Log::Procmail - Perl extension for reading procmail logfiles.

Log-Procmail documentation Contained in the Log-Procmail distribution.

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NAME

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Log::Procmail - Perl extension for reading procmail logfiles.

SYNOPSIS

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    use Log::Procmail;

    my $log = new Log::Procmail 'procmail.log';

    # loop on every abstract
    while(my $rec = $log->next) {
        # do something with $rec->folder, $rec->size, etc.
    }

DESCRIPTION

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Log::Procmail

Log::Procmail reads procmail(1) logfiles and returns the abstracts one by one.

$log = Log::Procmail->new( @files );

Constructor for the procmail log reader. Returns a reference to a Log::Procmail object.

The constructor accepts a list of file as parameter. This allows you to read records from several files in a row:

    $log = Log::Procmail->new( "$ENV{HOME}/.procmail/log.2",
                               "$ENV{HOME}/.procmail/log.1",
                               "$ENV{HOME}/.procmail/log", );

When $log reaches the end of the file "log", it doesn't close the file. So, after procmail processes some incoming mail, the next call to next() will return the new records.

$rec = $log->next

Return a Log::Procmail::Abstract object that represent an entry in the log file. Return undef if there is no record left in the file.

When the Log::Procmail object reaches the end of a file, and this file is not the last of the stack, it closes the current file and opens the next one.

When it reaches the end of the last file, the file is not closed. Next time the record method is called, it will check again in case new abstracts were appended.

Procmail(1) log look like the following:

    From karen644552@btinternet.com  Fri Feb  8 20:37:24 2002
     Subject: Stock Market Volatility Beating You Up? (18@2)
      Folder: /var/spool/mail/book						   2840

Some informational messages can be put by procmail(1) in the log file. If the errors attribute is true, these lines are returned one at a time.

With errors enabled, you have to check that next() actually returns a Log::Procmail::Abstract object. Here is an example:

    $log->errors(1);

    # fetch data
    while ( $rec = $log->next ) {

        # if it's an error line
        if ( !ref $rec ) {
            # this is not a log, but an informational message
            # do something with it
            next;
        }

        # normal log processing
    }
$log->push( $file [, $file2 ...] );

Push one or more files on top of the list of log files to examine. When Log::Procmail runs out of abstracts to return (i.e. it reaches the end of the file), it transparently opens the next file (if there is one) and keeps returning new abstracts.

$log->errors( [bool] );

Set or get the error flag. If set, when the next() method will return the string found in the log file, instead of ignoring it. Be careful: it is a simple string, not a Log::Procmail::Abstract object.

Default is to return no error.

$fh = $log->fh()

Returns the currently opened filehandle, from which the next call to next() will try to read a record.

$select = $log->select()

Return a IO::Select object that watches the currently opened filehandle.

You are not supposed to use add() or remove() on the returned IO::Select object.

Additional warning for MSWin32, NetWare, dos, VMS, riscos and beos: on those systems, select() returns undef. (Check ext/IO/t/io_sel.t in the Perl sources for details. Hint: look for the message 4-arg select is only valid on sockets.)

Log::Procmail::Abstract

Log::Procmail::Abstract is a class that hold the abstract information. Since the abstract hold From, Date, Subject, Folder and Size information, all this can be accessed and modified through the from(), date(), subject(), folder() and size() methods.

Log::Procmail::next() returns a Log::Procmail::Abstract object.

Log::Procmail::Abstract accessors

The Log::Procmail::Abstract object accessors are named from(), date(), subject(), folder() and size(). They return the relevant information when called without argument, and set it to their first argument otherwise.

    # count mail received per folder
    while( $rec = $log->next ) { $folder{ $rec->folder }++ }

The source() accessor returns the name of the log file or the string representation of the handle, if a filehandle was given.

$rec->ymd()

Return the date in the form yyyymmmddhhmmss where each field is what you think it is. ;-) This method is read-only.

EXAMPLES

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Here is an example procmail biff-like script, courtesy of Ian Langworth:

    #/usr/bin/perl -w
    use strict;
    use Log::Procmail;

    use constant LOGFILE       => "$ENV{HOME}/procmail.log";
    use constant VALID_FOLDERS => [qw( agent inbox perl systems )];
    my $format = "\%8s: \%-30.30s / %s\n";

    my $log = Log::Procmail->new( LOGFILE );
    $log->errors(1);

    while ( $log->select->can_read ) {
        my $rec = $log->next;

        # error?
        warn "$rec\n", next unless ref $rec;

        # ignore mailboxes we don't care about
        next unless grep { $_ eq $rec->folder } @{ VALID_FOLDERS() };

        # print data
        printf $format, From    => $rec->from;
        printf $format, Subject => $rec->subject, $rec->folder;
    }

TODO

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The Log::Procmail object should be able to read from STDIN.

BUGS

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Please report all bugs through the rt.cpan.org interface:

http://rt.cpan.org/NoAuth/Bugs.html?Dist=Log-Procmail

AUTHOR

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Philippe "BooK" Bruhat <book@cpan.org>.

ACKNOWLEDGMENTS

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Thanks to Briac "Oeufmayo" Pilpré and David "Sniper" Rigaudiere for early comments on irc. Thanks to Olivier "rs" Poitrey for giving me his huge procmail log file (51 Mb spanning over a two-year period) and for probably being the first user of this module. Many thanks to Michael Schwern for insisting so much on the importance of tests and documentation.

Many thanks to "Les Mongueurs de Perl" for making cvs.mongueurs.net available for Log::Procmail and many other projects.

COPYRIGHT

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Copyright (c) 2002-2004, Philippe Bruhat. All Rights Reserved.

LICENSE

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This module is free software. It may be used, redistributed and/or modified under the terms of the Perl Artistic License (see http://www.perl.com/perl/misc/Artistic.html)

SEE ALSO

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perl(1), procmail(1).

Log-Procmail documentation Contained in the Log-Procmail distribution. 
package Log::Procmail;

require 5.005;
use strict;
use IO::File;
use IO::Select;
use Carp;
use UNIVERSAL ();

use vars qw/ $VERSION /;
local $^W = 1;

$VERSION = '0.11';

my %month;
@month{qw/ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec /} = ( 0 .. 11 );

my $DATE = qr/(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun) (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) ([ \d]\d) (\d\d):(\d\d):(\d\d) .*(\d\d\d\d)/;

sub new {
    my $class = shift;
    return bless {
        fh     => new IO::File,
        files  => [@_],
        errors => 0,
        buffer => [],
    }, $class;
}

sub next {
    my $log = shift;    # who needs $self?

    # try to read a record (3 lines)
    my $fh  = $log->fh();
  READ:
    {
        my $read;

      LINE:
        while (<$fh>) {
            $read++;

            # should carp if doesn't get what's expected
            # (From, then Subject, then Folder)

            # From create a new Abstract
            /^From (.+?) +($DATE)$/o && do {
                push @{$log->{buffer}}, Log::Procmail::Abstract->new();

                # assert: $read == 1;
                $log->{buffer}[-1]->from($1);
                $log->{buffer}[-1]->date($2);

                # return ASAP
                last READ if @{$log->{buffer}} > 1;
                next LINE;
            };

            # assert: $read == 2;
            /^ Subject: (.*)/i && do {
                push @{$log->{buffer}}, Log::Procmail::Abstract->new()
                    unless @{$log->{buffer}};
                $log->{buffer}[0]->subject($1);
                next LINE;
            };

            # procmail tabulates with tabs and spaces... :-(
            # assert: $read == 3;
            # Folder means the end of this record
            /^  Folder: (.*?)\s+(\d+)$/ && do {
                push @{$log->{buffer}}, Log::Procmail::Abstract->new()
                  unless @{$log->{buffer}};

                # assert: $read == 3;
                $log->{buffer}[0]->folder($1);
                $log->{buffer}[0]->size($2);
                last READ;
            };

            # fall through: some error message
            # shall we ignore it?
            next LINE unless $log->{errors};

            # or return it?
            chomp;
            push @{$log->{buffer}}, $_;
            last LINE;
        }

        # in case we couldn't read the first line
        if ( !$read or @{$log->{buffer}} == 0 ) {

            # return ASAP
            last READ if @{$log->{buffer}};

            # go to next file
            redo READ if $log->_open_next;

            # unless it's the last one
            return;
        }
    }

    # we have an abstract
    my $rec = shift @{$log->{buffer}};
    if(UNIVERSAL::isa( $rec, 'Log::Procmail::Abstract')) {
        # the folder field is required
        goto READ unless defined $rec->folder;
        $rec->{source} = $log->{source};
    }

    return $rec;
}

sub push {
    my $log = shift;
    push @{ $log->{files} }, @_;
}

sub errors {
    my $self = shift;
    return @_ ? $self->{errors} = shift() : $self->{errors};
}

sub fh {
    my $log = shift;
    $log->_open_next unless $log->{fh}->opened();
    return $log->{fh};
}

sub select {
    my $log = shift;
    $log->fh(); # make sure the file is correctly opened and select is updated
    return $log->{select};
}

# *internal method*
# opens a file or replace the old filehandle by the new one
# push() can therefore accept refs to typeglobs, IO::Handle, or filenames
sub _open_next {
    my ( $log ) = @_;
    my $file;

    if ( @{ $log->{files} } ) {
        $file = shift @{ $log->{files} };
    } else { return 0 };

    if ( ref $file eq 'GLOB' ) {
        $log->{fh} = *$file{IO};
        carp "Closed filehandle $log->{fh}" unless $log->{fh}->opened;
    }
    elsif ( ref $file && $file->isa('IO::Handle') ) {
        $log->{fh} = $file;
    }
    else {
        $log->{fh}->open($file) or carp "Can't open $file: $!";
    }
    $log->{source} = $file;
    $log->{select} = ( grep $^O eq $_, qw(MSWin32 NetWare dos VMS riscos beos) )
                   ? undef
                   : IO::Select->new( $log->{fh} );
    1;
}

sub DESTROY {
    my $self = shift;
    if ( $self->{fh} && $self->{fh}->opened ) { $self->{fh}->close }
}

#
# a small class for the abstracts themselves
#
package Log::Procmail::Abstract;

use Carp;

sub new {
    my $class = shift;
    return bless {@_}, $class;
}

for my $attr (qw( from date subject size folder source ) ) {
    no strict 'refs';
    *$attr = sub {
        my $self = shift;
        @_ ? $self->{$attr} = shift: $self->{$attr};
    }
}

sub ymd {
    my $self = shift;
    croak("Log::Procmail::Abstract::ymd cannot be used to set the date")
      if @_;
    return undef unless defined $self->{date};
    $self->{date} =~ /^$DATE$/o;
    return undef unless $1;
    return sprintf( "%04d%02d%02d$3$4$5", $6, $month{$1} + 1, $2 );
}

1;

__END__