GET request parameters for a MessageField in AppEngine Endpoints is None

Question

For some reason I am unable to read request parameters when using http_method=GET instead of POST.

@endpoints.method(RequestMessage,
                  ResponseMessage,
                  name='get',
                  path='mypath',
                  http_method='GET')
def get_challenge(self, request):
    # This is None in http_method=GET but works on POST
    print request.my_message_field

My message class is like this:

class MyMessage(messages.Message):
    id = messages.StringField(1)
    name = messages.StringField(2)

class RequestMessage(messages.Message):
    my_message_field = messages.MessageField(MyMessage, 1)

I am testing the API through the API Explorer. Any idea if I am doing something wrong or what?

Thanks

Answer 1

The parameters should be showing up as my_message_field.id and my_message_field.name.

The fundamental difference is that GET has no payload and POST does. As a result, your parameter namespace must be "flat" instead of nested JSON. So to accomodate this we flatten out the parameters as I mentioned above.

UPDATE:

This must have been an issue with something not getting correctly ported to devappserver. I added a logger to endpoints.apiserving to determine what was passed from the API frontend to the App Engine backend:

In production:

'{"my_message_field":{"id":"x","name":"y"}}'

In devappserver2:

'{"my_message_field.name": ["y"], "my_message_field.id": ["x"]}'

When trying to parse via

from protorpc import remote
protocols = remote.Protocols.get_default()
json_protocol = protocols.lookup_by_content_type('application/json')
json_protocol.decode_message(RequestMessage, payload)

which is what the api_server does, this is what occurred

In production:

<RequestMessage
 my_message_field: <MyMessage
 id: u'x'
 name: u'y'>>

In devappserver2:

<RequestMessage>