yowu · July 20, 2025 12:48 · Aug 27, 2015 · Jul 28, 2015 · Jul 28, 2015 · Jul 28, 2015
diff --git a/HttpProxy.go b/HttpProxy.go
@@ -53,7 +53,7 @@ func (p *proxy) ServeHTTP(wr http.ResponseWriter, req *http.Request) {
 	log.Println(req.RemoteAddr, " ", req.Method, " ", req.URL)
 
 	if req.URL.Scheme != "http" && req.URL.Scheme != "https" {
-	  msg := "unsupported protocal scheme "+req.URL.Scheme
+	  	msg := "unsupported protocal scheme "+req.URL.Scheme
 		http.Error(wr, msg, http.StatusBadRequest)
 		log.Println(msg)
 		return

diff --git a/HttpProxy.go b/HttpProxy.go
@@ -88,7 +88,7 @@ func (p *proxy) ServeHTTP(wr http.ResponseWriter, req *http.Request) {
 }
 
 func main() {
-	var addr = flag.String("addr", ":8080", "The addr of the application.")
+	var addr = flag.String("addr", "127.0.0.1:8080", "The addr of the application.")
 	flag.Parse()
 
 	handler := &proxy{}

diff --git a/HttpProxy.go b/HttpProxy.go
@@ -6,7 +6,6 @@ import (
 	"log"
 	"net"
 	"net/http"
-	"net/url"
 	"strings"
 )
 

diff --git a/HttpProxy.go b/HttpProxy.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+// Hop-by-hop headers. These are removed when sent to the backend.
+// http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
+var hopHeaders = []string{
+	"Connection",
+	"Keep-Alive",
+	"Proxy-Authenticate",
+	"Proxy-Authorization",
+	"Te", // canonicalized version of "TE"
+	"Trailers",
+	"Transfer-Encoding",
+	"Upgrade",
+}
+
+func copyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
+func delHopHeaders(header http.Header) {
+	for _, h := range hopHeaders {
+		header.Del(h)
+	}
+}
+
+func appendHostToXForwardHeader(header http.Header, host string) {
+	// If we aren't the first proxy retain prior
+	// X-Forwarded-For information as a comma+space
+	// separated list and fold multiple headers into one.
+	if prior, ok := header["X-Forwarded-For"]; ok {
+		host = strings.Join(prior, ", ") + ", " + host
+	}
+	header.Set("X-Forwarded-For", host)
+}
+
+type proxy struct {
+}
+
+func (p *proxy) ServeHTTP(wr http.ResponseWriter, req *http.Request) {
+	log.Println(req.RemoteAddr, " ", req.Method, " ", req.URL)
+
+	if req.URL.Scheme != "http" && req.URL.Scheme != "https" {
+	  msg := "unsupported protocal scheme "+req.URL.Scheme
+		http.Error(wr, msg, http.StatusBadRequest)
+		log.Println(msg)
+		return
+	}
+
+	client := &http.Client{}
+
+	//http: Request.RequestURI can't be set in client requests.
+	//http://golang.org/src/pkg/net/http/client.go
+	req.RequestURI = ""
+
+	delHopHeaders(req.Header)
+
+	if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
+		appendHostToXForwardHeader(req.Header, clientIP)
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		http.Error(wr, "Server Error", http.StatusInternalServerError)
+		log.Fatal("ServeHTTP:", err)
+	}
+	defer resp.Body.Close()
+
+	log.Println(req.RemoteAddr, " ", resp.Status)
+
+	delHopHeaders(resp.Header)
+
+	copyHeader(wr.Header(), resp.Header)
+	wr.WriteHeader(resp.StatusCode)
+	io.Copy(wr, resp.Body)
+}
+
+func main() {
+	var addr = flag.String("addr", ":8080", "The addr of the application.")
+	flag.Parse()
+
+	handler := &proxy{}
+
+	log.Println("Starting proxy server on", *addr)
+	if err := http.ListenAndServe(*addr, handler); err != nil {
+		log.Fatal("ListenAndServe:", err)
+	}
+}