johnstcn · June 13, 2022 15:08
diff --git a/wsecho.go b/wsecho.go
 // This is lifted directly from https://github.com/gorilla/websocket/blob/master/examples/echo/server.go
 // without the build:ignore directives

 // Copyright 2015 The Gorilla WebSocket Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package main

 import (
 	"flag"
 	"html/template"
 	"log"
 	"net/http"

 	"github.com/gorilla/websocket"
 )

 var addr = flag.String("addr", "localhost:8080", "http service address")

 var upgrader = websocket.Upgrader{} // use default options

 func echo(w http.ResponseWriter, r *http.Request) {
 	c, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
 		log.Print("upgrade:", err)
 		return
 	}
 	defer c.Close()
 	for {
 		mt, message, err := c.ReadMessage()
 		if err != nil {
 			log.Println("read:", err)
 			break
 		}
 		log.Printf("recv: %s", message)
 		err = c.WriteMessage(mt, message)
 		if err != nil {
 			log.Println("write:", err)
 			break
 		}
 	}
 }

 func home(w http.ResponseWriter, r *http.Request) {
 	homeTemplate.Execute(w, "ws://"+r.Host+"/echo")
 }

 func main() {
 	flag.Parse()
 	log.SetFlags(0)
 	http.HandleFunc("/echo", echo)
 	http.HandleFunc("/", home)
 	log.Fatal(http.ListenAndServe(*addr, nil))
 }

 var homeTemplate = template.Must(template.New("").Parse(`
 <!DOCTYPE html>
 <html>
 <head>
 <meta charset="utf-8">
 <script>  
 window.addEventListener("load", function(evt) {

    var output = document.getElementById("output");
    var input = document.getElementById("input");
    var ws;

    var print = function(message) {
        var d = document.createElement("div");
        d.textContent = message;
        output.appendChild(d);
        output.scroll(0, output.scrollHeight);
    };

    document.getElementById("open").onclick = function(evt) {
        if (ws) {
            return false;
        }
        ws = new WebSocket("{{.}}");
        ws.onopen = function(evt) {
            print("OPEN");
        }
        ws.onclose = function(evt) {
            print("CLOSE");
            ws = null;
        }
        ws.onmessage = function(evt) {
            print("RESPONSE: " + evt.data);
        }
        ws.onerror = function(evt) {
            print("ERROR: " + evt.data);
        }
        return false;
    };

    document.getElementById("send").onclick = function(evt) {
        if (!ws) {
            return false;
        }
        print("SEND: " + input.value);
        ws.send(input.value);
        return false;
    };

    document.getElementById("close").onclick = function(evt) {
        if (!ws) {
            return false;
        }
        ws.close();
        return false;
    };

 });
 </script>
 </head>
 <body>
 <table>
 <tr><td valign="top" width="50%">
 <p>Click "Open" to create a connection to the server, 
 "Send" to send a message to the server and "Close" to close the connection. 
 You can change the message and send multiple times.
 <p>
 <form>
 <button id="open">Open</button>
 <button id="close">Close</button>
 <p><input id="input" type="text" value="Hello world!">
 <button id="send">Send</button>
 </form>
 </td><td valign="top" width="50%">
 <div id="output" style="max-height: 70vh;overflow-y: scroll;"></div>
 </td></tr></table>
 </body>
 </html>
 `))
	// This is lifted directly from https://github.com/gorilla/websocket/blob/master/examples/echo/server.go
	// without the build:ignore directives

	// Copyright 2015 The Gorilla WebSocket Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package main

	import (
	"flag"
	"html/template"
	"log"
	"net/http"

	"github.com/gorilla/websocket"
	)

	var addr = flag.String("addr", "localhost:8080", "http service address")

	var upgrader = websocket.Upgrader{} // use default options

	func echo(w http.ResponseWriter, r *http.Request) {
	c, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
	log.Print("upgrade:", err)
	return
	}
	defer c.Close()
	for {
	mt, message, err := c.ReadMessage()
	if err != nil {
	log.Println("read:", err)
	break
	}
	log.Printf("recv: %s", message)
	err = c.WriteMessage(mt, message)
	if err != nil {
	log.Println("write:", err)
	break
	}
	}
	}

	func home(w http.ResponseWriter, r *http.Request) {
	homeTemplate.Execute(w, "ws://"+r.Host+"/echo")
	}

	func main() {
	flag.Parse()
	log.SetFlags(0)
	http.HandleFunc("/echo", echo)
	http.HandleFunc("/", home)
	log.Fatal(http.ListenAndServe(*addr, nil))
	}

	var homeTemplate = template.Must(template.New("").Parse(`
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<script>
	window.addEventListener("load", function(evt) {

	var output = document.getElementById("output");
	var input = document.getElementById("input");
	var ws;

	var print = function(message) {
	var d = document.createElement("div");
	d.textContent = message;
	output.appendChild(d);
	output.scroll(0, output.scrollHeight);
	};

	document.getElementById("open").onclick = function(evt) {
	if (ws) {
	return false;
	}
	ws = new WebSocket("{{.}}");
	ws.onopen = function(evt) {
	print("OPEN");
	}
	ws.onclose = function(evt) {
	print("CLOSE");
	ws = null;
	}
	ws.onmessage = function(evt) {
	print("RESPONSE: " + evt.data);
	}
	ws.onerror = function(evt) {
	print("ERROR: " + evt.data);
	}
	return false;
	};

	document.getElementById("send").onclick = function(evt) {
	if (!ws) {
	return false;
	}
	print("SEND: " + input.value);
	ws.send(input.value);
	return false;
	};

	document.getElementById("close").onclick = function(evt) {
	if (!ws) {
	return false;
	}
	ws.close();
	return false;
	};

	});
	</script>
	</head>
	<body>
	<table>
	<tr><td valign="top" width="50%">
	<p>Click "Open" to create a connection to the server,
	"Send" to send a message to the server and "Close" to close the connection.
	You can change the message and send multiple times.
	<p>
	<form>
	<button id="open">Open</button>
	<button id="close">Close</button>
	<p><input id="input" type="text" value="Hello world!">
	<button id="send">Send</button>
	</form>
	</td><td valign="top" width="50%">
	<div id="output" style="max-height: 70vh;overflow-y: scroll;"></div>
	</td></tr></table>
	</body>
	</html>
	`))