init

telnet @ 744fe939

-Subproject commit 744fe939337506a1fe3ccdec3027e08dbe1d364f

telnet./Makefile

+name = telnet-cli
+
+build:
+	GOOS=windows GOARCH=amd64 go build -o $(name).win64.exe main.go
+	GOOS=windows GOARCH=386 go build -o $(name).win32.exe main.go
+	go build -o $(name).linux.bin main.go
+
+

telnet./cmd/network.go

+package cmd
+
+import (
+	"flag"
+	"github.com/assizkii/telnet/internal/client"
+	"github.com/assizkii/telnet/internal/server"
+	"log"
+	"time"
+)
+
+var (
+	timeoutFlag string
+)
+
+func init() {
+	flag.StringVar(&timeoutFlag, "timeout", "10s", "timeout durations")
+	flag.Parse()
+}
+
+func RunNetwork() {
+
+	host := flag.Arg(0)
+	port := flag.Arg(1)
+
+	networkType := flag.Arg(2)
+	// запускаем сервер
+	if networkType == "server" {
+		server.Start(server.Config{Host: host, Port: port})
+	} else {
+		timeout, err := time.ParseDuration(timeoutFlag)
+		if err != nil {
+			log.Fatalf("incorrect timeout")
+		}
+		// задаём конфиг клиента
+		var conf = client.Config{Host: host, Port: port, Timeout: timeout}
+		client.Start(conf)
+	}
+}

telnet./go.mod

+module github.com/assizkii/telnet
+
+go 1.13

telnet./internal/client/client.go

+package client
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"sync"
+	"time"
+)
+
+type Config struct {
+	Host    string
+	Port    string
+	Timeout time.Duration
+}
+
+func Start(conf Config) {
+
+	var timeout = conf.Timeout
+
+	dialer := &net.Dialer{
+		Timeout: timeout,
+	}
+	wg := &sync.WaitGroup{}
+	ctx, cancel := context.WithCancel(context.Background())
+	conn, err := dialer.DialContext(ctx, "tcp", conf.Host+":"+conf.Port)
+
+	if err != nil {
+		log.Fatalf("Cannot connect: %v", err)
+	}
+
+	wg.Add(1)
+	go func() {
+		readSocket(ctx, cancel, conn)
+		wg.Done()
+	}()
+
+	wg.Add(1)
+	go func() {
+		writeSocket(ctx, conn)
+		wg.Done()
+	}()
+
+	wg.Wait()
+	conn.Close()
+}
+
+func readSocket(ctx context.Context, cancel context.CancelFunc, conn net.Conn) {
+	scanner := bufio.NewScanner(conn)
+
+	for {
+		select {
+		case <-ctx.Done():
+			break
+		default:
+			if !scanner.Scan() {
+				cancel()
+				conn.Close()
+				log.Fatal("connection refused")
+				break
+			}
+			text := scanner.Text()
+			log.Printf("read from server %s", text)
+		}
+	}
+
+	log.Printf("finished reading")
+}
+
+func writeSocket(ctx context.Context, conn net.Conn) {
+	scanner := bufio.NewScanner(os.Stdin)
+	for {
+		select {
+		case <-ctx.Done():
+			break
+		default:
+			if !scanner.Scan() {
+				conn.Close()
+				log.Fatal("connection refused")
+				break
+			}
+			text := scanner.Text()
+			log.Printf("write to server %s", text)
+			conn.Write([]byte(fmt.Sprintf("%s\n", text)))
+		}
+	}
+	log.Printf("finished writing")
+}

telnet./internal/server/server.go

+package server
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"net"
+)
+
+type Config struct {
+	Host string
+	Port string
+}
+
+func handleConnection(conn net.Conn) {
+	defer conn.Close()
+	conn.Write([]byte(fmt.Sprintf("Welcome to %s, friend from %s\n", conn.LocalAddr(), conn.RemoteAddr())))
+
+	scanner := bufio.NewScanner(conn)
+	for scanner.Scan() {
+		text := scanner.Text()
+		log.Printf("RECEIVED: %s", text)
+		if text == "quit" || text == "exit" {
+			break
+		}
+
+		conn.Write([]byte(fmt.Sprintf("I have received '%s'\n", text)))
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Printf("Error happend on connection with %s: %v", conn.RemoteAddr(), err)
+	}
+
+	log.Printf("Closing connection with %s", conn.RemoteAddr())
+
+}
+
+func Start(conf Config) {
+	l, err := net.Listen("tcp", conf.Host+":"+conf.Port)
+	if err != nil {
+		log.Fatalf("Cannot listen: %v", err)
+	}
+	defer l.Close()
+
+	for {
+		conn, err := l.Accept()
+		if err != nil {
+			log.Fatalf("Cannot accept: %v", err)
+		}
+		go handleConnection(conn)
+	}
+}

telnet./main.go

+package main
+
+import (
+	"github.com/assizkii/telnet/cmd"
+)
+
+func main() {
+	cmd.RunNetwork()
+}