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I would like to stream chunks of data from a generator in flask after I called the function with jQuery $.post():
@app.route('/some/function', methods=['POST'])
def calculateSomething():
def g():
# do something here
yield 'result1'
# do more ...
yield 'result2'
return Response(g())
I call this function from jQuery:
$.post("/some/function", {"some": $data}, function(data) {
alert(result)
})
This only gives me one alert saying 'result1result2' and not two separate alerts for each yield. So the callback function is called after everything was 'yielded'.
How can I properly stream to jQuery with yield?
636
You can use server-sent events in this case. Check out the sample below:
from flask import Flask, Response
import time
app = Flask(__name__)
@app.route('/')
def index():
return """
<!DOCTYPE html>
<html>
<head>
<script>
if(typeof(EventSource)!=="undefined") {
var source=new EventSource("/stream");
source.onmessage=function(event) {
document.getElementById("result").innerHTML+=event.data + "<br>";
};
} else {
document.getElementById("result").innerHTML="Sorry, your browser does not support server-sent events...";
}
</script>
</head>
<body>
<h1>Data</h1>
<div id="result"></div>
</body>
</html>
"""
@app.route('/stream', methods=['GET', 'POST'])
def stream():
def event_stream():
n = 0
while True:
yield "data: %s\n\n" % n
n += 1
time.sleep(1)
return Response(event_stream(), mimetype='text/event-stream')
if __name__ == '__main__':
app.run()
Server sent events block your development server. To handle multiple connections look into using Gevent. http://flask.pocoo.org/docs/deploying/others/#gevent
59
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