This module defines a class, Message, which represents a
collection of ``email headers'' as defined by the Internet standard
RFC 822. It is used in various contexts, usually to read such
headers from a file. This module also defines a helper class
AddressList for parsing RFC822 addresses.
Note that there's a separate module to read Unix, MH, and MMDF
style mailbox files: mailbox.
- Message (file[, seekable])
A Message instance is instantiated with an input object as
parameter. Message relies only on the input object having a
readline method; in particular, ordinary file objects qualify.
Instantiation reads headers from the input object up to a delimiter
line (normally a blank line) and stores them in the instance.
This class can work with any input object that supports a readline
method. If the input object has seek and tell capability, the
rewindbody method will work; also, illegal lines will be pushed back
onto the input stream. If the input object lacks seek but has an
unread method that can push back a line of input, Message will use
that to push back illegal lines. Thus this class can be used to parse
messages coming from a buffered stream.
The optional seekable argument is provided as a workaround for
certain stdio libraries in which tell() discards buffered data before
discovering that the lseek() system call doesn't work. For
maximum portability, you should set the seekable argument to zero to
prevent that initial tell when passing in an unseekable object
such as a a file object created from a socket object.
Input lines as read from the file may either be terminated by CR-LF or
by a single linefeed; a terminating CR-LF is replaced by a single
linefeed before the line is stored.
All header matching is done independent of upper or lower case;
e.g. m['From'], m['from'] and
m['FROM'] all yield the same result.
- AddressList (field)
You may instantiate the AddresssList helper class using a single
string parameter, a comma-separated list of RFC822 addresses to be
parsed. (The parameter None yields an empty list.)
- parsedate (date)
Attempts to parse a date according to the rules in RFC 822.
however, some mailers don't follow that format as specified, so
parsedate() tries to guess correctly in such cases.
date is a string containing an RFC 822 date, such as
'Mon, 20 Nov 1995 19:12:08 -0500'. If it succeeds in parsing
the date, parsedate() returns a 9-tuple that can be passed
directly to time.mktime(); otherwise None will be
- parsedate_tz (date)
Performs the same function as parsedate(), but returns
either None or a 10-tuple; the first 9 elements make up a tuple
that can be passed directly to time.mktime(), and the tenth
is the offset of the date's timezone from UTC (which is the official
term for Greenwich Mean Time). (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 822.) If the input
string has no timezone, the last element of the tuple returned is
- mktime_tz (tuple)
Turn a 10-tuple as returned by parsedate_tz() into a UTC
timestamp. It the timezone item in the tuple is None, assume
local time. Minor deficiency: this first interprets the first 8
elements as a local time and then compensates for the timezone
difference; this may yield a slight error around daylight savings time
switch dates. Not enough to worry about for common use.