diff -r 5ff1fc726848 -r c6bca38c1cbf parts/django/docs/ref/files/file.txt --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/parts/django/docs/ref/files/file.txt Sat Jan 08 11:20:57 2011 +0530 @@ -0,0 +1,152 @@ +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', contents, save=False) + >>> car.save() + + are the same as this one line:: + + >>> car.photo.save('myphoto.jpg', contents, 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.