Make Message an interface with attached handling behavior.

ergonomadic.go

@@ -1,5 +1,4 @@
 package main
-// http://tools.ietf.org/html/rfc2812
 
 import (
 	"irc"

src/irc/client.go

@@ -1,21 +1,13 @@
 package irc
 
 import (
-	"log"
 	"net"
-	"strings"
 )
 
-type Message struct {
-	command string
-	args    string
-	client  *Client
-}
-
 type Client struct {
 	addr       net.Addr
-	send       chan string
+	send       chan<- string
-	recv       chan string
+	recv       <-chan string
 	username   string
 	realname   string
 	nick       string
@@ -31,19 +23,12 @@ func NewClient(conn net.Conn) *Client {
 }
 
 // Adapt `chan string` to a `chan Message`.
-func (c *Client) Communicate(server *Server) {
+func (c *Client) Communicate(server chan<- *ClientMessage) {
-	go func() {
 	for str := range c.recv {
-			parts := strings.SplitN(str, " ", 2)
+		m := ParseMessage(str)
-			server.Send(Message{parts[0], parts[1], c})
+		if m != nil {
+			server <- &ClientMessage{c, m}
 		}
-	}()
-}
-
-func (c *Client) Send(lines ...string) {
-	for _, line := range lines {
-		log.Printf("C <- S: %s", line)
-		c.send <- line
 	}
 }
 

src/irc/commands.go

@@ -0,0 +1,158 @@
+package irc
+
+import (
+	"strconv"
+	"strings"
+)
+
+type Message interface {
+	Handle(s *Server, c *Client)
+}
+
+type NewMessageFunc func([]string) Message
+
+type NickMessage struct {
+	nickname string
+}
+
+func NewNickMessage(args []string) Message {
+	if len(args) != 1 {
+		return nil
+	}
+	return &NickMessage{args[0]}
+}
+
+func (m *NickMessage) Handle(s *Server, c *Client) {
+	if s.nicks[m.nickname] != nil {
+		c.send <- ErrNickNameInUse(m.nickname)
+		return
+	}
+	if c.nick != "" {
+		delete(s.nicks, c.nick)
+	}
+	c.nick = m.nickname
+	s.nicks[c.nick] = c
+	tryRegister(s, c)
+}
+
+type UserMessage struct {
+	user string
+	mode uint8
+	unused string
+	realname string
+}
+
+func NewUserMessage(args []string) Message {
+	if len(args) != 4 {
+		return nil
+	}
+	msg := new(UserMessage)
+	msg.user = args[0]
+	mode, err := strconv.ParseUint(args[1], 10, 8)
+	if err == nil {
+		msg.mode = uint8(mode)
+	}
+	msg.unused = args[2]
+	msg.realname = args[3]
+	return msg
+}
+
+func (m *UserMessage) Handle(s *Server, c *Client) {
+	if c.username != "" {
+		c.send <- ErrAlreadyRegistered(c.Nick())
+		return
+	}
+	c.username, c.realname = m.user, m.realname
+	tryRegister(s, c)
+}
+
+type QuitMessage struct {
+	message string
+}
+
+func NewQuitMessage(args []string) Message {
+	msg := QuitMessage{}
+	if len(args) > 0 {
+		msg.message = args[0]
+	}
+	return &msg
+}
+
+func (m *QuitMessage) Handle(s *Server, c *Client) {
+	c.send <- MessageError()
+	delete(s.nicks, c.nick)
+}
+
+type UnknownMessage struct {
+	command string
+}
+
+func (m *UnknownMessage) Handle(s *Server, c *Client) {
+	c.send <- ErrUnknownCommand(c.Nick(), m.command)
+}
+
+type PingMessage struct {}
+
+func NewPingMessage(args []string) Message {
+	return &PingMessage{}
+}
+
+func (m *PingMessage) Handle(s *Server, c *Client) {
+	c.send <- MessagePong()
+}
+
+func tryRegister(s *Server, c *Client) {
+	if (!c.registered && c.nick != "" && c.username != "") {
+		c.registered = true
+		c.send <- ReplyWelcome(c.Nick(), c.username, "localhost")
+		c.send <- ReplyYourHost(c.Nick(), "irc.jlatt.com")
+		c.send <- ReplyCreated(c.Nick(), "2012/04/07")
+		c.send <- ReplyMyInfo(c.Nick(), "irc.jlatt.com")
+	}
+}
+
+func parseArg(line string) (string, string) {
+	if line == "" {
+		return "", ""
+	}
+
+	if strings.HasPrefix(line, ":") {
+		return line[1:], ""
+	}
+
+	parts := strings.SplitN(line, " ", 2)
+	arg := parts[0]
+	rest := ""
+	if len(parts) > 1 {
+		rest = parts[1]
+	}
+	return arg, rest
+}
+
+func parseLine(line string) (string, []string) {
+	args := make([]string, 0)
+	for arg, rest := parseArg(line); arg != ""; arg, rest = parseArg(rest) {
+		args = append(args, arg)
+	}
+	return args[0], args[1:]
+}
+
+var commands = map[string]NewMessageFunc {
+	"NICK": NewNickMessage,
+	"PING": NewPingMessage,
+	"QUIT": NewQuitMessage,
+	"USER": NewUserMessage,
+}
+
+func ParseMessage(line string) Message {
+	command, args := parseLine(line)
+	constructor := commands[command]
+	var msg Message
+	if constructor != nil {
+		msg = constructor(args)
+	}
+	if msg == nil {
+		msg = &UnknownMessage{command}
+	}
+	return msg
+}

src/irc/net.go

@@ -7,18 +7,23 @@ import (
 	"net"
 )
 
+func readTrimmedLine(reader *bufio.Reader) (string, error) {
+	line, err := reader.ReadString('\n')
+	return strings.TrimSpace(line), err
+}
+
 // Adapt `net.Conn` to a `chan string`.
-func StringReadChan(conn net.Conn) chan string {
+func StringReadChan(conn net.Conn) <-chan string {
 	ch := make(chan string)
 	reader := bufio.NewReader(conn)
 	go func() {
 		for {
-			line, err := reader.ReadString('\n')
+			line, err := readTrimmedLine(reader)
 			if (line != "") {
-				ch <- strings.TrimSpace(line)
+				ch <- line
+				log.Printf("%s -> %s", conn.RemoteAddr(), line)
 			}
 			if err != nil {
-				log.Print("StringReadChan[read]: ", err)
 				break
 			}
 		}
@@ -27,16 +32,16 @@ func StringReadChan(conn net.Conn) chan string {
 	return ch
 }
 
-func StringWriteChan(conn net.Conn) chan string {
+func StringWriteChan(conn net.Conn) chan<- string {
 	ch := make(chan string)
 	writer := bufio.NewWriter(conn)
 	go func() {
 		for str := range ch {
 			if _, err := writer.WriteString(str + "\r\n"); err != nil {
-				log.Print("StringWriteChan[write]: ", err)
 				break
 			}
 			writer.Flush()
+			log.Printf("%s <- %s", conn.RemoteAddr(), str)
 		}
 		close(ch)
 	}()

src/irc/protocol.go

@@ -1,3 +1,4 @@
+// http://tools.ietf.org/html/rfc2812
 package irc
 
 import (

src/irc/server.go

@@ -3,19 +3,24 @@ package irc
 import (
 	"log"
 	"net"
-	"regexp"
-	"strings"
 )
 
 type Server struct {
-	ch chan Message
+	ch chan *ClientMessage
 	nicks map[string]*Client
 }
 
+type ClientMessage struct {
+	client *Client
+	message Message
+}
+
 func NewServer() *Server {
-	server := Server{make(chan Message), make(map[string]*Client)}
+	server := new(Server)
+	server.ch = make(chan *ClientMessage)
+	server.nicks = make(map[string]*Client)
 	go server.Receive()
-	return &server
+	return server
 }
 
 func (s *Server) Listen(addr string) {
@@ -30,71 +35,12 @@ func (s *Server) Listen(addr string) {
 			log.Print("Server.Listen: ", err)
 			continue
 		}
-		go NewClient(conn).Communicate(s)
+		go NewClient(conn).Communicate(s.ch)
 	}
 }
 
 func (s *Server) Receive() {
-	for message := range s.ch {
+	for m := range s.ch {
-		log.Printf("C -> S: %s %s", message.command, message.args)
+		m.message.Handle(s, m.client)
-		switch message.command {
-		case "PING":
-			message.client.Send(MessagePong())
-		case "USER":
-			s.UserCommand(message.client, message.args)
-		case "NICK":
-			s.NickCommand(message.client, message.args)
-		case "QUIT":
-			s.QuitCommand(message.client, message.args)
-		default:
-			message.client.Send(ErrUnknownCommand(message.client.Nick(), message.command))
 	}
 }
-}
-
-func (s *Server) Send(m Message) {
-	s.ch <- m
-}
-
-// commands
-
-func (s *Server) UserCommand(c *Client, args string) {
-	parts := strings.SplitN(args, " ", 4)
-	username, _, _, realname := parts[0], parts[1], parts[2], parts[3]
-	if c.username != "" {
-		c.Send(ErrAlreadyRegistered(c.nick))
-		return
-	}
-	c.username, c.realname = username, realname
-	s.TryRegister(c)
-}
-
-func (s *Server) NickCommand(c *Client, nick string) {
-	if s.nicks[nick] != nil {
-		c.Send(ErrNickNameInUse(nick))
-		return
-	}
-	c.nick = nick
-	s.nicks[nick] = c
-	s.TryRegister(c)
-}
-
-func (s *Server) TryRegister(c *Client) {
-	if (!c.registered && c.nick != "" && c.username != "") {
-		c.registered = true
-		c.Send(
-			ReplyWelcome(c.Nick(), c.username, "localhost"),
-			ReplyYourHost(c.Nick(), "irc.jlatt.com"),
-			ReplyCreated(c.Nick(), "2012/04/07"),
-			ReplyMyInfo(c.Nick(), "irc.jlatt.com"))
-	}
-}
-
-func (s *Server) QuitCommand(c *Client, args string) {
-	re := regexp.MustCompile("^" + RE_QUIT + "$")
-	matches := re.FindAllStringSubmatch(args, -1)
-	if matches != nil {
-		c.Send(MessageError())
-	}
-	delete(s.nicks, c.nick)
-}