Firestore security rules for specific document - firebase

Question

I am trying to apply the following situation :
all authenticated users have read and write access to the database except for admin document.
Admin document is accessible only for him for read and write.
My rules:
service cloud.firestore {
match /databases/{database}/documents {
//Functions
function isAuthenticated(){
return request.auth != null;
}
function isAdministrator(){
return request.auth != null && request.auth.token.name == resource.data.oid;
}
//Administrator Identity Check Point
match /admin/identity {
allow read, write: if isAdministrator();
}
//Allow Reads and Writes for All Authenticated Users
match /{document=**}{
allow read, write: if isAuthenticated();
}
}//databases/{database}/documents
}//cloud.firestore
Is there any way i can achieve this, actually when testing these rules, the tests succeed because only isAuthenticated() is being called because of the tag /{document=**}. I also tried /{document!=/admin/identity} but it does not work.
How can I write a security rule that follow this model ?

Answer 1

Maybe on your default user rule you could check if the collection isn't admin, something like this:
//Allow Reads and Writes for All Authenticated Users
match /{collection}/{document=**}{
allow read, write: if (isAuthenticated() && collection != "admin") || isAdministrator();
}

Answer 2

Since June 17, Firebase has provided new improvements to Firestore Security Rules.
Firebase blog - 2020/06 - New Firestore Security Rules features
New Map methods
We'll use Map.get() to get the "roleToEdit" field. If the document doesn't have the field, it will default to the "admin" role. Then we'll compare that to the role that's on the user's custom claims:
allow update, delete: if resource.data.get("roleToEdit", "admin") == request.auth.token.role;
Local variables
Say you're commonly checking that a user meets the same three conditions before granting access: that they're an owner of the product or an admin user.
rules_version = '2';
service cloud.firestore {
match /databases/{database}/documents {
function privilegedAccess(uid, product) {
let adminDatabasePath = /databases/$(database)/documents/admins/$(uid);
let userDatabasePath = /databases/$(database)/documents/users/$(uid);
let ownerDatabasePath = /databases/$(database)/documents/$(product)/owner/$(uid);
let isOwnerOrAdmin = exists(adminDatabasePath) || exists(ownerDatabasePath);
let meetsChallenge = get(userDatabasePath).data.get("passChallenge", false) == true;
let meetsKarmaThreshold = get(userDatabasePath).get("karma", 1) > 5;
return isOwnerOrAdmin && meetsChallenge && meetsKarmaThreshold;
}
match /products/{product} {
allow read: if true;
allow write: if privilegedAccess();
}
match /categories/{category} {
allow read: if true;
allow write: if privilegedAccess();
}
match /brands/{brand} {
allow read, write: if privilegedAccess();
}
}
}
The same conditions grant access to write to documents in the three different collections.
Ternary operator
This is the first time we've introduced an if/else control flow, and we hope it will make rules smoother and more powerful.
Here's an example of using a ternary operator to specify complex conditions for a write.
A user can update a document in two cases: first, if they're an admin user, they need to either set the field overrideReason or approvedBy. Second, if they're not an admin user, then the update must include all the required fields:
allow update: if isAdminUser(request.auth.uid) ?
request.resource.data.keys().toSet().hasAny(["overrideReason", "approvedBy"]) :
request.resource.data.keys().toSet().hasAll(["all", "the", "required", "fields"])
It was possible to express this before the ternary, but this is a much more concise expression. ;)