Updating progress bar with Flask

Question

I am trying to get a progress bar to update - I tried to implement the code here here around my code below, but can't get it to work. When I run my code the progress bar appears but does not update.

I have also checked other answers but still can't figure out how to get this to work. If someone could help with the problem I would really appreciate it.

server.py

def create_app():
    app = Flask(__name__)

     app.add_url_rule("/", view_func=views.home_page)

    app.add_url_rule("/display", view_func=views.display_page)
    app.add_url_rule("/display_progress", methods=['GET', 'POST'], 
view_func=views.progress) 

return app

views.py

def display_page():      
    return send_file("templates/display.html")


def progress():
    def generate():
        x = 0
        while x <= 100:
            print(x)
            x = x + 10
            time.sleep(0.2)
            yield "data:" + str(x) +"\n\n"
     return Response(generate(), mimetype='text/event-stream')

display.html

<html lang="en">
<head>
    <title>Display Update</title>
    <meta charset="utf-8">
    <link rel="stylesheet" href="/static/bootstrap.css"></link>
    <script src="/static/jquery.js"></script>
    <script src="/static/bootstrap.js"></script>
    <script src="/static/websocket.js"></script>

    <script>
    var source = new EventSource("/display_progress");
    source.onmessage = function(event) {
        $('.progress-bar').css('width', event.data + '%').attr('aria- 
   valuenow', event.data);
    }
    </script>

</head>

<body>
        <h3>Update DTS Displays</h3>
        <div class="progress" style="width: 750px; height: 22px; margin: 
10px;">
            <div class="progress-bar progress-bar-striped active" 
role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100" 
style="width: 0%">
                <span class="progress-bar-label">0%</span>
            </div>

        </div>
        <button type="submit" class="btn btn-default" formaction="{{ 
url_for('progress') }}">Progress Bar</button>

</body>
</html>

score 2 · Accepted Answer · answered Jul 11 '19 at 15:03

In display.html update your script tag:

<script>
        var source = new EventSource("/display_progress");
        source.onmessage = function (event) {
            $('.progress-bar').css('width', event.data + '%').attr('aria-valuenow',event.data);
            $('.progress-bar-label').text(event.data + '%');
            if (event.data == 100) {
                source.close()
            }
    }
</script>

Updating progress bar with Flask

1 Answers1