code/unchat/server.go

package unchat

import (
	"fmt"
	"log"
	"net"
)

//A Server is a proposed type to hold details about itself and connected clients
type Server struct {
	alias    string
	version  string
	port     int32
	clients  map[string]Client
	listener net.Listener
}

//NewServer initialize a standard server with common attributes
func NewServer(alias string) Server {
	return Server{
		alias:   alias,
		port:    9999,
		version: "default",
	}
}

//Open expects the port and the ip address which a TCP listener will be started
func (s *Server) Open(listenAddress string) {

	var server net.Listener
	address := fmt.Sprintf("%s:%d", listenAddress, s.port)
	server, err := net.Listen("TCPV4", address)
	s.listener = server
	if err != nil {
		log.Fatalf("could not listen on %s %s", address, err)
	}
	defer s.listener.Close()
	for {
		conn, err := s.listener.Accept()
		if err != nil {
			log.Fatalf("could not accept connection %s", err)
		}

		go s.handleConnection(conn)
		defer conn.Close()

	}
}

func (s *Server) handleConnection(conn net.Conn) {
	c := &Client{
		client: conn,
		alias:  "undefined",
		server: s,
	}

	if s.clients == nil {
		s.clients = make(map[string]Client)
	}
	s.clients[c.alias] = *c
	s.Broadcast(fmt.Sprintf("> %s has joined the server", c.alias))
	c.ReadInput()
}

//Broadcast sends a message to all connected clients
func (s *Server) Broadcast(message string) error {
	for _, v := range s.clients {
		err := v.SendMessage(message)
		if err != nil {
			log.Printf("count not broadcast to %s: %s", s.alias, err)
		}
	}
	return nil
}