112 lines
1.9 KiB
Go
112 lines
1.9 KiB
Go
// Solution to part 6 of the Whispering Gophers code lab.
|
|
//
|
|
// This program is functionally equivalent to part 5,
|
|
// but the reading from standard input and writing to the
|
|
// network connection are done by separate goroutines.
|
|
//
|
|
package main
|
|
|
|
import (
|
|
"bufio"
|
|
"encoding/json"
|
|
"flag"
|
|
"fmt"
|
|
"log"
|
|
"net"
|
|
"os"
|
|
|
|
"code.osinet.fr/fgm/whispering_gophers/util"
|
|
)
|
|
|
|
var (
|
|
listenAddr = flag.String("listen", "", "peer host:port")
|
|
peerAddr = flag.String("peer", "", "peer host:port")
|
|
self string
|
|
)
|
|
|
|
type Message struct {
|
|
Addr string
|
|
Body string
|
|
}
|
|
|
|
func main() {
|
|
flag.Parse()
|
|
|
|
var l net.Listener
|
|
var err error
|
|
// Create a new listener using util.Listen and put it in a variable named l.
|
|
if *listenAddr == "" {
|
|
l, err = util.ListenOnFirstUsableInterface()
|
|
} else {
|
|
l, err = net.Listen("tcp4", *listenAddr)
|
|
}
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
self = l.Addr().String()
|
|
log.Println("Listening on", self)
|
|
|
|
go dial(*peerAddr)
|
|
go readInput()
|
|
|
|
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)
|
|
}
|
|
}
|
|
|
|
// Make a new channel of Messages.
|
|
var peer = make(chan Message)
|
|
|
|
func readInput() {
|
|
s := bufio.NewScanner(os.Stdin)
|
|
for s.Scan() {
|
|
m := Message{
|
|
Addr: self,
|
|
Body: s.Text(),
|
|
}
|
|
// Send the message to the channel of messages.
|
|
peer <- m
|
|
}
|
|
if err := s.Err(); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
os.Exit(0)
|
|
}
|
|
|
|
func dial(addr string) {
|
|
c, err := net.Dial("tcp", addr)
|
|
if err != nil {
|
|
log.Println(addr, err)
|
|
return
|
|
}
|
|
defer c.Close()
|
|
|
|
e := json.NewEncoder(c)
|
|
|
|
/* Receive messages from the channel using range, storing them in the variable m. */
|
|
for m := range peer {
|
|
err := e.Encode(m)
|
|
if err != nil {
|
|
log.Println(addr, err)
|
|
return
|
|
}
|
|
}
|
|
}
|