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` is a thin wrapper around Python's built-in file object with some Django-specific additions. Internally, Django uses this class any time it needs to represent a file. :class:`File` objects have the following attributes and methods: .. attribute:: name The name of file including the relative path from :setting:`MEDIA_ROOT`. .. attribute:: size The size of the file in bytes. .. attribute:: file The underlying Python ``file`` object passed to :class:`~django.core.files.File`. .. attribute:: mode The read/write mode for the file. .. method:: open([mode=None]) Open or reopen the file (which by definition also does ``File.seek(0)``). The ``mode`` argument allows the same values as Python's standard ``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:: read([num_bytes=None]) Read content from the file. The optional ``size`` is the number of bytes to read; if not specified, the file will be read to the end. .. 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:: write([content]) Writes the specified content string to the file. Depending on the storage system behind the scenes, this content might not be fully committed until ``close()`` is called on the file. .. method:: close() Close the file. In addition to the listed methods, :class:`~django.core.files.File` exposes the following attributes and methods of the underlying ``file`` object: ``encoding``, ``fileno``, ``flush``, ``isatty``, ``newlines``, ``read``, ``readinto``, ``readlines``, ``seek``, ``softspace``, ``tell``, ``truncate``, ``writelines``, ``xreadlines``. .. 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, rather than an actual file. For example:: from django.core.files.base import ContentFile f1 = ContentFile("my string content") f2 = ContentFile(u"my unicode content encoded as UTF-8".encode('UTF-8')) .. 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's 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 the same as this one line:: >>> 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:`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.