Question

I have this code that is supposed to pull a thumbnail image from a remote server and return it to be displayed in Flex. Unfortunately my code is throwing “No active security context” errors.

After searching I saw a trick with setTimeout that is supposed to fix this, but it isn’t working for me. What am I doing wrong?

Here is the Code in Flex 4.0 (Note: File is a custom class)

public function getThumbnail(file:File, callBack:Function):void
{
  // only for image files
  if (file.mimeType.indexOf("image") > -1) {
    var loader:Loader = new Loader();
    // create request
    var urlVars:URLVariables = new URLVariables();
    urlVars.id = file.id;
    var req:URLRequest = new URLRequest(THUMBNAIL_URL);
    req.data = urlVars;
    setTimeout(
      function():void {
        loader.load(req);
      }, 1);
    // set load handler
    loader.contentLoaderInfo.addEventListener(Event.COMPLETE,
      function(event:Event):void
      {
        var thumbnail:Image = new Image();
        thumbnail.source = event.currentTarget.content;
        callBack(thumbnail);
      });
    }
}

Update I placed this in my application.mxml

Security.allowDomain("*");
Security.allowInsecureDomain("*");
Security.loadPolicyFile("http://localhost:8080/crossdomain.xml");

And I modified the code in my action script file to

public function getThumbnail(file:File, callBack:Function):void
{
  // only for image files
  if (file.mimeType.indexOf("image") > -1) {
    var loader:Loader = new Loader();
    // create request
    var urlVars:URLVariables = new URLVariables();
    urlVars.id = file.id;
    var req:URLRequest = new URLRequest(THUMBNAIL_URL);
    req.data = urlVars;
    var context:LoaderContext = new LoaderContext(true);
    loader.load(req);
    // set load handler
    loader.contentLoaderInfo.addEventListener(Event.COMPLETE,
      function(event:Event):void
      {
        var thumbnail:Image = new Image();
        thumbnail.source = event.currentTarget.content;
        callBack(thumbnail);
      });
    }
}

I had to modify my server.xml on my J2EE backend to get the crossdomain.xml to show up at the root.

My crossdomain.xml looks like this:

<?xml version="1.0"?>

<!DOCTYPE cross-domain-policy SYSTEM "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">

<cross-domain-policy>

    <!--This domain can accept the SOAPAction header from a SWF file from www.example.com -->

    <site-control permitted-cross-domain-policies="all" />

    <allow-access-from domain="*" secure="false" />

    <allow-http-request-headers-from
        domain="*" headers="SOAPAction" />

</cross-domain-policy>

I still get the “No active security context” error in Firefox with the debug version of Flash Player.

Answer 1

I can’t find the link anymore, but there was a bug with version 10.2 of Flash with debugging. I recently upgraded to version 10.3 with the debugger and I no longer get this error.