Flask returning a generator and handling it in JavaScript

Question

I am trying to figure out how to send a constant stream of data in Flask and then read it in JavaScript.

This example is very basic because I am just trying to get it working.

Flask route:

@app.route("/gen", methods=["GET"])
def gen():
    def make():
        while True:
            yield "Hello"
            time.sleep(1)
    return Response(make())

JavaScript:

<script>
    const url = 'http://10.0.1.11:8001/gen';

    fetch(url)
        .then(function (response) {
            return response;
        })
        .then(function (data) {

            console.log(data)

        })
</script>

This prints to the console log only one time and I do not see the message "Hello". What I would like to see is "Hello" printed every second. My end goal is to send json from my generator and parse it in my html document.

Thanks, Chris

1. you need to change `return response;` to `return response.text();` 2. remove the time command and instead use [`setInterval(..., 1000)`](https://developer.mozilla.org/en-US/docs/Web/API/setInterval) in your client-side JS — , Jun 01 '22 at 20:48
Hello. I already know how to use setInterval but I thought using a stream would be the more proper way? This way there is only 1 request to flask instead of spamming the logs. — Chris, Jun 01 '22 at 20:56
I've never done that but you can check here: https://developer.mozilla.org/en-US/docs/Web/API/Streams_API/Using_readable_streams (or use socket.io instead) — , Jun 01 '22 at 20:59

Flask returning a generator and handling it in JavaScript

0 Answers0