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Python Websockets SSL with Lets Encrypt
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| ## Python Websockets SSL with Lets Encrypt | |
| This code uses the `python-websockets` library. | |
| You'll need to generate the certificate and keyfile using Let's Encrypt. | |
| After generating the files correctly, you need to make them accessible to the current user who runs the script, my way of doing this was to copy it to the home directory of the current user and change the owner to the current user, set the permissions of the files to 400. | |
| To know more about this process, read the blog here - https://xprilion.com/python-websockets-ssl-with-lets-encrypt/ |
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| <html> | |
| <head> | |
| <title>WebSocket demo</title> | |
| <style type="text/css"> | |
| body { | |
| font-family: "Courier New", sans-serif; | |
| text-align: center; | |
| } | |
| .buttons { | |
| font-size: 4em; | |
| display: flex; | |
| justify-content: center; | |
| } | |
| .button, .value { | |
| line-height: 1; | |
| padding: 2rem; | |
| margin: 2rem; | |
| border: medium solid; | |
| min-height: 1em; | |
| min-width: 1em; | |
| } | |
| .button { | |
| cursor: pointer; | |
| user-select: none; | |
| } | |
| .minus { | |
| color: red; | |
| } | |
| .plus { | |
| color: green; | |
| } | |
| .value { | |
| min-width: 2em; | |
| } | |
| .state { | |
| font-size: 2em; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <div class="buttons"> | |
| <div class="minus button">-</div> | |
| <div class="value">?</div> | |
| <div class="plus button">+</div> | |
| </div> | |
| <div class="state"> | |
| <span class="users">?</span> online | |
| </div> | |
| <script> | |
| var minus = document.querySelector('.minus'), | |
| plus = document.querySelector('.plus'), | |
| value = document.querySelector('.value'), | |
| users = document.querySelector('.users'), | |
| websocket = new WebSocket("wss://localhost:6789/"); | |
| minus.onclick = function (event) { | |
| websocket.send(JSON.stringify({action: 'minus'})); | |
| } | |
| plus.onclick = function (event) { | |
| websocket.send(JSON.stringify({action: 'plus'})); | |
| } | |
| websocket.onmessage = function (event) { | |
| data = JSON.parse(event.data); | |
| switch (data.type) { | |
| case 'state': | |
| value.textContent = data.value; | |
| break; | |
| case 'users': | |
| users.textContent = ( | |
| data.count.toString() + " user" + | |
| (data.count == 1 ? "" : "s")); | |
| break; | |
| default: | |
| console.error( | |
| "unsupported event", data); | |
| } | |
| }; | |
| </script> | |
| </body> | |
| </html |
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| #!/usr/bin/env python | |
| # WS server example that synchronizes state across clients | |
| import asyncio | |
| import json | |
| import logging | |
| import websockets | |
| import ssl | |
| logging.basicConfig() | |
| ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER) | |
| # Generate with Lets Encrypt, copied to this location, chown to current user and 400 permissions | |
| ssl_cert = "/home/username/fullchain.pem" | |
| ssl_key = "/home/username/privkey.pem" | |
| ssl_context.load_cert_chain(ssl_cert, keyfile=ssl_key) | |
| STATE = {"value": 0} | |
| USERS = set() | |
| def state_event(): | |
| return json.dumps({"type": "state", **STATE}) | |
| def users_event(): | |
| return json.dumps({"type": "users", "count": len(USERS)}) | |
| async def notify_state(): | |
| if USERS: # asyncio.wait doesn't accept an empty list | |
| message = state_event() | |
| await asyncio.wait([user.send(message) for user in USERS]) | |
| async def notify_users(): | |
| if USERS: # asyncio.wait doesn't accept an empty list | |
| message = users_event() | |
| await asyncio.wait([user.send(message) for user in USERS]) | |
| async def register(websocket): | |
| USERS.add(websocket) | |
| await notify_users() | |
| async def unregister(websocket): | |
| USERS.remove(websocket) | |
| await notify_users() | |
| async def counter(websocket, path): | |
| # register(websocket) sends user_event() to websocket | |
| await register(websocket) | |
| try: | |
| await websocket.send(state_event()) | |
| async for message in websocket: | |
| data = json.loads(message) | |
| if data["action"] == "minus": | |
| STATE["value"] -= 1 | |
| await notify_state() | |
| elif data["action"] == "plus": | |
| STATE["value"] += 1 | |
| await notify_state() | |
| else: | |
| logging.error("unsupported event: {}", data) | |
| finally: | |
| await unregister(websocket) | |
| start_server = websockets.serve(counter, "0.0.0.0", 6789, ssl=ssl_context) | |
| asyncio.get_event_loop().run_until_complete(start_server) | |
| asyncio.get_event_loop().run_forever() |
Thanks for the feedback @vuolo, your comment earlier today encouraged me to work on the blog! 😃 I figured the way I had written it initially was slightly tough to follow for folks who were doing socket SSL setup for the first time.
hi @xprilion ,
i launched the example on my local machine on port 12088 (... start_server = websockets.serve(counter, "0.0.0.0", 12088, ssl=ssl_context) ...)
i tested it from chrome browser from Developer tools->console :
try {
let s = new WebSocket('wss://127.0.0.1:12088');
s.onerror = e =>{console.error('onerror!!!', e)}
s.onopen = r => {
console.debug('onopen', r)
}
} catch (e) {
console.error('EEERRR', e)
}
console result:
VM132:2 WebSocket connection to 'wss://127.0.0.1:12088/' failed:
(anonymous) @ VM132:2
VM132:3 onerror!!! Event {isTrusted: true, type: 'error', target: WebSocket, currentTarget: WebSocket, eventPhase: 2, …}
as you can see it doesn't work. but if i launch the server script without ssl parameter (... start_server = websockets.serve(counter, "0.0.0.0", 12088...) it works:
try {
let s = new WebSocket('ws://127.0.0.1:12088');
s.onerror = e =>{console.error('onerror!!!', e)}
s.onopen = r => {
console.debug('onopen', r)
}
} catch (e) {
console.error('EEERRR', e)
}
result:
onopen Event {isTrusted: true, type: 'open', target: WebSocket, currentTarget: WebSocket, eventPhase: 2, …}
also, no any external web server is launched on my machine.
any suggestions?
thanks in advance
Awesome example of a secure websocket!
Thank you so much @xprilion!
how about if python is the client?
I wonder if any special configuration is needed to use python as a client for a websocket, maybe you can generate one easily using any GPT tools? Do let me know if that doesn't work for you.
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Dude. Great blog. Thanks a ton, super useful stuff especially with the chmod examples