Cannot access self hosted wcf service in silverlight application

Question

I am trying to hit a self hosted WCF service from my Silverlight application but it is not working. The service is configured to use SSL and I can hit it using the WCFTestClient tool, a web browser, and I can reference the service and update it from within the silverlight project. The problem is when the silverlight application tries to make a call to the service, it bombs with the following error:

The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error.

When I hit it using the WCF Test Client tool, it returns data without issues (as expected).

Any ideas?

Below is my app config:

<system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="basicHttp" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647" messageEncoding="Text" textEncoding="utf-8" useDefaultWebProxy="true" allowCookies="false">
          <readerQuotas maxDepth="32" maxStringContentLength="2147483647" maxArrayLength="6553600" maxBytesPerRead="4096" maxNameTableCharCount="16384"/>
          <security mode="Transport">
          </security>
        </binding>
      </basicHttpBinding>
      <webHttpBinding>
        <binding name="webHttp" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647" useDefaultWebProxy="true" allowCookies="false">
          <readerQuotas maxDepth="32" maxStringContentLength="2147483647" maxArrayLength="6553600" maxBytesPerRead="4096" maxNameTableCharCount="16384"/>
          <security mode="Transport">
          </security>
        </binding>
      </webHttpBinding>
    </bindings>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
    <services>
      <service name="Application.ServiceModel.ApplicationService" behaviorConfiguration="serviceBehavior">
        <host>
          <baseAddresses>
            <add baseAddress="https://192.168.1.171:8000/ApplicationServiceModel/service"/>
          </baseAddresses>
        </host>
        <endpoint address="" 
                  binding="basicHttpBinding" 
                  bindingConfiguration="basicHttp" 
                  contract="Application.ServiceModel.IApplicationService"  />
        <endpoint address="mex" 
                  binding="mexHttpsBinding" 
                  contract="IMetadataExchange"/>
        <endpoint address="http://localhost:8000/"
                  binding="webHttpBinding"
                  contract="Application.ServiceModel.IApplicationService"
                  behaviorConfiguration="webHttpBehavior" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="serviceBehavior">
          <serviceMetadata httpsGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true"/>
          <dataContractSerializer maxItemsInObjectGraph="2147483647"/>
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="webHttpBehavior">
          <webHttp />
        </behavior>
      </endpointBehaviors>
    </behaviors>
  </system.serviceModel>

Answer 1

@carlos: Your code works great for http. However, I am not able to get it to work for https. I simply get "clientaccesspolicy.xml" is not found...

I have made these modifications to the main function:

                public static void Main()
        {
            string baseAddress = "https://" + Environment.MachineName + ":8000";
            ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
            BasicHttpBinding basicHttpBinding = new BasicHttpBinding(BasicHttpSecurityMode.Transport);
            host.AddServiceEndpoint(typeof(ITest), basicHttpBinding, "basic");
            WebHttpBinding webHttpBinding = new WebHttpBinding(WebHttpSecurityMode.Transport);
            HttpTransportSecurity httpTransportSecurity = webHttpBinding.Security.Transport;
            httpTransportSecurity.ClientCredentialType = HttpClientCredentialType.None;
            httpTransportSecurity.ProxyCredentialType = HttpProxyCredentialType.None;
            WebHttpBehavior webHttpBehavior = new WebHttpBehavior();

            host.AddServiceEndpoint(typeof(IPolicyRetriever), webHttpBinding, "").Behaviors.Add(webHttpBehavior);
            ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
            smb.HttpsGetEnabled = true;
            host.Description.Behaviors.Add(smb);
            host.Open();
            Console.WriteLine("Host opened");
        }

Further, I have made these modifications to the GetSilverlightPolicy() function:

                     public Stream GetSilverlightPolicy()
        {
            string result =
                @"<?xml version=""1.0"" encoding=""utf-8""?>
                    <access-policy>
                        <cross-domain-access>
                            <policy>
                                <allow-from http-request-headers=""SOAPAction"">
                                    <domain uri=""https://""/>
                                    <domain uri=""http://""/>
                                </allow-from>
                                <grant-to>
                                    <resource path=""/"" include-subpaths=""true""/>
                                </grant-to>
                            </policy>
                        </cross-domain-access>
                    </access-policy>";
            return StringToStream(result);
        }

Answer 2

Silverlight clients cannot, by default, make networking requests to domains other than the one where the .XAP file was loaded (i.e., cross-domain requests). If you want to access a self-hosted WCF service (which means a X-domain request), the service must provide a policy file to the Silverlight runtime saying that it's OK for such requests to be made.

You can find an example of how to enable cross-domain calls for self-hosted services in the post at http://blogs.msdn.com/b/carlosfigueira/archive/2008/03/07/enabling-cross-domain-calls-for-silverlight-apps-on-self-hosted-web-services.aspx. Since your service uses HTTPS, you'll need to serve the policy using HTTPS as well, but otherwise the code in the post should work for you.