Go微服务网关的实现

GET/HTTP/1.1
Host：www.baidu.com
User-Agent:curl/7.55.1
Accept:*/*

func main() {
	//1、监听端口
	listener, err := net.Listen("tcp", "0.0.0.0:9090")
	if err != nil {
		fmt.Printf("listen fail, err: %v\n", err)
		return
	}
	//2.建立套接字连接
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Printf("accept fail, err: %v\n", err)
			continue
		}
		//3. 创建处理协程
		go func(conn net.Conn) {
			defer conn.Close() //思考题：这里不填写会有啥问题？
            //服务端就有一个close，wait状态,客户端就有一个finally 状态
			for {
				var buf [128]byte
				n, err := conn.Read(buf[:])
				if err != nil {
					fmt.Printf("read from connect failed, err: %v\n", err)
					break
				}
				str := string(buf[:n])
				fmt.Printf("receive from client, data: %v\n", str)
			}
		}(conn)
	}
}

func main() {
	//类比接收缓冲区
	bytesBuffer := bytes.NewBuffer([]byte{})
	// 发送
	if err := Encode(bytesBuffer, "hello world 0 !!"); err != nil {
		panic(err)
	}
	if err := Encode(bytesBuffer, "hello world 1 !!"); err != nil {
		panic(err)
	}
	//读取
	for {
		if bt, err := Decode(bytesBuffer); err == nil {
			fmt.Println(string(bt))
			continue
		}
		break
	}
}

func main() {
	//simple tcp server
	//1.监听端口
	listener, err := net.Listen("tcp", "127.0.0.1:9090")
	if err != nil {
		fmt.Printf("tcp Listen fail,err: %v\n", err)
		return
	}
	//2.接受请求
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Printf("tcp Accept fail,err: %v\n", err)
			continue
		}
		//3.创建协程
		go process(conn)
	}
}

//4.创建的协程里面实现解码的功能
func process(conn net.Conn) {
	defer conn.Close()
	for {
		bt, err := unpack.Decode(conn)
		if err != nil {
			fmt.Printf("read from connect failed, err: %v\n", err)
			break
		}
		str := string(bt)
		fmt.Printf("receive from client, data: %v\n", str)
	}
}

func main() {
	//1.连接tcp服务器
	conn, err := net.Dial("tcp", "localhost:9090")
	defer conn.Close()
	if err != nil {
		fmt.Printf("connect failed, err : %v\n", err.Error())
		return
	}
	//2.实现编码
	unpack.Encode(conn, "hello world 0!!!")
}

const Msg_Header = "12345678"
// 编码
func Encode(bytesBuffer io.Writer, content string) error {
	//msg_header+content_len+content
	//8+4+content_len
	if err := binary.Write(bytesBuffer, binary.BigEndian, []byte(Msg_Header)); err != nil {
		return err
	}
	clen := int32(len([]byte(content)))
    //  binary.BigEndian 大端字节实现的加密 ， 
	if err := binary.Write(bytesBuffer, binary.BigEndian, clen); err != nil {
		return err
	}
	if err := binary.Write(bytesBuffer, binary.BigEndian, []byte(content)); err != nil {
		return err
	}
	return nil
}
// 解码
func Decode(bytesBuffer io.Reader) (bodyBuf []byte, err error) {
	MagicBuf := make([]byte, len(Msg_Header))
    //先读取header的大小
	if _, err = io.ReadFull(bytesBuffer, MagicBuf); err != nil {
		return nil, err
	}
	//比较得到的header和实际的Msg_Header 是否相同
	if string(MagicBuf) != Msg_Header {
		return nil, errors.New("msg_header error")
	}

	lengthBuf := make([]byte, 4)
	if _, err = io.ReadFull(bytesBuffer, lengthBuf); err != nil {
		return nil, err
	}
    //  binary.BigEndian 大端字节实现的解密 ，得到实际数据的长度
	length := binary.BigEndian.Uint32(lengthBuf)
	bodyBuf = make([]byte, length)
	if _, err = io.ReadFull(bytesBuffer, bodyBuf); err != nil {
		return nil, err
	}
	return bodyBuf, err
}

func main() {
	//1.监听端口
	listen, err := net.ListenUDP("udp", &net.UDPAddr{
		IP:   net.IPv4(0, 0, 0, 0),
		Port: 9090,
	})
	if err != nil {
		fmt.Printf("listen udp failed ,err:%v\n", err)
		return
	}
	//2.循环读取消息内容
	for {
		var data [1024]byte
		n, addr, err := listen.ReadFromUDP(data[:])
		if err != nil {
			fmt.Printf("read failed from addr :%v,err%v\n", addr, err)
			break
		}
		go func() {
			//3.回复数据
			fmt.Printf("addr:%v data:%v count:%v\n", addr, string(data[:n]), n)
			_, err = listen.WriteToUDP([]byte("received success!"), addr)
			if err != nil {
				fmt.Printf("write failed,err :%v\n", err)
				return
			}
		}()
	}
}

func main() {
	//1. 连接udp服务器
	conn, err := net.DialUDP("udp", nil, &net.UDPAddr{
		IP:   net.IPv4(127, 0, 0, 1),
		Port: 9090,
	})
	if err != nil {
		fmt.Printf("connect failed ,err %v\n", err)
		return
	}
	for i := 0; i < 100; i++ {
		// 2.发送数据
		_, err := conn.Write([]byte("hello " +
			"server"))
		if err != nil {
			fmt.Printf("send data failed,err: %v\n", err)
			return
		}
		// 3. 接收数据
		result := make([]byte, 1024)
		n, remoteAddr, err := conn.ReadFromUDP(result)
		if err != nil {
			fmt.Printf("read data failed,err:%v\n", err)
			return
		}
		fmt.Printf("receive from addr:%v data:%v\n", remoteAddr, string(result[:n]))
	}
}

func main() {
	//1、监听端口
	listener, err := net.Listen("tcp", "0.0.0.0:9090")
	if err != nil {
		fmt.Printf("listen fail, err: %v\n", err)
		return
	}

	//2.建立套接字连接
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Printf("accept fail, err: %v\n", err)
			continue
		}

		//3. 创建处理协程
		go process(conn)
	}	
}

func process(conn net.Conn) {
	defer conn.Close()	//思考题：这里不填写会有啥问题？
	for {
		var buf [128]byte
		n, err := conn.Read(buf[:])

		if err != nil {
			fmt.Printf("read from connect failed, err: %v\n", err)
			break
		}
		str := string(buf[:n])
            fmt.Printf(" from client, data: %v\n", str)
	}
}

var (
	Addr = ":8000"
)

// http的服务器
func main() {
	//1.创建路由器
	mux := http.NewServeMux()
	// 2. 设置路由规则
	mux.HandleFunc("/bye", sayBye)

	// 3.创建服务器
	server := &http.Server{
		Addr:         Addr,
		WriteTimeout: time.Second * 3,
		Handler:      mux,
	}
	// 4. 监听端口并提供服务
	log.Println("starting httpserver at" + Addr)
	log.Fatal(server.ListenAndServe())
}
func sayBye(w http.ResponseWriter, r *http.Request) {
	time.Sleep(1 * time.Second)
	w.Write([]byte("bye bye,this is httpserver"))

}

func main() {
	//1. 创建连接池
	transport := &http.Transport{
		DialContext: (&net.Dialer{
			Timeout:   30 * time.Second, // 超时时间
			KeepAlive: 30 * time.Second, //长连接时间
		}).DialContext,
		MaxIdleConns:          100,              //最大空闲连接数
		IdleConnTimeout:       90 * time.Second, // 空闲超时时间
		TLSHandshakeTimeout:   10 * time.Second, // tls握手超时时间
		ExpectContinueTimeout: 1 * time.Second,  // 100-continue 状态码超时时间
	}
	//2. 创建客户端
	client := &http.Client{
		Timeout:   30 * time.Second,
		Transport: transport,
	}
	//3.请求数据
	resp, err := client.Get("http://127.0.0.1:8000/bye")
	if err != nil {
		fmt.Println("client get url failed ", err)
		return
	}
	defer resp.Body.Close()
	//4.读取内容
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		fmt.Println("Read body failed ", err)
		return
	}
	fmt.Println(string(b))

}

type HandleFunc func(http.ResponseWriter, *http.Request)

func (f HandleFunc) ServerHTTP(w http.ResponseWriter, r *http.Request) {
	f(w, r)
}

//函数是一等公民
func main() {
	hf := HandleFunc(HelloHandler)
	resp := httptest.NewRecorder()
	req := httptest.NewRequest("GET", "/", bytes.NewBuffer([]byte("test")))

	hf.ServerHTTP(resp, req)
	b, _ := ioutil.ReadAll(resp.Body)
	fmt.Println(string(b))
}
func HelloHandler(res http.ResponseWriter, req *http.Request) {
	res.Write([]byte("hello youMe "))
}