From b8bce433548600f77359ee8149daef56e0cb4eeb Mon Sep 17 00:00:00 2001
From: fghwett <1058178245@qq.com>
Date: Tue, 8 Mar 2022 15:08:20 +0800
Subject: [PATCH] gravatar reverse proxy test

---
 main.go | 128 ++++++--------------------------------------------------
 1 file changed, 13 insertions(+), 115 deletions(-)

diff --git a/main.go b/main.go
index 52e5574..9b2c869 100644
--- a/main.go
+++ b/main.go
@@ -3,126 +3,24 @@ package main
 import (
 	"fmt"
 	"net/http"
-	"regexp"
-	"strings"
+	"net/http/httputil"
+	"net/url"
 )
 
-const (
-	PREFIX = "/"
-
-	exp1 = `^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:releases|archive)\/.*$`
-	exp2 = `^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:blob|raw)\/.*$`
-	exp3 = `^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:info|git-).*$`
-	exp4 = `^(?:https?:\/\/)?raw\.(?:githubusercontent|github)\.com\/.+?\/.+?\/.+?\/.+$`
-	exp5 = `^(?:https?:\/\/)?gist\.(?:githubusercontent|github)\.com\/.+?\/.+?\/.+$`
-	exp6 = `^(?:https?:\/\/)?github\.com\/.+?\/.+?\/tags.*$`
-)
-
-func checkUrl(u string) bool {
-	for _, exp := range []string{exp1, exp2, exp3, exp4, exp5, exp6} {
-		if ok, _ := regexp.MatchString(exp, u); ok {
-			return true
-		}
-	}
-	return false
-}
-
 func fetchHandler(w http.ResponseWriter, r *http.Request) {
 	path := r.URL.Path
-	if !strings.Contains(path, "/") {
-		w.WriteHeader(http.StatusNotFound)
-		return
+
+	path = fmt.Sprintf("https://gravatar.com%s", path)
+
+	rpURL, _ := url.Parse(path)
+
+	proxy := httputil.NewSingleHostReverseProxy(rpURL)
+	director := proxy.Director
+	proxy.Director = func(r *http.Request) {
+		director(r)
+		r.Host = "gravatar.com"
 	}
-
-	path = strings.TrimPrefix(path, "/") // 获取到的URL
-	path = strings.Replace(path, "https:/", "https://", 1)
-
-	match1, _ := regexp.MatchString(exp1, path)
-	match2, _ := regexp.MatchString(exp2, path)
-	match3, _ := regexp.MatchString(exp3, path)
-	match4, _ := regexp.MatchString(exp4, path)
-	match5, _ := regexp.MatchString(exp5, path)
-	match6, _ := regexp.MatchString(exp6, path)
-
-	if match1 || match5 || match6 || match3 || match4 {
-		httpHandler(w, r, path)
-		return
-	} else if match2 {
-		path = strings.ReplaceAll(path, "/blob/", "/raw/")
-		httpHandler(w, r, path)
-		return
-	}
-
-	http.Error(w, fmt.Sprintf("%s is not support", path), http.StatusOK)
-}
-
-func httpHandler(w http.ResponseWriter, r *http.Request, pathname string) {
-	fmt.Println("Handle: ", pathname)
-	reqHdrRaw := r.Header
-
-	if r.Method == http.MethodOptions && reqHdrRaw.Get("Access-Control-Request-Headers") != "" {
-		w.Header().Set("Access-Control-Allow-Origin", "*")
-		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, TRACE, DELETE, HEAD, OPTIONS")
-		w.Header().Set("Access-Control-Max-Age", "1728000")
-		w.WriteHeader(http.StatusNoContent)
-		return
-	}
-
-	if strings.HasPrefix(pathname, "github") {
-		pathname = "https://" + pathname
-	}
-
-	client := &http.Client{
-		CheckRedirect: func(req *http.Request, via []*http.Request) error {
-			return http.ErrUseLastResponse
-		},
-	}
-
-	proxy(w, r, client, pathname)
-}
-
-func proxy(w http.ResponseWriter, r *http.Request, client *http.Client, pathname string) {
-	fmt.Println("Proxy: ", pathname, "Method: ", r.Method)
-	req, _ := http.NewRequest(r.Method, pathname, r.Body)
-	for k, v := range r.Header {
-		req.Header.Set(k, strings.Join(v, ","))
-		fmt.Println("Header: ", k, ":", strings.Join(v, ","))
-	}
-	res, e := client.Do(req)
-	if e != nil {
-		fmt.Println("Proxy Error: ", pathname, e)
-		http.Error(w, e.Error(), http.StatusOK)
-		return
-	}
-
-	if res.Header.Get("Location") != "" {
-		location := res.Header.Get("Location")
-		fmt.Println("Location: ", location)
-
-		if checkUrl(location) {
-			res.Header.Set("Location", PREFIX+location)
-		} else {
-			newReq, _ := http.NewRequest(r.Method, location, res.Body)
-			client.CheckRedirect = nil
-			proxy(w, newReq, client, location)
-			return
-		}
-	}
-
-	res.Header.Set("Access-Control-Expose-Headers", "*")
-	res.Header.Set("Access-Control-Allow-Origin", "*")
-
-	res.Header.Del("Content-Security-Policy")
-	res.Header.Del("Content-Security-Policy-Report-Only")
-	res.Header.Del("Clear-Site-Data")
-
-	for k, v := range res.Header {
-		w.Header().Set(k, strings.Join(v, ","))
-	}
-	if err := res.Write(w); err != nil {
-		fmt.Println("Write Response Error: ", pathname, err)
-	}
-	fmt.Println("result: ", res.StatusCode)
+	proxy.ServeHTTP(w, r)
 }
 
 func main() {