source: code/trunk/server.go@ 556

package soju

import (
        "fmt"
        "log"
        "mime"
        "net"
        "net/http"
        "strings"
        "sync"
        "sync/atomic"
        "time"

        "gopkg.in/irc.v3"
        "nhooyr.io/websocket"

        "git.sr.ht/~emersion/soju/config"
)

// TODO: make configurable
var retryConnectDelay = time.Minute
var connectTimeout = 15 * time.Second
var writeTimeout = 10 * time.Second
var upstreamMessageDelay = 2 * time.Second
var upstreamMessageBurst = 10

type Logger interface {
        Print(v ...interface{})
        Printf(format string, v ...interface{})
}

type prefixLogger struct {
        logger Logger
        prefix string
}

var _ Logger = (*prefixLogger)(nil)

func (l *prefixLogger) Print(v ...interface{}) {
        v = append([]interface{}{l.prefix}, v...)
        l.logger.Print(v...)
}

func (l *prefixLogger) Printf(format string, v ...interface{}) {
        v = append([]interface{}{l.prefix}, v...)
        l.logger.Printf("%v"+format, v...)
}

type Server struct {
        Hostname       string
        Logger         Logger
        HistoryLimit   int
        LogPath        string
        Debug          bool
        HTTPOrigins    []string
        AcceptProxyIPs config.IPSet
        Identd         *Identd // can be nil

        db     Database
        stopWG sync.WaitGroup

        lock      sync.Mutex
        listeners map[net.Listener]struct{}
        users     map[string]*user
}

func NewServer(db Database) *Server {
        return &Server{
                Logger:       log.New(log.Writer(), "", log.LstdFlags),
                HistoryLimit: 1000,
                db:           db,
                listeners:    make(map[net.Listener]struct{}),
                users:        make(map[string]*user),
        }
}

func (s *Server) prefix() *irc.Prefix {
        return &irc.Prefix{Name: s.Hostname}
}

func (s *Server) Start() error {
        users, err := s.db.ListUsers()
        if err != nil {
                return err
        }

        s.lock.Lock()
        for i := range users {
                s.addUserLocked(&users[i])
        }
        s.lock.Unlock()

        return nil
}

func (s *Server) Shutdown() {
        s.lock.Lock()
        for ln := range s.listeners {
                if err := ln.Close(); err != nil {
                        s.Logger.Printf("failed to stop listener: %v", err)
                }
        }
        for _, u := range s.users {
                u.events <- eventStop{}
        }
        s.lock.Unlock()

        s.stopWG.Wait()
}

func (s *Server) createUser(user *User) (*user, error) {
        s.lock.Lock()
        defer s.lock.Unlock()

        if _, ok := s.users[user.Username]; ok {
                return nil, fmt.Errorf("user %q already exists", user.Username)
        }

        err := s.db.StoreUser(user)
        if err != nil {
                return nil, fmt.Errorf("could not create user in db: %v", err)
        }

        return s.addUserLocked(user), nil
}

func (s *Server) getUser(name string) *user {
        s.lock.Lock()
        u := s.users[name]
        s.lock.Unlock()
        return u
}

func (s *Server) addUserLocked(user *User) *user {
        s.Logger.Printf("starting bouncer for user %q", user.Username)
        u := newUser(s, user)
        s.users[u.Username] = u

        s.stopWG.Add(1)

        go func() {
                u.run()

                s.lock.Lock()
                delete(s.users, u.Username)
                s.lock.Unlock()

                s.stopWG.Done()
        }()

        return u
}

var lastDownstreamID uint64 = 0

func (s *Server) handle(ic ircConn) {
        id := atomic.AddUint64(&lastDownstreamID, 1)
        dc := newDownstreamConn(s, ic, id)
        if err := dc.runUntilRegistered(); err != nil {
                dc.logger.Print(err)
        } else {
                dc.user.events <- eventDownstreamConnected{dc}
                if err := dc.readMessages(dc.user.events); err != nil {
                        dc.logger.Print(err)
                }
                dc.user.events <- eventDownstreamDisconnected{dc}
        }
        dc.Close()
}

func (s *Server) Serve(ln net.Listener) error {
        s.lock.Lock()
        s.listeners[ln] = struct{}{}
        s.lock.Unlock()

        s.stopWG.Add(1)

        defer func() {
                s.lock.Lock()
                delete(s.listeners, ln)
                s.lock.Unlock()

                s.stopWG.Done()
        }()

        for {
                conn, err := ln.Accept()
                // TODO: use net.ErrClosed when available
                if err != nil && strings.Contains(err.Error(), "use of closed network connection") {
                        return nil
                } else if err != nil {
                        return fmt.Errorf("failed to accept connection: %v", err)
                }

                go s.handle(newNetIRCConn(conn))
        }
}

func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
        conn, err := websocket.Accept(w, req, &websocket.AcceptOptions{
                OriginPatterns: s.HTTPOrigins,
        })
        if err != nil {
                s.Logger.Printf("failed to serve HTTP connection: %v", err)
                return
        }

        isProxy := false
        if host, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
                if ip := net.ParseIP(host); ip != nil {
                        isProxy = s.AcceptProxyIPs.Contains(ip)
                }
        }

        // Only trust the Forwarded header field if this is a trusted proxy IP
        // to prevent users from spoofing the remote address
        remoteAddr := req.RemoteAddr
        if isProxy {
                forwarded := parseForwarded(req.Header)
                if forwarded["for"] != "" {
                        remoteAddr = forwarded["for"]
                }
        }

        s.handle(newWebsocketIRCConn(conn, remoteAddr))
}

func parseForwarded(h http.Header) map[string]string {
        forwarded := h.Get("Forwarded")
        if forwarded == "" {
                return map[string]string{
                        "for":   h.Get("X-Forwarded-For"),
                        "proto": h.Get("X-Forwarded-Proto"),
                        "host":  h.Get("X-Forwarded-Host"),
                }
        }
        // Hack to easily parse header parameters
        _, params, _ := mime.ParseMediaType("hack; " + forwarded)
        return params
}