[Go language] WebSocket Usage Demo

This is a creation in Article, where the information may have evolved or changed.

HTML section

Place a button and a text box on the Web page that is used to send information to the server, which is used to display messages returned from the server.

<! DOCTYPE html>


WebSocket Part


Window.onload = Main;var ws;function main () {    var obtn = document.getElementById (' btn1 ');    Obtn.onclick = OnButton1;} function OnButton1 () {    ws = new WebSocket (' Ws://localhost/ws ');    Ws.onopen = OnOpen;    Ws.onmessage = OnMessage;} function OnOpen (event) {    ws.send (' Hello WebSocket ');} function OnMessage (event) {    var otxt = document.getElementById (' txt1 ');    Otxt.value = Event.data;};


Back-end Section

To handle WebSocket requests, you must have a

Func (*websocket. Conn)
Types of processing functions, such as:


Func onwebsocket (ws *websocket. Conn) {defer ws. Close () var err errorvar str stringfor {if err = WebSocket. Message.receive (WS, &STR); Err! = Nil {break} else {fmt. Println ("Received from client:", str)}str = "Hello, I ' m server." If Err = WebSocket. Message.send (WS, STR); Err! = Nil {break} else {fmt. Println ("Send to Client:", str)}}}

Then correspond with a URL:


http. Handle ("/ws", WebSocket. Handler (Onwebsocket))

The complete code is as follows:


Package Mainimport ("bytes" "Errors" "FMT" "Html/template" "Net/http" "Runtime" "Golang.org/x/net/websocket")//Port const (Http_port string = "Https_port string =" 443 ")//directory const (Css_client_path ="/css/"Dart_client_path ="/js/"Image_ Client_path = "/image/" Css_svr_path = "web" Dart_svr_path = "web" Image_svr_path = "web") Func init () {runtime. Gomaxprocs (runtime. NUMCPU ())}func main () {//the CSS and Scripting Services go to HTTP first. Handle (Css_client_path, HTTP. Fileserver (http. Dir (Css_svr_path))) HTTP. Handle (Dart_client_path, HTTP. Fileserver (http. Dir (Dart_svr_path))//URL corresponds to the processing logic HTTP. Handlefunc ("/", homepage) http. Handle ("/ws", WebSocket. Handler (Onwebsocket))//start service ERR: = http. Listenandserve (":" +http_port, nil) if err! = Nil {fmt. Println ("Service failed//", err)}}func Writetemplatetohttpresponse (res http. Responsewriter, T *template. Template) Error {if T = = Nil | | res = = NIL {return errors. New ("Writetemplatetohttpresponse:t must not being nil.")} var buf bytes. Buffererr: = T.execute (&buf, nil) if err! = Nil {return err}res. Header (). Set ("Content-type", "text/html; Charset=utf-8 ") _, Err = Res. Write (BUF. Bytes ()) Return Err}func homepage (res http. Responsewriter, req *http. Request) {T, err: = template. Parsefiles ("web/loli.html") if err! = Nil {fmt. PRINTLN (err) Return}err = Writetemplatetohttpresponse (res, t) if err! = Nil {fmt. PRINTLN (Err) return}}func onwebsocket (ws *websocket. Conn) {defer ws. Close () var err errorvar str stringfor {if err = WebSocket. Message.receive (WS, &AMP;STR); Err! = Nil {break} else {fmt. Println ("Received from client:", str)}str = "Hello, I ' m server." If Err = WebSocket. Message.send (WS, STR); Err! = Nil {break} else {fmt. Println ("Send to Client:", str)}}}