Tomcat in Docker with webapp: Error during WebSocket handshake - javascript

I have a Java webapp and a browser application that connects to it over WebSockets like this in my client-side Javascript code:
function connect() {
var username = 'my-user';
var url = `ws://${document.location.host}${document.location.pathname}chat/${username}`;
log(`making WebSocket connection to ${url}`)
var ws = new WebSocket(url);
ws.onmessage = (event) => {
var message = JSON.parse(event.data);
log(message.message);
};
ws.onerror = (event) => {
log(event);
}
}
The endpoint when running Tomcat locally is ws://localhost:8080/my-app/chat/my-user
The endpoint when running Tomcat under Docker is ws://localhost:8090/my-app/chat/my-user (port 8090)
This works fine when connecting to my local Tomcat, but not when connecting to Docker Tomcat.
The error I get back when trying to connect to the Docker Tomcat is:
WebSocket connection to 'ws://localhost:8090/my-app/chat/my-user' failed: Error during WebSocket handshake: Unexpected response code: 404
Any ideas? From what I can tell, I don't need to open any additional ports in Docker (I have 8090 mapped properly). I don't know if there is any additional logging I can turn on in Tomcat to show me the endpoints. Maybe I just am not specifying the right endpoint?

Related

How do I connect to Websockets program running on my server?

I have a Websocket program running on Ubuntu machine on Digital Ocean. The code is shortened below.
// server.ts
import ws from "ws";
const wss = new ws.Server({
port: 3002,
});
const handler = applyWSSHandler({ wss, router: appRouter, createContext });
console.log("WebSocket Server listening on ws://localhost:3002");
...
I host the server using nodemon server.ts or pm2 start server.ts. The program compiles and logs that Websocket Server is listening.
Now, here is a minimum code for a client which just checks if Websockets is active.
// client.js
const ws = new WebSocket('ws://xxx.xxx.xxx.xxx:3002'); // where xxx.xxx.xxx.xxx is the IPv4 of my Ubuntu machine
ws.onopen = function (event) {
console.log('connected');
};
Nothing gets logged, showing that the Websocket server isn't active.
I expect "connected" to be printed.
If I host my server locally instead of on Digital Ocean, and connect to "localhost:3002", "connected" does get printed out.
Is there something wrong with the way I am hosting the server, or am I connecting to the server wrongly?
Any help is appreciated. Thanks!

Node.js net.Socket().connect() hangs and doesn't connect to server

I have a server and a client set up using the net module for Node.js.
Here is my server's code:
const server = net.createServer(function(socket) {
socket.on("data", function(data) {
// Do stuff with the connection
socket.end();
});
});
server.listen(this.port);
Here is my client's code:
const client = new net.Socket();
client.connect(this.port, this.host, function() {
client.write("Test Message");
});
When run on the same machine, both of these work fine, but when I try to connect from a different computer, the client hangs at client.connect() forever (until I terminate the process). When I tried to use the telnet command in command prompt, I don't get a response from the server, but the client doesn't just say connection refused. What's going on here?

Websocket between python server and javascript client

I am very new to web development, so any tips regarding the following matter will be useful!
So, the client written in javascript is supposed to communicate with the server written in python. I am trying to establish websocket connection between two PCs running UBUNTU and Windows OS
They work perfectly fine when I run them using UBUNTU, using localhost.
Also, everything works fine when the server is in UBUNTU and the client is in Windows.
Only when the server is located in Windows and the client is in UBUNTU I keep running into the same error.
'Error in connection establishment: net::ERR_CONNECTION_TIMED_OUT.
I tried turning off the firewall settings in Windows, but it didn't work.
Any input will be very appreciated!
Python Server
import asyncio
import websockets
async def hello(websocket, path):
name = await websocket.recv()
print(f"< {name}")
greeting = f"Hello {name}!"
await websocket.send(greeting)
print(f"> {greeting}")
start_server = websockets.serve(hello, "localhost", 8765)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()
Javascript Client
var ws = new WebSocket("ws://localhost:1337/");
ws.onopen = function(){
console.log("Connection is Established");
ws.send("Message to Send");
};
ws.onmessage = function(evt) {
var received_msg = evt.data;
console.log(received_msg);
};
Okay, I found what was wrong.
Completely forgot that I had to change my router settings for port forwarding.

"Where" are Websocket servers hosted on Heroku?

I'm trying to host a Websocket server on my heroku app. There already is a GraphQL server running, but I don't think it's the cause of my problem.
So my server is started like this
const wss = new ws.Server({ port: port }, () => console.log(`Serveur WebSocket prĂȘt ${port}`));
There is no error, but when I try to connect to the server in my browser, just like this :
const ws = new WebSocket('wss://ethyme-api.herokuapp.com/');
I get an error 404.
So my question is, what is the path of the ws server, so I can connect to it ?
Thanks
If your Heroku app is called ethyme-api and and your locally run application is available under ws://localhost:$PORT/ the websocket will be available under wss://ethyme-api.herokuapp.com/ and ws://ethyme-api.herokuapp.com/

Web Socket handshake error in Docker

I use Python 3.5, Flask and Meinheld web socket middleware to serve sockets. Here is server side code sample:
#app.route('/chat')
def chat():
ws = request.environ.get('wsgi.websocket')
while True:
m = ws.wait()
if m is None:
break
ws.send(m)
return ""
Client side code sample:
var s = new WebSocket("ws://localhost:4567/chat");
However, everything works properly while I run it in local mode, but when i add this into docker container i always get error like this:
WebSocket connection to 'ws://localhost:4567/chat' failed: Error during WebSocket handshake: Unexpected response code: 500
It does not matter where docker container is run, on remote server or local environment, the error is always the same. All necessary ports are exposed.

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