1 :mod:`email`: Encoders

     2 ----------------------

     3 

     4 .. module:: email.encoders

     5    :synopsis: Encoders for email message payloads.

     6 

     7 

     8 When creating :class:`Message` objects from scratch, you often need to encode

     9 the payloads for transport through compliant mail servers. This is especially

    10 true for :mimetype:`image/\*` and :mimetype:`text/\*` type messages containing

    11 binary data.

    12 

    13 The :mod:`email` package provides some convenient encodings in its

    14 :mod:`encoders` module.  These encoders are actually used by the

    15 :class:`MIMEAudio` and :class:`MIMEImage` class constructors to provide default

    16 encodings.  All encoder functions take exactly one argument, the message object

    17 to encode.  They usually extract the payload, encode it, and reset the payload

    18 to this newly encoded value.  They should also set the

    19 :mailheader:`Content-Transfer-Encoding` header as appropriate.

    20 

    21 Here are the encoding functions provided:

    22 

    23 

    24 .. function:: encode_quopri(msg)

    25 

    26    Encodes the payload into quoted-printable form and sets the

    27    :mailheader:`Content-Transfer-Encoding` header to ``quoted-printable`` [#]_.

    28    This is a good encoding to use when most of your payload is normal printable

    29    data, but contains a few unprintable characters.

    30 

    31 

    32 .. function:: encode_base64(msg)

    33 

    34    Encodes the payload into base64 form and sets the

    35    :mailheader:`Content-Transfer-Encoding` header to ``base64``.  This is a good

    36    encoding to use when most of your payload is unprintable data since it is a more

    37    compact form than quoted-printable.  The drawback of base64 encoding is that it

    38    renders the text non-human readable.

    39 

    40 

    41 .. function:: encode_7or8bit(msg)

    42 

    43    This doesn't actually modify the message's payload, but it does set the

    44    :mailheader:`Content-Transfer-Encoding` header to either ``7bit`` or ``8bit`` as

    45    appropriate, based on the payload data.

    46 

    47 

    48 .. function:: encode_noop(msg)

    49 

    50    This does nothing; it doesn't even set the

    51    :mailheader:`Content-Transfer-Encoding` header.

    52 

    53 .. rubric:: Footnotes

    54 

    55 .. [#] Note that encoding with :meth:`encode_quopri` also encodes all tabs and space

    56    characters in the data.

    57