Flask-RESTful - Return custom Response format

In addition to @Martijin Pieters' answer here - https://stackoverflow.com/a/20246014/1869562. Where you return a raw response object, Flask-Restful also allows you to set status code and headers in your return values directly.

So in your case, this should also work

class Foo(restful.Resource):

    def get(self):
        return something, 201, {'content-type': 'application/octet-stream'}

The default mediatype for Flask-REstful is 'application/json', so put should work as is.

Just return Flask response objects in your methods.

A response class allows you to provide custom headers (including the content-type): http://flask.pocoo.org/docs/api/#response-objects

What representation is used is determined by the request, the Accept header mime type.

A request of application/octet-stream will be responded to by using your binary function.

If you need a specific response type from an API method, then you'll have to use flask.make_response() to return a 'pre-baked' response object:

def get(self):
    response = flask.make_response(something)
    response.headers['content-type'] = 'application/octet-stream'
    return response