A TCP Server/Client written in Go

01-tcp-server-client-go.md

A TCP Server/Client written in Go

client.go

package main

import (
	"bufio"
	"fmt"
	"net"
	"os"
)

func main() {
	// Connect to TCP Server
	conn, err := net.Dial("tcp", ":8080")
	if err != nil {
		fmt.Println(err)
		return
	}

	// Close the connection when the application finish.
	defer conn.Close()

	// Create a loop to interact with the server
	for {
		// Read input from stdin
		reader := bufio.NewReader(os.Stdin)
		fmt.Printf("Enter a name: ")
		text, err := reader.ReadString('\n')
		if err != nil {
			fmt.Println(err)
			return
		}

		// Send to server
		fmt.Fprintf(conn, text + "\n")

		// Listen the response
		message, err := bufio.NewReader(conn).ReadString('\n')
		if err != nil {
			fmt.Println(err)
			return
		}

		fmt.Printf("Server response: " + message)
	}
}

server.go

package main

import (
	"bufio"
	"fmt"
	"net"
	"strings"
)

func main() {
	// Create a TCP Server using the port 8080
	listener, err := net.Listen("tcp", ":8080")
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Printf("Server started. Listening on 8080\n")

	// Close the listener when the application finish.
	defer listener.Close()

	// Create a go routine for each connection
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println(err)
			return
		}

		go handleConnection(conn)
	}
}

func handleConnection(conn net.Conn) {
	fmt.Printf("Client connected from %s\n", conn.RemoteAddr().String())

	// Create a loop to interact with the client
	for {
		data, err := bufio.NewReader(conn).ReadString('\n')
		if err != nil {
			fmt.Println(err)
			return
		}

		name := strings.TrimSpace(string(data))
		if len(name) == 0 {
			// Missing the name. Return a message.
			conn.Write([]byte(string("Please provide a name\n")))
		} else{
			// Name received. Return the message.
			result := "Hello, " + name + "!\n"
			conn.Write([]byte(string(result)))
		}
	}
}