To run:
python3 -m pip install websockets
python3 simple_websocket_server.py
Then in another terminal, run
python3 -m http.server
Open a web browser and navigate to http://localhost:8000/index.html.
Note that after 10 seconds, we get rid of the reference to the websocket object (both via setting it to null as well as delete-ing the property). Despite this, the connection is unbroken and the messages keep coming.
| <!DOCTYPE html> | |
| <html lang="en"> | |
| <head> | |
| <style> | |
| #receivedTime, #receivedMsg { | |
| display: inline-block; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <h1>Websocket Test</h1> | |
| <div id="note"></div> | |
| <div id="receivedTime"></div> | <div id="receivedMsg"></div> | |
| <script> | |
| const obj = { | |
| ws: (() => { | |
| const ws = new WebSocket('ws://localhost:8080/'); | |
| ws.onopen = () => { | |
| console.log("Websocket opened"); | |
| }; | |
| ws.onmessage = (message) => { | |
| console.log("Received: " + message.data); | |
| document.getElementById("receivedTime").innerHTML = new Date().toISOString(); | |
| document.getElementById("receivedMsg").innerHTML = message.data; | |
| }; | |
| ws.onclose = () => { | |
| console.log("Websocket closed"); | |
| }; | |
| ws.onerror = () => { | |
| console.log("Websocket error"); | |
| }; | |
| })() | |
| }; | |
| setTimeout(() => { | |
| console.log("Deleting obj.ws"); | |
| obj.ws = null; | |
| delete obj.ws; | |
| console.log("Deleted obj.ws"); | |
| document.getElementById("note").innerHTML = `Deleted obj.ws at ${new Date().toISOString()}`; | |
| }, 10000); | |
| </script> | |
| </body> | |
| </html> |
| #!/usr/bin/env python | |
| import asyncio | |
| import json | |
| import time | |
| import websockets | |
| async def hello(websocket, path): | |
| print(f"Someone connected! {path}") | |
| while True: | |
| msg = "Hello, world!" | |
| await websocket.send(msg) | |
| time.sleep(1) | |
| if __name__ == "__main__": | |
| start_server = websockets.serve(hello, "localhost", 8080) | |
| asyncio.get_event_loop().run_until_complete(start_server) | |
| asyncio.get_event_loop().run_forever() |