Python screen sharing with flask app in python

Question

Python screen sharing with flask app in python

96 Views Asked by Hassan Shehzad At 03 April 2025 at 20:59

I am using flask app for screen sharing when I run the script it neither show screen sharing nor it gives any error but its does not stop loading, and shows nothing but white screen. It should have shown the screen on web.

python code:

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/screen_sharing')
def screen_sharing():
    client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    client_socket.connect(('192.168.1.112', 5000))
    def generate_frames():
        while True:
            try:
                data = b''
                while True:
                    packet = client_socket.recv(4096)
                    if not packet:
                        break
                    data += packet
                frame = np.frombuffer(zlib.decompress(data), dtype=np.uint8)
                frame = cv2.imdecode(frame, 1)
                
                if frame is not None:
                    _, buffer = cv2.imencode('.jpg', frame)
                    frame = buffer.tobytes()
                    yield (b'--frame\r\n'
                           b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')
                else:
                    break
            except Exception as e:
                print(f"Error: {str(e)}")
                break
    return Response(generate_frames(), mimetype='multipart/x-mixed-replace; boundary=frame')

if __name__ == "__main__":
    screen_thread = threading.Thread(target=screen_sharing)
    screen_thread.start()
    app.run(host='0.0.0.0', port=5000)

HTML code for web interface:

<!DOCTYPE html>
<html>
    <style>
        img {
            max-width: 100%;
            max-height: 100vh;
            height: auto;
        }
        .screen{
            /* background: #ff6860; */
            border: 1px solid #474e5d;
            border-radius: 1px;
            overflow: hidden;
        }
    </style>
<head>
    <title>Screen Sharing</title>
</head>
<body>
    <div class="row">
        <div class="col s12">
            <img class="screen" src="{{ url_for('screen_sharing') }}">
        </div>
    </div>
</body>
    <script>
      
    </script>
</html>

Output: " ** Serving Flask app 'main'

Debug mode: off WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
Running on all addresses (0.0.0.0)
Running on http://127.0.0.1:5000
Running on http://192.168.1.112:5000 Press CTRL+C to quit* "

What is it that I am doing wrong in this code,

Original Q&A

There are 1 best solutions below

**Mark Tolonen** · Answer 1

In TCP, the data is a byte stream, not messages. recv(n) receives either 0 (socket closed) or 1-n bytes. You must check the return value's length and buffer it until you have the amount requested.

If your packets are all the same size this is relatively easy, but if they vary you need have a protocol to determine the framing of packets. One way is to send the length and then the packet.

Buffering can be handled by wrapping the socket in socket.makefile. Then the TCP stream will act more like a file, with .readline() and .read(n) methods. .read(n) will wait until it receives n bytes or an error or end-of-file is encountered, whereas socket.recv(n) will give you whatever is in the TCP buffers (always at least 1 byte if the socket isn't closed, but up to n bytes depending on data availability).

Simple example that can send any blob of packet data:

import socket
import threading

class PacketError(Exception): pass

def server():
    s = socket.socket()
    s.bind(('', 5000))
    s.listen()
    print('Server started...')
    with s:
        while running:
            c, a = s.accept()
            # Wrap client in binary file-like object
            with c, c.makefile('rb') as infile:
                while True:
                    header = infile.readline()
                    if not header: break
                    length = int(header)
                    data = infile.read(length)
                    if len(data) != length:
                        raise PacketError('incomplete packet')
                    print(data)

running = True
t = threading.Thread(target=server)
t.start()

# Protocol: send length as decimal text terminated by newline,
# then exactly "length" data.
def send_data(sock, data):
    sock.sendall(f'{len(data)}\n'.encode())
    sock.sendall(data)

with socket.socket() as s:
    s.connect(('localhost', 5000))
    send_data(s, b'hello, world!')
    send_data(s, b'abcdefghijklmnopqrstuvwxyz')
    send_data(s, b'she sells seashells by the seashore')

running = False  # Signal server to exit
t.join()         # Wait for thread to exit
print('Server exited.')

Output:

Server started...
b'hello, world!'
b'abcdefghijklmnopqrstuvwxyz'
b'she sells seashells by the seashore'
Server exited.

Python screen sharing with flask app in python

There are 1 best solutions below

Related Questions in PYTHON

Related Questions in SOCKETS

Related Questions in FLASK

Related Questions in SCREENSHARING

Trending Questions

Popular # Hahtags

Popular Questions