Supporting Cross Origin Resource Sharing (CORS) requests in a WCF Rest service - Part 4

For background information, see part 1

For message inspection code, see part 2

For operation dispatcher code, see part 3

To include the message inspection in our wcf service for our service we need to bind it to our service. This is done using behaviors. To bind the IDispatchMessageInspector that works on the ServiceEndpoint level we need to implement an IEndpointBehavior and assign it to our endpoint.

To bind the IOperationInvoker and IDispatchMessageFormatter we need to implement the IOperationBehavior that works on the operation level.

This class also works as an attribute so you can decorate your contract and operations with it if need be. It also contains some properties if you want to control the header values.

https://github.com/dhvik/Wcf-cors-behavior/blob/master/CorsBehaviorAttribute.cs

Assigning can be done in many ways. By declarations on the contract (attribute), configuration in the applications configuration file or direct using code. I'm using code since I host the services in a windows service.

var host = new WebServiceHost2(serviceType, false,
new Uri(serviceBaseUrl + serviceName));
var endpoint = host.AddServiceEndpoint(contractType,
new WebHttpBinding(WebHttpSecurityMode.None), "");
//add support for cors (both for the endpoint to detect and create reply)
endpoint.Behaviors.Add(new CorsBehaviorAttribute());

foreach (var operation in endpoint.Contract.Operations) {
//add support for cors (and for operation to be able to not
//invoke the operation if we have a preflight cors request)
operation.Behaviors.Add(new CorsBehaviorAttribute());
}

When we now have all pieces in place we don't need to bother about cross domain requests. Our endpoint and operation behaviors handles this and we don't need to litter our service code with things that don't belong there anyway.