From 9b6491223b0695d17b712d22639c7f36d1599c67 Mon Sep 17 00:00:00 2001
From: talksik <patel.arjun@gmail.com>
Date: Thu, 11 May 2023 16:06:53 -0700
Subject: [PATCH] adding in simple implementations

---
 client/client.go | 46 +++++++++++++++++++++++++++++++
 go.mod           |  7 +++++
 go.sum           | 15 ++++++++++
 main.go          | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 140 insertions(+)
 create mode 100644 client/client.go
 create mode 100644 go.mod
 create mode 100644 go.sum
 create mode 100644 main.go

diff --git a/client/client.go b/client/client.go
new file mode 100644
index 0000000..bae78c9
--- /dev/null
+++ b/client/client.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+
+	"github.com/sirupsen/logrus"
+)
+
+func main() {
+	s, err := net.ResolveUDPAddr("udp4", "localhost:5000")
+	c, err := net.DialUDP("udp4", nil, s)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Printf("The UDP server is %s\n", c.RemoteAddr().String())
+	defer c.Close()
+
+	// send json data
+	data := map[string]interface{}{
+		"name":      "John",
+		"audioData": 30,
+	}
+	marshalledData, err := json.Marshal(data)
+	if err != nil {
+		logrus.Error("Error while marshalling data", err)
+		return
+	}
+
+	_, err = c.Write(marshalledData)
+	if err != nil {
+		logrus.Error("Error while writing data", err)
+		return
+	}
+
+	buffer := make([]byte, 1024)
+	n, _, err := c.ReadFromUDP(buffer)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Printf("Reply: %s\n", string(buffer[0:n]))
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..2d061b5
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,7 @@
+module github.com/talksik/simple-golang-udp
+
+go 1.20
+
+require github.com/sirupsen/logrus v1.9.0
+
+require golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..ed65537
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=
+github.com/sirupsen/logrus v1.9.0/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..493a6b4
--- /dev/null
+++ b/main.go
@@ -0,0 +1,72 @@
+package main
+
+import (
+	"math/rand"
+	"net"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+// port global variable
+const (
+	PORT = ":5000"
+)
+
+func udpServer() {
+	s, err := net.ResolveUDPAddr("udp4", PORT)
+	if err != nil {
+		logrus.Error("Error while resolving udp address", err)
+		return
+	}
+
+	connection, err := net.ListenUDP("udp4", s)
+	if err != nil {
+		logrus.Error("Error while listening to udp address", err)
+		return
+	}
+
+	defer connection.Close()
+	buffer := make([]byte, 1024)
+	rand.Seed(time.Now().Unix())
+
+	logrus.Infof("Starting listening for udp packets on port %s", PORT)
+
+	for {
+		n, addr, err := connection.ReadFromUDP(buffer)
+		if err != nil {
+			logrus.Error("Error while reading from udp address", err)
+			return
+		}
+
+		// go routine to process the request
+		go handleRequest(buffer[:n], connection, addr)
+	}
+}
+
+func handleRequest(data []byte, connection *net.UDPConn, addr *net.UDPAddr) {
+	logrus.Info("Processing request")
+
+  logrus.Info("===============")
+	logrus.Infof("raw byte array -> ", data)
+	logrus.Info("string -> ", string(data))
+  logrus.Infof("addr -> %s\n", addr.String())
+  logrus.Info("===============")
+
+	respondUdp(connection, addr)
+}
+
+func respondUdp(conn *net.UDPConn, addr *net.UDPAddr) {
+	message := "received message from you! " + addr.String()
+
+	data := []byte(message)
+	_, err := conn.WriteToUDP(data, addr)
+	if err != nil {
+		logrus.Error("Error while responding back to client", err)
+		return
+	}
+}
+
+func main() {
+	udpServer()
+}