first versiom

main.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+)
+
+const (
+	PREFIX = "https://gh.ncc.cx/"
+
+	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, e := regexp.MatchString(exp, u); ok {
+			return true
+		} else if e != nil {
+			fmt.Println(e)
+		}
+	}
+	return false
+}
+
+func fetchHandler(w http.ResponseWriter, r *http.Request) {
+	path := r.URL.Path
+	if !strings.Contains(path, "/") {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+
+	path = strings.TrimPrefix(path, "/") // 获取到的URL
+	path = strings.Replace(path, "https:/", "https://", 1)
+
+	u, _ := url.Parse(path)
+
+	match1, _ := regexp.MatchString(exp1, u.String())
+	match2, _ := regexp.MatchString(exp2, u.String())
+	match3, _ := regexp.MatchString(exp3, u.String())
+	match4, _ := regexp.MatchString(exp4, u.String())
+	match5, _ := regexp.MatchString(exp5, u.String())
+	match6, _ := regexp.MatchString(exp6, u.String())
+
+	if match1 || match5 || match6 || match3 || match4 {
+		httpHandler(w, r, path)
+		return
+	} else if match2 {
+		path = strings.ReplaceAll(u.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) {
+	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) {
+	r.URL, _ = url.Parse(pathname)
+	req, _ := http.NewRequest(r.Method, r.URL.String(), r.Body)
+	for k, v := range r.Header {
+		req.Header.Set(k, v[0])
+	}
+	for _, value := range r.Cookies() {
+		w.Header().Add(value.Name, value.Value)
+	}
+	res, e := client.Do(req)
+	if e != nil {
+		http.Error(w, e.Error(), http.StatusOK)
+		return
+	}
+
+	if res.Header.Get("location") != "" {
+		location := res.Header.Get("location")
+		if checkUrl(location) {
+			res.Header.Set("location", PREFIX+location)
+		} else {
+			newReq, _ := http.NewRequest(r.Method, location, res.Body)
+			proxy(w, newReq, http.DefaultClient, 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")
+
+	w.WriteHeader(res.StatusCode)
+	for k, v := range res.Header {
+		w.Header().Set(k, strings.Join(v, ","))
+	}
+	_ = res.Write(w)
+}
+
+func main() {
+	http.HandleFunc("/", fetchHandler)
+
+	err := http.ListenAndServe(fmt.Sprintf(":%d", 8091), nil)
+	if err != nil {
+		fmt.Println("run server error: ", err)
+		return
+	}
+}