Stream response with AsyncGenerator

[LorenzoVaccher01]

I would need to stream data to the user via an endpoint through a function that returns an AsyncGenerator

The idea is as follows:

message_route = Blueprint('message_route', __name__, template_folder='templates')

@message_route.route('/message/<string:key>/<string:chat_uuid>', methods=['POST'])
async def message(key, chat_uuid):
    
   # [...] Other endpoint logic not helpful in resolving the issue

    async def event_stream():
        agent_handler = agent.run(input=content['message'])

        # stream_events() return an AsyncGenerator[Event, None], so async is necessary
        async for ev in agent_handler.stream_events():
            if isinstance(ev, MessageOutputEvent):
                print(ev.message)
                yield ev.message

       # wait for the process to finish before continuing
        response = await agent_handler
        print(response)

    resp = make_response(event_stream())
    resp.mimetype = "text/event-stream"
    resp.set_cookie(key='user_uuid', samesite="none", value="user_123")
    return resp, 200

To be able to handle requests with async/await I installed flask[async] (3.0.3) but when I add async to the message() function I get the error:

TypeError: The view function did not return a valid response. The return type must be a string, dict, list, tuple with headers or status, Response instance, or WSGI callable, but it was a coroutine.