null

当我确实从Firebase云消息发送给自己一条测试消息时，它确实工作正常，并且成功地向每个设备发送了一个推送通知。

例如，以下是

 exports.observeLikes = functions.database.ref('/user-likes/{uid}/{postId}').onCreate((snapshot, event) => {
     var uid = event.params.uid;
     var postId = event.params.postId;

     return admin.database().ref('/users/' + uid).once('value', snapshot => {
       var userThatLikedPost = snapshot.val();

       return admin.database().ref('/posts/' + postId).once('value', snapshot => {
         var post = snapshot.val();

         if(uid === post.ownerUid) {
          return Promise.resolve();
        }


         return admin.database().ref('/users/' + post.ownerUid).once('value', snapshot => {
           var postOwner = snapshot.val();

           var payload = {
             notification: {
               body: userThatLikedPost.username + ' liked your post ',
              sound: 'default'
             }
           };

           admin.messaging().sendToDevice(postOwner.fcmToken, payload)
           .then((response) => {
             // Response is a message ID string.
             console.log('Successfully sent message:', response);
             return response;
           })
           .catch((error) => {
             console.log('Error sending message:', error);
             throw new Error('Error sending message:', error);
           });
             })
         })
       })
     })

null