Not able to emit from background thread. Similar to: https://github.com/miguelgrinberg/Flask-SocketIO/issues/434

[Aditya-Dexian]

Hi,

This problem has been described in #434 as well.

I am a beginner programmer trying to implement a real-time transcription solution using Python Flask, React.js, and websockets.

I am asking for help with my code.

I seriously appreciate any and all help with this query.

Note: This code is minimal, not my entire code

server.py:

# this one sends the transcript properly and properly sets it. this is how i know the frontend can definitely pick up these requests properly.

I would really appreciate all the help I can get. Thank you guys so much in advance.

[Aditya-Dexian]

Miguel responded to me in another place, suggesting that I enable logging for debugging purposes. I am looking into the docs currently to enable that. Thank you.

[Aditya-Dexian]

Further test..
Maybe I misunderstood your last comment about the application being on single page. I was thinking you were referring to the frontend but maybe you were referring to the backend?

server.py (flask host file):

opening/refreshing http://localhost:5000 will do /send request. 
trying to test stuff without all of the threads.

/send -> transcribers.test() -> return "result" -> emitting this returned value -> properly received by the front end

uncommenting the # server.emit_transcript("result") -> emit_transcript function is called with "result" parameter -> transcript_update request is sent -> not received

[miguelgrinberg]

I'm sorry, but I think you do not understand what I'm saying. You shared this log:

The top of the log shows that you had a Socket.IO connection. Then the client navigated to /send. And after that there are no more Socket.IO logs, which means that the connection disappeared. This is because the browser drops all connections when it goes to another page, so you should design your application so that the page does not change.

All the activity that appears in your log after /send was accessed are the emits that you say don't work. But they are working just fine. The problem is that you are emitting from a server that has no active connections to any client.

[Aditya-Dexian]

Thanks for your response.

I removed the /send thing completely from my code so I am pretty sure I am now not going to any other pages.

I think you are saying that the websocket connection is somehow being dropped. To my understanding, if it is dropped, I should not be able to make and receive any more requests after the fact.

Referring to the new screenshot:
1: upgrade to socket successful, pass email input from front end to back end (successful)
2. press start button, call start recording function in backend from the frontend (successful)
3. I say hello, transcriber picks it up, tries to shoot transcript_update, sentiment_update from backend to frontend. i don't see any updates on the front end like I should and like I did earlier when using the /send (unsuccessful)
4. press stop button, call stop recording function in backend from frontend. python errors because I have not implemented this function properly but the function is still being called (successful)

Please correct me if I'm wrong but even after the /send stuff is removed, I am still able to make a successful websocket request which implies the socket connection is not broken?

Once again, thank you for your continued time and assistance.

[miguelgrinberg]

The lines that start with 127.0.0.1 comes from the web server. They show connections that ended. The ones that have transport=websocket in the URL are Socket.IO connections that ended. I really can't tell for sure because you are using many connections in your client, but at least some connections are going away for some reason.

So first you need to figure out why you have many connections instead of just one. And second why they are getting closed.

[Aditya-Dexian]

Hi Miguel,

Thank you for your response and help.

I pondered upon your last reply for a while, and I thought maybe the way I've written my code to import each other is the issue. When I run server.py, it imports transcribers.py which imports server.py again, causing some weird issues.

I confirmed my issue by recombining all my files into one large 500+ line file and transcription ran as desired.

Now I realized exactly my issue, and I wrote the following code:

This code is separate from the stuff I've shared above.

server.py:

SocketConfig.py:

transcribers.py:

import server

note how importing server nolonger runs any of the stuff like app=Flask(__name__), socketio = SocketIO(app, ........)

This works.

Looking at the logs, I only see one socket connection (I think) sending the requests.

I seriously couldn't have gotten this far without you.

Thank you once again Miguel.