Small knowledge, big challenge! This article is participating in the creation activity of “Essential Tips for Programmers”.

Net package – based small application

The complete code has been uploaded to Github github-TCP

Welcome star and Issue

Start by creating two directories, one isclientThe client, the other one isserverThe service side.

1. The connection

1.1 the service side

• Listening to the connection

Net provides the Listen method, so that the server port listening

ADDRESS := "127.0.0.1:5000"
listener,err := net.Listen("tcp",ADDRESS)
iferr ! =nil {
	fmt.Printf("start tcp server %s failed ,err : %s ",listener,err)
	return
}
defer listener.Close()
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1.2 the client

• Establish a connection

Net provides Dail methods that let clients connect to servers

ADDRESS := "127.0.0.1:5000"
conn,err := net.Dial("tcp",ADDRESS) // Initiate a connection with the server
iferr ! =nil {
	fmt.Printf("dial %s failed; err :%s",ADDRESS,err)
	return
}
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2. Communication

2.1 the service side

• Receiving information

The transmitted data can be Read by.read.

	var data [1024]byte
	var msg string
	reader := bufio.NewReader(os.Stdin)
	for {   // The server is always waiting for incoming data, so use the for loop
		// Receive information
		n,err := conn.Read(data[:])
		if err == io.EOF{
			break
		}
		iferr ! =nil {
			fmt.Printf("read from conn failed,err:%s",err)
			return
		}
		fmt.Println("Access Info : ".string(data[:n]))
	}
	defer conn.Close()
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2.2 the client

• Send a message

It is also possible to transfer data over a transport connection via.write.

	for{ // Let the client keep sending messages, so we need a for loop to keep the connection going
		fmt.Print("Please enter:")
		msg,_ = reader.ReadString('\n')
		msg = strings.TrimSpace(msg)
		if msg == "exit" {
			break
		}
		_, _ = conn.Write([]byte(msg))
	}
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3. Reply

When the server receives the message, it should return the message to the client. Indicates that data has been received.

3.1 the service side

The server replies the message

	// Reply to the message
	fmt.Print("Reply message :")
	msg,_ = reader.ReadString('\n')
	msg = strings.TrimSpace(msg)
	if msg == "exit" {
		break
	}
	_ ,_ = conn.Write([]byte(msg))
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3.2 the client

The client received the message. Procedure

	// Receive information
	n,err:=conn.Read(data[:])
	if err == io.EOF {
		break
	}
	iferr ! =nil {
		fmt.Println("read from conn failed, err :",err)
		return
	}
	fmt.Println("Reply received :".string(data[:n]))
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The last

Xiao Sheng Fan Yi, looking forward to your attention.