apps/echo/main.go

// Copyright 2018 Venil Noronha. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

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

var port = flag.Int("port", 3000, "Port to listen on")

// main serves as the program entry point
func main() {
	flag.Parse()
	// create a tcp listener on the given port
	listener, err := net.Listen("tcp", fmt.Sprintf(":%d", *port))
	if err != nil {
		fmt.Println("failed to create listener, err:", err)
		os.Exit(1)
	}
	fmt.Printf("listening on %s\n", listener.Addr())

	// listen for new connections
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println("failed to accept connection, err:", err)
			continue
		}

		// pass an accepted connection to a handler goroutine
		go handleConnection(conn)
	}
}

// handleConnection handles the lifetime of a connection
func handleConnection(conn net.Conn) {
	defer conn.Close()
	reader := bufio.NewReader(conn)
	for {
		// read client request data
		bytes, err := reader.ReadBytes(byte('\n'))
		if err != nil {
			if err != io.EOF {
				fmt.Println("failed to read data, err:", err)
			}
			return
		}
		fmt.Printf("request: %s", bytes)
		conn.Write(bytes)
	}
}