Firebase Security rules, disable write on specific node - firebase

Question

My firebase structure looking like that:
{
"post": {
"uid": {
"text": "Name";
}
},
"games": {
"id": {
"title": "buttons",
"text": "(user id string)"
},
"id": {
"title": "navbars",
"text": "(id string)"
}
},
"guides": {
"1": {
"title": "guide",
"text": "unwriteable string"
}
}
}
(The value doesn't matter..)
I want to allow read and write on everynode, execpt the guides node,
so I tried the following rules:
{
"rules": {
".read": "auth == null",
".write": "auth == null",
"guides": {
".write": false
}
}
}
But. unfortunately, because of the 'father' allowance, firebase doesn't care about the guides specific rule,
Any idea how to achive my goal?

Answer 1

Bacause firebase security rules cascade you can't say someone has permission to write everywhere and later say but not here.
So in you case you would have to add rules for your other paths like this:
{
"rules": {
".read": "auth == null",
"guides": {
".write": false
},
"games": {
".write": "auth == null"
},
"post": {
".write": "auth == null"
}
}
}
As Kato stated this can also be done with the following rule:
{
"rules": {
".read": "auth == null",
".write": "auth == null && !newData.hasChild('guides')"
}
}
The first example will allow you to write only in the games and post nodes whereas the second example will allow you to write everywhere except for the guides node.