GO語言HTTPProxy 伺服器

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

package mainimport ("fmt""io""log""net/http""net/http/httputil""net/url")func httpUserInfo(w http.ResponseWriter, r *http.Request) {ret := "your addr is:" + r.RemoteAddr + "\r\n"ret += "request headers:" + fmt.Sprint(r.Header)io.WriteString(w, ret)}func main() {targetURL, err := url.Parse("http://127.0.0.1:80")log.Println("program start......")if err != nil {log.Println("bad url:", err)return}httpProxy := httputil.NewSingleHostReverseProxy(targetURL)http.HandleFunc("/myinfo/", httpUserInfo)http.Handle("/", httpProxy)log.Println("listen http proxy on :8001.....")http.ListenAndServe(":8001", nil)}

以上代碼有個缺陷，就是通過HTTP代理後HTTP協議頭的Host域不會改變，如代理到 www.qq.com,抓包時:

GET / HTTP/1.1
Host: 127.0.0.1:8001
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
Accept: text/html, application/xhtml+xml, */*
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN
X-Forwarded-For: 192.168.20.155

在伺服器沒有檢查host域的時候用這種方式代理最簡單。如果檢查host域的網站就自己修改包裡面的實現或自己處理http包頭，也簡單。