simple p2p comms

daytime.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+  "fmt"
+  "net"
+  "os"
+  "time"
+)
+
+func main() {
+  service := ":1200"
+  tcpAddr, err := net.ResolveTCPAddr("tcp4", service)
+  checkError(err)
+
+  listener, err := net.ListenTCP("tcp", tcpAddr)
+  checkError(err)
+
+  for {
+    conn, err := listener.Accept()
+    if err != nil {
+      continue
+    }
+
+    daytime := "Hahahaha virgin client vs chad server" + time.Now().String()
+    conn.Write([]byte(daytime))
+    conn.Close()
+  }
+}
+
+func checkError(err error) {
+  if err != nil {
+    fmt.Fprintf(os.Stderr, "Fatal error: %s", err.Error())
+    os.Exit(1)
+  }
+}

echo.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+  "net"
+  "os"
+  "fmt"
+)
+
+func main()  {
+  service := ":1201"
+  tcpAddr, err := net.ResolveTCPAddr("tcp4", service)
+  checkError(err)
+
+  listener, err := net.ListenTCP("tcp", tcpAddr)
+  checkError(err)
+
+  for {
+    conn, err := listener.Accept()
+    if err != nil {
+      continue
+    }
+
+    go handleClient(conn)
+  }
+}
+
+func handleClient(conn net.Conn) {
+  // close connection on exit
+  defer conn.Close()
+
+  var buf [512]byte
+
+  for {
+    // read up to 512 bytes
+    n, err := conn.Read(buf[0:])
+    if err != nil {
+      return
+    }
+
+    // write the n bytes read
+    _, err2 := conn.Write(buf[0:n])
+    if err2 != nil {
+      return
+    }
+  }
+}
+
+func checkError(err error) {
+  if err != nil {
+    fmt.Fprintf(os.Stderr, "Fatal error: %s", err.Error())
+    os.Exit(1)
+  }
+}

ip.go

@@ -0,0 +1,26 @@
+/* IP
+ */
+
+package main
+
+import (
+    "net"
+    "os"
+    "fmt"
+)
+
+func main() {
+    if len(os.Args) != 2 {
+        fmt.Fprintf(os.Stderr, "Usage: %s ip-addr\n", os.Args[0])
+        os.Exit(1)
+    }
+    name := os.Args[1]
+
+    addr := net.ParseIP(name)
+    if addr == nil {
+        fmt.Println("Invalid address")
+    } else {
+        fmt.Println("The address is ", addr.String())
+    }
+    os.Exit(0)
+}

p2p.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+  "net"
+  "os"
+  "fmt"
+  "strings"
+)
+
+func main() {
+  if len(os.Args) <= 1 {
+      fmt.Fprintf(os.Stderr, "Usage: %s <local node port> <remote node port>\n", os.Args[0])
+      os.Exit(1)
+  }
+
+  // Configure this local node's listening port.
+  service := ":" + os.Args[1]
+  tcpAddr, err := net.ResolveTCPAddr("tcp4", service)
+  checkError(err)
+
+  listener, err := net.ListenTCP("tcp", tcpAddr)
+  checkError(err)
+
+  // If a remote peer's port is specified, we want to connect and message it
+  if len(os.Args) == 3 {
+    fmt.Println("Found a remote peer")
+    remote := ":" + os.Args[2]
+    tcpRemote, err := net.ResolveTCPAddr("tcp4", remote)
+    checkError(err)
+
+    peerconn, err := net.DialTCP("tcp4", nil, tcpRemote)
+    checkError(err)
+
+    _, err = peerconn.Write([]byte("Hello from " + os.Args[1]))
+    checkError(err)
+
+    var buf [512]byte
+
+    n, err := peerconn.Read(buf[0:])
+    checkError(err)
+
+    result := string(buf[0:n])
+    fmt.Println(string(result))
+  }
+
+  fmt.Printf("(%s) Waiting for peer connections...\n", os.Args[1])
+  for {
+    conn, err := listener.Accept()
+    if err != nil {
+      continue
+    }
+
+    handleConnection(conn)
+  }
+}
+
+func handleConnection(conn net.Conn) {
+  // close connection on exit
+  defer conn.Close()
+
+  var buf [512]byte
+
+  for {
+    // read up to 512 bytes
+    n, err := conn.Read(buf[0:])
+    if err != nil {
+      return
+    }
+
+    message := string(buf[0:n])
+    fmt.Println(message)
+
+    tokens := strings.Split(message, " ")
+    if tokens[0] != "" {
+      response := "Hi " + tokens[2] + ", from " + os.Args[1]
+      // write the n bytes read
+      _, err2 := conn.Write([]byte(response))
+      if err2 != nil {
+        return
+      }
+    }
+
+  }
+}
+
+func checkError(err error) {
+  if err != nil {
+    fmt.Fprintf(os.Stderr, "Fatal error: %s", err.Error())
+    os.Exit(1)
+  }
+}