Securing your FlutterFlow app with Firebase Security Rules

Introduction

The security of your app’s data is paramount, and FirebaseSecurity Rules play a critical role in protecting your Firestore database.Properly configured security rules ensure that only authorized users can access and modify data, protecting sensitive information from unauthorized access and potential breaches.

In this blog, we will walk you through setting up FirebaseSecurity Rules, understanding their importance, and implementing best practices to keep your app secure. We’ll also explain how to manage these rules withinFlutterFlow & Firebase.

 How Firebase Security Rules work

Firebase Security Rules are expressions that define who can read and write data in your Firestore database. They are evaluated at the database level before any read or write operations are executed. This makes sure that unauthorized requests are denied upfront.

Why security rules are important

1. Data integrity – only allows authorized users can modify data, preventing unauthorized changes.
2. Data privacy – makes sure that sensitive user information from unauthorized access is always protected.
3. Application security – prevents malicious users from exploiting your database.

Implementing security rules in FlutterFlow

FlutterFlow provides an intuitive interface to manage security rules for your Firestore database. Here’s how you can configure these rules.

FlutterFlow security rules options

1. Create
2. Read
3. Write
4. Delete

Each action has four access levels:

1. No One: no users can perform this action.
2. Tagged Users: only users tagged with a specific identifier can perform this action.
3. Authenticated Users: any authenticated user can perform this action – authenticated user just means logged in user, so anyone that is logged into your app is authenticated.
4. Everyone: all users, including unauthenticated users, can perform this action.

Example scenario in FlutterFlow

Let’s take a social media app where users can create, read, update, and delete their posts. If you want only the user who created a post to be able to delete it:

1. Set the Delete rule to Tagged Users.
2. Tag the rule on the field user_id (assuming that user_id is a field of type reference to your users collection).

Tagged Users: This option lets you filter actions based on the current user making the request. If a post has a user_id field that matches the ID of the logged-in user, only that user can delete the post. 

For example, if I created a post on a social media app, I should be the only person allowed to delete it. Therefore, the rule on delete for that post should be “Tagged Users” on the field where my user reference (user_id) is set.

Setting up rules in FlutterFlow

1. Go to the Firestore section inFlutterFlow.
2. Navigate to the Security Rules tab.
3. Select the appropriate action (Create, Read, Write, Delete).
4. Choose the access level (No One, TaggedUsers, Authenticated Users, Everyone).
5. For Tagged Users, specify the field to filter by the current user.

Finding Firebase Security Rules inside Firebase

Firebase Security Rules can also be managed through the Firebase Console. To access them:

1. Go to the Firebase Console.
2. Select your project.
3. Navigate to Firestore Database.
4. Click on the “Rules” tab.

Here, you can write and edit rules that protect your Firestore collections and documents.

Firebase Security Rules example

Suppose you have a collection named “posts” where users can create, read, update, and delete posts.

service cloud.firestore {
  match /databases/{database}/documents {
    match /posts/{postId} {
      // Allow read access for authenticated users
      allow read: if request.auth != null;

      // Allow write access for the owner of the post
      allow write: if request.auth != null && request.auth.uid == resource.data.userId;
    }
  }
}

Explanation:

• allow read: if request.auth != null; - authenticated (logged in) users can read posts.
• allow write: if request.auth != null && request.auth.uid == resource.data.userId; - only the user who created the post (userId) can modify it.

Best practices for Firebase Security Rules

1. Principle of least privilege: grant the minimum necessary permissions to users.
2. Validate data: ensure that incoming data conforms to expected formats and values.
3. Use custom claims for roles: useFirebase Authentication custom claims to implement role-based access control (we didn’t cover that in this blog, but we will in another one).
4. Test rules thoroughly: use theFirebase Emulator Suite to test your security rules before deploying them.

Conclusion

Securing your Firebase database with proper security rules is essential for protecting your app and its users. By understanding and implementing Firebase Security Rules, you guarantee that your data remains safe and accessible only to authorized users. Using FlutterFlow’s interface, you can easily manage these rules and tailor them to your app’s specific needs.However, we recommend to always go into Firebase and try to tailor your rules even a little bit more!