cpython/Doc/library/email.mime.rst

:mod:`email.mime`: Creating email and MIME objects from scratch
---------------------------------------------------------------

.. module:: email.mime
   :synopsis: Build MIME messages.

**Source code:** :source:`Lib/email/mime/`

--------------

This module is part of the legacy (``Compat32``) email API.  Its functionality
is partially replaced by the :mod:`~email.contentmanager` in the new API, but
in certain applications these classes may still be useful, even in non-legacy
code.

Ordinarily, you get a message object structure by passing a file or some text to
a parser, which parses the text and returns the root message object.  However
you can also build a complete message structure from scratch, or even individual
:class:`~email.message.Message` objects by hand.  In fact, you can also take an
existing structure and add new :class:`~email.message.Message` objects, move them
around, etc.  This makes a very convenient interface for slicing-and-dicing MIME
messages.

You can create a new object structure by creating :class:`~email.message.Message`
instances, adding attachments and all the appropriate headers manually.  For MIME
messages though, the :mod:`email` package provides some convenient subclasses to
make things easier.

Here are the classes:

.. currentmodule:: email.mime.base

.. class:: MIMEBase(_maintype, _subtype, *, policy=compat32, **_params)

   Module: :mod:`email.mime.base`

   This is the base class for all the MIME-specific subclasses of
   :class:`~email.message.Message`.  Ordinarily you won't create instances
   specifically of :class:`MIMEBase`, although you could.  :class:`MIMEBase`
   is provided primarily as a convenient base class for more specific
   MIME-aware subclasses.

   *_maintype* is the :mailheader:`Content-Type` major type (e.g. :mimetype:`text`
   or :mimetype:`image`), and *_subtype* is the :mailheader:`Content-Type` minor
   type  (e.g. :mimetype:`plain` or :mimetype:`gif`).  *_params* is a parameter
   key/value dictionary and is passed directly to :meth:`Message.add_header
   <email.message.Message.add_header>`.

   If *policy* is specified, (defaults to the
   :class:`compat32 <email.policy.Compat32>` policy) it will be passed to
   :class:`~email.message.Message`.

   The :class:`MIMEBase` class always adds a :mailheader:`Content-Type` header
   (based on *_maintype*, *_subtype*, and *_params*), and a
   :mailheader:`MIME-Version` header (always set to ``1.0``).

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.


.. currentmodule:: email.mime.nonmultipart

.. class:: MIMENonMultipart()

   Module: :mod:`email.mime.nonmultipart`

   A subclass of :class:`~email.mime.base.MIMEBase`, this is an intermediate base
   class for MIME messages that are not :mimetype:`multipart`.  The primary
   purpose of this class is to prevent the use of the
   :meth:`~email.message.Message.attach` method, which only makes sense for
   :mimetype:`multipart` messages.  If :meth:`~email.message.Message.attach`
   is called, a :exc:`~email.errors.MultipartConversionError` exception is raised.


.. currentmodule:: email.mime.multipart

.. class:: MIMEMultipart(_subtype='mixed', boundary=None, _subparts=None, \
                         *, policy=compat32, **_params)

   Module: :mod:`email.mime.multipart`

   A subclass of :class:`~email.mime.base.MIMEBase`, this is an intermediate base
   class for MIME messages that are :mimetype:`multipart`.  Optional *_subtype*
   defaults to :mimetype:`mixed`, but can be used to specify the subtype of the
   message.  A :mailheader:`Content-Type` header of :mimetype:`multipart/_subtype`
   will be added to the message object.  A :mailheader:`MIME-Version` header will
   also be added.

   Optional *boundary* is the multipart boundary string.  When ``None`` (the
   default), the boundary is calculated when needed (for example, when the
   message is serialized).

   *_subparts* is a sequence of initial subparts for the payload.  It must be
   possible to convert this sequence to a list.  You can always attach new subparts
   to the message by using the :meth:`Message.attach
   <email.message.Message.attach>` method.

   Optional *policy* argument defaults to :class:`compat32 <email.policy.Compat32>`.

   Additional parameters for the :mailheader:`Content-Type` header are taken from
   the keyword arguments, or passed into the *_params* argument, which is a keyword
   dictionary.

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.

.. currentmodule:: email.mime.application

.. class:: MIMEApplication(_data, _subtype='octet-stream', \
                           _encoder=email.encoders.encode_base64, \
                           *, policy=compat32, **_params)

   Module: :mod:`email.mime.application`

   A subclass of :class:`~email.mime.nonmultipart.MIMENonMultipart`, the
   :class:`MIMEApplication` class is used to represent MIME message objects of
   major type :mimetype:`application`.  *_data* is a string containing the raw
   byte data.  Optional *_subtype* specifies the MIME subtype and defaults to
   :mimetype:`octet-stream`.

   Optional *_encoder* is a callable (i.e. function) which will perform the actual
   encoding of the data for transport.  This callable takes one argument, which is
   the :class:`MIMEApplication` instance. It should use
   :meth:`~email.message.Message.get_payload` and
   :meth:`~email.message.Message.set_payload` to change the payload to encoded
   form.  It should also add
   any :mailheader:`Content-Transfer-Encoding` or other headers to the message
   object as necessary.  The default encoding is base64.  See the
   :mod:`email.encoders` module for a list of the built-in encoders.

   Optional *policy* argument defaults to :class:`compat32 <email.policy.Compat32>`.

   *_params* are passed straight through to the base class constructor.

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.

.. currentmodule:: email.mime.audio

.. class:: MIMEAudio(_audiodata, _subtype=None, \
                     _encoder=email.encoders.encode_base64, \
                     *, policy=compat32, **_params)

   Module: :mod:`email.mime.audio`

   A subclass of :class:`~email.mime.nonmultipart.MIMENonMultipart`, the
   :class:`MIMEAudio` class is used to create MIME message objects of major type
   :mimetype:`audio`. *_audiodata* is a string containing the raw audio data.  If
   this data can be decoded as au, wav, aiff, or aifc, then the
   subtype will be automatically included in the :mailheader:`Content-Type` header.
   Otherwise you can explicitly specify the audio subtype via the *_subtype*
   argument.  If the minor type could not be guessed and *_subtype* was not given,
   then :exc:`TypeError` is raised.

   Optional *_encoder* is a callable (i.e. function) which will perform the actual
   encoding of the audio data for transport.  This callable takes one argument,
   which is the :class:`MIMEAudio` instance. It should use
   :meth:`~email.message.Message.get_payload` and
   :meth:`~email.message.Message.set_payload` to change the payload to encoded
   form.  It should also add
   any :mailheader:`Content-Transfer-Encoding` or other headers to the message
   object as necessary.  The default encoding is base64.  See the
   :mod:`email.encoders` module for a list of the built-in encoders.

   Optional *policy* argument defaults to :class:`compat32 <email.policy.Compat32>`.

   *_params* are passed straight through to the base class constructor.

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.

.. currentmodule:: email.mime.image

.. class:: MIMEImage(_imagedata, _subtype=None, \
                     _encoder=email.encoders.encode_base64, \
                    *, policy=compat32, **_params)

   Module: :mod:`email.mime.image`

   A subclass of :class:`~email.mime.nonmultipart.MIMENonMultipart`, the
   :class:`MIMEImage` class is used to create MIME message objects of major type
   :mimetype:`image`. *_imagedata* is a string containing the raw image data.  If
   this data type can be detected (jpeg, png, gif, tiff, rgb, pbm, pgm, ppm,
   rast, xbm, bmp, webp, and exr attempted), then the subtype will be
   automatically included in the :mailheader:`Content-Type` header. Otherwise
   you can explicitly specify the image subtype via the *_subtype* argument.
   If the minor type could not be guessed and *_subtype* was not given, then
   :exc:`TypeError` is raised.

   Optional *_encoder* is a callable (i.e. function) which will perform the actual
   encoding of the image data for transport.  This callable takes one argument,
   which is the :class:`MIMEImage` instance. It should use
   :meth:`~email.message.Message.get_payload` and
   :meth:`~email.message.Message.set_payload` to change the payload to encoded
   form.  It should also add
   any :mailheader:`Content-Transfer-Encoding` or other headers to the message
   object as necessary.  The default encoding is base64.  See the
   :mod:`email.encoders` module for a list of the built-in encoders.

   Optional *policy* argument defaults to :class:`compat32 <email.policy.Compat32>`.

   *_params* are passed straight through to the :class:`~email.mime.base.MIMEBase`
   constructor.

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.

.. currentmodule:: email.mime.message

.. class:: MIMEMessage(_msg, _subtype='rfc822', *, policy=compat32)

   Module: :mod:`email.mime.message`

   A subclass of :class:`~email.mime.nonmultipart.MIMENonMultipart`, the
   :class:`MIMEMessage` class is used to create MIME objects of main type
   :mimetype:`message`. *_msg* is used as the payload, and must be an instance
   of class :class:`~email.message.Message` (or a subclass thereof), otherwise
   a :exc:`TypeError` is raised.

   Optional *_subtype* sets the subtype of the message; it defaults to
   :mimetype:`rfc822`.

   Optional *policy* argument defaults to :class:`compat32 <email.policy.Compat32>`.

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.

.. currentmodule:: email.mime.text

.. class:: MIMEText(_text, _subtype='plain', _charset=None, *, policy=compat32)

   Module: :mod:`email.mime.text`

   A subclass of :class:`~email.mime.nonmultipart.MIMENonMultipart`, the
   :class:`MIMEText` class is used to create MIME objects of major type
   :mimetype:`text`. *_text* is the string for the payload.  *_subtype* is the
   minor type and defaults to :mimetype:`plain`.  *_charset* is the character
   set of the text and is passed as an argument to the
   :class:`~email.mime.nonmultipart.MIMENonMultipart` constructor; it defaults
   to ``us-ascii`` if the string contains only ``ascii`` code points, and
   ``utf-8`` otherwise.  The *_charset* parameter accepts either a string or a
   :class:`~email.charset.Charset` instance.

   Unless the *_charset* argument is explicitly set to ``None``, the
   MIMEText object created will have both a :mailheader:`Content-Type` header
   with a ``charset`` parameter, and a :mailheader:`Content-Transfer-Encoding`
   header.  This means that a subsequent ``set_payload`` call will not result
   in an encoded payload, even if a charset is passed in the ``set_payload``
   command.  You can "reset" this behavior by deleting the
   ``Content-Transfer-Encoding`` header, after which a ``set_payload`` call
   will automatically encode the new payload (and add a new
   :mailheader:`Content-Transfer-Encoding` header).

   Optional *policy* argument defaults to :class:`compat32 <email.policy.Compat32>`.

   .. versionchanged:: 3.5
      *_charset* also accepts :class:`~email.charset.Charset` instances.

   .. versionchanged:: 3.6
      Added *policy* keyword-only parameter.