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121 lines
3.4 KiB
Plaintext
121 lines
3.4 KiB
Plaintext
.. _ref-files-file:
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The ``File`` object
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===================
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.. currentmodule:: django.core.files
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.. class:: File(file_object)
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``File`` attributes and methods
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-------------------------------
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Django's ``File`` has the following attributes and methods:
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``File.path``
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~~~~~~~~~~~~~
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The absolute path to the file's location on a local filesystem.
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:ref:`Custom file storage systems <howto-custom-file-storage>` may not store
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files locally; files stored on these systems will have a ``path`` of ``None``.
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``File.url``
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~~~~~~~~~~~~
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The URL where the file can be retrieved. This is often useful in :ref:`templates
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<topics-templates>`; for example, a bit of a template for displaying a ``Car``
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(see above) might look like::
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<img src='{{ car.photo.url }}' alt='{{ car.name }}' />
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``File.size``
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~~~~~~~~~~~~~
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The size of the file in bytes.
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``File.open(mode=None)``
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~~~~~~~~~~~~~~~~~~~~~~~~
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Open or reopen the file (which by definition also does ``File.seek(0)``). The
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``mode`` argument allows the same values as Python's standard ``open()``.
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When reopening a file, ``mode`` will override whatever mode the file was
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originally opened with; ``None`` means to reopen with the original mode.
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``File.read(num_bytes=None)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Read content from the file. The optional ``size`` is the number of bytes to
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read; if not specified, the file will be read to the end.
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``File.__iter__()``
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~~~~~~~~~~~~~~~~~~~
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Iterate over the file yielding one line at a time.
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``File.chunks(chunk_size=None)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Iterate over the file yielding "chunks" of a given size. ``chunk_size`` defaults
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to 64 KB.
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This is especially useful with very large files since it allows them to be
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streamed off disk and avoids storing the whole file in memory.
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``File.multiple_chunks(chunk_size=None)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Returns ``True`` if the file is large enough to require multiple chunks to
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access all of its content give some ``chunk_size``.
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``File.write(content)``
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~~~~~~~~~~~~~~~~~~~~~~~
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Writes the specified content string to the file. Depending on the storage system
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behind the scenes, this content might not be fully committed until ``close()``
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is called on the file.
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``File.close()``
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~~~~~~~~~~~~~~~~
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Close the file.
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Additional ``ImageField`` attributes
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------------------------------------
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``File.width`` and ``File.height``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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These attributes provide the dimensions of the image.
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Additional methods on files attached to objects
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-----------------------------------------------
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Any ``File`` that's associated with an object (as with ``Car.photo``, above)
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will also have a couple of extra methods:
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``File.save(name, content, save=True)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Saves a new file with the file name and contents provided. This will not replace
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the existing file, but will create a new file and update the object to point to
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it. If ``save`` is ``True``, the model's ``save()`` method will be called once
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the file is saved. That is, these two lines::
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>>> car.photo.save('myphoto.jpg', contents, save=False)
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>>> car.save()
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are the same as this one line::
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>>> car.photo.save('myphoto.jpg', contents, save=True)
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Note that the ``content`` argument must be an instance of
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:class:`File` or of a subclass of :class:`File`.
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``File.delete(save=True)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~
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Remove the file from the model instance and delete the underlying file. The
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``save`` argument works as above.
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