golang代理服務器

package main import ( "bytes" "fmt" "io" "log" "net" "net/url" "strings" ) func main() { log.SetFlags(log.LstdFlags|log.Lshortfile) l, err := net.Listen("tcp", ":8081") if err != nil { log.Panic(err) } for { client, err := l.Accept() if err != nil { log.Panic(err) } go handleClientRequest(client) } } func handleClientRequest(client net.Conn) { if client == nil { return } defer client.Close() var b [1024]byte n, err := client.Read(b[:]) if err != nil { log.Println(err) return } var method, host, address string fmt.Sscanf(string(b[:bytes.IndexByte(b[:], '\n')]), "%s%s", &method, &host) hostPortURL, err := url.Parse(host) if err != nil { log.Println(err) return } if hostPortURL.Opaque == "443" { //https訪問 address = hostPortURL.Scheme + ":443" } else { //http訪問 if strings.Index(hostPortURL.Host, ":") == -1 { //host不帶端口， 默認80 address = hostPortURL.Host + ":80" } else { address = hostPortURL.Host } } //獲得了請求的host和port，就開始撥號吧 server, err := net.Dial("tcp", address) if err != nil { log.Println(err) return } if method == "CONNECT" { fmt.Fprint(client, "HTTP/1.1 200 Connection established\r\n\r\n") } else { server.Write(b[:n]) } //進行轉發 go io.Copy(server, client) io.Copy(client, server) }