Update 13. Apr: dart code works consistently
Background:
My TV (Samsung 2019 RU7000) offers a secure websocket connection with which json packets can be send to remote control it. For example
"method":"ms.remote.control",
"params":{ "Cmd": "Click", "DataOfCmd":"KEY_MUTE" }
can be send to mute the TV.
To enable access, a handshake is done. The client connects to wss://ip:8002/api/v2/samsung.remote.control?name=value where the value of name is a base64 encoded string. After a successful connection, a popup window appears on the TV which needs to be accepted. If the user accepts the request, the TV sends a JSON response containing a token:
"data":{
"clients":[ ... ],
"id":"...",
"token":"28852140"
},
"event":"ms.channel.connect"
This token is used for authenticating connections with the same name by attaching &token=value to the URL. Sending commands before the user accepts the popup is ignored.
What works
Command line approaches with wscat and curl are working. The TV shows a pop-up and sends a response:
$ wscat -n -c https://192.168.0.227:8002/api/v2/channels/samsung.remote.control?name=aW9Ccm9rZXI=
Connected (press CTRL+C to quit)
< {"data":{"clients":[...], "id":"...", "token":"57940060"}, "event":"ms.channel.connect"}
dart - dart.io.WebSocket
The following code triggers the popup and gets a response as well.
WebSocket ws = await WebSocket.connect(url,
compression: CompressionOptions.compressionOff);
ws.pingInterval = Duration(seconds: 10000);
ws.listen(print, onError: print, onDone: () {
print("done");
print(ws.closeCode);
print(ws.closeReason);
});
await Future.delayed(Duration(seconds: 30));
ws.close();
Problem
I want to use python to connect to the websocket, authenticate my session and send remote control commands. This does not work for the following implementations.
python - websocket liris
The popup does not appear and there is no response from the TV. The socket does not close.
from websocket import create_connection
from ssl import CERT_NONE
sock = create_connection(url, sslopt={"cert_reqs": CERT_NONE})
print(sock.recv())
python - websockets aaugustin
The pop-up does not appear as well and it seems the connection is closed by the TV.
from websockets.client import connect, WebSocketClientProtocol
import ssl
import asyncio
async def connect():
async with connect(url, ssl=ssl.CERT_NONE) as websocket:
res = await websocket.recv()
print(res)
asyncio.get_event_loop().run_until_complete(connect())
The wireshark log shows that it's sending an HTTP GET asking for a websocket upgrade. The TV responds by closing the connection with FIN and RST.
Observations
Connections to publicly available websocket servers do not share the same issues I am experiencing.
Many popular remote controls available for python have the two websocket libraries as the implemented solution. None of these were working for me.
Comparing the packets sent by the python implementations and the command line tools do not show a noticeable difference to me.
wscat sends an 80 byte long packet to the TV every four seconds. I suppose this is ping/pong.
How can I investigate further?
What about trying Tornado's websocket implementation?
async def samsung_ws():
ws_req = HTTPRequest("wss://ip:8002/api/v2/samsung.remote.control?name=value", validate_cert=False)
ws = await websocket_connect(ws_req)
ws.write_message("hello")
while True:
msg = await ws.read_message()
if not msg:
break
print(msg)
Depending on how the webserver is built, you might need to request the webpage before connecting to the websocket because in your wscat example I noticed you are using https:// instead of wss://.
Can you post a sample of a dart run (with the url used)?
Um.... I have some experience on websockets connection using python websockets.
In article, you indicate that your websockets connections will automatically disconnected from the server.
I think is the mechanism call "ping-pong" in the websockets module cause this problem.
The mechanism default status is true, that means you will send a ping sign to the websocket server periodically, if the server doesn't send pong back to you, module will consider that server have been shutdown.So you need to do is just set the "ping-pong"
status to False.
async def connect():
async with connect(url, ssl=ssl.CERT_NONE,close_timeout = None,ping_interval = None) as websocket:
res = await websocket.recv()
print(res)
asyncio.get_event_loop().run_until_complete(connect())
This is all my personal opinion, you can try this out.
Why not using a higher level Python module like requests?
You could try the following:
import requests
params = (
('name', 'aW9Ccm9rZXI='),
)
response = requests.get('https://192.168.0.227:8002/api/v2/channels/samsung.remote.control', params=params)
Related
I would like to set-up a server that can subscribe to an external stream over a websocket (ws_ext) and then republish that data (after curating) to internal clients connecting to this server over websockets (ws_int).
My approach so far is to set up a fastapi server that can open websockets (ws_int) with internal clients .
However, I don't understand how to have a listener embedded in this server that can listen to external stream and then publish to these internal clients in a non blocking way.
Can someone point me to a working example that can help?
Here is what i would like to achieve:
p.s: I HAVE BEEN able to make it work by decoupling broadcaster from subscriber using redis pubsub. So, what i have now setup is a client that listens to external stream, curate and pushes it to redis pubsub. then i have a separate broadcaster that listens to redis pubsub and pushes it out to clients after curating on its websockets. I would still love to combine these two without using redis or some such backend.
if you have all clients connected to an async ws located in the broadcaster then the same time push whatever that's coming asynchronously to broadcaster from external website the process should be unblocking supposedly
the update process can have a async stream pipeline to filter results coming from external website for each client in broadcaster
as for example to async client for WebSocket it can go by "with async"
async def hello():
async with websockets.connect(
'ws://localhost:8765', ssl=ssl_context) as websocket:
name = input("What's your name? ")
await websocket.send(name)
print(f"> {name}")
greeting = await websocket.recv()
print(f"< {greeting}")
asyncio.get_event_loop().run_until_complete(hello())
import python_http_client # 3.2.1
client = python_http_client.Client(host='https://www.google.com')
while True:
print(client.get()) # Has no request timeout
With this piece of code, the HTTP client gets stuck and hangs if I disconnect and reconnect my internet. Is this a bug with the package that I'm using or is this something that's inherently possible with HTTP protocol?
Looks like python_http_client.Client can take a timeout in seconds, like
client = python_http_client.Client(host='https://www.google.com', timeout=30)
Citation: https://github.com/sendgrid/python-http-client/blob/d99717c9e48f07a1a7d598e657838070704b4da7/python_http_client/client.py#L75
I have a very simple Python (Flask socket.io) application which works as a server and another app written in AngularJS which is a client.
In order to handle connected and disconnected client I use respectlivy:
#socketio.on('connect')
def on_connect():
print("Client connected")
#socketio.on('disconnect')
def on_disconnect():
print("Client disconnected")
When Client connects to my app I get information about it, in case if client disconnect (for example because of problems with a network) I don't get any information.
What is the proper way to handle the situation in which client disconnects unexpectedly?
There are two types of connections: using long-pooling or WebSocket.
When you use WebSocket clients knows instantly that server was disconnected.
In the case of long-polling, there is need to set ping_interval and pint_timeout parameters (I also find information about heartbeat_interval and heartbeat_timeout but I don't know how they are related to ping_*).
From the server perspective: it doesn't know that client was disconnected and the only way to get that information is to set ping_interval and ping_timeout.
I'm using the gevent-websocket module with Bottle Python framework.
When a client closes the browser, this code
$(window).on('beforeunload', function() { ws.close(); });
helps to close the websocket connection properly.
But if the client's network connection is interrupted, no "close" information can be sent to the server.
Then, often, even 1 minute later, the server still believes the client is connected, and the websocket is still open on the server.
Question: How to detect properly that a websocket is closed because the client is disconnected from network?
Is there a websocket KeepAlive feature available in Python/Bottle/gevent-websocket?
One answer from Web Socket: cannot detect client connection on internet disconnect suggests to use a heartbeat/ping packet every x seconds to tell the server "I'm still alive". The other answer suggests using a setKeepAlive(true). feature. Would this feature be available in gevent-websocket?
Example server code, taken from here:
from bottle import get, template, run
from bottle.ext.websocket import GeventWebSocketServer
from bottle.ext.websocket import websocket
users = set()
#get('/')
def index():
return template('index')
#get('/websocket', apply=[websocket])
def chat(ws):
users.add(ws)
while True:
msg = ws.receive()
if msg is not None:
for u in users:
u.send(msg)
else:
break
users.remove(ws)
run(host='127.0.0.1', port=8080, server=GeventWebSocketServer)
First you need to add a timeout to the receive() method.
with gevent.Timeout(1.0, False):
msg = ws.receive()
Then the loop will not block, if you send even an empty packet and the client doesn't respond, WebsocketError will be thrown and you can close the socket.
I am trying to connect to a website through a program, whose authentification protocol appears to be the following :
Connect to the websocket.
Receive crucial data for logging in.
Make a HTTP request with username/password/some of the datas THROUGH THIS CONNECTION.
This means that if i open another connection, the data linked to this connection, according to the server, will be different.
For exemple, receiving the data through the websocket, and doing a HTTP request with a browser will not work, as the browser is another connection.
By connection, i mean what is created at the start of the program, for exemple :
ws2= websocket.create_connection("ws://sim.smogon.com:8000/showdown/websocket") for the websocket module
h1 = httplib.HTTPConnection('www.cwi.nl') for the http module.
My problem is that i have to create 2 different connections to connect to websocket and make a http request. This means that the http request will not work with the websocket received data.
How to make these 2 connections the same ? Or, simplier said : how to solve the problem ?