Persist, renew and delete sessions, refactor storage package, move reusable packages to pkg

pkg/session/session.go

@@ -0,0 +1,106 @@
+package session
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"net/http"
+	"sync"
+	"time"
+)
+
+var (
+	CookieName = "session"
+
+	Expiration      = time.Hour * 24 * 7
+	RefreshInterval = time.Hour
+)
+
+type Session struct {
+	UserID uint64
+
+	key        string
+	createdAt  int64
+	expiration *time.Timer
+	lock       sync.Mutex
+}
+
+func New(id uint64) (*Session, error) {
+	key, err := newSessionKey()
+	if err != nil {
+		return nil, err
+	}
+
+	return &Session{
+		key:        key,
+		createdAt:  time.Now().Unix(),
+		UserID:     id,
+		expiration: time.NewTimer(Expiration),
+	}, nil
+}
+
+func (s *Session) Init() {
+	exp := time.Until(time.Unix(s.createdAt, 0).Add(Expiration))
+	s.expiration = time.NewTimer(exp)
+}
+
+func (s *Session) Key() string {
+	s.lock.Lock()
+	key := s.key
+	s.lock.Unlock()
+	return key
+}
+
+func (s *Session) SetCookie(w http.ResponseWriter, r *http.Request) {
+	http.SetCookie(w, &http.Cookie{
+		Name:     CookieName,
+		Value:    s.Key(),
+		Path:     "/",
+		Expires:  time.Now().Add(Expiration),
+		HttpOnly: true,
+		Secure:   r.TLS != nil,
+	})
+}
+
+func (s *Session) Expired() bool {
+	s.lock.Lock()
+	created := time.Unix(s.createdAt, 0)
+	s.lock.Unlock()
+	return time.Since(created) > Expiration
+}
+
+func (s *Session) Refresh() (string, bool, error) {
+	s.lock.Lock()
+	created := time.Unix(s.createdAt, 0)
+	s.lock.Unlock()
+
+	if time.Since(created) > Expiration {
+		return "", true, nil
+	}
+
+	if time.Since(created) > RefreshInterval {
+		key, err := newSessionKey()
+		if err != nil {
+			return "", false, err
+		}
+
+		s.expiration.Reset(Expiration)
+
+		s.lock.Lock()
+		s.createdAt = time.Now().Unix()
+		s.key = key
+		s.lock.Unlock()
+		return key, false, nil
+	}
+
+	return "", false, nil
+}
+
+func (s *Session) WaitUntilExpiration() {
+	<-s.expiration.C
+}
+
+func newSessionKey() (string, error) {
+	key := make([]byte, 32)
+	_, err := rand.Read(key)
+	return base64.RawURLEncoding.EncodeToString(key), err
+}