Firebase Security Rules with Firebase Authentication Tutorial

1. Introduction

This tutorial aims to introduce how Firebase Security Rules work in synergy with Firebase Authentication to provide robust security for your application. By the end of this tutorial, you will be able to write and implement security rules and integrate them with Firebase Authentication in your application.

Prerequisites:

• Basic knowledge of Firebase and its services.
• Familiarity with JavaScript and JSON.

2. Step-by-Step Guide

Firebase Security Rules are used to secure your data by controlling how your data in Cloud Firestore, Firebase Storage, and Realtime Database can be read and written. Firebase Authentication, on the other hand, is used to manage users in your application.

Understanding Security Rules

Firebase Security Rules language is a flexible, JSON-like syntax. For a document in Firestore, a rule might look like this:

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if false;
    }
  }
}

This rule denies all read and write operations on all documents in the database.

Understanding Firebase Authentication

Firebase Authentication provides backend services to authenticate users by verifying their identity. It supports authentication using passwords, phone numbers, popular federated identity providers like Google, Facebook, Twitter, and more.

3. Code Examples

Example 1: Allow read/write to authenticated users

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if request.auth != null;
    }
  }
}

This rule allows read and write operations for any user who is authenticated.

Example 2: Allow read/write to specific user

service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{userId} {
      allow read, write: if request.auth != null && request.auth.uid == userId;
    }
  }
}

This rule allows read and write operations only for the user who owns this specific document.

4. Summary

In this tutorial, we've covered the basics of Firebase Security Rules and Firebase Authentication, and we've seen how to combine them to secure your application. From here, you can explore more complex rules and conditions as per your application needs.

5. Practice Exercises

Exercise 1: Write a Security Rule that allows read operations to any authenticated user but only allows write operations to users with an email that ends with "@myapp.com".

Exercise 2: Write a Security Rule that only allows a user to write to their own user document.

Exercise 3: Write a Security Rule that allows read operations to any authenticated user but only allows write operations to users with verified email.

Solutions:

Exercise 1:

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read: if request.auth != null;
      allow write: if request.auth != null && request.auth.token.email.matches('.*@myapp.com$');
    }
  }
}

Exercise 2:

service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{userId} {
      allow read, write: if request.auth != null && request.auth.uid == userId;
    }
  }
}

Exercise 3:

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read: if request.auth != null;
      allow write: if request.auth.token.email_verified;
    }
  }
}

Remember, these rules are just the start. Firebase Security Rules offer a powerful and flexible way to manage your application's security. Be sure to consult the Firebase Security Rules documentation to learn more.