2 files changed, 115 insertions, 0 deletions
diff --git a/pkg/session/memory.go b/pkg/session/memory.go
new file mode 100644
index 0000000..96e416b
--- /dev/null
+++ b/pkg/session/memory.go
@@ -0,0 +1,95 @@
+package session
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"sync"
+	"time"
+)
+
+type memoryStore struct {
+	sessionsByToken map[string]*UserSession
+	sessionsBySID   map[uint]*UserSession
+	nextSessionId   uint
+	lock            sync.RWMutex
+}
+
+func NewMemoryStore() Service {
+	return &memoryStore{
+		sessionsByToken: make(map[string]*UserSession),
+		sessionsBySID:   make(map[uint]*UserSession),
+	}
+}
+
+func (s *memoryStore) GetByToken(token string) *UserSession {
+	if token == "" {
+		return nil
+	}
+
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.sessionsByToken[token]
+}
+
+func (s *memoryStore) GetBySID(sid uint) *UserSession {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.sessionsBySID[sid]
+}
+
+func (s *memoryStore) Create(uid int32, username string, ip string, ua string) (*UserSession, error) {
+	token := generateSessionToken()
+
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	sessionId := s.nextSessionId
+	s.nextSessionId++
+
+	_, sidExists := s.sessionsBySID[sessionId]
+	_, tokenExists := s.sessionsByToken[token]
+
+	// should never realistically happen but still theoretically possible
+	if sidExists || tokenExists {
+		return nil, fmt.Errorf("session conflict")
+	}
+
+	session := &UserSession{
+		UserID:    uid,
+		SessionID: sessionId,
+		Token:     token,
+		Username:  username,
+		IP:        ip,
+		UserAgent: ua,
+		LoginTime: time.Now(),
+	}
+	s.sessionsByToken[token] = session
+	s.sessionsBySID[sessionId] = session
+
+	return session, nil
+}
+
+func (s *memoryStore) Destroy(sid uint) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	session := s.sessionsBySID[sid]
+	if session == nil {
+		return fmt.Errorf("session does not exist")
+	}
+
+	delete(s.sessionsBySID, sid)
+	delete(s.sessionsByToken, session.Token)
+	return nil
+}
+
+func generateSessionToken() string {
+	b := make([]byte, 100)
+	if _, err := rand.Read(b); err != nil {
+		return ""
+	}
+	return hex.EncodeToString(b)
+}
diff --git a/pkg/session/service.go b/pkg/session/service.go
new file mode 100644
index 0000000..83009bc
--- /dev/null
+++ b/pkg/session/service.go
@@ -0,0 +1,20 @@
+package session
+
+import "time"
+
+type Service interface {
+	GetByToken(token string) *UserSession
+	GetBySID(sid uint) *UserSession
+	Create(uid int32, username string, ip string, ua string) (*UserSession, error)
+	Destroy(sid uint) error
+}
+
+type UserSession struct {
+	UserID    int32
+	SessionID uint
+	Token     string
+	Username  string
+	IP        string
+	LoginTime time.Time
+	UserAgent string
+}