WCF / Csla Hell

Question

I'm trying to build a proof of concept Csla 3.7/Silverlight 3 app and have been working my way through Rocky's tutorials. It's a really simple one form/one business object data editing app and everything is just peachy right up until the point where I try to get the Wcf configured so that the Silverlight app can talk to the Data Portal.

The error I'm getting is:

CommunicationException was unhandled by user code

An error occurred while trying to make a request to URI 'http://localhost:1406/WcfPortal.svc'. 
This could be due to attempting to access a service in a cross-domain way without a proper cross-domain policy in place, or a policy that is unsuitable for SOAP services. 
You may need to contact the owner of the service to publish a cross-domain policy file and to ensure it allows SOAP-related HTTP headers to be sent. 
This error may also be caused by using internal types in the web service proxy without using the InternalsVisibleToAttribute attribute. 
Please see the inner exception for more details.

I'm totally mystified by this as I'm a bit of a n00b to Silverlight & WCF. My setup is pretty straight forward for a Csla Silverlight app. I have 4 projects:

• CslaSilverlight : Silverlight Project
• CslaSilverlight.Client : Silverlight Class Library
• CslaSilverlight.Server : .NET Class Library
• CslaSilverlight.Web : ASPNET Project to host the SL app

Everything is running locally on my laptop under Cassini. I want the DataPortal to run outside of Silverlight so that I can access SQL Server. I think that the problem may be with my Wcf Config in the Silverlight application which is specified in a ServiceReferences.ClientConfig file:

<configuration>
    <system.serviceModel>
        <bindings>
            <basicHttpBinding>
                <binding name="BasicHttpBinding_IWcfPortal" maxBufferSize="65536"
                    maxReceivedMessageSize="65536" receiveTimeout="10" sendTimeout="10">
                </binding>
            </basicHttpBinding>
        </bindings>
        <client>
            <endpoint address="http://localhost:1406/WcfPortal.svc"
                binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_IWcfPortal"
                contract="Csla.WcfPortal.IWcfPortal" name="BasicHttpBinding_IWcfPortal" />
        </client>
    </system.serviceModel>
</configuration>

I'm wondering if the port number important, when I change it I get a different error. I'm also wondering if the format of the endpoint address correct.

Not sure if it's important, but my serviceModel settings from the ASPNet web.config are:

  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="WcfPortalBehavior">
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <services>
      <service behaviorConfiguration="WcfPortalBehavior" name="Csla.Server.Hosts.Silverlight.WcfPortal">
        <endpoint address="" binding="basicHttpBinding" contract="Csla.Server.Hosts.Silverlight.IWcfPortal">
          <identity>
            <dns value="localhost"/>
          </identity>
        </endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
      </service>
    </services>
  </system.serviceModel>

Answer 1

If I am thinking it right, then the error may be telling you the entirely correct thing, you are missing a cross domain policy. The silverlight app is accessing the WCF service from a remote location and needs the authorisation to accept the request.

This occured for me in dev when the project was in three parts, the SL App, the WCF web service and the website. The web site and WCF service are run independantly, although they were a part of the same solution. As such Cassini is run twice and you are crossing a boundary.

I have a clientaccesspolicy.xml file along with the web service in development that has the following:

<?xml version="1.0" encoding="utf-8" ?>
<access-policy>
<cross-domain-access>
    <policy>
        <allow-from http-request-headers="*">
            <domain uri="*"/>
        </allow-from>
        <grant-to>
            <resource path="/" include-subpaths="true"/>
        </grant-to>
    </policy>
</cross-domain-access>
</access-policy>

The file is a allowing anyone and everything, you would refine it for production, but in dev it was the easiest way. Google wcf client access policy / wcf cross domain policy - it is a common issue.