Скачать или смотреть Understanding Firebase Firestore Update Rules: Can You Have Multiple Rules for One Collection?

Explore how to handle multiple update rules in Firebase Firestore and learn how they affect your permissions for updating collections.
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Understanding Firebase Firestore Update Rules: Can You Have Multiple Rules for One Collection?

Managing permissions in Firebase Firestore can sometimes be tricky, especially when it comes to updating properties within a collection. If you've ever encountered permission issues when trying to update properties, you're not alone. In today’s guide, we’ll dive into the complexities of Firestore's security rules, specifically focusing on the ability to have multiple update rules for a collection.

The Problem: Multiple update Rules

Let’s outline the core issue faced by many developers:

A user is tasked with updating a property within a particular collection, but encounters permissions problems due to existing Firestore rules. They wonder if having multiple update rules is permissible and how it impacts their ability to successfully update properties when not all required fields are included in the request.

What Happens When You Have Multiple Rules?

Is It Allowed?: The short answer is yes; you can have multiple rules for a single access method like update. This can be beneficial as different conditions can be tailored to fit varied scenarios within your application.

Do Rules Get Skipped?: It's important to know that no rules are skipped in the evaluation process. Firestore computes the logical OR of all applicable rules. This means that if any one of your rules allows an update, the operation will succeed.

Dissecting the Rules

Let's delve deeper into the security rules provided in the scenario:

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Key Points of Concern

The first two rules for update enforce that the request must include keys for name, owners, and members.

This creates a situation where attempting to update only the members property could lead to rejection, as the rules expect additional fields.

The Solution: Understanding How Firestore Handles Data

The key takeaway here is understanding how request.resource.data operates:

Complete Data Object: When you attempt an update, request.resource.data contains the entire object being written, not just the specified fields. Therefore, if a name field exists already in the document, its value is considered during the rules evaluation.

Field Presence Matters: If you don’t provide a value for a required field during the update and that field does not exist in the original document, the rules will reject your update.

Steps to Proceed

Ensure Required Fields are Present: If you're looking to only update members, be certain that name and owners are also provided in your request if those rules are in place.

Consider Simplifying Rules: If your application requires frequent updates to members alone, consider modifying your security rules to allow this flexibility, depending on the needs of your application.

Testing with Rules Playground: Utilize the Rules Playground in Firebase to test your updates carefully while adjusting your rules.

Conclusion

In summary, Firebase Firestore does allow multiple update rules, but all relevant rules are evaluated collectively. Understanding how these rules operate can help you create a more robust security model for your application. Always ensure that the necessary fields are included in the requests as per your defined rules for smoother operations.

For anyone facing similar permissions issues, remember: no rule is skipped, and the overall structure of your requests is critical for successful updates.