golang gorilla websocket例子

野性酷女 2022-05-11 13:04 205阅读 0赞

WebSocket协议是基于TCP的一种新的网络协议。它实现了浏览器与服务器全双工(full-duplex)通信——允许服务器主动发送信息给客户端。  
WebSocket通信协议于2011年被IETF定为标准RFC 6455，并被RFC7936所补充规范。

在golang语言中，目前有两种比较常用的实现方式：一个是golang自带的库，另一个是gorilla，功能强大。

golang自带库的使用例子可参考以前的博文:[Golang如何使用websocket][Golang_websocket]

本文以gorilla为例，介绍websocket的使用。

## 下载gorilla ##

# go get github.com/gorilla/websocket

下面例子中主要包括两部分，server和client。  
client部分又包括：web client(浏览器)和非web client。

## server ##

server端是一个HTTP 服务器，监听8080端口。

当接收到连接请求后，将连接使用的http协议升级为websocket协议。后续通信过程中，使用websocket进行通信。

对每个连接，server端等待读取数据，读到数据后，打印数据，然后，将数据又发送给client.

**server启动方式**

# go run server.go

server.go代码如下：

// 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.
    
    // +build ignore
    
    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.innerHTML = message; output.appendChild(d); }; 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"></div> </td></tr></table> </body> </html> `))

server output:

> recv: 2018-10-20 17:09:12.497129965 +0800 CST m=+1.010137585  
> recv: 2018-10-20 17:09:13.495602484 +0800 CST m=+2.008641088  
> recv: 2018-10-20 17:09:14.49401062 +0800 CST m=+3.007080206  
> recv: 2018-10-20 17:09:15.497114615 +0800 CST m=+4.010215329  
> recv: 2018-10-20 17:09:16.494394706 +0800 CST m=+5.007526368  
> read: websocket: close 1000 (normal)

## 非web client ##

client启动后，首先连接server。

连接建立后，主routine每一秒钟向server发送消息(当前时间)。

另一个routine从server接收数据,并打印。

当client退出时，会向server发送关闭消息。接着，等待退出。

**client启动方式**

# go run client.go

client代码如下:

// 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.
    
    // +build ignore
    
    package main
    
    import (
    	"flag"
    	"log"
    	"net/url"
    	"os"
    	"os/signal"
    	"time"
    
    	"github.com/gorilla/websocket"
    )
    
    var addr = flag.String("addr", "localhost:8080", "http service address")
    
    func main() { 
    	flag.Parse()
    	log.SetFlags(0)
    
    	interrupt := make(chan os.Signal, 1)
    	signal.Notify(interrupt, os.Interrupt)
    
    	u := url.URL{ Scheme: "ws", Host: *addr, Path: "/echo"}
    	log.Printf("connecting to %s", u.String())
    
    	c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
    	if err != nil { 
    		log.Fatal("dial:", err)
    	}
    	defer c.Close()
    
    	done := make(chan struct{ })
    
    	go func() { 
    		defer close(done)
    		for { 
    			_, message, err := c.ReadMessage()
    			if err != nil { 
    				log.Println("read:", err)
    				return
    			}
    			log.Printf("recv: %s", message)
    		}
    	}()
    
    	ticker := time.NewTicker(time.Second)
    	defer ticker.Stop()
    
    	for { 
    		select { 
    		case <-done:
    			return
    		case t := <-ticker.C:
    			err := c.WriteMessage(websocket.TextMessage, []byte(t.String()))
    			if err != nil { 
    				log.Println("write:", err)
    				return
    			}
    		case <-interrupt:
    			log.Println("interrupt")
    
    			// Cleanly close the connection by sending a close message and then
    			// waiting (with timeout) for the server to close the connection.
    			err := c.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
    			if err != nil { 
    				log.Println("write close:", err)
    				return
    			}
    			select { 
    			case <-done:
    			case <-time.After(time.Second):
    			}
    			return
    		}
    	}
    }

client output:

> connecting to ws://localhost:8080/echo  
> recv: 2018-10-20 17:09:12.497129965 +0800 CST m=+1.010137585  
> recv: 2018-10-20 17:09:13.495602484 +0800 CST m=+2.008641088  
> recv: 2018-10-20 17:09:14.49401062 +0800 CST m=+3.007080206  
> recv: 2018-10-20 17:09:15.497114615 +0800 CST m=+4.010215329  
> recv: 2018-10-20 17:09:16.494394706 +0800 CST m=+5.007526368  
> ^Cinterrupt  
> read: websocket: close 1000 (normal)

## web client ##

web client，也就是使用浏览器。  
在浏览器中输入http://127.0.0.1:8080

![浏览器][70]

“Open”，然后"send"

server output:

> recv: Hello world!

## 参考 ##

百度百科

[https://baike.baidu.com/item/WebSocket][https_baike.baidu.com_item_WebSocket]

github

[https://github.com/gorilla/websocket][https_github.com_gorilla_websocket]

doc

[https://godoc.org/github.com/gorilla/websocket][https_godoc.org_github.com_gorilla_websocket]

example

[https://github.com/gorilla/websocket/blob/master/examples/][https_github.com_gorilla_websocket_blob_master_examples]

[Golang_websocket]: https://blog.csdn.net/lanyang123456/article/details/80712275
[70]: /images/20220505/a642fb8e8d8f41f4878b0c5c9cb5d168.png
[https_baike.baidu.com_item_WebSocket]: https://baike.baidu.com/item/WebSocket
[https_github.com_gorilla_websocket]: https://github.com/gorilla/websocket
[https_godoc.org_github.com_gorilla_websocket]: https://godoc.org/github.com/gorilla/websocket
[https_github.com_gorilla_websocket_blob_master_examples]: https://github.com/gorilla/websocket/blob/master/examples/