Golang : Serving HTTP and Websocket from different ports in a program example
Problem:
For some reason you want to split the port use by your program to serve HTTP and Web-socket traffic. How to write one program that is able to listen and serve HTTP/Web-socket traffics on different ports?
Solution:
Setup a http.NewServeMux()
and http.ListenAndServe()
for one port and launch it as go-routine. For example, one go-routine for handling web socket traffic and main routine in the program to handle HTTP traffic.
NOTE : Instead of web-socket, can you use for another HTTP server? Yes, of course.
Here you go!
package main
import (
"fmt"
"golang.org/x/net/websocket"
"io"
"net/http"
)
func homeHandler(w http.ResponseWriter, r *http.Request) {
html := `<!DOCTYPE html>
<html>
<head>
<title>One HTTP and Websocket serve with different ports example</title>
<script src="http://code.jquery.com/jquery-1.11.3.min.js"></script>
<script>
$(function() {
var ws = new WebSocket("ws://localhost:8082/"); // use port 8082 instead of 8080
var $ul = $('#msg-list');
$('#sendBtn').click(function(){
var data = $('#name').val();
ws.send(data);
console.log("Sending data to HTTP server via Websocket via port 8082 :" + data);
$('<li>').text(data).appendTo($ul);
});
});
</script>
</head>
<body>
<input id="name" type="text" />
<input type="button" id="sendBtn" value="send"></input>
<ul id="msg-list"></ul>
</body></html>`
w.Write([]byte(fmt.Sprintf(html)))
}
func wsHandler(ws *websocket.Conn) {
fmt.Println("Receive data from : ", ws.LocalAddr())
fmt.Println("Sending data to : ", ws.RemoteAddr())
// echo back
io.Copy(ws, ws)
}
func main() {
mxWS := http.NewServeMux()
mxWS.Handle("/", websocket.Handler(wsHandler))
fmt.Println("Listen and serve websocket on :8082")
go func() {
http.ListenAndServe(":8082", mxWS)
}()
mxHTTP := http.NewServeMux()
mxHTTP.HandleFunc("/", homeHandler)
fmt.Println("Listen and serve HTTP on :8080")
http.ListenAndServe(":8080", mxHTTP)
}
Run the code and point your browser to http://localhost:8080
. Open up the developer view to see the console messages.
References:
https://www.socketloop.com/tutorials/golang-web-javascript-to-server-side-websocket-example
By Adam Ng
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