easy to configure, node membership was simple, locking was disk based (so very slow but it existed), you could create regular files and do regular filesystem operations to a certain extend but anything that was not database data file related was just not very useful in general. Logfiles ok, standard filesystem use, not so much. Up to this point, all the work was done, at Oracle, by Oracle developers. Once OCFS (1) was out for a while and there was a lot of use in the database RAC world, many customers wanted to do more and were asking for features that you'd expect in a normal native filesystem, a real "general purposes cluster filesystem". So the team sat down and basically started from scratch to implement what's now known as OCFS2 (Oracle Cluster FileSystem release 2). Some basic criteria were : Design it with a real Distributed Lock Manager and use the network for lock negotiation instead of the disk Make it a Linux native filesystem instead of a native shim layer and a portable core Support standard Posix compliancy and be fully cache coherent with all operations Support all the filesystem features Linux offers (ACL, extended Attributes, quotas, sparse files,...) Be modern, support large files, 32/64bit, journaling, data ordered journaling, endian neutral, we can mount on both endian /cross architecture,.. Needless to say, this was a huge development effort that took many years to complete. A few big milestones happened along the way... OCFS2 was development in the open, we did not have a private tree that we worked on without external code review from the Linux Filesystem maintainers, great folks like Christopher Hellwig reviewed the code regularly to make sure we were not doing anything out of line, we submitted the code for review on lkml a number of times to see if we were getting close for it to be included into the mainline kernel. Using this development model is standard practice for anyone that wants to write code that goes into the kernel and having any chance of doing so without a complete rewrite or.. shall I say flamefest when submitted. It saved us a tremendous amount of time by not having to re-fit code for it to be in a Linus acceptable state. Some other filesystems that were trying to get into the kernel that didn't follow an open development model had a lot harder time and a lot harsher criticism. March 2006, when Linus released 2.6.16, OCFS2 officially became part of the mainline kernel, it was accepted a little earlier in the release candidates but in 2.6.16. OCFS2 became officially part of the mainline Linux kernel tree as one of the many filesystems. It was the first cluster filesystem to make it into the kernel tree. Our hope was that it would then end up getting picked up by the distribution vendors to make it easy for everyone to have access to a CFS. Today the source code for OCFS2 is approximately 85000 lines of code. We made OCFS2 production with full support for customers that ran Oracle database on Linux, no extra or separate support contract needed. OCFS2 1.0.0 started being built for RHEL4 for x86, x86-64, ppc, s390x and ia64. For RHEL5 starting with OCFS2 1.2. SuSE was very interested in high availability and clustering and decided to build and include OCFS2 with SLES9 for their customers and was, next to Oracle, the main contributor to the filesystem for both new features and bug fixes. Source code was always available even prior to inclusion into mainline and as of 2.6.16, source code was just part of a Linux kernel download from kernel.org, which it still is, today. So the latest OCFS2 code is always the upstream mainline Linux kernel. OCFS2 is the cluster filesystem used in Oracle VM 2 and Oracle VM 3 as the virtual disk repository filesystem. Since the filesystem is in the Linux kernel it's released under the GPL v2 The release model has always been that new feature development happened in the mainline kernel and we then built consistent, well tested, snapshots that had versions, 1.2, 1.4, 1.6, 1.8. But these releases were effectively just snapshots in time that were tested for stability and release quality. OCFS2 is very easy to use, there's a simple text file that contains the node information (hostname, node number, cluster name) and a file that contains the cluster heartbeat timeouts. It is very small, and very efficient. As Sunil Mushran wrote in the manual : OCFS2 is an efficient, easily configured, quickly installed, fully integrated and compatible, feature-rich, architecture and endian neutral, cache coherent, ordered data journaling, POSIX-compliant, shared disk cluster file system. Here is a list of some of the important features that are included : Variable Block and Cluster sizes Supports block sizes ranging from 512 bytes to 4 KB and cluster sizes ranging from 4 KB to 1 MB (increments in power of 2). Extent-based Allocations Tracks the allocated space in ranges of clusters making it especially efficient for storing very large files. Optimized Allocations Supports sparse files, inline-data, unwritten extents, hole punching and allocation reservation for higher performance and efficient storage. File Cloning/snapshots REFLINK is a feature which introduces copy-on-write clones of files in a cluster coherent way. Indexed Directories Allows efficient access to millions of objects in a directory. Metadata Checksums Detects silent corruption in inodes and directories. Extended Attributes Supports attaching an unlimited number of name:value pairs to the file system objects like regular files, directories, symbolic links, etc. Advanced Security Supports POSIX ACLs and SELinux in addition to the traditional file access permission model. Quotas Supports user and group quotas. Journaling Supports both ordered and writeback data journaling modes to provide file system consistency in the event of power failure or system crash. Endian and Architecture neutral Supports a cluster of nodes with mixed architectures. Allows concurrent mounts on nodes running 32-bit and 64-bit, little-endian (x86, x86_64, ia64) and big-endian (ppc64) architectures. In-built Cluster-stack with DLM Includes an easy to configure, in-kernel cluster-stack with a distributed lock manager. Buffered, Direct, Asynchronous, Splice and Memory Mapped I/Os Supports all modes of I/Os for maximum flexibility and performance. Comprehensive Tools Support Provides a familiar EXT3-style tool-set that uses similar parameters for ease-of-use. The filesystem was distributed for Linux distributions in separate RPM form and this had to be built for every single kernel errata release or every updated kernel provided by the vendor. We provided builds from Oracle for Oracle Linux and all kernels released by Oracle and for Red Hat Enterprise Linux. SuSE provided the modules directly for every kernel they shipped. With the introduction of the Unbreakable Enterprise Kernel for Oracle Linux and our interest in reducing the overhead of building filesystem modules for every minor release, we decide to make OCFS2 available as part of UEK. There was no more need for separate kernel modules, everything was built-in and a kernel upgrade automatically updated the filesystem, as it should. UEK allowed us to not having to backport new upstream filesystem code into an older kernel version, backporting features into older versions introduces risk and requires extra testing because the code is basically partially rewritten. The UEK model works really well for continuing to provide OCFS2 without that extra overhead. Because the RHEL kernel did not contain OCFS2 as a kernel module (it is in the source tree but it is not built by the vendor in kernel module form) we stopped adding the extra packages to Oracle Linux and its RHEL compatible kernel and for RHEL. Oracle Linux customers/users obviously get OCFS2 included as part of the Unbreakable Enterprise Kernel, SuSE customers get it by SuSE distributed with SLES and Red Hat can decide to distribute OCFS2 to their customers if they chose to as it's just a matter of compiling the module and making it available. OCFS2 today, in the mainline kernel is pretty much feature complete in terms of integration with every filesystem feature Linux offers and it is still actively maintained with Joel Becker being the primary maintainer. Since we use OCFS2 as part of Oracle VM, we continue to look at interesting new functionality to add, REFLINK was a good example, and as such we continue to enhance the filesystem where it makes sense. Bugfixes and any sort of code that goes into the mainline Linux kernel that affects filesystems, automatically also modifies OCFS2 so it's in kernel, actively maintained but not a lot of new development happening at this time. We continue to fully support OCFS2 as part of Oracle Linux and the Unbreakable Enterprise Kernel and other vendors make their own decisions on support as it's really a Linux cluster filesystem now more than something that we provide to customers. It really just is part of Linux like EXT3 or BTRFS etc, the OS distribution vendors decide. Do not confuse OCFS2 with ACFS (ASM cluster Filesystem) also known as Oracle Cloud Filesystem. ACFS is a filesystem that's provided by Oracle on various OS platforms and really integrates into Oracle ASM (Automatic Storage Management). It's a very powerful Cluster Filesystem but it's not distributed as part of the Operating System, it's distributed with the Oracle Database product and installs with and lives inside Oracle ASM. ACFS obviously is fully supported on Linux (Oracle Linux, Red Hat Enterprise Linux) but OCFS2 independently as a native Linux filesystem is also, and continues to also be supported. ACFS is very much tied into the Oracle RDBMS, OCFS2 is just a standard native Linux filesystem with no ties into Oracle products. Customers running the Oracle database and ASM really should consider using ACFS as it also provides storage/clustered volume management. Customers wanting to use a simple, easy to use generic Linux cluster filesystem should consider using OCFS2. To learn more about OCFS2 in detail, you can find good documentation on http://oss.oracle.com/projects/ocfs2 in the Documentation area, or get the latest mainline kernel from http://kernel.org and read the source. One final, unrelated note - since I am not always able to publicly answer or respond to comments, I do not want to selectively publish comments from readers. Sometimes I forget to publish comments, sometime I publish them and sometimes I would publish them but if for some reason I cannot publicly comment on them, it becomes a very one-sided stream. So for now I am going to not publish comments from anyone, to be fair to all sides. You are always welcome to email me and I will do my best to respond to technical questions, questions about strategy or direction are sometimes not possible to answer for obvious reasons.

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Please Help with ATI Radeon 4250 and Xinerama

- by Luis Enrique

I am using ubuntu 11.10 fresh install and I am having problems making the second screen to work, I remember before I was able to do it by extending the desktop to a larger number like 3840 X 1080 but since I am new I completely forgot how to do it, Now I have a philips 230 E monitor full 1920 X 1080 and a Toshiba tv HDMI and I want to activate the second monitor to be able to use Xinerama but I don't know how to go about this, I want to keep the Phillips as a primary monitor since it's the smaller one and use the TV from time to time to play videos movies and presentations. I installed all the additional drivers and don't know what else to do. I would prefer if I can use a list of exact commands to copy and paste onto the terminal since that is all I know how to use LOL . Thank you so much for your help. If you need more details of my mother board or video card or cpu just ask thank you. Luis

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Microsoft Woos Developers with Latest IE9 Preview

The second platform preview may help Redmond improve developer relations.

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Microsoft Woos Developers with Latest IE9 Preview

The second platform preview may help Redmond improve developer relations.

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ROI is Dead, Long Live ROI

- by frank.buytendijk

Here's my second video blog. Click here to watch it. frank

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Can't recognize local webserver

- by Syed Khalil-ur-Rehman

My Internet Cable provider has set up a web server which hosts different entertainment material like movies, songs, tv shows and games etc. While using windows the pc recognises it as a local web server and downloads files with full LAN speed of 10 mb per second. On the contrary when using Ubuntu I am only able to download the files on my Internet speed not more than 100 kb per second. What ever I try ubuntu does not recognizes the webserver as a local area network web server but as a normal internet website. How to make Ubuntu download files from this server with full LAN speed. Please help in this regard. The url is http://dmasti.pk and yes it is a web server browsable by a web browser like firefox or ie.

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CodePlex Daily Summary for Saturday, December 04, 2010

CodePlex Daily Summary for Saturday, December 04, 2010Popular ReleasesMiniTwitter: 1.62: MiniTwitter 1.62 ???? ?? ??????????????????????????????????????? 140 ?????????????????????????? ???????????????????????????????? ?? ??????????????????????????????????Chronos WPF: Chronos v2.0 Beta 3: Release notes: Updated introduction document. Updated Visual Studio 2010 Extension (vsix) package. Added horizontal scrolling to the main window TaskBar. Added new styles for ListView, ListViewItem, GridViewColumnHeader, ... Added a new WindowViewModel class (allowing to fetch data). Added a new Navigate method (with several overloads) to the NavigationViewModel class (protected). Reimplemented Task usage for the WorkspaceViewModel.OnDelete method. Removed the reflection effect...MDownloader: MDownloader-0.15.26.7024: Fixed updater; Fixed MegauploadDJ - jQuery WebControls for ASP.NET: DJ 1.2: What is new? Update to support jQuery 1.4.2 Update to support jQuery ui 1.8.6 Update to Visual Studio 2010 New WebControls with samples added Autocomplete WebControl Button WebControl ToggleButt WebControl The example web site is including in source code project.LateBindingApi.Excel: LateBindingApi.Excel Release 0.7g: Unterschiede zur Vorgängerversion: - Zusätzliche Interior Properties - Group / Ungroup Methoden für Range - Bugfix COM Reference Handling für Application Objekt in einigen Klassen Release+Samples V0.7g: - Enthält Laufzeit DLL und Beispielprojekte Beispielprojekte: COMAddinExample - Demonstriert ein versionslos angebundenes COMAddin Example01 - Background Colors und Borders für Cells Example02 - Font Attributes undAlignment für Cells Example03 - Numberformats Example04 - Shapes, WordArts, P...ESRI ArcGIS Silverlight Toolkit: November 2010 - v2.1: ESRI ArcGIS Silverlight Toolkit v2.1 Added Windows Phone 7 build. New controls added: InfoWindow ChildPage (Windows Phone 7 only) See what's new here full details for : http://help.arcgis.com/en/webapi/silverlight/help/#/What_s_new_in_2_1/016600000025000000/ Note: Requires Visual Studio 2010, .NET 4.0 and Silverlight 4.0.ASP .NET MVC CMS (Content Management System): Atomic CMS 2.1.1: Atomic CMS 2.1.1 release notes Atomic CMS installation guide Winware: Winware 3.0 (.Net 4.0): Winware 3.0 is base on .Net 4.0 with C#. Please open it with Visual Studio 2010. This release contains a lab web application.WTV-MetaRenamer: Build 6910: Includes two new areas of functionality - the ability to move renamed files and not just rename them, and the ability to "remap" characters that might cause problems. These address #308, #281 and #417. Please read the documentation carefully as the configuration file has new options to support this functionality. There are now TWO XML files included in the download Zip file. The 2nd one has some additional lines for example reasons. This version is considered to be stable enough and feature...Free Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts v3.6.5 beta Released: Hi, Today we are releasing Visifire 3.6.5 beta with the following new feature: New property AutoFitToPlotArea has been introduced in DataSeries. AutoFitToPlotArea will bring bubbles inside the PlotArea in order to avoid clipping of bubbles in bubble chart. Also this release includes few bug fixes: AxisXLabel label were getting clipped if angle was set for AxisLabels and ScrollingEnabled was not set in Chart. If LabelStyle property was set as 'Inside', size of the Pie was not proper. Yo...EnhSim: EnhSim 2.1.1: 2.1.1This release adds in the changes for 4.03a. To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - Switched Searing Flames bac...Microsoft - Domain Oriented N-Layered .NET 4.0 App Sample (Microsoft Spain): V1.0 - N-Layer DDD Sample App .NET 4.0: Required Software (Microsoft Base Software needed for Development environment) Visual Studio 2010 RTM & .NET 4.0 RTM (Final Versions) Expression Blend 4 SQL Server 2008 R2 Express/Standard/Enterprise Unity Application Block 2.0 - Published May 5th 2010 http://www.microsoft.com/downloads/en/details.aspx?FamilyID=2D24F179-E0A6-49D7-89C4-5B67D939F91B&displaylang=en http://unity.codeplex.com/releases/view/31277 PEX & MOLES 0.94.51023.0, 29/Oct/2010 - Visual Studio 2010 Power Tools http://re...Sense/Net Enterprise Portal & ECMS: SenseNet 6.0.1 Community Edition: Sense/Net 6.0.1 Community Edition This half year we have been working quite fiercely to bring you the long-awaited release of Sense/Net 6.0. Download this Community Edition to see what we have been up to. These months we have worked on getting the WebCMS capabilities of Sense/Net 6.0 up to par. New features include: New, powerful page and portlet editing experience. HTML and CSS cleanup, new, powerful site skinning system. Upgraded, lightning-fast indexing and query via Lucene. Limita...Minecraft GPS: Minecraft GPS 1.1.1: New Features Compass! New style. Set opacity on main window to allow overlay of Minecraft. Open World in any folder. Fixes Fixed style so listbox won't grow the window size. Fixed open file dialog issue on non-vista kernel machines.DotSpatial: DotSpatial 11-28-2001: This release introduces some exciting improvements. Support for big raster, both in display and changing the scheme. Faster raster scheme creation for all rasters. Caching of the "sample" values so once obtained the raster symbolizer dialog loads faster. Reprojection supported for raster and image classes. Affine transform fully supported for images and rasters, so skewed images are now possible. Projection uses better checks when loading unprojected layers. GDAL raster support f...Virtu: Virtu 0.9.0: Source Requirements.NET Framework 4 Visual Studio 2010 or Visual Studio 2010 Express Silverlight 4 Tools for Visual Studio 2010 Windows Phone 7 Developer Tools (which includes XNA Game Studio 4) Binaries RequirementsSilverlight 4 .NET Framework 4 XNA Framework 4SuperWebSocket: SuperWebSocket(60438): It is the first release of SuperWebSocket. Because it is base on SuperSocket, most features of SuperSocket are supported in SuperWebSocket. The source code include a LiveChat demo.Cropper: 1.9.4: Mostly fixes for issues with a few feature requests. Fixed Issues 2730 & 3638 & 14467 11044 11447 11448 11449 14665 Implemented Features 6123 11581PFC: PFC for PB 11.5: This is just a migration from the 11.0 code. No changes have been made yet (and they are needed) for it to work properly with 11.5.PDF Rider: PDF Rider 0.5: This release does not add any new feature for pdf manipulation, but enables automatic updates checking, so it is reccomended to install it in order to stay updated with next releases. Prerequisites * Microsoft Windows Operating Systems (XP - Vista - 7) * Microsoft .NET Framework 3.5 runtime * A PDF rendering software (i.e. Adobe Reader) that can be opened inside Internet Explorer. Installation instructionsChoose one of the following methods: 1. Download and run the "pdfRider0...New ProjectsAnimal Rescue: Animal Rescue will provide a single application for animal rescue groups to maintain any group, animal, foster, medical, etc information and publish the information to various locations. AR is developed in C# and will provide Web and WinForm presentations. ASP.NET 4.0 in practice: ASP.NET 4.0 in Practice contains real world techniques from well-known professionals who have been using ASP.NET since the first previews. Published by Manning, 2011 - Contains code samples from the book.Aspx to Razor Converter: An experimental project to create ASP.NET MVC webform view pages to Razor view pages.AutoWinUI: Automate Application on Windows by UI AutomationBookstore_web: lame ass comment C++ Galois Field Arithmetic Library: The C++ Galois Field Arithmetic Library, implements a specialised version of Galois Fields known as extension fields or in other words fields of the form GF(2^m) and was developed as a base for programming tasks that involved cryptography and error correcting codes.C++ TCP Proxy Server: The C++ TCP Proxy server is a simple utility using the ASIO networking library, for proxying (tunneling or redirecting) connections from external clients to a specific server. The TCP Proxy server can be used to easily and efficiently.Cache Providers For .NET: Cache Provider for .NET helps enterprise applications use popular Provider model. It ships with AppFabric Cache Provider (code named Velocity) and Classic Cache Provider and can be used with ASP.NET, Windows Forms, Windows Services, WCF and WPF.Columbus: Windows Phone 7 MVC framework: Columbus is MVC framework designed specifically for WP7 platform and supports: - Strongly typed navigation with history - View Models that can survive tombstoning - Asynchronous and cancelable controller actions with execution progress - Commands (CAB style)ComplexCode: complex codeDice Shaker: Coding4Fun Windows Phone 7 Dice Shaker applicationEscola do Futuro: Escola do Futuro será mais do que um simples repositório de aulas (mp3 ou mp4) ! Nosso intuito é gerar um projeto que além de ensinar ou repassar o conhecimento, iremos formar as pessoas. O usuário do projeto será capaz de obter o conhecimento com apenas poucos clicks! ExpressionParser: A library designed to read user entered string and evaluate it as an math expression. - Able to understand all the operators that Excel users are used to. - Expose the System.Math functions, but allow additional functions to be added by API - Allow variables access via delegategrouptalk: grouptalkIn-House Normal Report: it is a normal report, just for practice, thanks very much.Jetnett Common Controls: Controls used related to and used by various JetNett productsJSON Tiny Serializer dedicated to output JavaScript string fom C# object: This C# JSon Serializer is dedicated to output JavaScript string from .Net managed object. The code is oriented performance and running more than twice fast as the standard .Net 4 JavaScriptSerializer. Recursive Check and Size limit are implemented. MSX jIDE: Kit de Ferramentas , IDE e Framework para MSX feitos em JAVAMy Text Editor: This is a simple text editor in C# written and compiled in Visual studio 2005. It's in a beta version and needs feedbacks and comments..........Online Course Feedback System: Online Course Feedback System is used to automate the collection of Course Feedback in an academic institution.PerformanceTester: Application to test performance using 5 criteriaPersonal Activity Monitor: simple, personal activity monitor. See how much time do you spend using different applications. Localize your time wasters and minimize them and be happy with more time for your productivityphuongnamco: Products of PhuongNam companypocketpalireader: PocketPC application for reading Pali Tipitaka. Includes Pali Canon library and Pali-English dictionary.Powershell Script for associating Workflow for a library iteratively: Workflow associator powershell script makes easier for associating the workflows for a particular document library to all webs inside a particular site collection. It is no longer a manual activity. Its developed in Powershell 2.0Rotempco.Core: Rotempco.CoreTkalm - A Social Chat System: Tkalm is a social chat system. Important Note: This is part of an ASP.NET Development training, so don't expect too muchTrueForecast: Just a test-project...Weak-coupling Develop Framework: Use like csla objectWeather Report: I Was feeling very cold from last two days and wanted to plan an outing so got to see weather forcast and from there got idea to develop this software which is a kind of Desktop Gadget.Windows Phone Notification Pusher: Application to push notifications to Windows Phone.Words Reminder: A software for people with Persian language who want to learn English language. It reminds the words that user marked them to remind. This software is also a perfect English-to-Persian dictionary with ability to pronounce the words.XEMail: XEMail is a webservice that provides SMTP / POP3 / IMAP functionality

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