I have developed a chat application by using Spring Stomp and socketjs .
I have successfully connected to the websocket over my clients but I can not connect to websocket by using Advanced Restclient -> socket implementation.
Why?
Thanks
if i didnt use socketjs , i can succeed to connect over Advanced Rest Client. To connect websocket without using socketjs, you should set the allowed origins : setAllowedOrigins('*')
Also if you are using stomp without socketjs , you can succeed to open a websocket connection via Advanced Rest Client, because stomp just a sub-protocol over websocket connection. But to receive messages over websocket, you should subscribe to STOMP queue, it is impossible with Advanced Rest Client.
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Restclients runs on http protocol. Restclients not yet understand the web socket and sock JS protocol. That is the reason your rest client didn't connected to server.
Related
I have implemented mqtt using server connection tcp socket on my machine with mosquitto broker. I have totally understood the mqtt protocol and its frame format. I want to publish my data over webserver which supports mqtt over websocket.
How can I start with this thing?
I am not clear with websocket concept
Can I implement websocket using tcp or is there any other method.
do i have to use http to implement mqtt over web socket as to send data over webserver?
As http and mqtt use different methods to send or receive data.
I don't want to use ready libraries such as paho.
I am totally new to this socket programming.any help or guideline will greatly appreciated!!!
Websockets are an extension to the HTTP protocol, you need to use a correctly formatted HTTP request to setup a new Websocket connection.
Once the connection is setup it can be used to send the exact same binary MQTT packets that you would send over an existing TCP connection.
I suggest you look at using an existing library like libwebsockets to handle the Websocket connection setup, then you should be able to interface your existing code to just use the websocket handle instead of the socket handle.
If you REALLY don't want to use a library then you will need to start by reading the Websocket RFC https://www.rfc-editor.org/rfc/rfc6455
wss://www.mysite.ca/socket.io/?EIO=3&transport=websocket
This is how chrome webdevoloper tools shows the request url of a socket io.
I am trying to understand more about EIO=3&transport=websocket .
I have to invoke the url from an API tool
These are query parameters that the socket.io client sends to the socket.io server as part of the initial connection request.
EIO=3, I believe, is the version number of the engine.io sub-system in socket.io. If the server is not compatible with this version number, it will likely fail the attempt to connect.
transport=websocket says that socket.io wants to use the websocket protocol as the eventual transport. socket.io has several different transports it supports including web polling and a flash-based protocol.
To connect to socket.io server, you will need a full-fledged socket.io client. You can't make a socket.io connection by just sending a URL from a tool to the server. There's a lot more involved than that in establishing a working socket.io connection.
There's a fantastic answer which goes into detail as to how REST apis work.
How do websockets work in the similar detail?
Websockets create and represent a standard for bi-directional communication between a server and client. This communication channel creates a TCP connection which is outside of HTTP and is run on a seperate server.
To start this process a handshake is performed between the server and client.
Here is the work flow
1) The user makes an HTTP request to the server with an upgrade header, indicating that the client wishes to establish a WebSocket connection.
2) If the server uses the WebSocket protocol, then it will accept the upgrade and send a response back.
3) With the handshake finished, the WebSocket protocol is used from now on. All communications will use the same underlying TCP port. The new returning status code, 101, signifies Switching Protocols.
As part of HTML5 it should work with most modern browsers.
I noticed that WSO2 5.0 released new functionality - websockets. I have familiarized a little bit with these tutorials:
WebSocket Support
I see that it is possible to send messages from client to WSO2/Backend via WebSockets, but I did not understand if revers communication is available - from WSO2 to client via WebSockets.
I would like to read the message from RabbitMQ in WSO2 ESB and send that message to the JavaScript client connected to the WSO2 via WebSocket.
I will appreciate any code examples.
Thank you in advance!
By assuming your jvascript as a web socket endpoint, you can merely use web socket sender [1] to send the message there.
[1] https://docs.wso2.com/display/ESB500/Sending+a+Message+from+a+HTTP+Client+to+a+WebSocket+Endpoint
Is it possible to setup RabbitMQ Web STOMP connection without SockJS library?
I have played around with rabbitmq-web-stomp plugin without a success as the initial response generated by the server is Welcome to SockJS! (which is obviously not a STOMP based message).
Is SockJS really required? What does it bring into the game (besides legacy browser support)?
SockJS protocol does support raw WebSocket clients under /websocket path.
Any SockJS server complying with 0.3 protocol does support a raw WebSocket url. The raw WebSocket url for the test server looks like:
ws://localhost:8081/echo/websocket
You can connect any WebSocket RFC 6455 compliant WebSocket client to this url.
This is supported by Rabbit's implementation as well. So the default endpoint is: http://example.com:15674/stomp/websocket.