librapi/services/authentication.go
2025-01-03 14:17:37 +01:00

158 lines
3.0 KiB
Go

package services
import (
"context"
"crypto/rand"
"encoding/hex"
"errors"
"net/http"
"sync"
"time"
"github.com/rs/zerolog/log"
)
var (
ErrSessionIDCollision = errors.New("sessionId collision")
ErrUnauthorized = errors.New("unauthorized")
)
func generateSessionID() (string, error) {
sessionID := make([]byte, 32) //nolint
if _, err := rand.Read(sessionID); err != nil {
return "", err
}
return hex.EncodeToString(sessionID), nil
}
type Session struct {
l sync.RWMutex
sessionID string
expirationTime time.Time
}
func (s *Session) GenerateCookie() *http.Cookie {
s.l.RLock()
defer s.l.RUnlock()
return &http.Cookie{
Name: "session_id",
Value: s.sessionID,
HttpOnly: true,
Secure: GetEnv().isSecure,
Expires: s.expirationTime,
}
}
type IAuthenticate interface {
IsLogged(r *http.Request) bool
Authenticate(username, password string) (*Session, error)
}
var _ IAuthenticate = (*Authentication)(nil)
type Authentication struct {
l sync.RWMutex
ctx context.Context
fnCancel context.CancelFunc
sessions map[string]*Session
}
func NewAuthentication(ctx context.Context) *Authentication {
ctxChild, fnCancel := context.WithCancel(ctx)
s := &Authentication{
ctx: ctxChild,
fnCancel: fnCancel,
sessions: map[string]*Session{},
}
s.purgeWorker()
return s
}
func (a *Authentication) purge() {
a.l.Lock()
defer a.l.Unlock()
now := time.Now()
toDelete := []*Session{}
for _, session := range a.sessions {
if now.After(session.expirationTime) {
toDelete = append(toDelete, session)
}
}
for _, session := range toDelete {
log.Debug().Str("sessionId", session.sessionID).Msg("purge expired session")
delete(a.sessions, session.sessionID)
}
}
func (a *Authentication) purgeWorker() {
ticker := time.NewTicker(10 * time.Second) //nolint
go func() {
for {
select {
case <-ticker.C:
a.purge()
case <-a.ctx.Done():
log.Info().Msg("purge worker stopped")
ticker.Stop()
return
}
}
}()
}
func (a *Authentication) Stop() {
a.fnCancel()
}
func (a *Authentication) Done() <-chan struct{} {
return a.ctx.Done()
}
func (a *Authentication) Authenticate(username, password string) (*Session, error) {
adminUsername, adminPassword := GetEnv().GetCredentials()
if username != adminUsername || password != adminPassword {
return nil, ErrUnauthorized
}
sessionID, err := generateSessionID()
if err != nil {
log.Err(err).Msg("unable to generate sessionId")
return nil, err
}
a.l.Lock()
defer a.l.Unlock()
if _, ok := a.sessions[sessionID]; ok {
log.Error().Str("sessionId", sessionID).Msg("sessionId collision")
return nil, ErrSessionIDCollision
}
now := time.Now().Add(GetEnv().GetSessionExpirationDuration())
session := Session{expirationTime: now, sessionID: sessionID}
a.sessions[sessionID] = &session
return &session, nil
}
func (a *Authentication) IsLogged(r *http.Request) bool {
cookie, err := r.Cookie("session_id")
if err != nil {
return false
}
a.l.RLock()
defer a.l.RUnlock()
_, ok := a.sessions[cookie.Value]
return ok
}