.. currentmodule:: aiohttp

.. _aiohttp-multipart-reference:

Multipart reference
===================

.. class:: MultipartResponseWrapper(resp, stream)

   Wrapper around the :class:`MultipartReader` to take care about
   underlying connection and close it when it needs in.


   .. method:: at_eof()

      Returns ``True`` when all response data had been read.

      :rtype: bool

   .. method:: next()
      :async:

      Emits next multipart reader object.

   .. method:: release()
      :async:

      Releases the connection gracefully, reading all the content
      to the void.


.. class:: BodyPartReader(boundary, headers, content)

   Multipart reader for single body part.

   .. method:: read(*, decode=False)
      :async:

      Reads body part data.

      :param bool decode: Decodes data following by encoding method
                          from ``Content-Encoding`` header. If it
                          missed data remains untouched

      :rtype: bytearray

   .. method:: read_chunk(size=chunk_size)
      :async:

      Reads body part content chunk of the specified size.

      :param int size: chunk size

      :rtype: bytearray

   .. method:: readline()
      :async:

      Reads body part by line by line.

      :rtype: bytearray

   .. method:: release()
      :async:

      Like :meth:`read`, but reads all the data to the void.

      :rtype: None

   .. method:: text(*, encoding=None)
      :async:

      Like :meth:`read`, but assumes that body part contains text data.

      :param str encoding: Custom text encoding. Overrides specified
                           in charset param of ``Content-Type`` header

      :rtype: str

   .. method:: json(*, encoding=None)
      :async:

      Like :meth:`read`, but assumes that body parts contains JSON data.

      :param str encoding: Custom JSON encoding. Overrides specified
                           in charset param of ``Content-Type`` header

   .. method:: form(*, encoding=None)
      :async:

      Like :meth:`read`, but assumes that body parts contains form
      urlencoded data.

      :param str encoding: Custom form encoding. Overrides specified
                           in charset param of ``Content-Type`` header

   .. method:: at_eof()

      Returns ``True`` if the boundary was reached or ``False`` otherwise.

      :rtype: bool

   .. method:: decode(data)

      Decodes data synchronously according the specified ``Content-Encoding``
      or ``Content-Transfer-Encoding`` headers value.

      Supports ``gzip``, ``deflate`` and ``identity`` encodings for
      ``Content-Encoding`` header.

      Supports ``base64``, ``quoted-printable``, ``binary`` encodings for
      ``Content-Transfer-Encoding`` header.

      :param bytearray data: Data to decode.

      :raises: :exc:`RuntimeError` - if encoding is unknown.

      :rtype: bytes

      .. note::

         For large payloads, consider using :meth:`decode_iter` instead
         to avoid blocking the event loop during decompression.

   .. method:: decode_iter(data)
      :async:

      Decodes data asynchronously according the specified ``Content-Encoding``
      or ``Content-Transfer-Encoding`` headers value.

      This is an async iterator and will return decoded data in chunks. This
      can be used to avoid loading large payloads into memory.

      This method offloads decompression to an executor for large payloads
      to avoid blocking the event loop.

      Supports ``gzip``, ``deflate`` and ``identity`` encodings for
      ``Content-Encoding`` header.

      Supports ``base64``, ``quoted-printable``, ``binary`` encodings for
      ``Content-Transfer-Encoding`` header.

      :param bytearray data: Data to decode.

      :raises: :exc:`RuntimeError` - if encoding is unknown.

      :rtype: bytes

      .. versionadded:: 3.13.4

   .. method:: get_charset(default=None)

      Returns charset parameter from ``Content-Type`` header or default.

   .. attribute:: name

      A field *name* specified in ``Content-Disposition`` header or ``None``
      if missed or header is malformed.

      Readonly :class:`str` property.

   .. attribute:: filename

      A field *filename* specified in ``Content-Disposition`` header or ``None``
      if missed or header is malformed.

      Readonly :class:`str` property.


.. class:: MultipartReader(headers, content)

   Multipart body reader.

   .. classmethod:: from_response(cls, response)

      Constructs reader instance from HTTP response.

      :param response: :class:`~aiohttp.ClientResponse` instance

   .. method:: at_eof()

      Returns ``True`` if the final boundary was reached or
      ``False`` otherwise.

      :rtype: bool

   .. method:: next()
      :async:

      Emits the next multipart body part.

   .. method:: release()
      :async:

      Reads all the body parts to the void till the final boundary.

   .. method:: fetch_next_part()
      :async:

      Returns the next body part reader.


.. class:: MultipartWriter(subtype='mixed', boundary=None, close_boundary=True)

   Multipart body writer.

   ``boundary`` may be an ASCII-only string.

   .. attribute:: boundary

      The string (:class:`str`) representation of the boundary.

      .. versionchanged:: 3.0

         Property type was changed from :class:`bytes` to :class:`str`.

   .. method:: append(obj, headers=None)

      Append an object to writer.

   .. method:: append_payload(payload)

      Adds a new body part to multipart writer.

   .. method:: append_json(obj, headers=None)

      Helper to append JSON part.

   .. method:: append_form(obj, headers=None)

      Helper to append form urlencoded part.

   .. attribute:: size

      Size of the payload.

   .. method:: write(writer, close_boundary=True)
      :async:

      Write body.

      :param bool close_boundary: The (:class:`bool`) that will emit
                                  boundary closing. You may want to disable
                                  when streaming (``multipart/x-mixed-replace``)

      .. versionadded:: 3.4

         Support ``close_boundary`` argument.
