// Solution to part 5 of the Whispering Gophers code lab. // // This program extends part 4. // // It listens on an available public IP and port, and for each incoming // connection it decodes JSON-encoded messages and writes them to standard // output. // It simultaneously makes a connection to the host and port specified by -peer, // reads lines from standard input, and writes JSON-encoded messages to the // network connection. // The messages include the listen address. For example: // {"Addr": "127.0.0.1:41232", "Body": "Hello"!} // // You can test this program by listening with the dump program: // $ dump -listen=localhost:8000 // In another terminal, running this program: // $ part5 -peer=localhost:8000 // And in a third terminal, running part2 with the address printed by part5: // $ part2 -dial=192.168.1.200:54312 // Lines typed in the third terminal should appear in the second, and those // typed in the second window should appear in the first. // package main import ( "bufio" "encoding/json" "flag" "fmt" "log" "net" "os" "github.com/campoy/whispering-gophers/util" ) var ( peerAddr = flag.String("peer", "", "peer host:port") self string ) type Message struct { Addr string Body string } func main() { flag.Parse() // TODO: Create a new listener using util.Listen and put it in a variable named l. // TODO: Set the global variable self with the address of the listener. // TODO: Print the address to the standard output go dial(*peerAddr) for { c, err := l.Accept() if err != nil { log.Fatal(err) } go serve(c) } } func serve(c net.Conn) { defer c.Close() d := json.NewDecoder(c) for { var m Message err := d.Decode(&m) if err != nil { log.Println(err) return } fmt.Printf("%#v\n", m) } } func dial(addr string) { c, err := net.Dial("tcp", addr) if err != nil { log.Fatal(err) } s := bufio.NewScanner(os.Stdin) e := json.NewEncoder(c) for s.Scan() { m := Message{ // TODO: Put the self variable in the new Addr field. Body: s.Text(), } err := e.Encode(m) if err != nil { log.Fatal(err) } } if err := s.Err(); err != nil { log.Fatal(err) } }