Programming with .NET - General

Problem with Cross-Domain access

I'm trying to use Silverlight to access data that is sourced by a mod_python module on an Apache server.

string requestUriString =
    string.Format("http://127.0.0.1:80/ord-svg/ordData.py/GetDataOnChange?unitId=X05&basetime={0}", ++requestId);
Uri requestUri = new Uri(requestUriString);
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(requestUri);
request.BeginGetResponse(new AsyncCallback(ResponseCallback), request);

I'm getting a "System.Security.SecurityException: Security error." exception, which I assume because it is cross-domain.

I have a clientaccesspolicy.xml file at the root of http://127.0.0.1:80. If I use IE7 to browse to http://127.0.0.1:80/clientaccesspolicy.xml and View Source, I get

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

But my Apache access logs don't show any attempt to retrieve that file before the Security Error is thrown when I run my Silverlight app in VS2008.

I'd appreciate any help. What am I missing?

Re: Problem with Cross-Domain access

Are you using a proxy server in your browser settings?

Have you tried a Flash crossdomain.xml ?:

<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-access-from domain="*" />
</cross-domain-policy>

Re: Problem with Cross-Domain access

I hadn't, because I wanted to eventually edit the "grant-to" section. But I gave it a try just now and it didn't help. The Apache logs just don't show any attempt by the Silverlight app to access the site at all. Neither for clientaccesspolicy.xml nor for crossdomain.xml.

Re: Problem with Cross-Domain access

I've noticed that when the cross-domain policy file is missing I don't get an exception but rather the HttpResponse instance has a StatusCode set to HttpStatusCode.NotFound in the callback.

I do recall though that I got some form of security exception when I tried to access the web and my test web page was being served off disk and not from a web project. Could that be the issue?

Re: Problem with Cross-Domain access

The traceback looks like this...

System.Security.SecurityException: Security error.
   at MS.Internal.InternalWebRequest.Send()
   at System.Net.BrowserHttpWebRequest.BeginGetResponse(AsyncCallback callback, Object state)
   ...

Re: Problem with Cross-Domain access

CraigN
I do recall though that I got some form of security exception when I tried to access the web and my test web page was being served off disk and not from a web project. Could that be the issue?

Very likely that is the issue. I see that VS2008 is now (Silverlight 2.0b1) serving the page off disk. Before (Silverlight 1.1a) it seemed to start a server on some arbitary port and to run my web app from there. Is that kind of behavior still available?

Re: Problem with Cross-Domain access

I can see where the exception is thrown in the code, its in response to a System.UnauthorizedAccessException being thrown when trying to execute the native windows method. Is the site possibly not in a trusted browser zone or something?

Re: Problem with Cross-Domain access

shacktoms
I see that VS2008 is now (Silverlight 2.0b1) serving the page off disk. Before (Silverlight 1.1a) it seemed to start a server on some arbitary port and to run my web app from there. Is that kind of behavior still available?

Yeah still available and the default way of doing things if you use the new wizard to create a Silverlight Application. Simply create a new or use an existing Web Application Project (my preferred project type) or a Web Site project and use the "Add Silverlight Link" functionality to do the same thing. It should create an HTML test page and I believe an ASPX one as well.

Re: Problem with Cross-Domain access

That solved the problem. The access doesn't even seem to considered cross-domain. Thanks, CraigN.

Re: Problem with Cross-Domain access

My pleasure, glad I could help. Its an odd one, but most likely well justified as most security exceptions.

Re: Problem with Cross-Domain access

I am running into the same issue and getting "security error". I have created a web app and this is running on my localhost. When i try to invoke a service on a different domain using HTTPWebrequest or webclient, i get the "Security Error". I checked for calls using Fiddler2 and the call isn't even made to my apache server (hosting the service).

I have also added the crossdomain.xml and clientaccesspolicy.xml on the root of my server hosting the service.

If i use proxy generated classes against my wsdl on the server, i get a "CrossDomainError".

please suggest what could be going on. Is there some setting in IIS that could be preventing this call?

BTW. I am running Silverlight 2 Beta 1 with vs2008

Re: Re: Problem with Cross-Domain access

I got this working once i added both localhost and the site that hosted my webservices to trusted zone.