防止从 Firebase 数据库中删除现有数据

Question

I want to allow read and write but not delete existing nodes. these are the rules I have but is still allowing to delete (update)

"messages_test": {
    ".read": "true",
    ".write": "true",
    "$message": {
        ".write": "false",
    }
},

this is how I´m removing the node (succesffuly, but i should get permission denied instead)

    firebase.database().ref('messages_test').child(id).remove()
        .catch(error => console.log(error.message));

thanks for your help

Answer 1

I guess I found the way. restricting the write for existing data

"messages_test": {
    ".read": "true",
    "$message": {
      ".write": "!data.exists() && newData.exists()",
    }
},

Answer 2

"messages_test": {
    ".read": "true",
    "$message": {
      ".write": "newData.exists()",
    }
},