Question

I have a WCF service method I’ve implemented that gets passed an IEnumerable

    [OperationContract]
    List<Item> GetItems(DateTime sinceDate, IEnumerable<Guid> idList);

The method works as intended when passing in an IEnumerable of size 1000 or fewer; the service returns with an expected response. At some point, the array passed in is too large (seen at 2000 items) and a System.ServiceModel.ProtocolException is thrown, "{"The remote server returned an unexpected response: (400) Bad Request."}"

I’m not sure what’s governing the array size limitation. I’m aware of the readerQuotas section of a binding, and the maxArrayLength is set to the default 16384. My buffer sizes are set large enough, but I’m not sure why the service call is failing. Is there a limitation on the basicHttpBinding for array sizes passed in? What needs to change in my configuration so that I can pass in large arrays?

Here is my app.config in the client side. Server side is equivilant.

<binding name="BasicHttpBinding_IMyService" closeTimeout="00:01:00"
      openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:10:00"
      allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
      maxBufferSize="20000000" maxBufferPoolSize="524288" maxReceivedMessageSize="20000000"
      messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
      useDefaultWebProxy="true">
      <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
            maxBytesPerRead="4096" maxNameTableCharCount="16384" />
      <security mode="None">
            <transport clientCredentialType="None" proxyCredentialType="None"
                  realm="" />
            <message clientCredentialType="UserName" algorithmSuite="Default" />
      </security>
</binding>

Answer 1

You need to register a service behavior that increase the max object items in graph:

<serviceBehaviors>
    <behavior name="IncreadedSizeBehavior">
      <dataContractSerializer maxItemsInObjectGraph="100000"/>
    </behavior>
  </serviceBehaviors>

You then need to register this behavior in your endpoint:

<services>
    <service name="MyService" behaviorConfiguration="IncreadedSizeBehavior">
        <host />
        <endpoint />
</services>

The thing that is most helpful when debugging wcf issues is enabled trace error logging:

<system.diagnostics>
        <trace autoflush="true" />
        <sources>
            <source name="System.ServiceModel"
                            switchValue="Error"
                            propagateActivity="true">
                <listeners>
                    <add name="sdt"
                            type="System.Diagnostics.XmlWriterTraceListener"
                            initializeData= "ErrorTrace.svclog"
                            />
                </listeners>
            </source>
        </sources>
    </system.diagnostics>

Then opening that trace file with the svc trace viewer, downloadable with the windows sdk. You get a nice view of all the errors and what the actual error was when the message was being processed.