Handle errors for Cloud Storage on Flutter

Sometimes when you're building an app, things don't go as planned and an error occurs!

When in doubt, catch the exception thrown by the function and see what the error message has to say.

final storageRef = FirebaseStorage.instance.ref().child("files/uid");
try {
  final listResult = await storageRef.listAll();
} on FirebaseException catch (e) {
  // Caught an exception from Firebase.
  print("Failed with error '${e.code}': ${e.message}");
}

Note: By default, a Cloud Storage for Firebase bucket requires Firebase Authentication to perform any action on the bucket's data or files. You can change your Firebase Security Rules for Cloud Storage to allow unauthenticated access for specific situations. However, for most situations, we strongly recommend restricting access and setting up robust security rules (especially for production apps). Note that if you use Google App Engine and have a default Cloud Storage bucket with a name format of *.appspot.com, you may need to consider how your security rules impact access to App Engine files.

Handle Error Messages

There are a number of reasons why errors may occur, including the file not existing, the user not having permission to access the desired file, or the user cancelling the file upload.

To properly diagnose the issue and handle the error, here is a full list of all the errors our client will raise, and how they occurred.

Code	Description
storage/unknown	An unknown error occurred.
storage/object-not-found	No object exists at the desired reference.
storage/bucket-not-found	No bucket is configured for Cloud Storage
storage/project-not-found	No project is configured for Cloud Storage
storage/quota-exceeded	Quota on your Cloud Storage bucket has been exceeded. If you're on the Spark pricing plan, consider upgrading to the pay-as-you-go Blaze pricing plan. If you're already on the Blaze pricing plan, reach out to Firebase Support. Important: Starting October 1, 2025, the Blaze pricing plan will be required to use Cloud Storage, even default buckets.
storage/unauthenticated	User is unauthenticated, please authenticate and try again.
storage/unauthorized	User is not authorized to perform the desired action, check your security rules to ensure they are correct.
storage/retry-limit-exceeded	The maximum time limit on an operation (upload, download, delete, etc.) has been excceded. Try uploading again.
storage/invalid-checksum	File on the client does not match the checksum of the file received by the server. Try uploading again.
storage/canceled	User canceled the operation.
storage/invalid-event-name	Invalid event name provided. Must be one of [running, progress, pause]
storage/invalid-url	Invalid URL provided to refFromURL(). Must be of the form: gs://bucket/object or https://firebasestorage.googleapis.com/v0/b/bucket/o/object?token=<TOKEN>
storage/invalid-argument	The argument passed to put() must be File, Blob, or UInt8 Array. The argument passed to putString() must be a raw, Base64, or Base64URL string.
storage/no-default-bucket	No bucket has been set in your config's storageBucket property.
storage/cannot-slice-blob	Commonly occurs when the local file has changed (deleted, saved again, etc.). Try uploading again after verifying that the file hasn't changed.
storage/server-file-wrong-size	File on the client does not match the size of the file received by the server. Try uploading again.