网络代理【3】Golang实现简单的反向代理

￡神魔★判官ぃ 2023-07-11 15:06 52阅读 0赞

*  一、创建资源服务器(RealServer)
 *  二、创建代理服务器(Proxy)
 *  三、测试

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\*\* 一、创建资源服务器(RealServer)\*\*

type RealServer struct { 
    	Addr string
    }
    
    func (r *RealServer) Run() { 
    	mux := http.NewServeMux()
    	mux.HandleFunc("/", func(rw http.ResponseWriter, req *http.Request) { 
    		req.Header.Set("X-Forwarded-For", req.RemoteAddr)
    		backend := fmt.Sprintf("Backend=http://%s%s?%s\n", r.Addr, req.URL.Path, req.URL.RawQuery)
    		realIP := fmt.Sprintf("RemoteAddr=%s,X-Forwarded-For=%v,X-Real-Ip=%v\n", req.RemoteAddr, req.Header.Get("X-Forwarded-For"), req.Header.Get("X-Real-Ip"))
    		header := fmt.Sprintf("Headers =%v\n", req.Header)
    		io.WriteString(rw, backend)
    		io.WriteString(rw, realIP)
    		io.WriteString(rw, header)
    	})
    	mux.HandleFunc("/error", func(rw http.ResponseWriter, req *http.Request) { 
    		rw.WriteHeader(500)
    		io.WriteString(rw, "error handler")
    	})
    	server := &http.Server{ Addr: r.Addr, Handler: mux, WriteTimeout: time.Second * 3}
    	go func() { 
    		log.Fatal(server.ListenAndServe())
    	}()
    	log.Println("Starting httpserver at " + r.Addr)
    }
    
    func main() { 
    	server1 := &RealServer{ Addr: "172.*.*.249:8081"}
    	server2 := &RealServer{ Addr: "172.*.*.249:6061"}
    	server1.Run()
    	server2.Run()
    	//监听关闭信号
    	quit := make(chan os.Signal)
    	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
    	<-quit
    }

**二、创建代理服务器(Proxy)**

var realAddr, proxyAddr = "http://172.*.*.248:8081", "172.*.*.249:3000"
    
    func ProxyHandler(rw http.ResponseWriter, req *http.Request) { 
    	// 0.浅拷贝请求对象组装新请求体
    	var newReq = new(http.Request)
    	*newReq = *req
    	proxy, _ := url.Parse(realAddr)
    	newReq.URL.Scheme = proxy.Scheme
    	newReq.URL.Host = proxy.Host
    	newReq.Header.Set("X-Real-Ip", proxy.Host)
    
    	// 1.请求后端资源
    	transport := http.DefaultTransport
    	resp, err := transport.RoundTrip(newReq)
    
    	// 2.回写客户端
    	if err != nil { 
    		rw.WriteHeader(http.StatusBadGateway)
    		log.Println(err)
    		return
    	}
    	defer resp.Body.Close()
    	for k, v := range resp.Header { 
    		for _, vv := range v { 
    			rw.Header().Add(k, vv)
    		}
    	}
    	io.Copy(rw, resp.Body) // 或者bufio.NewReader(resp.Body).WriteTo(rw)
    }
    
    func main() { 
    	http.HandleFunc("/", ProxyHandler)
    	log.Print("start proxy server on: ", proxyAddr)
    	log.Fatal(http.ListenAndServe(proxyAddr, nil))
    }

**三、测试**  
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