Opened 7 years ago
Last modified 6 years ago
#28144 closed New feature
Add allow_overwrite kwarg to FileSystemStorage._save — at Version 1
| Reported by: | Jon Prindiville | Owned by: | nobody |
|---|---|---|---|
| Component: | File uploads/storage | Version: | 1.11 |
| Severity: | Normal | Keywords: | file storage overwrite |
| Cc: | Triage Stage: | Accepted | |
| Has patch: | yes | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | yes |
| Easy pickings: | no | UI/UX: | no |
Description (last modified by )
I want to be able to construct a filesystem storage backend that will let me overwrite files while still leveraging FileSystemStorage.
This set of changes (https://github.com/django/django/compare/master...jonprindiville:ticket_28144) would enable that without changing any of the default behaviour of FileSystemStorage. In addition to the new kwarg, this adds a test for the existing no-overwriting behaviour, and a test for the newly enabled overwriting behaviour.
I'm not sure about what I should enter here for "Version" (could go in anywhere, really) and "Has patch" (I don't have a patch, but I do have a PR-able branch, linked above. I am assuming that I should wait for review here before actually submitting a PR, though)
HOW?
Just add an allow_overwrite kwarg to FileSystemStorage._save that a subclasser can optionally take advantage of.
WHY?
You can't do this in a good way today.
A piece of advice I've seen in several places (see Refs) for creating an overwriting storage backend is to create a subclass of FileSystemStorage where the get_available_name deletes an existing file of the same name. This, in my opinion, is a sneaky use of this function, based on the name. I guess it works, but that function is not called get_available_name_and_maybe_delete_some_stuff_also
A less sneaky (but more race-conditiony) implementation I have seen is to have _save delete the existing file before calling FileSystemStorage._save.
One of these is deceptive and one loops forever if you're unlucky.
Refs:
Various incarnations of this "ovewriting" implementation:
- django-storages, marked as deprecated (https://github.com/jschneier/django-storages/blob/1.5.2/storages/backends/overwrite.py)
- djangosnippets (https://djangosnippets.org/snippets/976/)
- someone's gist (https://gist.github.com/fabiomontefuscolo/1584462)
- django-overwrite-storage (https://github.com/ckot/django-overwrite-storage/blob/master/overwrite_storage/storage.py)