[RequestHook]: add methods for manipulation with response headers

https://devexpress.github.io/testcafe/documentation/test-api/intercepting-http-requests/creating-a-custom-http-request-hook.html#the-onresponse-method

ResponseEvent.setHeader(name, value) ResponseEvent.removeHeader(name)

[miherlosev]

Yes, it’s more appropriate to mark the onConfigureResponse event as public and remove the default implementation from the RequestHook base class. We will do it only before the testcafe@1.0.0 was released, because it’s a breaking change. Now, let’s keep this method as is. So, the use of the setHeader and removeHeader methods will look like this:

class CustomRequestHook extends RequestHook {
    _onConfigureResponse (event) {
      super._onConfigureResponse(event);
 
     event.setHeader('x-frame-options', 'allow-from https://example.com/');
     event.removeHeader('x-header-name');
    }
}

[miherlosev]

Having discussed this with the team, we can suggest the following API:

• removeHeader(name)
• setHeader(name, value)

These methods will be defined as methods of the ConfigureResponseEvent class.

The feature implementation can be divided into 2 parts:

• split the header-transforms.js file into two parts:

  1. header-transforms.js - contains only transformations for request and response headers
  2. header-transform-api.js - contains the forRequest, forResponse and transformHeadersCaseToRaw methods

• change response headers transformation order.

  1. apply all header changes from request hooks
  2. apply header transformation
  3. write updated headers to the response.