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111 lines
4.3 KiB
TeX
111 lines
4.3 KiB
TeX
\section{Built-in module \sectcode{rfc822}}
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\stmodindex{rfc822}
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\renewcommand{\indexsubitem}{(in module rfc822)}
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This module defines a class, \code{Message}, which represents a
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collection of ``email headers'' as defined by the Internet standard
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RFC 822. It is used in various contexts, usually to read such headers
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from a file.
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A \code{Message} instance is instantiated with an open file object as
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parameter. Instantiation reads headers from the file up to a blank
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line and stores them in the instance; after instantiation, the file is
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positioned directly after the blank line that terminates the headers.
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Input lines as read from the file may either be terminated by CR-LF or
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by a single linefeed; a terminating CR-LF is replaced by a single
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linefeed before the line is stored.
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All header matching is done independent of upper or lower case;
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e.g. \code{m['From']}, \code{m['from']} and \code{m['FROM']} all yield
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the same result.
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A \code{Message} instance has the following methods:
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\begin{funcdesc}{rewindbody}{}
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Seek to the start of the message body. This only works if the file
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object is seekable.
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\end{funcdesc}
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\begin{funcdesc}{getallmatchingheaders}{name}
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Return a list of lines consisting of all headers matching
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\var{name}, if any. Each physical line, whether it is a continuation
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line or not, is a separate list item. Return the empty list if no
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header matches \var{name}.
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\end{funcdesc}
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\begin{funcdesc}{getfirstmatchingheader}{name}
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Return a list of lines comprising the first header matching
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\var{name}, and its continuation line(s), if any. Return \code{None}
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if there is no header matching \var{name}.
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\end{funcdesc}
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\begin{funcdesc}{getrawheader}{name}
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Return a single string consisting of the text after the colon in the
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first header matching \var{name}. This includes leading whitespace,
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the trailing linefeed, and internal linefeeds and whitespace if there
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any continuation line(s) were present. Return \code{None} if there is
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no header matching \var{name}.
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\end{funcdesc}
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\begin{funcdesc}{getheader}{name}
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Like \code{getrawheader(\var{name})}, but strip leading and trailing
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whitespace (but not internal whitespace).
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\end{funcdesc}
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\begin{funcdesc}{getaddr}{name}
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Return a pair (full name, email address) parsed from the string
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returned by \code{getheader(\var{name})}. If no header matching
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\var{name} exists, return \code{None, None}; otherwise both the full
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name and the address are (possibly empty )strings.
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Example: If \code{m}'s first \code{From} header contains the string
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\code{'guido@cwi.nl (Guido van Rossum)'}, then
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\code{m.getaddr('From')} will yield the pair
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\code{('Guido van Rossum', 'guido@cwi.nl')}.
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If the header contained
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\code{'Guido van Rossum <guido@cwi.nl>'} instead, it would yield the
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exact same result.
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\end{funcdesc}
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\begin{funcdesc}{getaddrlist}{name}
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This is similar to \code{getaddr(\var{list})}, but parses a header
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containing a list of email addresses (e.g. a \code{To} header) and
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returns a list of (full name, email address) pairs (even if there was
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only one address in the header). If there is no header matching
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\var{name}, return an empty list.
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XXX The current version of this function is not really correct. It
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yields bogus results if a full name contains a comma.
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\end{funcdesc}
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\begin{funcdesc}{getdate}{name}
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Retrieve a header using \code{getheader} and parse it into a 9-tuple
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compatible with \code{time.mktime()}. If there is no header matching
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\var{name}, or it is unparsable, return \code{None}.
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Date parsing appears to be a black art, and not all mailers adhere to
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the standard. While it has been tested and found correct on a large
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collection of email from many sources, it is still possible that this
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function may occasionally yield an incorrect result.
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\end{funcdesc}
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\code{Message} instances also support a read-only mapping interface.
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In particular: \code{m[name]} is the same as \code{m.getheader(name)};
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and \code{len(m)}, \code{m.has_key(name)}, \code{m.keys()},
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\code{m.values()} and \code{m.items()} act as expected (and
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consistently).
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Finally, \code{Message} instances have two public instance variables:
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\begin{datadesc}{headers}
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A list containing the entire set of header lines, in the order in
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which they were read. Each line contains a trailing newline. The
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blank line terminating the headers is not contained in the list.
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\end{datadesc}
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\begin{datadesc}{fp}
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The file object passed at instantiation time.
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\end{datadesc}
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