245 lines
8.7 KiB
Plaintext
245 lines
8.7 KiB
Plaintext
==================================
|
|
Uploaded Files and Upload Handlers
|
|
==================================
|
|
|
|
.. module:: django.core.files.uploadedfile
|
|
:synopsis: Classes representing uploaded files.
|
|
|
|
Uploaded files
|
|
==============
|
|
|
|
.. class:: UploadedFile
|
|
|
|
During file uploads, the actual file data is stored in :attr:`request.FILES
|
|
<django.http.HttpRequest.FILES>`. Each entry in this dictionary is an
|
|
``UploadedFile`` object (or a subclass) -- a simple wrapper around an uploaded
|
|
file. You'll usually use one of these methods to access the uploaded content:
|
|
|
|
.. method:: UploadedFile.read()
|
|
|
|
Read the entire uploaded data from the file. Be careful with this method:
|
|
if the uploaded file is huge it can overwhelm your system if you try to
|
|
read it into memory. You'll probably want to use ``chunks()`` instead; see
|
|
below.
|
|
|
|
.. method:: UploadedFile.multiple_chunks(chunk_size=None)
|
|
|
|
Returns ``True`` if the uploaded file is big enough to require reading in
|
|
multiple chunks. By default this will be any file larger than 2.5 megabytes,
|
|
but that's configurable; see below.
|
|
|
|
.. method:: UploadedFile.chunks(chunk_size=None)
|
|
|
|
A generator returning chunks of the file. If ``multiple_chunks()`` is
|
|
``True``, you should use this method in a loop instead of ``read()``.
|
|
|
|
In practice, it's often easiest simply to use ``chunks()`` all the time.
|
|
Looping over ``chunks()`` instead of using ``read()`` ensures that large
|
|
files don't overwhelm your system's memory.
|
|
|
|
Here are some useful attributes of ``UploadedFile``:
|
|
|
|
.. attribute:: UploadedFile.name
|
|
|
|
The name of the uploaded file (e.g. ``my_file.txt``).
|
|
|
|
.. attribute:: UploadedFile.size
|
|
|
|
The size, in bytes, of the uploaded file.
|
|
|
|
.. attribute:: UploadedFile.content_type
|
|
|
|
The content-type header uploaded with the file (e.g. :mimetype:`text/plain`
|
|
or :mimetype:`application/pdf`). Like any data supplied by the user, you
|
|
shouldn't trust that the uploaded file is actually this type. You'll still
|
|
need to validate that the file contains the content that the content-type
|
|
header claims -- "trust but verify."
|
|
|
|
.. attribute:: UploadedFile.content_type_extra
|
|
|
|
.. versionadded:: 1.7
|
|
|
|
A dictionary containing extra parameters passed to the ``content-type``
|
|
header. This is typically provided by services, such as Google App Engine,
|
|
that intercept and handle file uploads on your behalf. As a result your
|
|
handler may not receive the uploaded file content, but instead a URL or
|
|
other pointer to the file. (see `RFC 2388`_ section 5.3).
|
|
|
|
.. _RFC 2388: http://www.ietf.org/rfc/rfc2388.txt
|
|
|
|
.. attribute:: UploadedFile.charset
|
|
|
|
For :mimetype:`text/*` content-types, the character set (i.e. ``utf8``)
|
|
supplied by the browser. Again, "trust but verify" is the best policy here.
|
|
|
|
.. note::
|
|
|
|
Like regular Python files, you can read the file line-by-line simply by
|
|
iterating over the uploaded file:
|
|
|
|
.. code-block:: python
|
|
|
|
for line in uploadedfile:
|
|
do_something_with(line)
|
|
|
|
However, *unlike* standard Python files, :class:`UploadedFile` only
|
|
understands ``\n`` (also known as "Unix-style") line endings. If you know
|
|
that you need to handle uploaded files with different line endings, you'll
|
|
need to do so in your view.
|
|
|
|
Subclasses of ``UploadedFile`` include:
|
|
|
|
.. class:: TemporaryUploadedFile
|
|
|
|
A file uploaded to a temporary location (i.e. stream-to-disk). This class
|
|
is used by the
|
|
:class:`~django.core.files.uploadhandler.TemporaryFileUploadHandler`. In
|
|
addition to the methods from :class:`UploadedFile`, it has one additional
|
|
method:
|
|
|
|
.. method:: TemporaryUploadedFile.temporary_file_path()
|
|
|
|
Returns the full path to the temporary uploaded file.
|
|
|
|
.. class:: InMemoryUploadedFile
|
|
|
|
A file uploaded into memory (i.e. stream-to-memory). This class is used
|
|
by the :class:`~django.core.files.uploadhandler.MemoryFileUploadHandler`.
|
|
|
|
Built-in upload handers
|
|
=======================
|
|
|
|
.. module:: django.core.files.uploadhandler
|
|
:synopsis: Django's handlers for file uploads.
|
|
|
|
Together the :class:`MemoryFileUploadHandler` and
|
|
:class:`TemporaryFileUploadHandler` provide Django's default file upload
|
|
behavior of reading small files into memory and large ones onto disk. They
|
|
are located in ``django.core.files.uploadhandler``.
|
|
|
|
.. class:: MemoryFileUploadHandler
|
|
|
|
File upload handler to stream uploads into memory (used for small files).
|
|
|
|
.. class:: TemporaryFileUploadHandler
|
|
|
|
Upload handler that streams data into a temporary file using
|
|
:class:`~django.core.files.uploadedfile.TemporaryUploadedFile`.
|
|
|
|
.. _custom_upload_handlers:
|
|
|
|
Writing custom upload handlers
|
|
==============================
|
|
|
|
.. class:: FileUploadHandler
|
|
|
|
All file upload handlers should be subclasses of
|
|
``django.core.files.uploadhandler.FileUploadHandler``. You can define upload
|
|
handlers wherever you wish.
|
|
|
|
Required methods
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
Custom file upload handlers **must** define the following methods:
|
|
|
|
.. method:: FileUploadHandler.receive_data_chunk(raw_data, start)
|
|
|
|
Receives a "chunk" of data from the file upload.
|
|
|
|
``raw_data`` is a byte string containing the uploaded data.
|
|
|
|
``start`` is the position in the file where this ``raw_data`` chunk
|
|
begins.
|
|
|
|
The data you return will get fed into the subsequent upload handlers'
|
|
``receive_data_chunk`` methods. In this way, one handler can be a
|
|
"filter" for other handlers.
|
|
|
|
Return ``None`` from ``receive_data_chunk`` to short-circuit remaining
|
|
upload handlers from getting this chunk. This is useful if you're
|
|
storing the uploaded data yourself and don't want future handlers to
|
|
store a copy of the data.
|
|
|
|
If you raise a ``StopUpload`` or a ``SkipFile`` exception, the upload
|
|
will abort or the file will be completely skipped.
|
|
|
|
.. method:: FileUploadHandler.file_complete(file_size)
|
|
|
|
Called when a file has finished uploading.
|
|
|
|
The handler should return an ``UploadedFile`` object that will be stored
|
|
in ``request.FILES``. Handlers may also return ``None`` to indicate that
|
|
the ``UploadedFile`` object should come from subsequent upload handlers.
|
|
|
|
Optional methods
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
Custom upload handlers may also define any of the following optional methods or
|
|
attributes:
|
|
|
|
.. attribute:: FileUploadHandler.chunk_size
|
|
|
|
Size, in bytes, of the "chunks" Django should store into memory and feed
|
|
into the handler. That is, this attribute controls the size of chunks
|
|
fed into ``FileUploadHandler.receive_data_chunk``.
|
|
|
|
For maximum performance the chunk sizes should be divisible by ``4`` and
|
|
should not exceed 2 GB (2\ :sup:`31` bytes) in size. When there are
|
|
multiple chunk sizes provided by multiple handlers, Django will use the
|
|
smallest chunk size defined by any handler.
|
|
|
|
The default is 64*2\ :sup:`10` bytes, or 64 KB.
|
|
|
|
.. method:: FileUploadHandler.new_file(field_name, file_name, content_type, content_length, charset, content_type_extra)
|
|
|
|
Callback signaling that a new file upload is starting. This is called
|
|
before any data has been fed to any upload handlers.
|
|
|
|
``field_name`` is a string name of the file ``<input>`` field.
|
|
|
|
``file_name`` is the unicode filename that was provided by the browser.
|
|
|
|
``content_type`` is the MIME type provided by the browser -- E.g.
|
|
``'image/jpeg'``.
|
|
|
|
``content_length`` is the length of the image given by the browser.
|
|
Sometimes this won't be provided and will be ``None``.
|
|
|
|
``charset`` is the character set (i.e. ``utf8``) given by the browser.
|
|
Like ``content_length``, this sometimes won't be provided.
|
|
|
|
``content_type_extra`` is extra information about the file from the
|
|
``content-type`` header. See :attr:`UploadedFile.content_type_extra
|
|
<django.core.files.uploadedfile.UploadedFile.content_type_extra>`.
|
|
|
|
This method may raise a ``StopFutureHandlers`` exception to prevent
|
|
future handlers from handling this file.
|
|
|
|
.. versionadded:: 1.7
|
|
|
|
The ``content_type_extra`` parameter was added.
|
|
|
|
.. method:: FileUploadHandler.upload_complete()
|
|
|
|
Callback signaling that the entire upload (all files) has completed.
|
|
|
|
.. method:: FileUploadHandler.handle_raw_input(input_data, META, content_length, boundary, encoding)
|
|
|
|
Allows the handler to completely override the parsing of the raw
|
|
HTTP input.
|
|
|
|
``input_data`` is a file-like object that supports ``read()``-ing.
|
|
|
|
``META`` is the same object as ``request.META``.
|
|
|
|
``content_length`` is the length of the data in ``input_data``. Don't
|
|
read more than ``content_length`` bytes from ``input_data``.
|
|
|
|
``boundary`` is the MIME boundary for this request.
|
|
|
|
``encoding`` is the encoding of the request.
|
|
|
|
Return ``None`` if you want upload handling to continue, or a tuple of
|
|
``(POST, FILES)`` if you want to return the new data structures suitable
|
|
for the request directly.
|