Fixed: #2034

feat(proxy): centralize proxy handling with `proxyutil` package and enhance test coverage

- Added `proxyutil` package to simplify proxy handling across the codebase.
- Refactored various components (`executor`, `cliproxy`, `auth`, etc.) to use `proxyutil` for consistent and reusable proxy logic.
- Introduced support for "direct" proxy mode to explicitly bypass all proxies.
- Updated tests to validate proxy behavior (e.g., `direct`, HTTP/HTTPS, and SOCKS5).
- Enhanced YAML configuration documentation for proxy options.

sdk/cliproxy/rtprovider.go

@@ -1,16 +1,13 @@
 package cliproxy
 
 import (
-	"context"
-	"net"
 	"net/http"
-	"net/url"
 	"strings"
 	"sync"
 
 	coreauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
+	"github.com/router-for-me/CLIProxyAPI/v6/sdk/proxyutil"
 	log "github.com/sirupsen/logrus"
-	"golang.org/x/net/proxy"
 )
 
 // defaultRoundTripperProvider returns a per-auth HTTP RoundTripper based on
@@ -39,35 +36,12 @@ func (p *defaultRoundTripperProvider) RoundTripperFor(auth *coreauth.Auth) http.
 	if rt != nil {
 		return rt
 	}
-	// Parse the proxy URL to determine the scheme.
-	proxyURL, errParse := url.Parse(proxyStr)
-	if errParse != nil {
-		log.Errorf("parse proxy URL failed: %v", errParse)
+	transport, _, errBuild := proxyutil.BuildHTTPTransport(proxyStr)
+	if errBuild != nil {
+		log.Errorf("%v", errBuild)
 		return nil
 	}
-	var transport *http.Transport
-	// Handle different proxy schemes.
-	if proxyURL.Scheme == "socks5" {
-		// Configure SOCKS5 proxy with optional authentication.
-		username := proxyURL.User.Username()
-		password, _ := proxyURL.User.Password()
-		proxyAuth := &proxy.Auth{User: username, Password: password}
-		dialer, errSOCKS5 := proxy.SOCKS5("tcp", proxyURL.Host, proxyAuth, proxy.Direct)
-		if errSOCKS5 != nil {
-			log.Errorf("create SOCKS5 dialer failed: %v", errSOCKS5)
-			return nil
-		}
-		// Set up a custom transport using the SOCKS5 dialer.
-		transport = &http.Transport{
-			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
-				return dialer.Dial(network, addr)
-			},
-		}
-	} else if proxyURL.Scheme == "http" || proxyURL.Scheme == "https" {
-		// Configure HTTP or HTTPS proxy.
-		transport = &http.Transport{Proxy: http.ProxyURL(proxyURL)}
-	} else {
-		log.Errorf("unsupported proxy scheme: %s", proxyURL.Scheme)
+	if transport == nil {
 		return nil
 	}
 	p.mu.Lock()

sdk/cliproxy/rtprovider_test.go

@@ -0,0 +1,22 @@
+package cliproxy
+
+import (
+	"net/http"
+	"testing"
+
+	coreauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
+)
+
+func TestRoundTripperForDirectBypassesProxy(t *testing.T) {
+	t.Parallel()
+
+	provider := newDefaultRoundTripperProvider()
+	rt := provider.RoundTripperFor(&coreauth.Auth{ProxyURL: "direct"})
+	transport, ok := rt.(*http.Transport)
+	if !ok {
+		t.Fatalf("transport type = %T, want *http.Transport", rt)
+	}
+	if transport.Proxy != nil {
+		t.Fatal("expected direct transport to disable proxy function")
+	}
+}