flask socketio 400 (BAD REQUEST)

Question

I'm trying to use flask socketio to retrieve some live tweets and currently I'm playing around with the socketio to see how it works. But in my test, I get 400 (BAD REQUEST) from time to time. I'm wondering what is the issue.

here's the error sample:

socket.io.js:3511 POST http://127.0.0.1:5000/socket.io/?EIO=3&transport=polling&t=LOMYW0D&sid=c81baa220764437184a14366357c6d3d 400 (BAD REQUEST)Request.create @ socket.io.js:3511Request @ socket.io.js:3424XHR.request @ socket.io.js:3352XHR.doWrite @ socket.io.js:3365(anonymous function) @ socket.io.js:3884(anonymous function) @ socket.io.js:4747proxy @ socket.io.js:1197(anonymous function) @ socket.io.js:4762(anonymous function) @ socket.io.js:4742exports.encodePacket @ socket.io.js:4541encodeOne @ socket.io.js:4741eachWithIndex @ socket.io.js:4760map @ socket.io.js:4767exports.encodePayload @ socket.io.js:4746Polling.write @ socket.io.js:3883Transport.send @ socket.io.js:2912Socket.flush @ socket.io.js:2623Socket.sendPacket @ socket.io.js:2683Socket.ping @ socket.io.js:2587(anonymous function) @ socket.io.js:2574 socket.io.js:3511 GET http://127.0.0.1:5000/socket.io/?EIO=3&transport=polling&t=LOMYPYb&sid=c81baa220764437184a14366357c6d3d 400 (BAD REQUEST)Request.create @ socket.io.js:3511Request @ socket.io.js:3424XHR.request @ socket.io.js:3352XHR.doPoll @ socket.io.js:3382Polling.poll @ socket.io.js:3795Polling.onData @ socket.io.js:3834(anonymous function) @ socket.io.js:3385Emitter.emit @ socket.io.js:4389Request.onData @ socket.io.js:3546Request.onLoad @ socket.io.js:3627xhr.onreadystatechange @ socket.io.js:3499 socket.io.js:3511 POST http://127.0.0.1:5000/socket.io/?EIO=3&transport=polling&t=LOMYeOF&sid=c81baa220764437184a14366357c6d3d 400 (BAD REQUEST)

my server side code (python flask):

from flask import Flask
from flask_socketio import SocketIO
app = Flask(__name__)
app.config["SECRET_KEY"] = "secret!"
socketio = SocketIO(app)

def root():
    return app.send_static_file("index.html")

@socketio.on("connect", namespace="/npTweet")
def connectServer():
    print("Client connected")
    socketio.emit("connected", namespace="/npTweet")


@socketio.on("startTweets", namespace="/npTweet")
def tweetStreaming():
    print("Start streaming tweets...")
    socketio.emit("streamTweets", {"stream_result": "test"}, namespace="/npTweet")


if __name__ == "__main__":
    socketio.run(app, debug=True)

my client side code:

socket = io.connect("http://" + document.domain + ":" + location.port + "/npTweet");
console.log("http://" + document.domain + ":" + location.port + "/npTweet");
// listen to the event 'connected'
socket.on("connected", function(data){
  console.log("listening connected...");
  socket.emit("startTweets")
});

socket.on("streamTweets", function(data){
  console.log("listen streamTweets...");
  console.log(data.stream_result)
});

These are the initial output when I start the index.html page:

http://127.0.0.1:5000/npTweet
listening connected...
listen streamTweets...
test

but after like 30 second or so, it began to have the previous 400 bad request error, followed by the following result:

listening connected...
listen streamTweets...
test

Then after like 30 seconds, it does the bad request and the result all over again. where am I doing wrong? any help will be appreciated.

for the client side, I'm using socketio js 1.4.5

for python: Flask-SocketIO==2.5 python-engineio==0.9.2

Miguel Miguel · Accepted Answer · 2016-07-23T23:36:11

This was also posted as a GitHub issue here.

The problem was that the Flask server was started as flask run, according to the new Flask 0.11 CLI. Unfortunately this method of starting the server bypasses the Socket.IO code. The solution is to run the script, so that the code inside the if __name__ == 'main': block gets to run.

flask socketio 400 (BAD REQUEST)

1 Answers