Do not forward messages to Firebase if topic is not world-readable

auth/auth.go

@@ -64,8 +64,8 @@ type User struct {
 // Grant is a struct that represents an access control entry to a topic
 type Grant struct {
 	TopicPattern string // May include wildcard (*)
-	Read         bool
-	Write        bool
+	AllowRead    bool
+	AllowWrite   bool
 }
 
 // Permission represents a read or write permission to a topic

auth/auth_sqlite.go

@@ -281,8 +281,8 @@ func (a *SQLiteAuth) readGrants(username string) ([]Grant, error) {
 		}
 		grants = append(grants, Grant{
 			TopicPattern: fromSQLWildcard(topic),
-			Read:         read,
-			Write:        write,
+			AllowRead:    read,
+			AllowWrite:   write,
 		})
 	}
 	return grants, nil

cmd/access.go

@@ -144,11 +144,11 @@ func showUsers(c *cli.Context, manager auth.Manager, users []*auth.User) error {
 			fmt.Fprintf(c.App.ErrWriter, "- read-write access to all topics (admin role)\n")
 		} else if len(user.Grants) > 0 {
 			for _, grant := range user.Grants {
-				if grant.Read && grant.Write {
+				if grant.AllowRead && grant.AllowWrite {
 					fmt.Fprintf(c.App.ErrWriter, "- read-write access to topic %s\n", grant.TopicPattern)
-				} else if grant.Read {
+				} else if grant.AllowRead {
 					fmt.Fprintf(c.App.ErrWriter, "- read-only access to topic %s\n", grant.TopicPattern)
-				} else if grant.Write {
+				} else if grant.AllowWrite {
 					fmt.Fprintf(c.App.ErrWriter, "- write-only access to topic %s\n", grant.TopicPattern)
 				} else {
 					fmt.Fprintf(c.App.ErrWriter, "- no access to topic %s\n", grant.TopicPattern)

server/server.go

@@ -117,14 +117,6 @@ const (
 // New instantiates a new Server. It creates the cache and adds a Firebase
 // subscriber (if configured).
 func New(conf *Config) (*Server, error) {
-	var firebaseSubscriber subscriber
-	if conf.FirebaseKeyFile != "" {
-		var err error
-		firebaseSubscriber, err = createFirebaseSubscriber(conf)
-		if err != nil {
-			return nil, err
-		}
-	}
 	var mailer mailer
 	if conf.SMTPSenderAddr != "" {
 		mailer = &smtpSender{config: conf}
@@ -151,6 +143,14 @@ func New(conf *Config) (*Server, error) {
 			return nil, err
 		}
 	}
+	var firebaseSubscriber subscriber
+	if conf.FirebaseKeyFile != "" {
+		var err error
+		firebaseSubscriber, err = createFirebaseSubscriber(conf, auther)
+		if err != nil {
+			return nil, err
+		}
+	}
 	return &Server{
 		config:    conf,
 		cache:     cache,
@@ -172,7 +172,7 @@ func createCache(conf *Config) (cache, error) {
 	return newMemCache(), nil
 }
 
-func createFirebaseSubscriber(conf *Config) (subscriber, error) {
+func createFirebaseSubscriber(conf *Config, auther auth.Auther) (subscriber, error) {
 	fb, err := firebase.NewApp(context.Background(), nil, option.WithCredentialsFile(conf.FirebaseKeyFile))
 	if err != nil {
 		return nil, err
@@ -182,7 +182,7 @@ func createFirebaseSubscriber(conf *Config) (subscriber, error) {
 		return nil, err
 	}
 	return func(m *message) error {
-		var data map[string]string // Matches https://ntfy.sh/docs/subscribe/api/#json-message-format
+		var data map[string]string // Mostly matches https://ntfy.sh/docs/subscribe/api/#json-message-format
 		switch m.Event {
 		case keepaliveEvent, openEvent:
 			data = map[string]string{
@@ -192,6 +192,11 @@ func createFirebaseSubscriber(conf *Config) (subscriber, error) {
 				"topic": m.Topic,
 			}
 		case messageEvent:
+			allowForward := true
+			if auther != nil {
+				allowForward = auther.Authorize(nil, m.Topic, auth.PermissionRead) == nil
+			}
+			if allowForward {
 				data = map[string]string{
 					"id":       m.ID,
 					"time":     fmt.Sprintf("%d", m.Time),
@@ -211,6 +216,16 @@ func createFirebaseSubscriber(conf *Config) (subscriber, error) {
 					data["attachment_expires"] = fmt.Sprintf("%d", m.Attachment.Expires)
 					data["attachment_url"] = m.Attachment.URL
 				}
+			} else {
+				// If anonymous read for a topic is not allowed, we cannot send the message along
+				// via Firebase. Instead, we send a "poll_request" message, asking the client to poll.
+				data = map[string]string{
+					"id":    m.ID,
+					"time":  fmt.Sprintf("%d", m.Time),
+					"event": pollRequestEvent,
+					"topic": m.Topic,
+				}
+			}
 		}
 		var androidConfig *messaging.AndroidConfig
 		if m.Priority >= 4 {

server/types.go

@@ -11,6 +11,7 @@ const (
 	openEvent        = "open"
 	keepaliveEvent   = "keepalive"
 	messageEvent     = "message"
+	pollRequestEvent = "poll_request"
 )
 
 const (