如何找出滥用Firestore请求的用户？客户端与Firebase方案选择

Hey Nick, let's tackle your Firestore quota problem step by step—first figuring out who's hammering your database, then deciding whether client-side fixes or Firebase rules/functions are the way to go.

First: Identify the Overusing User #

You need visibility into which user is sending those repeated requests. Here's how to get it:

• Leverage Firebase Console Monitoring: Head to the Firestore section in your Firebase Console, click the "Monitoring" tab, and check the Usage panel. This shows overall request volumes by operation type (read/write/delete). If you're using Firebase Auth, you can tie this data to user IDs by adding custom logging.
• Add Custom Logging: In your client code or cloud functions, log every Firestore operation with the user's ID. For example, in your frontend:

  console.log(`Firestore ${operationType} request from user: ${currentUser.uid}`);
  

  In cloud functions, just add a console.log with the authenticated user's UID whenever a Firestore operation is processed. Then head to Cloud Logging, filter logs by user ID, and count up their requests to spot the culprit.
• BigQuery Export + SQL Queries: Export your Firestore usage data to BigQuery (you can set this up in the Firebase Console's "Export" section). Then run a simple SQL query to aggregate requests per user—this is great for analyzing historical usage over days or weeks.

Client-Side vs. Firebase Rules/Functions: Which Is Better? #

Let's cut to the chase: client-side fixes are not reliable for stopping malicious users. Here's why:

Client-Side Limitations #

Any rate-limiting or checks you add to your frontend can be easily bypassed. A determined user can edit your client code, use browser dev tools, or write their own script to send unlimited requests. Client-side code is only useful for friendly rate-limiting (like showing a "please wait" message to legitimate users who click too fast)—it won't stop abuse.

Firebase Rules + Cloud Functions: The Real Solution #

This combo is the way to go for enforcing limits and banning bad actors:

1. Firebase Rules for Basic Protection:
   You can write rules to restrict how often a user can perform operations. For example, limit write requests to 10 per minute by tracking counts in a separate user_requests collection:

   match /databases/{database}/documents {
     match /{document=**} {
       allow write: if request.auth != null &&
         get(/databases/$(database)/documents/user_requests/$(request.auth.uid)).data.minute_count < 10;
     }
   }
   

   You'll need a cloud function to increment this count on each write and reset it every minute (using a scheduled function or timestamp checks).
   You can also restrict access to specific documents/collections to prevent bulk abuse.

2. Cloud Functions for Dynamic Banning:
   Write a cloud function that listens to Firestore operations (or acts as a proxy for your requests) and tracks user request volumes. When a user exceeds your threshold, you can:

   • Immediately reject their request with an error.
   • Add a custom claim to their Firebase Auth account (like banned: true) using admin.auth().setCustomUserClaims(uid, { banned: true }).
   • Then update your Firestore rules to block any requests from banned users:

     match /databases/{database}/documents {
       match /{document=**} {
         allow read, write: if request.auth != null && !request.auth.token.banned;
       }
     }
     

Bonus: Set Up Quota Alerts #

Don't wait until you hit the daily limit! In the Firebase Console's "Quota" page, set up alerts for when your Firestore usage reaches 80% of the daily quota. This way you'll get notified early and can intervene before things break.

Final Takeaways #

• Finding the user: Combine custom logging with Cloud Logging or BigQuery exports to pinpoint who's overusing your Firestore.
• Fixing the problem: Always rely on Firebase rules and cloud functions—client-side code is too easy to bypass. Use rules for basic rate-limiting and functions to dynamically ban abusive users.
• Prevent future issues: Quota alerts will help you catch problems before they hit your limit.

内容的提问来源于stack exchange，提问作者Nick Pampoukidis