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.
Note that there's a separate module to read Unix, MH, and MMDF style mailbox files: mailbox.
A Message instance is instantiated with an open file object as parameter. The optional seekable parameter indicates if the file object is seekable; the default value is 1 for true. Instantiation reads headers from the file up to a blank line and stores them in the instance; after instantiation, the file is positioned directly after the blank line that terminates the headers.
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.