Firebase how check path contains value and allow read and write other path-CodePudding

At the moment i try to build a chat in flutter with google firebase. Now i would like my database more secure. That means only users (room_3) in chat can read and write data data.

Is it possible to check a path contains a user value and if the user value is contains allow read a other path?

Here my database structer:

/chat/product_id/product_id_12345/chat_room_id/room_1/message_1/message2...

My idea is i add in 'room_1' the user id. Then i check the user is contains in 'room_1'. If the user is contains i allow read and write data the complete path (message_1/message_2...).

Here my example:

If you have any questions fell free to ask me. Many thx.

CodePudding user response：

In the security rules for the messages subcollection you can read the parent document and check whether the current user is in the user_id field with:

...
match /messages/{message} {
  allow read: 
    if request.auth != null && 
       request.auth.uid in 
         get(/databases/$(database)/documents/chat_room/$(chat_room_id)).data.user_id
}