CORS Support within WCF REST Services

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This guy saved my day.

http://blogs.microsoft.co.il/blogs/idof/archive/2011/07.aspx

I am going to place some of his notes here, just in case that web page dies some day.
(I hate finding “Your answer is right HERE” links, and then the link is dead.)

<behaviors> 
  <endpointBehaviors> 
    <behavior name="webSupport"> 
      <webHttp /> 
      <CorsSupport /> 
    </behavior> 
  </endpointBehaviors> 
</behaviors> 
<extensions> 
  <behaviorExtensions> 
    <add name="CorsSupport" type="WebHttpCors.CorsSupportBehaviorElement, WebHttpCors, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" /> 
  </behaviorExtensions> 
</extensions> 
<services> 
  <service name="Service.JSonService"> 
    <endpoint address="http://localhost:8080" behaviorConfiguration="webSupport” binding="webHttpBinding" contract="Service.IJSonService" /> 
  </service> 
</services>

Now, you have to find his downloadable library called “WebHttpCors.dll”.

But there is enough there (above) to help you google/bing your way to a resolution.

The part that was throwing me for a loop (in my scenario) is that IE was working, but Firefox was not working.

My originating page was:

http://localhost:53692/test/WCFCallTestViaJQ14.htm

So my service is at:

http://localhost:8002/MyWCFService/MyWCFMethodByWebGet?state=NC&city=Raleigh

So I had localhost <<–>> localhost traffic.

**** But the ports were different. (53692 and 8002) ****

IE was ok with it. Firefox was not ok with it.

Then you gotta remember that each browser handles their .Send() requests differently (inside JQUERY that is).

It all makes sense now. 

//JavaScript snipplet from JQuery library

if (window.XMLHttpRequest) {

    returnObject = new XMLHttpRequest();

} else if (window.ActiveXObject) {

    returnObject = new ActiveXObject("Microsoft.XMLHTTP");

} else {

msg = "Your browser doesn't support AJAX!";

}

Here are some key words, phrases that I’ve been googling/binging that finally led me somewhere.

    Result: [Exception... "Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIXMLHttpRequest.statusText]" nsresult: "0x80040111 (NS_ERROR_NOT_AVAILABLE)" location: "JS frame :: http://localhost:53692/test/WCFCallTestViaJQ14.htm :: HandleJQueryError :: line 326" data: no]


XMLHttpRequest Send "NS_ERROR_FAILURE"

JQuery Ajax WCF Self Hosted CORS JSON

NOW, YOU NEED TO READ HIS BLOG BLOGS TO UNDERSTAND WHAT THE CODE IS DOING:

For example, he says:

“Access-Control-Allow-Origin” header with the value of “*”

This may or may not be what you want. You may want to have better control of this value (headers) and the others (methods and the origins).

Development environment is one thing. (Use all the *’s you want).

Production is something else, you may want to tweak down those * values to something more discriminate. In a nutshell, you need to understand what CORS is actually doing for you in terms of security, and not just add a behavior that lets everything in.

  allowed-origins: '*'
  allowed-headers: '*'
  allowed-methods: '*'

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