I had this problem when connecting to a WCF RESTful service via AJAX calls
My javascript was this:
var GetData= function(){
var data;
$.ajax({
url: this.server + "/data",
async: false,
type: "GET",
success: function (success) {
data = success;
}
});
return data;
};
My service endpoint was opened with this code
ServiceHost host = new ServiceHost(new MyService());
host.Open();
All the important data is stored in the App.config file, I did not have to change that file for this fix.
I knew I had to add the headers somewhere before the response message was sent.
After some searching and hacking I found the Authorization property of a ServiceHost object. The Authorization property is an instance of the ServiceAuthorizationBehavior class whose objects have a property called ServiceAuthorizationManager which is an instance of the ServiceAuthorizationManager class.
By creating a new class that inherits from the ServiceAuthorizationManager and setting it to the ServiceAuthorizationManager property of the Authorization behavior of your ServiceHost instance, you can intercept all calls to your service.
This is how I have implemented my class
public class MyServiceAuthorizationManager : ServiceAuthorizationManager
{
protected override bool CheckAccessCore(OperationContext operationContext)
{
HttpResponseMessageProperty prop = new HttpResponseMessageProperty();
prop.Headers.Add("Access-Control-Allow-Origin", "*");
operationContext.OutgoingMessageProperties.Add(HttpResponseMessageProperty.Name, prop);
return true;
}
}
then right after I declare my ServiceHost object (before the host is opened) I add this line
host.Authorization.ServiceAuthorizationManager = new MyServiceAuthorizationManager();
After doing this, rebuilding, and running my service the error message stopped showing up. Hooray!
Lastly, I read an article that described the ServiceHost class was designed for SOAP/WSDL services not RESTful services. For RESTful services the WebServiceHost object should be used.
So
ServiceHost host = new ServiceHost(new MyService());
host.Open();
becomes
WebServiceHost host = new WebServiceHost(new MyService());
host.Open();
You must add references to the following assemblies:
Hope this helps.
Sources: