WCF Data Services 5.5.0 Release

WCF Data Services 5.5.0 has officially been released! The 5.5.0 release will be another NuGet-only release as we did not make any updates to the Visual Studio tooling.

The last tooling update was version 5.3.0. Services created using this version of tooling should update the runtime binaries to 5.5.0 with NuGet.

What is in the release:

This release has two primary features: 1) significant enhancements to the URI parser and 2) public data source providers. In addition to the primary features, there are two secondary enhancements and over 40 bug fixes included with this release.

URI Parser

In the 5.2.0 release ODataLib provided a way to parse $filter and $orderby expressions into a metadata-bound abstract syntax tree (AST). In the 5.5.0 release we have updated the URI parser with support for most OData URIs. The newly introduced support for parsing $select and $expand is particularly notable. With the 5.5.0 release the URI Parser is mostly done. Future releases will focus on higher-order functions to further improve the developer experience. 

Public Data Source Providers

In this release we have made the Entity Framework and Reflection data source providers public. This gives more control to service writers. There is more work planned in the future but the work we’ve completed allows some advanced scenarios which were not possible earlier. For example, a service writer can now make use of the Entity Framework query-caching feature by intercepting the request and parameterizing the LINQ query before handing it off to Entity Framework. (Note that parameterizing a LINQ query is not the same as parameterizing a SQL query; EF always does the latter and therefore there is no security implications to failing to parameterize a LINQ to Entities query, the only impact is performance related.)

While the potential unlocked with this release is limited, this is the first move in a direction which will unlock many previously unachievable scenarios with the built in providers.

Performance Improvements

We constantly strive to improve performance and reliability with every release. In this release, we have increased performance by double digit percentages for service authors that want to respond with JSON but are not able to (or don't want to) provide a data model to ODataLib.

Improved Developer Experience

In this release we have caught up with some missing IntelliSense guidance and we are uploading symbols and source to SymbolSource.org. We will upload symbols for many of our past releases as well.

Bug Fixes

In addition to the features above, we have included fixes for the following notable bugs:

  • Fixes an issue where the reflection provider would not work properly if the generic parameter provided to DataService<T> was an interface
  • Fixes an issue where some system headers were not being set when a client called BuildingRequest
  • Fixes an issue where setting InstanceContextMode to Single on DataService would result in cache result being returned for subsequent requests
  • Fixes an issue where ODataLib would sometimes allow null to be written whether or not the expected type was nullable
  • Fixes a regression in 5.4 where ODataLib started writing unnecessary type information in certain instances
  • Fixes an issue where the WCF DS client would sometimes not dispose the response if the response had no content
  • Improves a number of errors and error messages
Comments (14)

  1. MikeH says:

    Can you give an example of how to hook in to the Entity Framework data source provider?

  2. Stu says:

    Seconding MikeH's comment. Please provide an example.

    This leads on to more general feedback. Whilst it is great that you're regularly releasing updates, can you please ensure all new features are documented, as they aren't much use if I don't know how to use them (and if they already are documented, these blog announcements would be a great place to link to updated documentation).

    Looking forward to seeing what is possible with the new public providers. Cheers.

  3. Josh says:

    Did you guys ever officially include the OData T4 for C# functionality described here:


    What I'm trying to do is to auto-generate Knockout.js bindable javascript / coffeescript classes using oData MetaData and T4 templates.  Is this possible?

  4. Great stuff. Any chance the Entity Framework would ever be able to support properties that are only part of the c# classes but not of the database itself? e.g. any sort of computed properties / complex types / classes and properties that would automatically fallback to the reflection provider?

    Also is there any way of adding an "AfterSave" interceptor? This way you could trigger certain c# actions such as sending an email after a save operation was done on a certain resource.

  5. @DotNetWise Would appreciate such a feature as well!

  6. Oisin Grehan says:

    I just updated my WCF DS Toolkit fork with 5.5.0, if anyone is interested. Get it at: github.com/oising/WCFDS-Toolkit  — there's a link to the NuGet package too.

  7. @Josh Good question! I'm also using the prerelease version of the T4 template looking further to a released one

  8. @MikeH/Stu – I totally hear you. Getting better at documentation is something we're working on, and I encourage you to continue to comment if we DON'T get those samples/documents available to you. So often it's easy for us to focus on getting the next feature out when there are hundreds of features people don't use simply because they aren't documented.

    @Josh/Chris – T4 has been on the back burner as we've had other priorities. We're debating a lot right now about how we hook into VS and what that experience looks like. At any rate, the T4 experience is likely not going to get a lot of love in the next six months. I do apologize if that's a disappointment – it's certainly a disappointment to me!

    @DotNetWise – While I can't comment on EF feature requests, they are much better than we are at taking both pull requests as well as feature requests. As far as the AfterSave interceptor, I'd like to see our extensibility story get a lot better in general but as with many other things, there are finite resources and we wind up focusing on a limited set of things. I would hope our direction with the public providers will give you what you're looking for, so maybe we should let that mature through the next release before considering next steps.

    And just endorsing Oisin's work: he's done an awesome job updating the WCF DS toolkit and I'm sure he'd love to have both feedback and contributions. The toolkit is a great way to get some of the extensibility points we don't currently provide.

  9. Hello

    I have the following trouble (WCF Data Services 5.5.0):

       •   I have one project “A” containing complex type classes.

       •   I have one project “B” containing entity type classes.

       •   I have one project “C” where I have a custom WCF Data Service implementation based on the class types of “B” and they references complex types in “A”.

    I don’t know why if I directly create a resource types with one “NamedNamespace” the metadata refers the resource types with the CLR type (InstanceType) namespace. In consequence when I like have all the resource type under this “NamedNamespace” I have 3 schema with namespaces: “A” because the complex type classes, “B” because the entity type classes and “NamedNamespace” I am not sure exactly why: could be because the resource type namespaces I built or because the namespace of the assembly containing the custom WCF Data Service implementation (are the same this time).

    The worst is when I add service reference I have one error because the code namespaces generated are not recognized in code!


  10. Hello Again:

    I forgot to include other questions with my last post.

    1 – I have received errors browsing the custom data service when I don’t set the resources like ReadOnly, I don’t know why, but I think me missing something.  

    2 – I had to refuse the use the public reflection provider because it do not allow me skip the SetReadOnly step to be able add more logic to the resource definitions.

    I commented about my scenary on WCF Data Service 5.5.0 prerelease, I cited here:  

    "Tue, May 21 2013 3:51 PM

    Thanks you guys, you are doing amazing work here with WCF Data Services, I really appreciate you make  public the built-in providers. I had been making pitfalls loading them through reflection.

    I have been moving towards some scenaries where a different perspective could be nice. For example I’ve been working around to generate a custom WCF Data Service Provider from one Entity Data Model (it is extended with custom annotations to guide layer code generation). I’ve read your source code to follow your logic, but I discovered many logic that I cannot do myself because it requires access to internal members, for example the custom annotations.

    I use the EDM on design mode, that means you must create a EDM, annotate it with custom annotations on EF designer and I generate the source code to cover the application architecture logic, but you really don’t have the EDM on runtime.  It means I cannot use the built-in WCF Data Service EF provider, then I use your Reflection Provider.  Of course I dealt too with missing features like enum support. I don’t understand why, at least, you don't generate enum properties based on numeric enum type (byte, int). Is there any problem with this temporal solution?

    The reflection provider requires one defined type with properties and all steps you know it’s needed. Could the reflection provider do expose members to make fluent and interactive metadata generation? For example: GetResourceType(Type t), GetResourceProperty(PropertyInfo info), it can allow to me useyour baseline logic and insert my own information including but not limited to virtual properties and/or associations.

    I guess I cannot emit the virtual types because on these cases the InstanceType will not be the real type.


    PD: If you need I can write more details about my scenary."


  11. JasonBSteele says:

    I switched to using the WebApi OData solution as this seemed to be where MS was putting in more effort, but now you guys have just done a new release. Can you help me decide which one I should be using?!

  12. Lima says:

    please!!!! renew documentation  for custom provider dev.

    please!!!! some words about ASYNC on SERVER SIDE.

  13. Alberto Silva says:


    I've found an issue similar to the one reported here:


    What seems to be happening is that when a FK is based on more than one column, the WCF Data Services somehow forgets which column in one table links to the column in the other table, and if they have diferente datatypes, the reported error happens.

    I've posted a longer comment last weekend but it never showed up, so if you have both comment waiting to be published, choose one 🙂

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