Box::Parser(3)

NAME
Mail::Box::Parser - reading and writing messages

CLASS HIERARCHY
 Mail::Box::Parser
 is a Mail::Reporter

SYNOPSIS

DESCRIPTION
The "Mail::Box::Parser" manages the parsing of folders. Usually, you won't need to know anything about this module, except the options which are involved with this code.

There are two implementations of this module included in this distribution:

* "Mail::Box::Parser::C"
    A fast parser written in "C", using "Inline::C". If it is possible to install "Inline::C" on your system, this module will automatically compiled during installation. It will be much faster than the other option.

* "Mail::Box::Parser::Perl"
    A slower parser which only uses plain Perl. This module is a bit slower, and does less checking and less recovery.

Each implementation supplies the same methods, as described below.

METHOD INDEX
Methods prefixed with an abbreviation are described in Mail::Reporter (MR).

The general methods for "Mail::Box::Parser" objects:

      bodyAsFile FILEHANDLE [,CHA...       new [OPTIONS]
      bodyAsList [,CHARS [,LINES]]         popSeparator
      bodyAsString [,CHARS [,LINES]]       pushSeparator STRING|REGEXP
      bodyDelayed [,CHARS [,LINES]]        readHeader WRAP
      defaultParserType [CLASS]            readSeparator OPTIONS
   MR errors                            MR report [LEVEL]
      fileChanged                       MR reportAll [LEVEL]
      filePosition [POSITION]              start OPTIONS
      filename                             stop
      foldHeaderLine LINE, LENGTH          takeFileInfo
      lineSeparator                     MR trace [LEVEL]
   MR log [LEVEL [,STRINGS]]            MR warnings

The extra methods for extension writers:

   MR AUTOLOAD                          MR logPriority LEVEL
   MR DESTROY                           MR logSettings
   MR inGlobalDestruction               MR notImplemented

METHODS

new [OPTIONS]
    (Class method) Create a parser object which can handle one file. For mbox-like mailboxes, this object can be used to read a whole folder. In case of MH-like mailboxes, each message is contained in a single file, so each message has its own parser object.

    The OPTIONS can be

     OPTIONS           DESCRIBED IN          DEFAULT
     filename          Mail::Box::Parser     <required>
     file              Mail::Box::Parser     undef
     log               Mail::Reporter        'WARNINGS'
     mode              Mail::Box::Parser     'r'
     trace             Mail::Reporter        'WARNINGS'

    The options specific to "Mail::Box::Parser" are:

    * filename => FILENAME
        (Required) The name of the file to be read.

    * file => HANDLE
        Any "IO::File" or "GLOB" which can be used to read the data from. In case this option is specified, the "filename" is informational only.

    * mode => OPENMODE
        File-open mode, which defaults to 'r', which means `read-only'. See "perldoc -f open" for possible modes. Only applicable when no "file" is specified.

defaultParserType [CLASS]
    (Class or instance method) Returns the parser to be used to parse all subsequent messages, possibly first setting the parser using the optional argument. Usually, the parser is autodetected; the "C"-based parser will be used when it can be, and the "Perl"-based parser will be used otherwise.

    The CLASS argument allows you to specify a package name to force a particular parser to be used (such as your own custom parser). You have to "use" or "require" the package yourself before calling this method with an argument. The parser must be a sub-class of "Mail::Box::Parser".

start OPTIONS
    Start the parser. The parser is automatically started when the parser is created, however can be stopped (see "stop()" below). During the start, the file to be parsed will be opened.

    Start has the following OPTIONS:

    * trust_file => BOOLEAN
        When we continue with the parsing of the folder, and the modification-time (on operating-systems which support that) or size changed, the parser will refuse to start, unless this option is true.

stop
    Stop the parser, which will include a close of the file. The lock on the folder will not be removed (is not the responsibility of the parser).

takeFileInfo
    Capture some dat about the file being parsed, to be compared later.

fileChanged
    Returns wether the file which is parsed has changed after the last time "takeFileInfo" was called.

filename
    Returns the name of the file this parser is working on.

filePosition [POSITION]
    Returns the location of the next byte to be used in the file which is parsed. When a POSITION is specified, the location in the file is moved to the indicated spot first.

pushSeparator STRING|REGEXP
    Add a boundary line. Separators tell the parser where to stop reading. A famous seperator is the "From"-line, which is used in Mbox-like folders to separate messages. But also parts (attachments) is a message are devided by separators.

    The specified STRING describes the start of the separator-line. The REGEXP can specify a more complicated format.

popSeparator
    Remove the last-pushed separator from the list which is maintained by the parser. This will return "undef" when there is none left.

readSeparator OPTIONS
    Read the currently active separator (the last one which was pushed). The line (or "undef") is returned. Blank-lines before the separator lines are ignored.

    The return are two scalars, where the first gives the location of the separator in the file, and the second the line which is found as separator. A new separator is activated using the "pushSeparator" method.

readHeader WRAP
    Read the whole message-header and return it as list "field =" value, field => value>. Mind that some fields will appear more than once. The WRAP is the expected length of lines, but is not yet used.

    The first element will represent the position in the file where the header starts. The follows the list of headerfield names and bodies.

    Example:

      my ($where, @header) = $parser->readHeader(72);

bodyAsString [,CHARS [,LINES]]
    Try to read one message-body from the file. Optionally, the predicted number of CHARacterS and/or LINES to be read can be supplied. These values may be "undef" and may be wrong.

    The return is a list of three scalars, the location in the file where the body starts, where the body ends, and the string containing the whole body.

bodyAsList [,CHARS [,LINES]]
    Try to read one message-body from the file. Optionally, the predicted number of CHARacterS and/or LINES to be read can be supplied. These values may be "undef" and may be wrong.

    The return is a list of scalars, each containing one line (including line terminator), preceeded by two integers representing the location in the file where this body started and ended.

bodyAsFile FILEHANDLE [,CHARS [,LINES]]
    Try to read one message-body from the file, and immediately write it to the specified file-handle. Optionally, the predicted number of CHARacterS and/or LINES to be read can be supplied. These values may be "undef" and may be wrong.

    The return is a list of three scalars: the location of the body (begin and end) and the number of lines in the body.

bodyDelayed [,CHARS [,LINES]]
    Try to read one message-body from the file, but the data is skipped. Optionally, the predicted number of CHARacterS and/or LINES to be skipped can be supplied. These values may be "undef" and may be wrong.

    The return is a list of four scalars: the location of the body (begin and end), the size of the body, and the number of lines in the body. The number of lines may be "undef".

lineSeparator
    Returns the character or characters which are used to separate lines in the folder file. This is based on the first line of the file. UNIX systems use a single LF to separate lines. Windows uses a CR and a LF. Mac uses CR.

foldHeaderLine LINE, LENGTH
    (Class method) Fold the specified line (which is a header-line with a structured format) into multiple lines. Each line is terminated by a newline.

    This method is called by "Mail::Message::Field::toString()" to format headers before writing them to a file.

    Example:

      my $string = 'From: me; very long comment';
      print Mail::Box::Parser::C->foldHeaderLine($string, 40);

SEE ALSO
Mail::Box-Overview

For support and additional documentation, see http://perl.overmeer.net/mailbox/

AUTHOR
Mark Overmeer (mailbox@overmeer.net). All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

VERSION
This code is beta, version 2.018.

Copyright (c) 2001-2002 Mark Overmeer. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.