Usage

S3

Pre-signed URLs

The link_to function for the S3 backend creates a temporary, pre-signed URL that can be used for uploads or downloads.

Uploads

• PUT request required

• Must have a header of content-type: application/octet-stream set

  • If header doesn’t match the expected value, you will get a 400 error

• Make sure you have permissions to the key you are creating

  • The SDK will happily generate pre-signed URLs that are not available to the generating user

• Body is file contents

JavaScript example:

const resp = await axios.default.put(storageUrl, file, {
    headers: { "content-type": "application/octet-stream" },
});

StorageOperations wrapper/mixin

class keg_storage.StorageOperations

Ops wrapper for storage operations that will typically occur in a flask app.

Assumes the storage plugin is being used and configured with storage profiles.

Class properties storage_location and storage_profile may be assigned defaults in a subclass direct any of the operations to that folder path or configured interface. storage_location is expected to be an Enum.

Each method will also take storage_location and storage_profile, so they can be provided directly for one-offs. So, this class can be used directly or as a mixin.

classmethod storage_delete_file(filename, storage_location=None, storage_profile=None)

Remove file data from storage.

classmethod storage_download_file(filename, storage_location=None, storage_profile=None)

Pull file data from storage, return BytesIO stream.

classmethod storage_duplicate_file(filename, storage_location=None, storage_profile=None)

Copy file data already in storage to a new file object. Generates the new filename using a UUID.

static storage_generate_filename(filename)

Generate a UUID-based filename for an object, typically for upload to prevent path collisions. If the provided original filename has an extension, honor that extension.

classmethod storage_get_download_link(filename, expire_minutes, storage_location=None, storage_profile=None, **kwargs)

Generate an expiring download link to pass to client for a stored object.

classmethod storage_get_profile(storage_profile=None)

Get configured storage interface. Either specify which interface via the storage_profile kwarg, or it will fall back to the first defined profile.

classmethod storage_get_upload_link(filename, expire_minutes, storage_location=None, storage_profile=None)

Generate an expiring upload link to pass to client for data to be stored.

static storage_prefix_path(location: Enum | None, filename: str)

Join the location path with the filename to get the full object path

classmethod storage_upload_file(file_object, filename, preserve_filename=False, storage_location=None, storage_profile=None, content_type=None, content_encoding=None)

Push file data to storage. A UUID-based filename will be generated to prevent path collisions unless preserve_filename is set.

classmethod storage_upload_form_file(form_field: str, storage_location=None, storage_profile=None)

Shortcut to push file data from posted form to storage.