/Doc/library/email.util.rst
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- :mod:`email`: 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)
- 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.
- .. 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:: mktime_tz(tuple)
- Turn a 10-tuple as returned by :func:`parsedate_tz` into a UTC timestamp. It
- the timezone item in the tuple is ``None``, assume local time. Minor
- deficiency: :func:`mktime_tz` interprets the first 8 elements of *tuple* as a
- local time and then compensates for the timezone difference. This may yield a
- slight error around changes in daylight savings time, though not worth worrying
- about for common use.
- .. function:: formatdate([timeval[, localtime][, usegmt]])
- 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``.
- .. versionadded:: 2.4
- .. function:: make_msgid([idstring])
- 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.
- .. function:: decode_rfc2231(s)
- Decode the string *s* according to :rfc:`2231`.
- .. function:: encode_rfc2231(s[, charset[, language]])
- 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[, fallback_charset]])
- 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 the built-in
- :func:`unicode` function; 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)``.
- .. versionchanged:: 2.4
- The :func:`dump_address_pair` function has been removed; use :func:`formataddr`
- instead.
- .. versionchanged:: 2.4
- The :func:`decode` function has been removed; use the
- :meth:`Header.decode_header` method instead.
- .. versionchanged:: 2.4
- The :func:`encode` function has been removed; use the :meth:`Header.encode`
- method instead.
- .. 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`.