Common rule patterns in Firebase - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of Firebase security rules?

Firebase security rules control who can read or write data in your database or storage. They protect your data from unauthorized access.

beginner

Explain the 'allow read, write: if false;' rule pattern.

This rule denies all reads and writes. It is used to block access completely until you define more specific rules.

beginner

What does 'allow read, write: if request.auth != null;' do?

It allows only authenticated users to read and write data. Users must be signed in to access the data.

intermediate

How do you allow users to only modify their own data in Firebase rules?

Use a rule that checks if the user ID matches the data owner ID, for example: 'allow write: if request.auth.uid == resource.data.userId;'.

intermediate

What is the benefit of using data validation in Firebase rules?

Data validation checks that data meets certain conditions before it is saved, helping keep your data clean and consistent.

Which Firebase rule pattern blocks all access to data?

A allow read, write: if true;

B allow read, write: if false;

C allow read: if request.auth != null;

D allow write: if request.auth.uid == resource.data.userId;

The rule 'allow read, write: if false;' denies all reads and writes, blocking all access.

What does 'request.auth != null' check in Firebase rules?

A If the user is an admin

B If the data exists

C If the request is from the server

D If the user is authenticated

It checks if the user is signed in (authenticated).

How can you restrict write access to only the owner of the data?

A allow write: if request.auth.uid == resource.data.userId;

B allow write: if true;

C allow write: if request.time < timestamp;

D allow write: if request.auth == null;

This rule allows writes only if the signed-in user's ID matches the data owner's ID.

What is the role of data validation in Firebase rules?

A To allow all reads

B To authenticate users

C To check data format before saving

D To deny all writes

Data validation ensures data meets conditions before it is saved.

Which rule allows anyone to read data but only authenticated users to write?

A allow read: if true; allow write: if request.auth != null;

B allow read, write: if request.auth != null;

C allow read, write: if false;

D allow write: if true;

This pattern lets anyone read but restricts writes to signed-in users.

Describe how Firebase rules can restrict data access to only authenticated users.

Think about how to check if a user is signed in.

Explain how to write a Firebase rule that lets users only change their own data.

Consider comparing user IDs in the rule.