init

2026-08-22 02:59:16 +02:00
commit 6a5bb1d699
100 changed files with 17409 additions and 0 deletions
@@ -0,0 +1,243 @@
+package auth
+
+import (
+	"context"
+	"crypto/hmac"
+	"crypto/sha256"
+	"crypto/subtle"
+	"database/sql"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+	"golang.org/x/crypto/bcrypt"
+)
+
+const (
+	sessionCookieName = "studio_session"
+	visitorCookieName = "studio_visitor"
+	accessCookieName  = "studio_gallery_access"
+	sessionDuration   = 7 * 24 * time.Hour
+	accessDuration    = 12 * time.Hour
+)
+
+var (
+	ErrInvalidCredentials = errors.New("invalid credentials")
+	ErrInvalidSession     = errors.New("invalid session")
+)
+
+type Service struct {
+	repository *Repository
+	secret     []byte
+	secure     bool
+}
+
+func NewService(repository *Repository, secret string, secureCookie bool) (*Service, error) {
+	if len(secret) < 32 {
+		return nil, fmt.Errorf("session secret must be at least 32 characters")
+	}
+	return &Service{repository: repository, secret: []byte(secret), secure: secureCookie}, nil
+}
+
+func (s *Service) Register(ctx context.Context, email, password, name string) (User, error) {
+	email = strings.ToLower(strings.TrimSpace(email))
+	name = strings.TrimSpace(name)
+	if !strings.Contains(email, "@") || len(email) > 254 {
+		return User{}, fmt.Errorf("enter a valid email address")
+	}
+	if len(password) < 8 {
+		return User{}, fmt.Errorf("password must be at least 8 characters")
+	}
+	if name == "" || len(name) > 120 {
+		return User{}, fmt.Errorf("name is required")
+	}
+
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return User{}, fmt.Errorf("hash password: %w", err)
+	}
+	return s.repository.CreateUser(ctx, email, string(hash), name)
+}
+
+func (s *Service) Login(ctx context.Context, email, password string) (User, error) {
+	user, err := s.repository.FindByEmail(ctx, email)
+	if errors.Is(err, sql.ErrNoRows) {
+		return User{}, ErrInvalidCredentials
+	}
+	if err != nil {
+		return User{}, err
+	}
+	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(password)); err != nil {
+		return User{}, ErrInvalidCredentials
+	}
+	return user.User, nil
+}
+
+func (s *Service) SetSession(w http.ResponseWriter, user User) {
+	payload := sessionPayload{UserID: user.ID.String(), ExpiresAt: time.Now().Add(sessionDuration).Unix()}
+	token, err := s.signJSON(payload)
+	if err != nil {
+		return
+	}
+	http.SetCookie(w, &http.Cookie{
+		Name:     sessionCookieName,
+		Value:    token,
+		Path:     "/",
+		MaxAge:   int(sessionDuration.Seconds()),
+		HttpOnly: true,
+		Secure:   s.secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func (s *Service) ClearSession(w http.ResponseWriter) {
+	http.SetCookie(w, &http.Cookie{
+		Name:     sessionCookieName,
+		Value:    "",
+		Path:     "/",
+		MaxAge:   -1,
+		HttpOnly: true,
+		Secure:   s.secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func (s *Service) UserFromRequest(ctx context.Context, r *http.Request) (User, error) {
+	cookie, err := r.Cookie(sessionCookieName)
+	if err != nil {
+		return User{}, ErrInvalidSession
+	}
+	var payload sessionPayload
+	if err := s.verifyJSON(cookie.Value, &payload); err != nil {
+		return User{}, ErrInvalidSession
+	}
+	userID, err := uuid.Parse(payload.UserID)
+	if err != nil || payload.ExpiresAt <= time.Now().Unix() {
+		return User{}, ErrInvalidSession
+	}
+	user, err := s.repository.FindByID(ctx, userID)
+	if errors.Is(err, sql.ErrNoRows) {
+		return User{}, ErrInvalidSession
+	}
+	return user, err
+}
+
+type contextKey string
+
+const userContextKey contextKey = "authenticated-user"
+
+func (s *Service) Require(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user, err := s.UserFromRequest(r.Context(), r)
+		if err != nil {
+			writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "authentication required"})
+			return
+		}
+		next.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), userContextKey, user)))
+	})
+}
+
+func UserFromContext(ctx context.Context) (User, bool) {
+	user, ok := ctx.Value(userContextKey).(User)
+	return user, ok
+}
+
+func (s *Service) EnsureVisitor(w http.ResponseWriter, r *http.Request) string {
+	if cookie, err := r.Cookie(visitorCookieName); err == nil {
+		if _, err := uuid.Parse(cookie.Value); err == nil {
+			return cookie.Value
+		}
+	}
+
+	visitorID := uuid.NewString()
+	http.SetCookie(w, &http.Cookie{
+		Name:     visitorCookieName,
+		Value:    visitorID,
+		Path:     "/",
+		MaxAge:   int(365 * 24 * time.Hour / time.Second),
+		HttpOnly: true,
+		Secure:   s.secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+	return visitorID
+}
+
+func (s *Service) GrantGalleryAccess(w http.ResponseWriter, slug string) {
+	payload := accessPayload{Slug: slug, ExpiresAt: time.Now().Add(accessDuration).Unix()}
+	token, err := s.signJSON(payload)
+	if err != nil {
+		return
+	}
+	http.SetCookie(w, &http.Cookie{
+		Name:     accessCookieName,
+		Value:    token,
+		Path:     "/",
+		MaxAge:   int(accessDuration.Seconds()),
+		HttpOnly: true,
+		Secure:   s.secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func (s *Service) HasGalleryAccess(r *http.Request, slug string) bool {
+	cookie, err := r.Cookie(accessCookieName)
+	if err != nil {
+		return false
+	}
+	var payload accessPayload
+	if err := s.verifyJSON(cookie.Value, &payload); err != nil {
+		return false
+	}
+	return payload.Slug == slug && payload.ExpiresAt > time.Now().Unix()
+}
+
+type sessionPayload struct {
+	UserID    string `json:"userId"`
+	ExpiresAt int64  `json:"expiresAt"`
+}
+
+type accessPayload struct {
+	Slug      string `json:"slug"`
+	ExpiresAt int64  `json:"expiresAt"`
+}
+
+func (s *Service) signJSON(value any) (string, error) {
+	data, err := json.Marshal(value)
+	if err != nil {
+		return "", err
+	}
+	encoded := base64.RawURLEncoding.EncodeToString(data)
+	return encoded + "." + s.signature(encoded), nil
+}
+
+func (s *Service) verifyJSON(token string, target any) error {
+	encoded, signature, ok := strings.Cut(token, ".")
+	if !ok || subtle.ConstantTimeCompare([]byte(signature), []byte(s.signature(encoded))) != 1 {
+		return ErrInvalidSession
+	}
+	data, err := base64.RawURLEncoding.DecodeString(encoded)
+	if err != nil {
+		return ErrInvalidSession
+	}
+	if err := json.Unmarshal(data, target); err != nil {
+		return ErrInvalidSession
+	}
+	return nil
+}
+
+func (s *Service) signature(value string) string {
+	hash := hmac.New(sha256.New, s.secret)
+	_, _ = hash.Write([]byte(value))
+	return base64.RawURLEncoding.EncodeToString(hash.Sum(nil))
+}
+
+func writeJSON(w http.ResponseWriter, status int, value any) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(value)
+}