Now server/auth is completely generic on the user type

server/auth.go

@@ -56,10 +56,15 @@ func (service *simpleAuthenticator) SessionTokenFromUser(userID string) (string,
 	return token, nil
 }
 
-func (service *simpleAuthenticator) UserFromSessionToken(session string) (string, error) {
-	user, present := service.sessions[session]
+func (service *simpleAuthenticator) UserFromSessionToken(session string) (*db.User, error) {
+	userID, present := service.sessions[session]
 	if !present {
-		return "", auth.ErrNoUserForSession
+		return nil, auth.ErrNoUserForSession
+	}
+
+	user, err := service.database.GetUser(userID)
+	if err != nil {
+		return nil, err
 	}
 
 	return user, nil

server/auth/auth.go

@@ -7,24 +7,30 @@ import (
 	"errors"
 	"net/http"
 	"time"
+
+	"git.phc.dm.unipi.it/aziis98/posti-dm/server/util"
 )
 
 var (
 	ErrNoUserForSession = errors.New(`no user for session token`)
 )
 
+type User[IdType any] interface {
+	UID() IdType
+}
+
 // Authenticator should be used by clients to provide authentication functions and mapping of session tokens to users
-type Authenticator interface {
+type Authenticator[UserID any, U User[UserID]] interface {
 	// CheckUserPassword is called to login a user and create a corresponding session, see also "SessionTokenFromUser"
-	CheckUserPassword(userID string, password string) error
+	CheckUserPassword(user UserID, password string) error
 
 	// GetUserPermissions gets the list of permissions for this user
-	UserPermissions(userID string) ([]string, error)
+	UserPermissions(user UserID) ([]string, error)
 
 	// SessionTokenFromUser returns a (new) session token that represents this user
-	SessionTokenFromUser(userID string) (string, error)
+	SessionTokenFromUser(user UserID) (string, error)
 	// UserFromSessionToken returns the corresponding user for this session token or "service.ErrNoUserForSession"
-	UserFromSessionToken(session string) (string, error)
+	UserFromSessionToken(session string) (U, error)
 
 	// AuthenticationFailed handles failed authentications
 	AuthenticationFailed(error) http.Handler
@@ -42,19 +48,19 @@ type MiddlewareConfig struct {
 }
 
 // AuthSessionService given an Authenticator provides functions to login and logout users and an http.Handler middleware that accept users based on permissions and login status
-type AuthSessionService struct {
+type AuthSessionService[UserID any, U User[UserID]] struct {
 	SessionCookieName     string
 	SessionCookiePath     string
 	SessionCookieDuration time.Duration
 
-	Authenticator
+	Authenticator Authenticator[UserID, U]
 }
 
 // NewAuthSessionService creates a new "*AuthSessionService" with a default session cookie name and path
-func NewAuthSessionService(auth Authenticator) *AuthSessionService {
+func NewAuthSessionService[UserID any, U User[UserID]](auth Authenticator[UserID, U]) *AuthSessionService[UserID, U] {
 	oneWeek := 7 * 24 * time.Hour
 
-	return &AuthSessionService{
+	return &AuthSessionService[UserID, U]{
 		"session",
 		"/",
 		oneWeek,
@@ -63,7 +69,7 @@ func NewAuthSessionService(auth Authenticator) *AuthSessionService {
 }
 
 // Login tries to login a user given its id and password
-func (service *AuthSessionService) Login(w http.ResponseWriter, userID, password string) error {
+func (service *AuthSessionService[UserID, U]) Login(w http.ResponseWriter, userID UserID, password string) error {
 	if err := service.Authenticator.CheckUserPassword(userID, password); err != nil {
 		return err
 	}
@@ -84,7 +90,7 @@ func (service *AuthSessionService) Login(w http.ResponseWriter, userID, password
 }
 
 // Logout clears the session cookie from a request effectively logging out the user for future requests
-func (service *AuthSessionService) Logout(w http.ResponseWriter) {
+func (service *AuthSessionService[UserID, U]) Logout(w http.ResponseWriter) {
 	http.SetCookie(w, &http.Cookie{
 		Name:    service.SessionCookieName,
 		Path:    service.SessionCookiePath,
@@ -94,7 +100,7 @@ func (service *AuthSessionService) Logout(w http.ResponseWriter) {
 }
 
 // Middleware returns an http middleware that accepts users based on login status and permissions
-func (service *AuthSessionService) Middleware(config *MiddlewareConfig) func(http.Handler) http.Handler {
+func (service *AuthSessionService[UserID, U]) Middleware(config *MiddlewareConfig) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			cookie, err := r.Cookie(service.SessionCookieName)
@@ -112,7 +118,7 @@ func (service *AuthSessionService) Middleware(config *MiddlewareConfig) func(htt
 				return
 			}
 
-			userID, err := service.Authenticator.UserFromSessionToken(cookie.Value)
+			user, err := service.Authenticator.UserFromSessionToken(cookie.Value)
 			if err == ErrNoUserForSession {
 				service.Logout(w)
 				w.WriteHeader(http.StatusUnauthorized)
@@ -124,7 +130,7 @@ func (service *AuthSessionService) Middleware(config *MiddlewareConfig) func(htt
 			}
 
 			if config.RequireLogged {
-				userPerms, err := service.Authenticator.UserPermissions(userID)
+				userPerms, err := service.Authenticator.UserPermissions(user.UID())
 				if err != nil {
 					service.Authenticator.OtherError(err).ServeHTTP(w, r)
 					return
@@ -168,7 +174,7 @@ func (service *AuthSessionService) Middleware(config *MiddlewareConfig) func(htt
 //	Middleware(*AuthMiddlewareConfig)
 //
 // that only accepts logged in users, no special permissions are checked
-func (service *AuthSessionService) LoggedMiddleware() func(http.Handler) http.Handler {
+func (service *AuthSessionService[UserID, U]) LoggedMiddleware() func(http.Handler) http.Handler {
 	return service.Middleware(&MiddlewareConfig{
 		RequireLogged:   true,
 		NeedPermissions: []string{},
@@ -181,16 +187,16 @@ func (service *AuthSessionService) LoggedMiddleware() func(http.Handler) http.Ha
 //	func (auth *AuthService[U]) RequestUser(r *http.Request) *U
 //
 // and will just return nil if no user is present.
-func (service *AuthSessionService) RequestUser(r *http.Request) (string, error) {
+func (service *AuthSessionService[UserID, U]) RequestUser(r *http.Request) (U, error) {
 	cookie, err := r.Cookie(service.SessionCookieName)
 	if err != nil {
-		return "", err
+		return util.Zero[U](), err
 	}
 
-	userID, err := service.Authenticator.UserFromSessionToken(cookie.Value)
+	user, err := service.Authenticator.UserFromSessionToken(cookie.Value)
 	if err == ErrNoUserForSession {
-		return "", err
+		return util.Zero[U](), err
 	}
 
-	return userID, nil
+	return user, nil
 }

server/db/database.go

@@ -38,6 +38,10 @@ type User struct {
 	// passwordSaltHash string
 }
 
+func (user User) UID() string {
+	return user.ID
+}
+
 // Room represents a room in the database, a room has an id, a name and a collection of seatIDs of this room.
 type Room struct {
 	ID      string   `json:"id"`

server/server.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"net/http"
 
 	"git.phc.dm.unipi.it/aziis98/posti-dm/server/auth"
@@ -11,7 +12,7 @@ import (
 )
 
 type Server struct {
-	auth *auth.AuthSessionService
+	auth *auth.AuthSessionService[string, *db.User]
 
 	roomServerEventStreams map[string]serverevents.Handler
 
@@ -24,7 +25,7 @@ func NewServer() *Server {
 
 	server := &Server{
 		Database: database,
-		auth: auth.NewAuthSessionService(
+		auth: auth.NewAuthSessionService[string, *db.User](
 			&simpleAuthenticator{
 				make(map[string]string),
 				database,
@@ -84,17 +85,12 @@ func (server *Server) setupRoutes() {
 		})
 
 	api.Get("/user", func(w http.ResponseWriter, r *http.Request) {
-		userID, err := auth.RequestUser(r)
+		user, err := auth.RequestUser(r)
 		if err != nil {
 			httputil.WriteJSON(w, nil)
 			return
 		}
 
-		user, err := database.GetUser(userID)
-		if err != nil {
-			http.Error(w, err.Error(), http.StatusNotFound)
-		}
-
 		httputil.WriteJSON(w, user)
 	})
 
@@ -134,38 +130,40 @@ func (server *Server) setupRoutes() {
 		server.roomServerEventStreams[roomID[0]].ServeHTTP(w, r)
 	})
 
+	requestSeat := func(r *http.Request) (*db.Seat, error) {
+		seatID, ok := r.URL.Query()["id"]
+		if !ok {
+			return nil, fmt.Errorf(`missing seat id`)
+		}
+
+		seat, err := database.GetSeat(seatID[0])
+		if err != nil {
+			return nil, err
+		}
+
+		return seat, nil
+	}
+
 	api.With(auth.LoggedMiddleware()).
 		Post("/seat/occupy", func(w http.ResponseWriter, r *http.Request) {
 			database.BeginTransaction()
 			defer database.EndTransaction()
 
-			userID, err := auth.RequestUser(r)
+			user, err := auth.RequestUser(r)
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusUnauthorized)
 				return
 			}
 
-			user, err := database.GetUser(userID)
-			if err != nil {
-				http.Error(w, err.Error(), http.StatusInternalServerError)
-				return
-			}
-
-			seatID, ok := r.URL.Query()["id"]
-			if !ok {
-				http.Error(w, `missing seat id`, http.StatusBadRequest)
-				return
-			}
-
-			seat, err := database.GetSeat(seatID[0])
+			seat, err := requestSeat(r)
 			if err != nil {
-				http.Error(w, err.Error(), http.StatusInternalServerError)
+				http.Error(w, err.Error(), http.StatusBadRequest)
 				return
 			}
 
 			// a seat can be occupied only if empty; simple users can occupy a seat only if they have occupied no other seat; admins and moderator (for now) can occupy even more than one seat (as occupied by an anonymous?) to fix the free seat count of the room
 			if len(seat.OccupiedBy) == 0 {
-				userSeats, err := database.GetUserSeats(userID)
+				userSeats, err := database.GetUserSeats(user.ID)
 				if err != nil {
 					http.Error(w, err.Error(), http.StatusInternalServerError)
 					return
@@ -176,7 +174,7 @@ func (server *Server) setupRoutes() {
 					return
 				}
 
-				if err := database.OccupySeat(seatID[0], userID); err != nil {
+				if err := database.OccupySeat(seat.ID, user.ID); err != nil {
 					http.Error(w, err.Error(), http.StatusInternalServerError)
 					return
 				}
@@ -190,34 +188,22 @@ func (server *Server) setupRoutes() {
 
 	api.With(auth.LoggedMiddleware()).
 		Post("/seat/leave", func(w http.ResponseWriter, r *http.Request) {
-			userID, err := auth.RequestUser(r)
+			user, err := auth.RequestUser(r)
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusUnauthorized)
 				return
 			}
 
-			user, err := database.GetUser(userID)
-			if err != nil {
-				http.Error(w, err.Error(), http.StatusInternalServerError)
-				return
-			}
-
-			seatID, ok := r.URL.Query()["id"]
-			if !ok {
-				http.Error(w, `missing seat id`, http.StatusBadRequest)
-				return
-			}
-
-			seat, err := database.GetSeat(seatID[0])
+			seat, err := requestSeat(r)
 			if err != nil {
-				http.Error(w, err.Error(), http.StatusInternalServerError)
+				http.Error(w, err.Error(), http.StatusBadRequest)
 				return
 			}
 
 			// Check permissions, if the place is occupied then only its owner, a moderator or an admin can clear it
 			if len(seat.OccupiedBy) > 0 {
 				if user.ID == seat.OccupiedBy[0] || user.Permissions.HasAny(db.PermissionAdmin, db.PermissionModerator) {
-					if err := database.FreeSeat(seatID[0]); err != nil {
+					if err := database.FreeSeat(seat.ID); err != nil {
 						http.Error(w, err.Error(), http.StatusInternalServerError)
 						return
 					}

server/util/generics.go

@@ -0,0 +1,5 @@
+package util
+
+func Zero[T any]() T {
+	return *new(T)
+}