Wcf webHttpBinding Response for preflight has invalid HTTP status code 400

Question

I followed Ido Flatow's post to create a cross-origin request and created the following:

On my service interface:

[OperationContract]
[WebInvoke(Method = "*", ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.WrappedRequest)]
bool GetUserAuthentication(string userLoginName, string password);

On app.config:

<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>

Now I'm sending a simple post request using angular $http service and it's working on IE & Edge (also on Postman) but fails to work on Chrome & Firefox with the following error:

XMLHttpRequest cannot load http://localhost:5280/MetaDataService/GetUserAuthentication. Response for preflight has invalid HTTP status code 400

Chrome error printscreen:

Answer 1

Chrome is preflighting the request to look for CORS headers. If the request is acceptable, it will then send the real request.

My problem was that the OPTIONS request which sent to my WCF server was rejected I defined Method="*" for my method, causing the options request to be directed to my method and was expecting to get also parameters.

The solution for this based on How to handle Ajax JQUERY POST request with WCF self-host question was to add new OperationContract for dealing with OPTIONS requests:

[OperationContract]
[WebInvoke(Method = "OPTIONS", UriTemplate = "*")]
void GetOptions();

public void GetOptions()
{
}

this method gets all options request and allowing the real POST method being directed to my service method.