I understand that I can specify rules for some features in firebase like real-time database and firebase storage.
Example:
I can specify a rule in real time database that allows only users to update their data under their specific UID.
Question:
Is it possible to specify a rule in firebase storage such that a user can download a file (ex: image) if and only if he exists under a certain node in the real time database?
Is this communication between security rules of different products possible?
If no, what can I do?
Thanks.
You can't communicate between products like this.
What you can do instead is use custom claims on authenticated user profiles to control who can access what locations in various products.
Read more about custom claims here.
Read more about realtime database rules with custom claims. Read about auth.token.
In Firestore, you can use request.auth.token to access custom claims.
In Cloud Storage, you can also use request.auth.token.
Related
I have the file stored in firebase cloud storage. This file will only available for the paid user download.
How to set up security rules to allow the paid user to have read access to that file?
[Updated]
I use the cloud firestore to store user collection
Each user doc contain
uid
email
name
photoUrl
provider
status
stripeCustomerId
purchasedProducts << this is the array of product name
I can verify paid user by looking if the product exist in purchasedProducts array.
However, inside the security rule from Firebase storage, it seem I can't access resource (user collection) in there. Or am I missing something?
Thanks
There is no way to access Cloud Firestore from within the security rules for Firebase Storage.
That means the only ways to currently implement your use-case is to:
include the necessary information in the ID token of the user, as a custom claim, which is then also available in security rules.
include the necessary information about the user (probably their UID) in your security rules
Since the second approach requires that you update your rules for every paying user, it's not very common.
Setting a custom claim can be done through the Firebase Admin SDK, for example from a Cloud Function that triggers when you write their payment information to Cloud Firestore.
Once you set the custom claim it may take up to an hour before it's available on the client, and from there in the security rules. The reason for that is that the claims are included in the ID token, which only auth-refreshes once an hour. If you want to get the updated claims sooner, you can force a refresh of the user's profile on the client.
Another approach you can try is to delete a file right after it was uploaded using the functions.storage.object().onFinalize webhook - this is wehere you can access the database and check if the user was allowed to upload the file.
Even though it may look a bit 'hacky' at the first glance, this is really a precaution measure in the first place - the UI itself would restrict the upload for the "good" users. And for those who messes up with the source code and tries to circumvent the system, onFinalize would do the job.
You can access cloud firestore through the firestorage service security rules:
https://firebase.google.com/docs/storage/security/rules-conditions#enhance_with_firestore
I have migrated data to firebase storage, which have structure like:
<fileId>/<filename>
I can store fileIds associated with user in firebase database like:
<userId>/<fileids>
Is there anyway I can get something like auth.uid/fileids from firebase database in security rules of firestorage, to only allow to read file to auth user, if fileIds belong to him. If not, what all options are available to achieve the same and which one is best among them?
It's currently not possible to use data from databases in your Cloud Storage security rules. You can only use information about the object stored in the bucket.
You could instead write a backend API that performs all the checks and then operates on the object in storage, or store information about the file in its metadata for use in rules.
I have a database having multiple groups - each having their own roles (admins, mods, etc..)
I have rules setup on firestore.
How do I replicate that on storage rules ?
To put it briefly, you can't without serious modifications.
Storage rules can't access Firestore documents. So all of the relationship you have in Firestore can not be used in Storage.
You can use Firebase Auth custom claims to attach per-user data that can be used in both Firestore and Storage, but this means you will have to duplicate that relationship data into those claims and keep them in sync in backend code.
You can also duplicate data from Firestore into metadata attached to files in Storage, and use that metadata in security rules to determine who can read or write individual files.
These are your only viable options without creating your own backend API endpoints that enforce security.
I have created an app, that allows users to create a simple photo collection. All the data is stored in the Firebase Cloud Firestore. The images are uploaded to Firebase Storage.
The owner of a collection can invite any other user to access his collection and upload photos.
The sharing of data in Firestore works fine. But now I have problems with writing the security rules for Storage. Does anyone know, how I have to write the rules, so that any user added to the collection can access the images as well? The files for each collection are stored in separate folders.
Firebase security rules currently do not bridge between products. You can't use data in Cloud Firestore in security rules for Cloud Storage. The only things you have access to in security rules for Cloud Storage are object metadata and Firebase Authentication custom claims per user. You will have to figure out a way to make changes to either one of those things to implement your permissions.
Alternatively, you can direct all access through Cloud Functions to decide if the user should be able to access the content, but bear in mind that Cloud Functions responses can only be 10MB maximum.
You should look into creating a private group and authenticate the group with help of private token.
https://firebase.google.com/docs/storage/security/user-security#group_private
I need to check a document's data in Firestore to allow someone to view an image in Firebase Storage. Is this possible?
It is currently not possible to access Cloud Firestore documents directly from Cloud Storage rules. You have two options:
Somehow use Firebase Authentication custom claims on the user account to determine if a user should be able to access a file.
Use some backend code (maybe a Cloud Functions HTTP trigger) that the user accesses to download the file if the conditions are met.
In either case, you will need some backend code that checks and sets the appropriate data.