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Lib/email/mime/text.py

Source:

cpython 3.14 @ ab2d84fe1023/Lib/email/mime/text.py

Lib/email/mime/text.py defines MIMEText, the standard way to create a text/* MIME part. It wraps MIMENonMultipart and calls set_payload with a Charset object, which handles encoding and sets Content-Transfer-Encoding automatically.

Map​

LinesSymbolRole
1-10importsMIMENonMultipart, email.charset
12-60MIMETextConstructor accepting text, subtype, charset

Reading​

Constructor and charset handling​

MIMEText.__init__ accepts the text payload, a subtype (default plain), and a charset (default us-ascii). The charset can be either a string or a Charset instance. It delegates to MIMENonMultipart.__init__ to set up the Content-Type header, then calls set_payload.

# CPython: Lib/email/mime/text.py:12 MIMEText.__init__
class MIMEText(MIMENonMultipart):
    def __init__(self, _text, _subtype='plain', _charset=None,
                 *, policy=None):
        if _charset is None:
            _charset = 'us-ascii'
        MIMENonMultipart.__init__(self, 'text', _subtype,
                                  policy=policy,
                                  **{'charset': str(_charset)})
        self.set_payload(_text, _charset)

set_payload and Content-Transfer-Encoding​

Message.set_payload(payload, charset) calls charset.body_encode(payload) which encodes the text and sets the Content-Transfer-Encoding header. For us-ascii and iso-8859-1, the encoding is 7bit or 8bit. For utf-8, it is base64 or quoted-printable depending on the charset's body_encoding attribute.

# CPython: Lib/email/message.py:258 Message.set_payload
def set_payload(self, payload, charset=None):
    if charset is not None and not isinstance(charset, Charset):
        charset = Charset(charset)
    if charset is not None:
        payload = charset.body_encode(payload)
        self.add_header('Content-Transfer-Encoding',
                        charset.get_body_encoding())
    self._payload = payload

Subtype variants​

While the default is text/plain, the same class constructs text/html, text/csv, and any other text/* subtype by passing _subtype. The Content-Type charset parameter is set from str(_charset) so the header reads Content-Type: text/plain; charset="utf-8".

gopy notes​

Not yet ported. The planned package path is module/email/mime/. The Go equivalent is a factory function that builds a Message with a pre-set Content-Type and encodes the body using Go's mime/quotedprintable or encoding/base64 packages.