cpython/Doc/library/email.mime.rst
2017-05-19 23:37:57 +03:00

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: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 by the standard Python module :mod:`sndhdr`, 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 can be decoded by the standard Python module :mod:`imghdr`, 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.