FR: Generation Number For Downloading

[A-G91]

Feature proposal

• Firebase Component: Storage

In the FIRStorageReference's 'writeToFile' method, provide an option to specify a generation number so we can download a non-live version from the cloud storage bucket.

The FIRStorageDownloadTask is only setting 'alt=media' in the query parameter and provides no options to set other query parameters, such as the generation number.

If there is a way to do this via the iOS SDK that I am unaware of, please let me know.

[morganchen12]

Firebase Storage doesn't keep older copies of a file when you write to it; that file is overwritten and older versions become inaccessible. If you'd like to avoid this, you should store the files at different paths and use a service like RTDB to track additional file metadata.

[A-G91]

Thanks for the response Morgan.

My understanding was Firebase Storage was built on GCS, so the features in GCS would be available in Firebase Storage. In this case, object versioning. If I enable object versioning on my Firebase Storage bucket, I can use gsutil to see all the old non-live versions that I uploaded via the storage client SDK.

That is why I'm confused by your comment "Firebase Storage doesn't keep older copies of a file when you write to it; that file is overwritten and older versions become inaccessible". Based on my tests, if I modify the FIRStorageDownloadTask and add my own query parameters to specify a generation number, I am able to get that specific file (even if it is not the live version).

Is there a reason you do not want to allow the client SDK to specify a generation number in the query parameters?

Thanks in advance!

[schmidt-sebastian]

Firebase Storage is an abstraction that is built on top of GCS. It adds some functionality (such as long-lived download URLs that you can store in Firestore and the RTDB), but it hides other functionality that is not commonly requested on Mobile. Every request from our SDKs is first handled by a Firebase Storage backend and as such, it requires a considerable amount of work from our backend team to enable functionality even if it already exists as part of GCS.

We will keep this feature request open to gather more feedback, but we do not have immediate plans to expand the scope of the features we offer.