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|
package server
import (
"errors"
"fmt"
"log"
"net"
"sync"
"git.sr.ht/~rctt/solec/core"
)
type Server struct {
listenAddr string
users map[string]User
mu sync.Mutex
}
type User struct {
Name string
Conns map[net.Conn]struct{}
}
func NewServer(listenAddr string) *Server {
return &Server{
listenAddr: listenAddr,
users: make(map[string]User),
}
}
func (s *Server) Start() error {
ln, err := net.Listen("tcp", s.listenAddr)
if err != nil {
return err
}
for {
conn, err := ln.Accept()
if err != nil {
log.Print("cannot accept connection: ", err)
}
log.Print("received connection from: ", conn.RemoteAddr())
go s.handleConn(conn)
}
}
func (s *Server) handleConn(conn net.Conn) {
if err := s.performHandshake(conn); err != nil {
log.Println("handshake error", err)
return
}
user, err := s.performAuth(conn)
if err != nil {
log.Println("auth error", err)
return
}
defer func() {
s.mu.Lock()
log.Println("client disconnected: ", user.Name)
delete(s.users[user.Name].Conns, conn)
if len(s.users[user.Name].Conns) == 0 {
log.Println("all connections closed for user:", user.Name)
delete(s.users, user.Name)
}
s.mu.Unlock()
}()
if err := s.readInput(conn, user); err != nil {
log.Println("cannot read incomming data", err)
}
}
func (s *Server) performHandshake(conn net.Conn) error {
serverHs := core.Handshake{0, 1}
if err := core.Send(conn, serverHs); err != nil {
return err
}
clientPayload, err := core.Decode(conn)
if err != nil {
return err
}
clientHs, ok := clientPayload.(core.Handshake)
if !ok {
return errors.New("received payload of invalid type")
}
if serverHs.Major != clientHs.Major {
return errors.New("server and client are using different protocol version")
}
return nil
}
func (s *Server) performAuth(conn net.Conn) (User, error) {
clientPayload, err := core.Decode(conn)
if err != nil {
return User{}, err
}
clientAuth, ok := clientPayload.(core.Auth)
if !ok {
return User{}, errors.New("received payload of invalid type")
}
user, ok := s.users[clientAuth.Name]
if !ok {
log.Println("initial connection from user:", clientAuth.Name)
user = newUser(conn, clientAuth)
s.users[clientAuth.Name] = user
return user, nil
}
log.Println("next connection from user:", user.Name)
user.Conns[conn] = struct{}{}
return user, nil
}
func newUser(conn net.Conn, auth core.Auth) User {
u := User{
Name: auth.Name,
Conns: make(map[net.Conn]struct{}),
}
u.Conns[conn] = struct{}{}
return u
}
func (s *Server) readInput(conn net.Conn, user User) error {
for {
payload, err := core.Decode(conn)
if err != nil {
return fmt.Errorf("decoder error: %w", err)
}
if err := s.handlePayload(conn, user, payload); err != nil {
return fmt.Errorf("payload handler error: %w", err)
}
}
}
func (s *Server) handlePayload(conn net.Conn, user User, payload any) error {
switch v := payload.(type) {
case core.Message:
return s.handleMessage(conn, user, v)
default:
return errors.New("invalid payload")
}
}
func (s *Server) handleMessage(conn net.Conn, user User, msg core.Message) error {
log.Println("message:", user.Name, "->", msg.Target, msg.Content)
if msg.Target == "*" {
return s.broadcastMessage(conn, user, msg)
}
return nil
}
func (s *Server) broadcastMessage(conn net.Conn, user User, msg core.Message) error {
for _, u := range s.users {
if u.Name == user.Name {
continue
}
for c := range u.Conns {
if err := core.Send(c, msg); err != nil {
log.Println("cannot send", err)
}
}
}
// Forward message for other connections from the same user
for c := range s.users[user.Name].Conns {
if err := core.Send(c, msg); err != nil {
log.Println("cannot send", err)
}
}
return nil
}
|
