Added examples golang net lib, tcp and udp

examples/golang/cource/06e_network/clients/tcp.go

@@ -0,0 +1,24 @@
+package client
+
+import (
+	"fmt"
+	"net"
+	"bufio"
+)
+
+func TCPClient() {
+	buf := make([]byte, 1024)
+	conn, err := net.Dial("tcp", "localhost:1900")
+	if err != nil {
+		fmt.Printf("Connection error: %v", err)
+		return
+	}
+	fmt.Fprintf(conn, "Some message to server!")
+	_, err = bufio.NewReader(conn).Read(buf)
+	if err == nil {
+		fmt.Printf("Some in buf: %s", buf)
+	} else {
+		fmt.Printf("Read error: %s", err)
+	}
+	conn.Close()
+}

examples/golang/cource/06e_network/clients/udp.go

@@ -0,0 +1,24 @@
+package client
+
+import (
+	"fmt"
+	"net"
+	"bufio"
+)
+
+func UDPClient() {
+	buf := make([]byte, 1024)
+	conn, err := net.Dial("udp", "localhost:1901")
+	if err != nil {
+		fmt.Printf("Connection error: %v", err)
+		return
+	}
+	fmt.Fprintf(conn, "Some message to UDP server!")
+	_, err = bufio.NewReader(conn).Read(buf)
+	if err == nil {
+		fmt.Printf("Some in buf: %s", buf)
+	} else {
+		fmt.Printf("Read error: %s", err)
+	}
+	conn.Close()
+}

examples/golang/cource/06e_network/go.mod

@@ -0,0 +1,3 @@
+module 06e_network
+
+go 1.23.2

examples/golang/cource/06e_network/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+//	"golang/cource/06e_network/servers"
+	"golang/cource/06e_network/clients"
+)
+
+func main() {
+	fmt.Println("Started test servers.")
+//	server.TCPServer()
+//	server.UDPServer()
+//	client.TCPClient()
+	client.UDPClient()
+}

examples/golang/cource/06e_network/servers/tcp.go

@@ -0,0 +1,41 @@
+package server
+
+import (
+	"fmt"
+	"net"
+	"os"
+)
+
+func TCPServer() {
+	listener, err := net.Listen("tcp", "localhost:1900")
+	if err != nil {
+		fmt.Println("Bind listener error: ", err.Error())
+		os.Exit(1)
+	}
+	defer listener.Close()
+	fmt.Println("Bind on: localhost:1900")
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			fmt.Println("Error accepting: ", err.Error())
+			os.Exit(1)
+		}
+		go handleRequest(conn)
+	}
+}
+
+func handleRequest(conn net.Conn) {
+	buf := make([]byte, 1024)
+
+	reqLen, err := conn.Read(buf)
+	if err != nil {
+		fmt.Println("Error reading: ", err.Error())
+	}
+	fmt.Println("Some recieved:", reqLen)
+	bytesWritten, err := conn.Write([]byte("Something recieved."))
+	if err != nil {
+		fmt.Println("Error writing: ", err.Error())
+	}
+	fmt.Printf("Bytes written: %d\n", bytesWritten)
+	conn.Close()
+}

examples/golang/cource/06e_network/servers/udp.go

@@ -0,0 +1,36 @@
+package server
+
+import (
+	"fmt"
+	"net"
+)
+
+func sendResponse(conn *net.UDPConn, addr *net.UDPAddr) {
+	_, err := conn.WriteToUDP([]byte("Response from server..."), addr)
+	if err != nil {
+		fmt.Printf("Couldn't send response: %v\n", err)
+	}
+}
+
+func UDPServer() {
+	buf := make([]byte, 2048)
+	addr := net.UDPAddr{
+		Port: 1901, 
+		IP: net.ParseIP("127.0.0.1"),
+	}
+	listener, err := net.ListenUDP("udp", &addr)
+	if err != nil {
+		fmt.Printf("Listen UDP error: %v\n", err)
+		return
+	}
+	fmt.Println("listening on localhost:1901.")
+	for {
+		_, remoteaddr, err := listener.ReadFromUDP(buf)
+		fmt.Printf("Buffer recieved: %s", buf)
+		if err != nil {
+			fmt.Printf("Read UDP error: %v\n", err)
+			return
+		}
+		go sendResponse(listener, remoteaddr)
+	}
+}