增加基础正向代理实现

proxy/config.go

@@ -0,0 +1,20 @@
+// Package proxy ...
+//
+// Description : 代理转发的配置
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 2021-08-06 3:34 下午
+package proxy
+
+// Server 服务器配置
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 3:34 下午 2021/8/6
+type Server struct {
+	Scheme        string            // 转发scheme
+	Host          string            // 服务器地址
+	URI           string            // 转发接口
+	RewriteHeader map[string]string // 重写header
+}

proxy/forward.go

@@ -0,0 +1,66 @@
+// Package proxy...
+//
+// Description : 正向代理的实现
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 2021-08-06 2:07 下午
+package proxy
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+)
+
+// Forward 正向代理的实现
+//
+// Author : go_developer@163.com<白茶清欢>
+//
+// Date : 2:08 下午 2021/8/6
+func Forward(rw http.ResponseWriter, req *http.Request, serverConfig *Server) {
+	fmt.Printf("Received request %s %s %s\n", req.Method, req.Host, req.RemoteAddr)
+
+	transport := http.DefaultTransport
+
+	// step 1
+	outReq := new(http.Request)
+	*outReq = *req // this only does shallow copies of maps
+
+	if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
+		if prior, ok := outReq.Header["X-Forwarded-For"]; ok {
+			clientIP = strings.Join(prior, ", ") + ", " + clientIP
+		}
+		outReq.Header.Set("X-Forwarded-For", clientIP)
+	}
+
+	// 写入重写的请求Header
+	for k, v := range serverConfig.RewriteHeader {
+		outReq.Header.Set(k, v)
+	}
+
+	// 重写请求地址
+	outReq.Host = serverConfig.Host
+	outReq.URL.Path = serverConfig.URI
+	outReq.URL.Scheme = serverConfig.Scheme
+	outReq.URL.Host = serverConfig.Host
+	// step 2
+	res, err := transport.RoundTrip(outReq)
+	if err != nil {
+		rw.WriteHeader(http.StatusBadGateway)
+		return
+	}
+
+	// step 3
+	for key, value := range res.Header {
+		for _, v := range value {
+			rw.Header().Add(key, v)
+		}
+	}
+
+	rw.WriteHeader(res.StatusCode)
+	io.Copy(rw, res.Body)
+	res.Body.Close()
+}