Metadata field should be passed through the input channel

To use metadata with the input channel, you currently have to overwrite several functions in the RestInputChannel (e.g. receive, stream_response, on_message_wrapper).

Potential Solution:

• Would be cool if we implement a function get_metadata(request) which returns None by default, and can be overwritten to return a dict of metadata
• stream_response, on_message_wrapper should pass on a potential metadata object to UserMessage by default

https://github.com/RasaHQ/rasa/blob/master/rasa/core/channels/channel.py#L398

[erohmensing]

would be good if all the supported channels did this by default also

[wochinge]

Thanks!

I think maybe by default just the entire payload that comes in with the response, or something like that.

In my opinion that’s too much guessing. It would add a lot of overhead for certain channels to the tracker which is only required by a small subset of people. Hence, I’d prefer if we rather clarify how to quickly extend an input channel to get the required information.