Go Network Programming (i) (TCP)

This is a creation in Article, where the information may have evolved or changed.

// tcp.gopackage mainimport ("bytes""fmt""io""net""os")func main() {if len(os.Args) != 2 {fmt.Fprintf(os.Stderr, "Usage %s host:port", os.Args[0])os.Exit(1)}service := os.Args[1]conn, err := net.Dial("tcp", service)checkError(err)_, err = conn.Write([]byte("HEAD / HTTP/1.0\r\n\r\n"))checkError(err)result, err := readFully(conn)checkError(err)fmt.Println(string(result))fmt.Printf("result len = %d\n", len(result))os.Exit(0)}func checkError(err error) {if err != nil {fmt.Fprintf(os.Stderr, "Fatal error: %s", err.Error())os.Exit(1)}}func readFully(conn net.Conn) ([]byte, error) {defer conn.Close()result := bytes.NewBuffer(nil)var buf [512]bytefor {n, err := conn.Read(buf[0:])result.Write(buf[0:n])if err != nil {if err == io.EOF {break}return nil, err}}return result.Bytes(), nil}

Output Result:

C:\Users\Administrator>C:/Go/mycode/20170507/http/http.exe www.oschina.net:80HTTP/1.1 200 OKServer: CDN_NWS_4.2.0Connection: closeDate: Sun, 07 May 2017 10:17:31 GMTLast-Modified: Mon, 11 Jul 2016 11:18:41 GMTContent-Type: application/octet-streamContent-Length: 4096result len = 206