:mod:`email.utils`: Miscellaneous utilities ------------------------------------------- .. module:: email.utils :synopsis: Miscellaneous email package utilities. There are several useful utilities provided in the :mod:`email.utils` module: .. 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 `. 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:: 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. .. 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 ` 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`.