chatserver

.gitignore

@@ -49,3 +49,4 @@ tcpserver/tcpserver
 echoserver/echoserver
 example-redis/example-redis
 echorot13/echorot13
+chatserver/chatserver

chatserver/main.go

@@ -0,0 +1,144 @@
+package main
+
+import (
+	"bufio"
+	"io"
+	"log"
+	"net"
+)
+
+type Client struct {
+	Connection *net.Conn
+	Name       string
+	Send       chan string
+}
+
+type Message struct {
+	cli     *Client
+	message string
+}
+
+type Server struct {
+	net.Listener
+	Clients     []Client
+	NewClients  chan Client
+	NewMessages chan Message
+}
+
+func (cli Client) Prompt() string {
+	return "<" + cli.Name + "> "
+}
+
+func (cli Client) SendMessages() {
+	for msg := range cli.Send {
+		io.WriteString(*cli.Connection, msg)
+	}
+}
+
+func (cli Client) WaitMessage(server *Server) {
+	scanner := bufio.NewScanner(*cli.Connection)
+	io.WriteString(*cli.Connection, cli.Prompt())
+	for scanner.Scan() {
+		msg := Message{&cli, scanner.Text()}
+		if len(msg.message) > 0 {
+			log.Println("New message from", cli.Name, msg.message)
+			server.NewMessages <- msg
+		}
+		io.WriteString(*cli.Connection, cli.Prompt())
+	}
+}
+
+func NewServer(addr string) (*Server, error) {
+	ln, err := net.Listen("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+	return &Server{
+		ln,
+		make([]Client, 0),
+		make(chan Client),
+		make(chan Message),
+	}, nil
+}
+
+func (server *Server) NewClient(conn *net.Conn) {
+	io.WriteString(*conn, "What is your name? ")
+	scanner := bufio.NewScanner(*conn)
+	for scanner.Scan() {
+		str := scanner.Text()
+		log.Println("New client", str)
+		cli := &Client{
+			conn,
+			str,
+			make(chan string),
+		}
+		server.NewClients <- *cli
+		return
+	}
+}
+
+func (server *Server) MessageDispatcher() {
+	for msg := range server.NewMessages {
+		log.Println("Dispatching message", msg.message, "from", msg.cli.Name)
+		for _, dest := range server.Clients {
+			if dest.Name != msg.cli.Name {
+				log.Println("Send message", msg.message, "from", msg.cli.Name, "to", dest.Name)
+				dest.Send <- "\n" + msg.cli.Prompt() + msg.message + "\n" + dest.Prompt()
+			}
+		}
+	}
+}
+
+func (server *Server) CreateClients() {
+	for cli := range server.NewClients {
+		exists := false
+		for _, c := range server.Clients {
+			if c.Name == cli.Name {
+				exists = true
+			}
+		}
+		if exists {
+			io.WriteString(*cli.Connection, "Name already in use\n")
+			go server.NewClient(cli.Connection)
+		} else {
+			server.Clients = append(server.Clients, cli)
+			log.Println("Client ready to chat", cli.Name)
+			log.Println(len(server.Clients), "clients connected")
+			go cli.WaitMessage(server)
+			go cli.SendMessages()
+		}
+	}
+}
+
+// wait connections from clients
+func (server *Server) handle() {
+	for {
+		conn, err := server.Accept()
+		if err != nil {
+			log.Println("Connection error", err)
+		}
+		go server.NewClient(&conn)
+		// TODO disconnect?
+	}
+	defer server.stop()
+}
+
+func (server *Server) stop() {
+	// TODO close connections
+	defer server.Close()
+}
+
+func (server *Server) start() {
+	log.Println("Starting server...")
+	go server.MessageDispatcher()
+	go server.CreateClients() // create client one at a time (race condition)
+	server.handle()
+}
+
+func main() {
+	server, err := NewServer(":9000")
+	if err != nil {
+		panic(err)
+	}
+	server.start()
+}