Category: | Text Processing |
Author/Contact Info | Ton Sistos antonio@moonlight.com |
Description: | Data::Dumper is a great utility that converts Perl structures into eval-able strings. These strings can be stored to text files, providing an easy way to save the state of your program. Unfortunately, evaling strings from a file is usually a giant security hole; imagine if someone replaced your stucture with system("rm -R /"), for instance. This code provides a non-eval way of reading in Data::Dumper structures. Note: This code requires Parse::RecDescent.
Update: Added support for blessed references. |
##### # Package: Undumper # Author: Ton Sistos # # Usage: # # my $undumper = Undumper->new(); # my $string = my <<'_EOSTRING_'; # { # '1' => {string=>"hello"}, # '2' => [2,4,6,[0,3],[1,2]], # bar => [1, 2, { this => 'that', 5, "world"}, baz], # 5, 4.023421, # 'foo', "hello world" # } # _EOSTRING_ # my $struct = $undumper->Undump($string) or die "Bad string"; ##### package Undumper; use Parse::RecDescent; use strict; use vars qw($grammar); # Enable warnings within the Parse::RecDescent module. $::RD_ERRORS = 1; # Make sure the parser dies when it encounters an er +ror $::RD_WARN = 1; # Enable warnings. This will warn on unused rules &c +. $::RD_HINT = 1; # Give out hints to help fix problems. $grammar = <<'_GRAMMAR_'; { my $u = '^%$&undef&$*!'; } # Terminals first INTEGER : /[-+]?\d+/ { $return = int($item[1]); } FLOAT : /[-+]?\d*\.\d+[eE][-+]?\d+/ | /[-+]?\d+\.\d*[eE][-+]?\d+/ | /[-+]?\d*\.\d+/ STRING : /"((.*?(\\\\)*(\\")*)*?)"/s { $return = $1; $return =~ s/\\"/"/g; $return =~ s/\\\\/\\/ +g; } | /'((.*?(\\\\)*(\\')*)*?)'/s { $return = $1; $return =~ s/\\'/'/g; $return =~ s/\\\\/\\/ +g; } SIMPLESTRING : /[a-zA-Z]\w*/ term : FLOAT | INTEGER | STRING | SIMPLESTRING goodterm : FLOAT | INTEGER | STRING anystring : STRING | SIMPLESTRING hashpair : goodterm ',' expression { $return = [$item[1], $item[3] eq $u ? undef : $item[3]] +; } | term '=>' expression { $return = [$item[1], $item[3] eq $u ? undef : $item[3]] +; } arraylist : expression ',' arraylist { $return = [$item[1] eq $u ? undef : $item[1], @{$item[ +3]}]; } | expression ',' { $return = [$item[1] eq $u ? undef : $item[1]]; } | expression { $return = [$item[1] eq $u ? undef : $item[1]]; } hashlist : hashpair ',' hashlist { $return = [@{$item[1]}, @{$item[3]}]; } | hashpair ',' { $return = $item[1]; } | hashpair { $return = $item[1]; } array : '[' arraylist ']' { $return = $item[2]; } | '[' ']' { $return = []; } hash : '{' hashlist '}' { $return = { @{$item[2]} }; } | '{' '}' { $return = {}; } object : 'bless' '(' primitive ',' anystring ')' { $return = bless($item[3], $item[5]); } primitive : hash | array | term expression : object | 'undef' { $return = $u; } | primitive startrule : expression { $return = (($text =~ m/^[\s;]*$/) ? ($item[1] eq $u ? +undef : $item[1]) : undef); } _GRAMMAR_ sub new($$) { my $invocant = shift; my $paramHRef = shift; my $class = ref($invocant) || $invocant; # object or class name my $self = { }; bless($self, $class); $self->_Initialize(); return $self; } sub Undump($$) { my $self = shift; my $string = shift; return $self->{'parser'}->startrule($string); } sub _Initialize($) { my $self = shift; my $parser = Parse::RecDescent->new($grammar); $self->{'parser'} = $parser; } |
|
---|
Replies are listed 'Best First'. | |
---|---|
Re: Undumper
by mirod (Canon) on Jun 29, 2001 at 11:09 UTC | |
Re: Undumper
by DrZaius (Monk) on Jun 29, 2001 at 20:30 UTC | |
Re: Undumper
by mugwumpjism (Hermit) on Jul 01, 2001 at 20:47 UTC | |
•Re: Undumper
by merlyn (Sage) on Mar 30, 2003 at 19:01 UTC | |
Re: Undumper
by epoptai (Curate) on Jun 29, 2001 at 11:57 UTC | |
by tadman (Prior) on Jun 29, 2001 at 12:20 UTC | |
by petral (Curate) on Jun 30, 2001 at 01:18 UTC |
Back to
Code Catacombs