=================== The ``File`` object =================== The :mod:`django.core.files` module and its submodules contain built-in classes for basic file handling in Django. .. currentmodule:: django.core.files The ``File`` class ================== .. class:: File(file_object) The :class:`File` class is a thin wrapper around a Python :py:term:`file object` with some Django-specific additions. Internally, Django uses this class when it needs to represent a file. :class:`File` objects have the following attributes and methods: .. attribute:: name The name of the file including the relative path from :setting:`MEDIA_ROOT`. .. attribute:: size The size of the file in bytes. .. attribute:: file The underlying :py:term:`file object` that this class wraps. .. admonition:: Be careful with this attribute in subclasses. Some subclasses of :class:`File`, including :class:`~django.core.files.base.ContentFile` and :class:`~django.db.models.fields.files.FieldFile`, may replace this attribute with an object other than a Python :py:term:`file object`. In these cases, this attribute may itself be a :class:`File` subclass (and not necessarily the same subclass). Whenever possible, use the attributes and methods of the subclass itself rather than the those of the subclass's ``file`` attribute. .. attribute:: mode The read/write mode for the file. .. method:: open(mode=None) Open or reopen the file (which also does ``File.seek(0)``). The ``mode`` argument allows the same values as Python's built-in :func:`python:open()`. When reopening a file, ``mode`` will override whatever mode the file was originally opened with; ``None`` means to reopen with the original mode. .. method:: __iter__() Iterate over the file yielding one line at a time. .. method:: chunks(chunk_size=None) Iterate over the file yielding "chunks" of a given size. ``chunk_size`` defaults to 64 KB. This is especially useful with very large files since it allows them to be streamed off disk and avoids storing the whole file in memory. .. method:: multiple_chunks(chunk_size=None) Returns ``True`` if the file is large enough to require multiple chunks to access all of its content give some ``chunk_size``. .. method:: close() Close the file. In addition to the listed methods, :class:`~django.core.files.File` exposes the following attributes and methods of its ``file`` object: ``encoding``, ``fileno``, ``flush``, ``isatty``, ``newlines``, ``read``, ``readinto``, ``readline``, ``readlines``, ``seek``, ``softspace``, ``tell``, ``truncate``, ``write``, ``writelines``, ``xreadlines``, ``readable()``, ``writable()``, and ``seekable()``. .. versionchanged:: 1.11 The ``readable()`` and ``writable()`` methods were added and the ``seekable()`` method was made available on Python 2. .. currentmodule:: django.core.files.base The ``ContentFile`` class ========================= .. class:: ContentFile(File) The ``ContentFile`` class inherits from :class:`~django.core.files.File`, but unlike :class:`~django.core.files.File` it operates on string content (bytes also supported), rather than an actual file. For example:: from __future__ import unicode_literals from django.core.files.base import ContentFile f1 = ContentFile("esta sentencia está en español") f2 = ContentFile(b"these are bytes") .. currentmodule:: django.core.files.images The ``ImageFile`` class ======================= .. class:: ImageFile(file_object) Django provides a built-in class specifically for images. :class:`django.core.files.images.ImageFile` inherits all the attributes and methods of :class:`~django.core.files.File`, and additionally provides the following: .. attribute:: width Width of the image in pixels. .. attribute:: height Height of the image in pixels. .. currentmodule:: django.core.files Additional methods on files attached to objects =============================================== Any :class:`File` that is associated with an object (as with ``Car.photo``, below) will also have a couple of extra methods: .. method:: File.save(name, content, save=True) Saves a new file with the file name and contents provided. This will not replace the existing file, but will create a new file and update the object to point to it. If ``save`` is ``True``, the model's ``save()`` method will be called once the file is saved. That is, these two lines:: >>> car.photo.save('myphoto.jpg', content, save=False) >>> car.save() are equivalent to:: >>> car.photo.save('myphoto.jpg', content, save=True) Note that the ``content`` argument must be an instance of either :class:`File` or of a subclass of :class:`File`, such as :class:`~django.core.files.base.ContentFile`. .. method:: File.delete(save=True) Removes the file from the model instance and deletes the underlying file. If ``save`` is ``True``, the model's ``save()`` method will be called once the file is deleted.