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.

internal/api/handlers/management/api_tools.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"net"
 	"net/http"
 	"net/url"
 	"strings"
@@ -14,8 +13,8 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/runtime/geminicli"
 	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"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 )
@@ -660,45 +659,10 @@ func (h *Handler) apiCallTransport(auth *coreauth.Auth) http.RoundTripper {
 }
 
 func buildProxyTransport(proxyStr string) *http.Transport {
-	proxyStr = strings.TrimSpace(proxyStr)
-	if proxyStr == "" {
+	transport, _, errBuild := proxyutil.BuildHTTPTransport(proxyStr)
+	if errBuild != nil {
+		log.WithError(errBuild).Debug("build proxy transport failed")
 		return nil
 	}
-
-	proxyURL, errParse := url.Parse(proxyStr)
-	if errParse != nil {
-		log.WithError(errParse).Debug("parse proxy URL failed")
-		return nil
-	}
-	if proxyURL.Scheme == "" || proxyURL.Host == "" {
-		log.Debug("proxy URL missing scheme/host")
-		return nil
-	}
-
-	if proxyURL.Scheme == "socks5" {
-		var proxyAuth *proxy.Auth
-		if proxyURL.User != nil {
-			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.WithError(errSOCKS5).Debug("create SOCKS5 dialer failed")
-			return nil
-		}
-		return &http.Transport{
-			Proxy: nil,
-			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
-				return dialer.Dial(network, addr)
-			},
-		}
-	}
-
-	if proxyURL.Scheme == "http" || proxyURL.Scheme == "https" {
-		return &http.Transport{Proxy: http.ProxyURL(proxyURL)}
-	}
-
-	log.Debugf("unsupported proxy scheme: %s", proxyURL.Scheme)
-	return nil
+	return transport
 }