package proxyutil import ( "context" "fmt" "net" "net/http" "net/url" "strings" "golang.org/x/net/proxy") // Mode describes how a proxy setting should be interpreted.type Mode int const ( // ModeInherit means no explicit proxy behavior was configured. ModeInherit Mode = iota // ModeDirect means outbound requests must bypass proxies explicitly. ModeDirect // ModeProxy means a concrete proxy URL was configured. ModeProxy // ModeInvalid means the proxy setting is present but malformed or unsupported. ModeInvalid) // Setting is the normalized interpretation of a proxy configuration value.type Setting struct { Raw string Mode Mode URL *url.URL} // Parse normalizes a proxy configuration value into inherit, direct, or proxy modes.func Parse(raw string) (Setting, error) { trimmed := strings.TrimSpace(raw) setting := Setting{Raw: trimmed} if trimmed == "" { setting.Mode = ModeInherit return setting, nil } if strings.EqualFold(trimmed, "direct") || strings.EqualFold(trimmed, "none") { setting.Mode = ModeDirect return setting, nil } parsedURL, errParse := url.Parse(trimmed) if errParse != nil { setting.Mode = ModeInvalid return setting, fmt.Errorf("parse proxy URL failed: %w", errParse) } if parsedURL.Scheme == "" || parsedURL.Host == "" { setting.Mode = ModeInvalid return setting, fmt.Errorf("proxy URL missing scheme/host") } switch parsedURL.Scheme { case "socks5", "socks5h", "http", "https": setting.Mode = ModeProxy setting.URL = parsedURL return setting, nil default: setting.Mode = ModeInvalid return setting, fmt.Errorf("unsupported proxy scheme: %s", parsedURL.Scheme) }} func cloneDefaultTransport() *http.Transport { if transport, ok := http.DefaultTransport.(*http.Transport); ok && transport != nil { return transport.Clone() } return &http.Transport{}} // NewDirectTransport returns a transport that bypasses environment proxies.func NewDirectTransport() *http.Transport { clone := cloneDefaultTransport() clone.Proxy = nil return clone} // BuildHTTPTransport constructs an HTTP transport for the provided proxy setting.func BuildHTTPTransport(raw string) (*http.Transport, Mode, error) { setting, errParse := Parse(raw) if errParse != nil { return nil, setting.Mode, errParse } switch setting.Mode { case ModeInherit: return nil, setting.Mode, nil case ModeDirect: return NewDirectTransport(), setting.Mode, nil case ModeProxy: if setting.URL.Scheme == "socks5" || setting.URL.Scheme == "socks5h" { var proxyAuth *proxy.Auth if setting.URL.User != nil { username := setting.URL.User.Username() password, _ := setting.URL.User.Password() proxyAuth = &proxy.Auth{User: username, Password: password} } dialer, errSOCKS5 := proxy.SOCKS5("tcp", setting.URL.Host, proxyAuth, proxy.Direct) if errSOCKS5 != nil { return nil, setting.Mode, fmt.Errorf("create SOCKS5 dialer failed: %w", errSOCKS5) } transport := cloneDefaultTransport() transport.Proxy = nil transport.DialContext = func(_ context.Context, network, addr string) (net.Conn, error) { return dialer.Dial(network, addr) } return transport, setting.Mode, nil } transport := cloneDefaultTransport() transport.Proxy = http.ProxyURL(setting.URL) return transport, setting.Mode, nil default: return nil, setting.Mode, nil }} // BuildDialer constructs a proxy dialer for settings that operate at the connection layer.func BuildDialer(raw string) (proxy.Dialer, Mode, error) { setting, errParse := Parse(raw) if errParse != nil { return nil, setting.Mode, errParse } switch setting.Mode { case ModeInherit: return nil, setting.Mode, nil case ModeDirect: return proxy.Direct, setting.Mode, nil case ModeProxy: dialer, errDialer := proxy.FromURL(setting.URL, proxy.Direct) if errDialer != nil { return nil, setting.Mode, fmt.Errorf("create proxy dialer failed: %w", errDialer) } return dialer, setting.Mode, nil default: return nil, setting.Mode, nil }}
package proxyutil
import (
"context"
"fmt"
"net"
"net/http"
"net/url"
"strings"
"golang.org/x/net/proxy"
)
// Mode describes how a proxy setting should be interpreted.
type Mode int
const (
// ModeInherit means no explicit proxy behavior was configured.
ModeInherit Mode = iota
// ModeDirect means outbound requests must bypass proxies explicitly.
ModeDirect
// ModeProxy means a concrete proxy URL was configured.
ModeProxy
// ModeInvalid means the proxy setting is present but malformed or unsupported.
ModeInvalid
)
// Setting is the normalized interpretation of a proxy configuration value.
type Setting struct {
Raw string
Mode Mode
URL *url.URL
}
// Parse normalizes a proxy configuration value into inherit, direct, or proxy modes.
func Parse(raw string) (Setting, error) {
trimmed := strings.TrimSpace(raw)
setting := Setting{Raw: trimmed}
if trimmed == "" {
setting.Mode = ModeInherit
return setting, nil
}
if strings.EqualFold(trimmed, "direct") || strings.EqualFold(trimmed, "none") {
setting.Mode = ModeDirect
return setting, nil
}
parsedURL, errParse := url.Parse(trimmed)
if errParse != nil {
setting.Mode = ModeInvalid
return setting, fmt.Errorf("parse proxy URL failed: %w", errParse)
}
if parsedURL.Scheme == "" || parsedURL.Host == "" {
setting.Mode = ModeInvalid
return setting, fmt.Errorf("proxy URL missing scheme/host")
}
switch parsedURL.Scheme {
case "socks5", "socks5h", "http", "https":
setting.Mode = ModeProxy
setting.URL = parsedURL
return setting, nil
default:
setting.Mode = ModeInvalid
return setting, fmt.Errorf("unsupported proxy scheme: %s", parsedURL.Scheme)
}
}
func cloneDefaultTransport() *http.Transport {
if transport, ok := http.DefaultTransport.(*http.Transport); ok && transport != nil {
return transport.Clone()
}
return &http.Transport{}
}
// NewDirectTransport returns a transport that bypasses environment proxies.
func NewDirectTransport() *http.Transport {
clone := cloneDefaultTransport()
clone.Proxy = nil
return clone
}
// BuildHTTPTransport constructs an HTTP transport for the provided proxy setting.
func BuildHTTPTransport(raw string) (*http.Transport, Mode, error) {
setting, errParse := Parse(raw)
if errParse != nil {
return nil, setting.Mode, errParse
}
switch setting.Mode {
case ModeInherit:
return nil, setting.Mode, nil
case ModeDirect:
return NewDirectTransport(), setting.Mode, nil
case ModeProxy:
if setting.URL.Scheme == "socks5" || setting.URL.Scheme == "socks5h" {
var proxyAuth *proxy.Auth
if setting.URL.User != nil {
username := setting.URL.User.Username()
password, _ := setting.URL.User.Password()
proxyAuth = &proxy.Auth{User: username, Password: password}
}
dialer, errSOCKS5 := proxy.SOCKS5("tcp", setting.URL.Host, proxyAuth, proxy.Direct)
if errSOCKS5 != nil {
return nil, setting.Mode, fmt.Errorf("create SOCKS5 dialer failed: %w", errSOCKS5)
}
transport := cloneDefaultTransport()
transport.Proxy = nil
transport.DialContext = func(_ context.Context, network, addr string) (net.Conn, error) {
return dialer.Dial(network, addr)
}
return transport, setting.Mode, nil
}
transport := cloneDefaultTransport()
transport.Proxy = http.ProxyURL(setting.URL)
return transport, setting.Mode, nil
default:
return nil, setting.Mode, nil
}
}
// BuildDialer constructs a proxy dialer for settings that operate at the connection layer.
func BuildDialer(raw string) (proxy.Dialer, Mode, error) {
setting, errParse := Parse(raw)
if errParse != nil {
return nil, setting.Mode, errParse
}
switch setting.Mode {
case ModeInherit:
return nil, setting.Mode, nil
case ModeDirect:
return proxy.Direct, setting.Mode, nil
case ModeProxy:
dialer, errDialer := proxy.FromURL(setting.URL, proxy.Direct)
if errDialer != nil {
return nil, setting.Mode, fmt.Errorf("create proxy dialer failed: %w", errDialer)
}
return dialer, setting.Mode, nil
default:
return nil, setting.Mode, nil
}
}