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