feat: proxy rotation for 9proxy.com

.env.example

@@ -0,0 +1,5 @@
+PROXY_USER=user-ssid-
+PROXY_PASS=123
+PROXY_HOST=localhost
+PROXY_PORT=8080
+PORT=80

.gitignore

@@ -1 +1,2 @@
 /pp
+.env

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"crypto/rand"
 	"encoding/base64"
 	"fmt"
 	"io"
@@ -11,9 +12,18 @@ import (
 	"net/url"
 	"os"
 	"strings"
+	"sync/atomic"
 	"time"
 )
 
+var (
+	proxyUser     string
+	proxyPass     string
+	proxyHost     string
+	sessionID     string
+	rotateCounter atomic.Int64
+)
+
 func getEnvDefault(name, def string) string {
 	v := os.Getenv(name)
 	if v != "" {
@@ -22,37 +32,85 @@ func getEnvDefault(name, def string) string {
 	return def
 }
 
-func parseProxy() *url.URL {
-	raw := strings.TrimPrefix(strings.TrimSpace(os.Getenv("PROXY")), "http://")
-	if raw == "" {
-		log.Fatal("missing PROXY (format: login:password@ip:port)")
+func generateSessionID(length int) string {
+	b := make([]byte, length)
+	if _, err := rand.Read(b); err != nil {
+		log.Fatalf("failed to generate session ID: %v", err)
 	}
-
-	creds, hostPort, ok := strings.Cut(raw, "@")
-	if !ok {
-		log.Fatal("expected login:password@ip:port")
-	}
-
-	login, password, ok := strings.Cut(creds, ":")
-	if !ok || strings.TrimSpace(login) == "" || strings.TrimSpace(password) == "" {
-		log.Fatal("expected login:password before @")
-	}
-
-	hostPort = strings.TrimSpace(hostPort)
-	if _, _, err := net.SplitHostPort(hostPort); err != nil {
-		log.Fatalf("invalid ip:port: %v", err)
-	}
-
-	return &url.URL{Scheme: "http", User: url.UserPassword(login, password), Host: hostPort}
+	return base64.RawURLEncoding.EncodeToString(b)[:length]
 }
 
-func proxyHandler(transport *http.Transport, upstream *url.URL) http.HandlerFunc {
+func getUpstreamURL() *url.URL {
+	counter := rotateCounter.Load()
+	user := fmt.Sprintf("%s%s%d", proxyUser, sessionID, counter)
+	return &url.URL{
+		Scheme: "http",
+		User:   url.UserPassword(user, proxyPass),
+		Host:   proxyHost,
+	}
+}
+
+func parseProxyConfig() {
+	proxyUser = os.Getenv("PROXY_USER")
+	if proxyUser == "" {
+		log.Fatal("missing PROXY_USER")
+	}
+
+	proxyPass = os.Getenv("PROXY_PASS")
+	if proxyPass == "" {
+		log.Fatal("missing PROXY_PASS")
+	}
+
+	proxyHost = os.Getenv("PROXY_HOST")
+	if proxyHost == "" {
+		log.Fatal("missing PROXY_HOST")
+	}
+
+	port := os.Getenv("PROXY_PORT")
+	if port == "" {
+		log.Fatal("missing PROXY_PORT")
+	}
+	proxyHost = net.JoinHostPort(proxyHost, port)
+
+	sessionID = generateSessionID(11)
+	rotateCounter.Store(0)
+}
+
+func getCurrentIP() string {
+	upstream := getUpstreamURL()
+	transport := &http.Transport{Proxy: http.ProxyURL(upstream)}
+	client := &http.Client{Transport: transport, Timeout: 10 * time.Second}
+
+	resp, err := client.Get("https://checkip.amazonaws.com")
+	if err != nil {
+		return fmt.Sprintf("error: %v", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return fmt.Sprintf("error reading: %v", err)
+	}
+	return strings.TrimSpace(string(body))
+}
+
+func proxyHandler() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		if r.URL.Path == "/health" {
+		switch r.URL.Path {
+		case "/health":
 			w.Write([]byte("ok"))
 			return
+		case "/rotate":
+			newCounter := rotateCounter.Add(1)
+			ip := getCurrentIP()
+			log.Printf("Rotated to counter=%d, IP=%s", newCounter, ip)
+			w.Write([]byte(fmt.Sprintf("%s\n", ip)))
+			return
 		}
 
+		upstream := getUpstreamURL()
+		transport := &http.Transport{Proxy: http.ProxyURL(upstream)}
+
 		if r.Method == http.MethodConnect {
 			handleTunneling(w, r, upstream)
 			return
@@ -173,10 +231,10 @@ func copyHeader(dst, src http.Header) {
 
 func main() {
 	listenAddr := ":" + getEnvDefault("PORT", "80")
-	upstream := parseProxy()
+	parseProxyConfig()
 
-	transport := &http.Transport{Proxy: http.ProxyURL(upstream)}
-
-	log.Printf("Proxy running on %s -> http://%s@%s", listenAddr, upstream.User.Username(), upstream.Host)
-	log.Fatal(http.ListenAndServe(listenAddr, proxyHandler(transport, upstream)))
+	upstream := getUpstreamURL()
+	ip := getCurrentIP()
+	log.Printf("started listen=%s upstream=http://%s ip=%s", listenAddr, upstream.Host, ip)
+	log.Fatal(http.ListenAndServe(listenAddr, proxyHandler()))
 }