Writing a custom storage system =============================== .. currentmodule:: django.core.files.storage 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 :doc:`/ref/files/storage`, but you **must** implement the following methods: * :meth:`Storage.delete` * :meth:`Storage.exists` * :meth:`Storage.listdir` * :meth:`Storage.size` * :meth:`Storage.url` 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.