I am working on web application for client side which is user websocket connection to send/receive data.
Here is my problem.
If some parameter change on client side, I want to close my web socket connection and initiate new connection with new paramaeters.
I tried to close web socket connection bu using close(). But when I checked my browser console, websocket status is always 2.
Please help me to resolve this.
I am not completely sure of what problem you have, but if you set a handler for onclose, it will be triggered when you call close.
var ws = new WebSocket('wss://wss://echo.websocket.org');
ws.onclose=function(){
alert('The websocket just closed, readyState: ' + ws.readyState);
}
Demo: http://jsfiddle.net/6kh20bdy/
ReadyState 3 means closed: https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#Constants
Related
This seems to be the canonical way to open a browser-side websocket and then wait for the open event...
// Create WebSocket connection.
const socket = new WebSocket('ws://localhost:8080');
// Connection opened
socket.addEventListener('open', (event) => {
socket.send('Hello Server!');
});
According to the standard...
socket = new WebSocket(url [, protocols ])
Creates a new WebSocket object, immediately establishing the associated WebSocket connection.
If the new immediately starts establishing the connection, is it possible on a very fast link (like, say, to localhost?) that the connection could be established and the open event fired before the line adding the listener is reached? And then the event would be missed?
I followed the tutorial on the official site of the django channels. Everything is fine. But now, how do I connect to the ongoing socket and push message to the group in the server side (i.e. via django) ?
In the tutorial, following line of code in the js opens up a WebSocket connection simply by calling the WebSocket constructor:
var chatSocket = new WebSocket('ws://' + window.location.host + '/ws/chat/' + roomName + '/');
And I want to connect to the same socket in the server side. I tried this:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('ws://127.0.0.1/ws/chat/2', 6379))
but I get error saying
socket.gaierror: [Errno -2] Name or service not known
I am a complete beginner in socket programming, and apologize if there is anything minor that I may have skipped.
From Using the JavaScript Client:
Notice the lack of a protocol prefix on the server URL. Do not add http:// or ws:// to the URL that you pass to the new dispatcher. WebSocketRails will choose the best available transport for you and prepend the correct prefix automatically.
I'm using WebSocketRails for the first time. I'm getting this error in the client:
WebSocket connection to 'ws://localhost:3000/websocket' failed: Connection closed before receiving a handshake response
If I navigate my browser to http://localhost:3000/websocket, I get the messages that I am expecting. If I navigate to the ws URL, I get ERR_DISALLOWED_URL_SCHEME. So it appears that the server is producing the messages, but the client is trying the wrong protocol.
How do I force the client to use the http protocol rather than ws, or force the server to broadcast it with ws rather than http?
Finally found the answer by digging into the source code. The second parameter of the constructor is called use_websockets and defaults to true. Setting it to false apparently forces it to use http instead of ws.
var dispatcher = new WebSocketRails('localhost:3000/websocket',false);
I see that client side websockets have an onlClose stream which is useful, but why isn't there a complimentary onclose stream on the server side websocket? I would like to be able to clean up my websessions on the server side when the web socket closes but Im not sure how to detect that event occuring on the server side.
The server-side WebSocket API is a Stream. That means that to listen on data, you can do the following:
websocket.listen((data) {
// Do something with data.
}, onDone: () {
// No more data - read-direction was closed.
});
Where the onDone callback is invoked, when the WebSocket is closed.
I'm picking my way through the dartiverse_search example from the welcome page in dart editor. I see that it uses a path route to decide whether to transform a request into a websocket:
// The client will connect using a WebSocket. Upgrade requests to '/ws' and
// forward them to 'handleWebSocket'.
router.serve('/ws')
.transform(new WebSocketTransformer())
.listen(handleWebSocket);
Is it possible to turn a request into a websocket without using a routing path, for example using a query string to the root url?
You can specify any condition for upgrading to a WebSocket connection. You can even upgrade any connection request to a WebSocket connection without specifying a condition like this:
WebSocketTransformer.upgrade(request).then((WebSocket websocket) {
websocket.listen((String text) {
// process sent data
});
websocket.add(JSON.encode("Hello"));
});
If the request is not a valid web socket upgrade request a HTTP response with status code 500 will be returned. Otherwise the returned future will complete with the [WebSocket] when the upgrade process is complete.