Request error with WCF Data Services

Question

Its my first time setting up an OData Service and I'm of course having some problems...

The problem is that I can't get the service running, I keep getting an "Request Error".

I have researched on what the problem can be and I found that a common issue is that the access rules are incorrectly typed. So I have tried fixing this both with Singular names, Plural names and I have also tried with typeof(Post).getType().Name

Well here is my code. I hope you can help me, I've been stuck for hours.

public class ODataService : DataService<Entity>
{
    // This method is called only once to initialize service-wide policies.
    public static void InitializeService( DataServiceConfiguration config )
    {
        //config.SetEntitySetAccessRule( "Users", EntitySetRights.All );
        //config.SetEntitySetAccessRule( "Posts", EntitySetRights.All );
        //config.SetEntitySetAccessRule( "Albums", EntitySetRights.All );


        config.SetEntitySetAccessRule( "*", EntitySetRights.AllRead );
        config.SetServiceOperationAccessRule( "*", ServiceOperationRights.AllRead );
        //config.SetServiceOperationAccessRule( "GetPosts", ServiceOperationRights.AllRead );

        config.UseVerboseErrors = true;
        config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;
    }

    [WebGet]
    public IQueryable<Post> GetPosts()
    {
        return CurrentDataSource.Posts.AsQueryable();
    }
}

The structure of my EntityFramework class (db first)

Methods and Members for Entity class. Here the entities are spelled in plural.

This is my Web.config:

<?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <connectionStrings>
    <add name="Entity" connectionString="metadata=res://*/;provider=System.Data.SqlClient;provider connection string=&quot;data source=XXX;Initial Catalog=XXX;persist security info=True;user id=XXX;password=XXX;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
    <add key="ValidationSettings:UnobtrusiveValidationMode" value="WebForms" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime requestValidationMode="4.5" targetFramework="4.5" encoderType="System.Web.Security.AntiXss.AntiXssEncoder, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    <pages controlRenderingCompatibilityVersion="4.5" />
    <machineKey compatibilityMode="Framework45" />
  </system.web>
<system.serviceModel>
    <services>
      <service name="LinkIT.Core.OData.ODataService"  behaviorConfiguration ="DebugEnabled">
      </service>
    </services>
    <behaviors>
      <serviceBehaviors >
        <behavior name="DebugEnabled">
          <serviceDebug includeExceptionDetailInFaults="True"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
  </system.serviceModel>
</configuration>

A detailed error message:

The server encountered an error processing the request. The exception message is 'Value cannot be null. Parameter name: propertyResourceType'. See server logs for more details. The exception stack trace is:

at System.Data.Services.WebUtil.CheckArgumentNull[T](T value, String parameterName) at System.Data.Services.Providers.ResourceProperty..ctor(String name, ResourcePropertyKind kind, ResourceType propertyResourceType) at System.Data.Services.Providers.ObjectContextServiceProvider.PopulateMemberMetadata(ResourceType resourceType, IProviderMetadata workspace, IDictionary2 knownTypes, PrimitiveResourceTypeMap primitiveResourceTypeMap) at System.Data.Services.Providers.ObjectContextServiceProvider.PopulateMetadata(IDictionary2 knownTypes, IDictionary2 childTypes, IDictionary2 entitySets) at System.Data.Services.Providers.BaseServiceProvider.PopulateMetadata() at System.Data.Services.Providers.BaseServiceProvider.LoadMetadata() at System.Data.Services.DataService1.CreateMetadataAndQueryProviders(IDataServiceMetadataProvider& metadataProviderInstance, IDataServiceQueryProvider& queryProviderInstance, BaseServiceProvider& builtInProvider, Object& dataSourceInstance) at System.Data.Services.DataService1.CreateProvider() at System.Data.Services.DataService1.HandleRequest() at System.Data.Services.DataService1.ProcessRequestForMessage(Stream messageBody) at SyncInvokeProcessRequestForMessage(Object , Object[] , Object[] ) at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs) at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc) at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

Answer 1

WCF Data Services team confirms - this is the exact error faced when you use Enums (which is not yet supported).

Remove the Enum types (or use their suggested work-around and use a wrapper around the enum properties) and this should go away.