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For practice, I'm trying to get the Flask server to constantly print "Hello" to the HTML page's console. I'm currently lost with how to proceed.
Currently, my server code looks something like this
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app)
@socketio.on('message')
def handle_message(message):
print('Message: ' + message)
send(message)
@socketio.on('json')
def handle_json(json):
send(json, json=True)
@socketio.on('my event')
def handle_my_custom_event(json):
emit('my response', json, broadcast=True)
def hello():
emit('message', {'hello':"Hello"})
@app.route('/')
def index():
return render_template('index.html')
if __name__ == '__main__':
socketio.run(app)
while True:
hello()
While my client code looks like this:
<head>
<script type="text/javascript" charset="utf-8">
var socket = io.connect('http://' + document.domain + ':' + location.port);
socket.on('connect', function() {
socket.emit('connected');
});
socket.on('message', function(data) {
console.log(data);
});
</script>
</head>
But I'm not getting anything in my console log for the page. How do I get it to print the message sent from the Flask server to the console? What am I doing wrong?
I understand right now, it should print the JSON instead of the "Hello" string, and that's ok too. I just want something to print on the web console from the server.
442
Here's a simple example showing how to connect to the SocketIO server and receive a message from the server upon that connection.
app.py
from flask import Flask, render_template
from flask_socketio import SocketIO, emit
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app)
@socketio.on('connect')
def connect():
emit('message', {'hello': "Hello"})
@app.route('/')
def index():
return render_template('index.html')
if __name__ == '__main__':
socketio.run(app, debug=True)
templates/index.html
<head>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/1.3.6/socket.io.min.js"></script>
<script type="text/javascript" charset="utf-8">
var socket = io.connect('http://' + document.domain + ':' + location.port);
socket.on('connect', function() {
console.log('connected');
});
socket.on('message', function(data) {
console.log(data);
});
</script>
</head>
Edit:
To have the server send a socketio message every five seconds, you can use a background thread:
app.py
from flask import Flask, render_template
from flask_socketio import SocketIO, emit
import time
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app)
thread = None
def background_thread():
while True:
socketio.emit('message', {'goodbye': "Goodbye"})
time.sleep(5)
@socketio.on('connect')
def connect():
global thread
if thread is None:
thread = socketio.start_background_task(target=background_thread)
@app.route('/')
def index():
return render_template('index.html')
if __name__ == '__main__':
socketio.run(app, debug=True)
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