Writing a custom storage system¶
If you need to provide custom file storage – a common example is storing files on some remote system – you can do so by defining a custom storage class. You’ll need to follow these steps:
Your custom storage system must be a subclass of
django.core.files.storage.Storage
:from django.core.files.storage import Storage class MyStorage(Storage): ...
Django must be able to instantiate your storage system without any arguments. This means that any settings should be taken from
django.conf.settings
:from django.conf import settings from django.core.files.storage import Storage class MyStorage(Storage): def __init__(self, option=None): if not option: option = settings.CUSTOM_STORAGE_OPTIONS ...
Your storage class must implement the
_open()
and_save()
methods, along with any other methods appropriate to your storage class. See below for more on these methods.In addition, if your class provides local file storage, it must override the
path()
method.
Your custom storage system may override any of the storage methods explained in File storage API, but you must implement the following methods:
You’ll also usually want to use hooks specifically designed for custom storage objects. These are:
-
_open
(name, mode='rb')¶
Required.
Called by Storage.open()
, this is the actual mechanism the storage class
uses to open the file. This must return a File
object, though in most cases,
you’ll want to return some subclass here that implements logic specific to the
backend storage system.
-
_save
(name, content)¶
Called by Storage.save()
. The name
will already have gone through
get_valid_name()
and get_available_name()
, and the content
will be a
File
object itself.
Should return the actual name of name of the file saved (usually the name
passed in, but if the storage needs to change the file name return the new name
instead).
-
get_valid_name
(name)¶
Returns a filename suitable for use with the underlying storage system. The
name
argument passed to this method is the original filename sent to the
server, after having any path information removed. Override this to customize
how non-standard characters are converted to safe filenames.
The code provided on Storage
retains only alpha-numeric characters, periods
and underscores from the original filename, removing everything else.
-
get_available_name
(name)¶
Returns a filename that is available in the storage mechanism, possibly taking
the provided filename into account. The name
argument passed to this method
will have already cleaned to a filename valid for the storage system, according
to the get_valid_name()
method described above.
The code provided on Storage
simply appends "_1"
, "_2"
, etc. to the
filename until it finds one that’s available in the destination directory.