Batter handling of malformed WS message bodies.

[hishnash]

Is your feature request related to a problem? Please describe. When sending messages, if the expected data for a given action is not present at the moment the consumer closes, rather than responding with an error message.

Describe the solution you'd like Response with an error json message when:

• malformed JSON is sent over the websocket connection
• the action keyword is missing
• the action method expects a kwarge that was not provided as part of the action json

[jakiro2017]

I think I will help you do this. Please write some notes about how you want it to be implemented

[hishnash]

@jakiro2017 That would be great.

the action keyword is missing

might be best to check in AsyncAPIConsumer.receive_json update the pop to return None if the key is not there. Then in handle_action inside the try block check that it is not None if it is raise the MethodNotAllowed error.

the action method expects a kwarge that was not provided as part of the action json

To produce a nice error message you could use

from inspect import signature
sig =  signature(method)

then validate that all the args in the sig match up to args in the message.

this would could be place somere here: https://github.com/hishnash/djangochannelsrestframework/blob/master/djangochannelsrestframework/consumers.py#L140

Then you could raise a DRF 400 error.

malformed JSON is sent over the websocket connection

This is a little more complex complex since Django Channels is doing the json decoding we need to move that try catch up one more level.

def receive(self, text_data=None, bytes_data=None, **kwargs):
     try:
         super().receive(text_data=text_data, bytes_data, **kwargs)
    except ...

Here you need to capture the json decoding and instead return the proper DRF error response.