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author | Zhiming Wang <github@zmwang.pw> | 2018-11-21 12:41:07 (GMT) |
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committer | Julien Palard <julien@palard.fr> | 2018-11-21 12:41:07 (GMT) |
commit | 361e8683e7340c600b22f4a514b81448ccec66dc (patch) | |
tree | 4b62dae1d84eab752488433ac920bc5bc38ec6de /Doc/library/email.utils.rst | |
parent | 7c2d5702d11b41dd9a2391e6813fbaef5dbda79a (diff) | |
download | cpython-361e8683e7340c600b22f4a514b81448ccec66dc.zip cpython-361e8683e7340c600b22f4a514b81448ccec66dc.tar.gz cpython-361e8683e7340c600b22f4a514b81448ccec66dc.tar.bz2 |
bpo-35035: Rename email.utils documentation to email.utils.rst (GH-10023)
I'll watch for 404 on the old URL and will setup an HTTP redirection if needed.
Diffstat (limited to 'Doc/library/email.utils.rst')
-rw-r--r-- | Doc/library/email.utils.rst | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/Doc/library/email.utils.rst b/Doc/library/email.utils.rst new file mode 100644 index 0000000..63fae2a --- /dev/null +++ b/Doc/library/email.utils.rst @@ -0,0 +1,218 @@ +:mod:`email.utils`: Miscellaneous utilities +------------------------------------------- + +.. module:: email.utils + :synopsis: Miscellaneous email package utilities. + +**Source code:** :source:`Lib/email/utils.py` + +-------------- + +There are a couple of useful utilities provided in the :mod:`email.utils` +module: + +.. function:: localtime(dt=None) + + Return local time as an aware datetime object. If called without + arguments, return current time. Otherwise *dt* argument should be a + :class:`~datetime.datetime` instance, and it is converted to the local time + zone according to the system time zone database. If *dt* is naive (that + is, ``dt.tzinfo`` is ``None``), it is assumed to be in local time. In this + case, a positive or zero value for *isdst* causes ``localtime`` to presume + initially that summer time (for example, Daylight Saving Time) is or is not + (respectively) in effect for the specified time. A negative value for + *isdst* causes the ``localtime`` to attempt to divine whether summer time + is in effect for the specified time. + + .. versionadded:: 3.3 + + +.. function:: make_msgid(idstring=None, domain=None) + + Returns a string suitable for an :rfc:`2822`\ -compliant + :mailheader:`Message-ID` header. Optional *idstring* if given, is a string + used to strengthen the uniqueness of the message id. Optional *domain* if + given provides the portion of the msgid after the '@'. The default is the + local hostname. It is not normally necessary to override this default, but + may be useful certain cases, such as a constructing distributed system that + uses a consistent domain name across multiple hosts. + + .. versionchanged:: 3.2 + Added the *domain* keyword. + + +The remaining functions are part of the legacy (``Compat32``) email API. There +is no need to directly use these with the new API, since the parsing and +formatting they provide is done automatically by the header parsing machinery +of the new API. + + +.. function:: quote(str) + + Return a new string with backslashes in *str* replaced by two backslashes, and + double quotes replaced by backslash-double quote. + + +.. function:: unquote(str) + + Return a new string which is an *unquoted* version of *str*. If *str* ends and + begins with double quotes, they are stripped off. Likewise if *str* ends and + begins with angle brackets, they are stripped off. + + +.. function:: parseaddr(address) + + Parse address -- which should be the value of some address-containing field such + as :mailheader:`To` or :mailheader:`Cc` -- into its constituent *realname* and + *email address* parts. Returns a tuple of that information, unless the parse + fails, in which case a 2-tuple of ``('', '')`` is returned. + + +.. function:: formataddr(pair, charset='utf-8') + + The inverse of :meth:`parseaddr`, this takes a 2-tuple of the form ``(realname, + email_address)`` and returns the string value suitable for a :mailheader:`To` or + :mailheader:`Cc` header. If the first element of *pair* is false, then the + second element is returned unmodified. + + Optional *charset* is the character set that will be used in the :rfc:`2047` + encoding of the ``realname`` if the ``realname`` contains non-ASCII + characters. Can be an instance of :class:`str` or a + :class:`~email.charset.Charset`. Defaults to ``utf-8``. + + .. versionchanged:: 3.3 + Added the *charset* option. + + +.. function:: getaddresses(fieldvalues) + + This method returns a list of 2-tuples of the form returned by ``parseaddr()``. + *fieldvalues* is a sequence of header field values as might be returned by + :meth:`Message.get_all <email.message.Message.get_all>`. Here's a simple + example that gets all the recipients of a message:: + + from email.utils import getaddresses + + tos = msg.get_all('to', []) + ccs = msg.get_all('cc', []) + resent_tos = msg.get_all('resent-to', []) + resent_ccs = msg.get_all('resent-cc', []) + all_recipients = getaddresses(tos + ccs + resent_tos + resent_ccs) + + +.. function:: parsedate(date) + + Attempts to parse a date according to the rules in :rfc:`2822`. however, some + mailers don't follow that format as specified, so :func:`parsedate` tries to + guess correctly in such cases. *date* is a string containing an :rfc:`2822` + date, such as ``"Mon, 20 Nov 1995 19:12:08 -0500"``. If it succeeds in parsing + the date, :func:`parsedate` returns a 9-tuple that can be passed directly to + :func:`time.mktime`; otherwise ``None`` will be returned. Note that indexes 6, + 7, and 8 of the result tuple are not usable. + + +.. function:: parsedate_tz(date) + + Performs the same function as :func:`parsedate`, but returns either ``None`` or + a 10-tuple; the first 9 elements make up a tuple that can be passed directly to + :func:`time.mktime`, and the tenth is the offset of the date's timezone from UTC + (which is the official term for Greenwich Mean Time) [#]_. If the input string + has no timezone, the last element of the tuple returned is ``None``. Note that + indexes 6, 7, and 8 of the result tuple are not usable. + + +.. function:: parsedate_to_datetime(date) + + The inverse of :func:`format_datetime`. Performs the same function as + :func:`parsedate`, but on success returns a :mod:`~datetime.datetime`. If + the input date has a timezone of ``-0000``, the ``datetime`` will be a naive + ``datetime``, and if the date is conforming to the RFCs it will represent a + time in UTC but with no indication of the actual source timezone of the + message the date comes from. If the input date has any other valid timezone + offset, the ``datetime`` will be an aware ``datetime`` with the + corresponding a :class:`~datetime.timezone` :class:`~datetime.tzinfo`. + + .. versionadded:: 3.3 + + +.. function:: mktime_tz(tuple) + + Turn a 10-tuple as returned by :func:`parsedate_tz` into a UTC + timestamp (seconds since the Epoch). If the timezone item in the + tuple is ``None``, assume local time. + + +.. function:: formatdate(timeval=None, localtime=False, usegmt=False) + + Returns a date string as per :rfc:`2822`, e.g.:: + + Fri, 09 Nov 2001 01:08:47 -0000 + + Optional *timeval* if given is a floating point time value as accepted by + :func:`time.gmtime` and :func:`time.localtime`, otherwise the current time is + used. + + Optional *localtime* is a flag that when ``True``, interprets *timeval*, and + returns a date relative to the local timezone instead of UTC, properly taking + daylight savings time into account. The default is ``False`` meaning UTC is + used. + + Optional *usegmt* is a flag that when ``True``, outputs a date string with the + timezone as an ascii string ``GMT``, rather than a numeric ``-0000``. This is + needed for some protocols (such as HTTP). This only applies when *localtime* is + ``False``. The default is ``False``. + + +.. function:: format_datetime(dt, usegmt=False) + + Like ``formatdate``, but the input is a :mod:`datetime` instance. If it is + a naive datetime, it is assumed to be "UTC with no information about the + source timezone", and the conventional ``-0000`` is used for the timezone. + If it is an aware ``datetime``, then the numeric timezone offset is used. + If it is an aware timezone with offset zero, then *usegmt* may be set to + ``True``, in which case the string ``GMT`` is used instead of the numeric + timezone offset. This provides a way to generate standards conformant HTTP + date headers. + + .. versionadded:: 3.3 + + +.. function:: decode_rfc2231(s) + + Decode the string *s* according to :rfc:`2231`. + + +.. function:: encode_rfc2231(s, charset=None, language=None) + + Encode the string *s* according to :rfc:`2231`. Optional *charset* and + *language*, if given is the character set name and language name to use. If + neither is given, *s* is returned as-is. If *charset* is given but *language* + is not, the string is encoded using the empty string for *language*. + + +.. function:: collapse_rfc2231_value(value, errors='replace', fallback_charset='us-ascii') + + When a header parameter is encoded in :rfc:`2231` format, + :meth:`Message.get_param <email.message.Message.get_param>` may return a + 3-tuple containing the character set, + language, and value. :func:`collapse_rfc2231_value` turns this into a unicode + string. Optional *errors* is passed to the *errors* argument of :class:`str`'s + :func:`~str.encode` method; it defaults to ``'replace'``. Optional + *fallback_charset* specifies the character set to use if the one in the + :rfc:`2231` header is not known by Python; it defaults to ``'us-ascii'``. + + For convenience, if the *value* passed to :func:`collapse_rfc2231_value` is not + a tuple, it should be a string and it is returned unquoted. + + +.. function:: decode_params(params) + + Decode parameters list according to :rfc:`2231`. *params* is a sequence of + 2-tuples containing elements of the form ``(content-type, string-value)``. + + +.. rubric:: Footnotes + +.. [#] Note that the sign of the timezone offset is the opposite of the sign of the + ``time.timezone`` variable for the same timezone; the latter variable follows + the POSIX standard while this module follows :rfc:`2822`. |