golang代理websocket请求

基础：

golang websocket github地址:

GitHub - gorilla/websocket: A fast, well-tested and widely used WebSocket implementation for Go.

github库官方文档:

websocket package - github.com/gorilla/websocket - Go Packages

golang websocket运行机制以及原理：

https://www.jianshu.com/p/65ef71ddb910

golang websocket在线测试地址：

websocket在线测试

golang websocket官方客户端以及服务端demo:

websocket/examples/echo at master · gorilla/websocket · GitHub

golang websocket http代理实现:

主要在http代理的基础上（见上一篇博客http代理：golang实现http(s)代理_GT19930910的博客-CSDN博客_golang http 代理），检查是否有http头中带有Upgrade字段的，如果有则说明是websocket请求需要作相应的协议升级，具体细节在代码中呈现遇到的坑也在代码中有详细说明。此处代理的https请求(http请求不会自动302跳转)以及wss请求(wss比ws更加复杂一些需要跳过证书)。

package main
import (//"fmt""net/http""io/ioutil""strings""io""crypto/tls""net/url""github.com/gorilla/websocket"
)type HttpProxyHandle struct {
}//类似一个c++类，里面的属性初始化的时候是是可以赋值的
var upgrader = websocket.Upgrader {//此处给CheckOrigin默认一个返回true保证，否则会出现报错自动跳转CheckOrigin: func(r *http.Request) bool {return true},
} // use default optionsfunc (h *HttpProxyHandle) ServeHTTP(w http.ResponseWriter, req *http.Request) {config := getConfig()body, err := ioutil.ReadAll(req.Body)if err != nil {//mainLog.Println("body = NULL:", err.Error())//return,没有数据也是可以的，不需要直接结束}//debugLog.Printf("new HttpProxy:")//fmt.Printf("\nmethod:%s Host:%s RemoteAddr:%s URL:%s, bodycount:%d\n", req.Method, req.Host, req.RemoteAddr, req.URL.String(), len(body))//debugLog.Printf("target server addr:%s\n", config.HttpProxy[0].Server[0])//fmt.Println("send to target server:", config.HttpProxy[0].Server[0])//for k, v := range req.Header {//fmt.Println(k, v[0])//}//此处检测到websocket请求if req.Header.Get("Upgrade") != "" {/************进行协议升级************/upgrader.Subprotocols = []string{req.Header.Get("Sec-WebSocket-Protocol")}//upgrader.Upgrade内部会返回握手信息，我们做代理需要将dialer.Dial客户端收到的下层返回的握手信息返回给上层，源码Upgrade函数中将//Sec-WebSocket-Protocol这个头去掉了，所以我们给加上,保证在upgrader.Upgrade调用的上方加上//func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header) (*Conn, error) {}//upgrader.Subprotocols是属性，upgrader.Upgrade是方法，属性可以初始化，方法在函数定义前进行关联//具体实现在 https://github.com/gorilla/websocket/blob/master/server.goc_this, err := upgrader.Upgrade(w, req, nil)if err != nil {debugLog.Println("upgrade:", err)return}defer c_this.Close()/******************启动websocket转发客户端*********///此处使用req.URL.Path+req.URL.RawQuer代替 req.URL.String()是因为使用后者之后下面的u.String()使用url加密，导致url错误造成404u := url.URL{Scheme: "wss", Host: config.HttpProxy[0].Server[0], Path: req.URL.Path, RawQuery: req.URL.RawQuery}debugLog.Printf("connecting to %s\n", u.String())//添加头部的时候不能照搬，需要去掉几个固有的，因为库里面已经给你加了，所以代理的时候把重复的去掉，详见源码219行//https://github.com/gorilla/websocket/blob/master/client.goheaders := make(http.Header)for k, v := range req.Header {if k == "Upgrade" ||k == "Connection" ||k == "Sec-Websocket-Key" ||k == "Sec-Websocket-Version" ||k == "Sec-Websocket-Extensions"{} else {headers.Set(k, v[0])//fmt.Println("set ==>", k, v[0])}}dialer := websocket.Dialer{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}}c_to_next, resp, err := dialer.Dial(u.String(), headers)if err != nil {debugLog.Println("dial:", err)debugLog.Println("StatusCode:", resp.StatusCode)}//fmt.Println(resp.Header)defer c_to_next.Close()/*****************接收返回并转回给浏览器*******************/go func() {debugLog.Println("run read from next proc")for {mt, message, err := c_to_next.ReadMessage()if err != nil {debugLog.Println("read from next:", err)break}//fmt.Println("read from next:", message)err = c_this.WriteMessage(mt, message)if err != nil {debugLog.Println("write to priv:", err)break}}}()/*****************接收浏览器信息并转发*******************///此处不能再协程了，否则会defer c_to_next.Close()debugLog.Println("run read from priv proc")for {mt1, message1, err1 := c_this.ReadMessage()if err1 != nil {debugLog.Println("read from priv:", err1)break}//fmt.Println("read from priv:", message1)err1 = c_to_next.WriteMessage(mt1, message1)if err1 != nil {debugLog.Println("write to next:", err1)break}}/********************************************/return}tr := &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true},}cli := &http.Client{Transport:tr}reqUrl := "https://" + config.HttpProxy[0].Server[0] + req.URL.String()proxy_req, err := http.NewRequest(req.Method, reqUrl, strings.NewReader(string(body)))if err != nil {debugLog.Println("http.NewRequest(to target server addr):", err.Error())return}//type Header map[string][]stringfor k, v := range req.Header {proxy_req.Header.Set(k, v[0])//debugLog.Println(k, v[0])}countSplit := strings.Split(config.HttpProxy[0].HeadExtend, ",")for _, v1 := range countSplit {countSplit := strings.Split(v1, ":")proxy_req.Header.Add(countSplit[0], countSplit[1])//debugLog.Printf("HeadExtend %s:%s\n", countSplit[0], countSplit[1])}res, err := cli.Do(proxy_req)if err != nil {debugLog.Println("cli.Do(req):", err.Error())return}defer res.Body.Close()for k, v := range res.Header {w.Header().Set(k, v[0])//dbeugLog.Println(k, v[0])}io.Copy(w, res.Body)
}func startHttpProxy() {c := getConfig()for _, v := range c.HttpProxy {debugLog.Printf("new HttpProxy. listening%s target:%s\n", v.ListenAddr, v.Server[0])s := &http.Server{Addr: v.ListenAddr,Handler: &HttpProxyHandle{},}go func() {mainLog.Fatal(s.ListenAndServeTLS(c.HttpApi.CrtFile, c.HttpApi.KeyFile))}()}
}