Thanks Tim.
I’ll try to explain my best (sorry, it will be long):
The idea is that the app sends a message to a certain server.
App writes the message at the project's FireBase Real Time Data Base, at /UID/node/.
The server (currently it's also implemented as another AppInventor app running on a tablet) has Administrator privileges and has a listener set up on this node, so it receives the message.
Once enough time is allowed for the message to be received by the server (some hundred milliseconds), the app cleans the message from DB.
The reason to delete the messages this way, is that the server would be to busy to take care of that (because there will be too many apps accessing a single server).
Everything was working fine with the standard Fire Base App Inventor blocks.
But every day I received an email from FireBase, warning that current rules allow that anyone could read or write on the database. So I tried to secure the data base.
In order to protect the communication between apps and server from possible pirates, I tried that only authenticated apps could write messages to server. So I set up some rules on FirebaseDB:
"$uid" : {
".write" : "$uid === auth.uid",
"node" : {
".read" : false,
},
}
Now, writing on /UID/node/ was prevented, unless app has previously authenticated at FBAuth (I do this using the Gustavo Arango's extension).
Upon authenticating, an IdToken is received by the app, which includes the UID.
This UID, is the same of the path /UID/node/.
When I tried to secure the database, I discovered that the standard AppInventor FireBase blocks doesn't allow to write authenticated requests. So I had to redesign the whole communications part of the app, to write http REST authenticated requests instead.
With the help of your explanations I achieved to send them. And the receipt of those messages by server succeeded most of the times, but not always.
Randomly (let's say once every 7 times) I got an 1103 error reply from FireBase to the app (and, of course, this message was missing and was never received by the server).
I also had problemns deleting the messages:
FB always returned a 200 answer.
But I could see from FireBase console, that some times the message was still there on the data base.
I couldn't find the reason, nor solve the issue. So I surrendered.
I had to think of different FB rules (more relaxed and less secure), and come back to using the standard FB App Inventor blocks, that work so fine, and never fail.
