satococoa · May 7, 2019 10:30 · May 7, 2019 · May 7, 2019
diff --git a/tcp_server.go → server.go b/tcp_server.go → server.go
diff --git a/tcp_server.go b/tcp_server.go
@@ -0,0 +1,118 @@
+package server
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Server is a echo server.
+type Server struct {
+	listener *net.TCPListener
+	timeout  time.Duration
+	quit     chan bool
+	exited   chan bool
+}
+
+func logf(format string, v ...interface{}) {
+	log.Printf(format, v...)
+}
+
+// NewServer retruns Server with given listener and response.
+func NewServer(port int, timeout time.Duration) (*Server, error) {
+	tcpAddr, err := net.ResolveTCPAddr("tcp", fmt.Sprintf("0.0.0.0:%d", port))
+	if err != nil {
+		return nil, err
+	}
+	l, err := net.ListenTCP("tcp", tcpAddr)
+	if err != nil {
+		return nil, err
+	}
+	s := &Server{
+		listener: l,
+		quit:     make(chan bool),
+		exited:   make(chan bool),
+		timeout:  timeout,
+	}
+	return s, nil
+}
+
+// Start starts echo server.
+func (server *Server) Start() {
+	logf("Server Listening on %s", server.listener.Addr())
+
+	var handlers sync.WaitGroup
+	for {
+		select {
+		case <-server.quit:
+			logf("Shutting down...")
+			handlers.Wait()
+			close(server.exited)
+			return
+		default:
+			conn, err := server.listener.Accept()
+			if err != nil {
+				if opErr, ok := err.(*net.OpError); ok && opErr.Temporary() {
+					continue
+				}
+				// socket has been closed.
+				if strings.Contains(err.Error(), "use of closed network connection") {
+					continue
+				}
+			}
+			handlers.Add(1)
+			go func() {
+				if err := server.handleConnection(conn); err != nil {
+					logf("handle error: %v", err)
+				}
+				handlers.Done()
+			}()
+		}
+	}
+}
+
+// Stop stops server.
+func (server *Server) Stop() error {
+	logf("Server is stopping...")
+	if err := server.listener.Close(); err != nil {
+		return err
+	}
+	close(server.quit)
+	<-server.exited
+	logf("Server stopped successfully.")
+	return nil
+}
+
+func (server *Server) handleConnection(conn net.Conn) error {
+	logf("Connection accepted: %v -> %v", conn.RemoteAddr(), conn.LocalAddr())
+	defer conn.Close()
+	conn.SetDeadline(time.Now().Add(server.timeout))
+
+	buf := make([]byte, 4*1024)
+	for {
+		n, err := conn.Read(buf)
+		if err != nil {
+			if opErr, ok := err.(*net.OpError); ok {
+				if opErr.Timeout() {
+					return err
+				}
+				if opErr.Temporary() {
+					continue
+				}
+				return err
+			}
+			logf("read error: %v", err)
+			return err
+		}
+		logf("read: %s", buf[:n])
+		response := fmt.Sprintf("> %s", buf[:n])
+		if _, err := conn.Write([]byte(response)); err != nil {
+			logf("write error: %v", err)
+			return nil
+		}
+		logf("write: %s", buf[:n])
+	}
+}