1:mod:`email.encoders`: Encoders 2------------------------------- 3 4.. module:: email.encoders 5 :synopsis: Encoders for email message payloads. 6 7**Source code:** :source:`Lib/email/encoders.py` 8 9-------------- 10 11This module is part of the legacy (``Compat32``) email API. In the 12new API the functionality is provided by the *cte* parameter of 13the :meth:`~email.message.EmailMessage.set_content` method. 14 15This module is deprecated in Python 3. The functions provided here 16should not be called explicitly since the :class:`~email.mime.text.MIMEText` 17class sets the content type and CTE header using the *_subtype* and *_charset* 18values passed during the instantiation of that class. 19 20The remaining text in this section is the original documentation of the module. 21 22When creating :class:`~email.message.Message` objects from scratch, you often 23need to encode the payloads for transport through compliant mail servers. This 24is especially true for :mimetype:`image/\*` and :mimetype:`text/\*` type messages 25containing binary data. 26 27The :mod:`email` package provides some convenient encoders in its 28:mod:`encoders` module. These encoders are actually used by the 29:class:`~email.mime.audio.MIMEAudio` and :class:`~email.mime.image.MIMEImage` 30class constructors to provide default encodings. All encoder functions take 31exactly one argument, the message object to encode. They usually extract the 32payload, encode it, and reset the payload to this newly encoded value. They 33should also set the :mailheader:`Content-Transfer-Encoding` header as appropriate. 34 35Note that these functions are not meaningful for a multipart message. They 36must be applied to individual subparts instead, and will raise a 37:exc:`TypeError` if passed a message whose type is multipart. 38 39Here are the encoding functions provided: 40 41 42.. function:: encode_quopri(msg) 43 44 Encodes the payload into quoted-printable form and sets the 45 :mailheader:`Content-Transfer-Encoding` header to ``quoted-printable`` [#]_. 46 This is a good encoding to use when most of your payload is normal printable 47 data, but contains a few unprintable characters. 48 49 50.. function:: encode_base64(msg) 51 52 Encodes the payload into base64 form and sets the 53 :mailheader:`Content-Transfer-Encoding` header to ``base64``. This is a good 54 encoding to use when most of your payload is unprintable data since it is a more 55 compact form than quoted-printable. The drawback of base64 encoding is that it 56 renders the text non-human readable. 57 58 59.. function:: encode_7or8bit(msg) 60 61 This doesn't actually modify the message's payload, but it does set the 62 :mailheader:`Content-Transfer-Encoding` header to either ``7bit`` or ``8bit`` as 63 appropriate, based on the payload data. 64 65 66.. function:: encode_noop(msg) 67 68 This does nothing; it doesn't even set the 69 :mailheader:`Content-Transfer-Encoding` header. 70 71.. rubric:: Footnotes 72 73.. [#] Note that encoding with :meth:`encode_quopri` also encodes all tabs and space 74 characters in the data. 75 76