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#============================================================= -*-Perl-*-
#
# Template::Filters
#
# DESCRIPTION
# Defines filter plugins as used by the FILTER directive.
#
# AUTHORS
# Andy Wardley <abw@wardley.org>, with a number of filters contributed
# by Leslie Michael Orchard <deus_x@nijacode.com>
#
# COPYRIGHT
# Copyright (C) 1996-2022 Andy Wardley. All Rights Reserved.
#
# This module is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.
#
#============================================================================
package Template::Filters;
use strict;
use warnings;
use locale;
use base 'Template::Base';
use Template::Constants;
use Scalar::Util 'blessed';
our $VERSION = '3.100';
our $AVAILABLE = { };
our $TRUNCATE_LENGTH = 32;
our $TRUNCATE_ADDON = '...';
#------------------------------------------------------------------------
# standard filters, defined in one of the following forms:
# name => \&static_filter
# name => [ \&subref, $is_dynamic ]
# If the $is_dynamic flag is set then the sub-routine reference
# is called to create a new filter each time it is requested; if
# not set, then it is a single, static sub-routine which is returned
# for every filter request for that name.
#------------------------------------------------------------------------
our $FILTERS = {
# static filters
'html' => \&html_filter,
'html_para' => \&html_paragraph,
'html_break' => \&html_para_break,
'html_para_break' => \&html_para_break,
'html_line_break' => \&html_line_break,
'xml' => \&xml_filter,
'uri' => \&uri_filter,
'url' => \&url_filter,
'upper' => sub { uc $_[0] },
'lower' => sub { lc $_[0] },
'ucfirst' => sub { ucfirst $_[0] },
'lcfirst' => sub { lcfirst $_[0] },
'stderr' => sub { print STDERR @_; return '' },
'trim' => sub { for ($_[0]) { s/^\s+//; s/\s+$// }; $_[0] },
'null' => sub { return '' },
'collapse' => sub { for ($_[0]) { s/^\s+//; s/\s+$//; s/\s+/ /g };
$_[0] },
# dynamic filters
'html_entity' => [ \&html_entity_filter_factory, 1 ],
'indent' => [ \&indent_filter_factory, 1 ],
'format' => [ \&format_filter_factory, 1 ],
'truncate' => [ \&truncate_filter_factory, 1 ],
'repeat' => [ \&repeat_filter_factory, 1 ],
'replace' => [ \&replace_filter_factory, 1 ],
'remove' => [ \&remove_filter_factory, 1 ],
'eval' => [ \&eval_filter_factory, 1 ],
'evaltt' => [ \&eval_filter_factory, 1 ], # alias
'perl' => [ \&perl_filter_factory, 1 ],
'evalperl' => [ \&perl_filter_factory, 1 ], # alias
'redirect' => [ \&redirect_filter_factory, 1 ],
'file' => [ \&redirect_filter_factory, 1 ], # alias
'stdout' => [ \&stdout_filter_factory, 1 ],
};
# name of module implementing plugin filters
our $PLUGIN_FILTER = 'Template::Plugin::Filter';
#========================================================================
# -- PUBLIC METHODS --
#========================================================================
#------------------------------------------------------------------------
# fetch($name, \@args, $context)
#
# Attempts to instantiate or return a reference to a filter sub-routine
# named by the first parameter, $name, with additional constructor
# arguments passed by reference to a list as the second parameter,
# $args. A reference to the calling Template::Context object is
# passed as the third parameter.
#
# Returns a reference to a filter sub-routine or a pair of values
# (undef, STATUS_DECLINED) or ($error, STATUS_ERROR) to decline to
# deliver the filter or to indicate an error.
#------------------------------------------------------------------------
sub fetch {
my ($self, $name, $args, $context) = @_;
my ($factory, $is_dynamic, $filter, $error);
$self->debug("fetch($name, ",
defined $args ? ('[ ', join(', ', @$args), ' ]') : '<no args>', ', ',
defined $context ? $context : '<no context>',
')') if $self->{ DEBUG };
# allow $name to be specified as a reference to
# a plugin filter object; any other ref is
# assumed to be a coderef and hence already a filter;
# non-refs are assumed to be regular name lookups
if (ref $name) {
if (blessed($name) && $name->isa($PLUGIN_FILTER)) {
$factory = $name->factory()
|| return $self->error($name->error());
}
else {
return $name;
}
}
else {
return (undef, Template::Constants::STATUS_DECLINED)
unless ($factory = $self->{ FILTERS }->{ $name }
|| $FILTERS->{ $name });
}
# factory can be an [ $code, $dynamic ] or just $code
if (ref $factory eq 'ARRAY') {
($factory, $is_dynamic) = @$factory;
}
else {
$is_dynamic = 0;
}
if (ref $factory eq 'CODE') {
if ($is_dynamic) {
# if the dynamic flag is set then the sub-routine is a
# factory which should be called to create the actual
# filter...
eval {
($filter, $error) = &$factory($context, $args ? @$args : ());
};
$error ||= $@;
$error = "invalid FILTER for '$name' (not a CODE ref)"
unless $error || ref($filter) eq 'CODE';
}
else {
# ...otherwise, it's a static filter sub-routine
$filter = $factory;
}
}
else {
$error = "invalid FILTER entry for '$name' (not a CODE ref)";
}
if ($error) {
return $self->{ TOLERANT }
? (undef, Template::Constants::STATUS_DECLINED)
: ($error, Template::Constants::STATUS_ERROR) ;
}
else {
return $filter;
}
}
#------------------------------------------------------------------------
# store($name, \&filter)
#
# Stores a new filter in the internal FILTERS hash. The first parameter
# is the filter name, the second a reference to a subroutine or
# array, as per the standard $FILTERS entries.
#------------------------------------------------------------------------
sub store {
my ($self, $name, $filter) = @_;
$self->debug("store($name, $filter)") if $self->{ DEBUG };
$self->{ FILTERS }->{ $name } = $filter;
return 1;
}
#========================================================================
# -- PRIVATE METHODS --
#========================================================================
#------------------------------------------------------------------------
# _init(\%config)
#
# Private initialisation method.
#------------------------------------------------------------------------
sub _init {
my ($self, $params) = @_;
$self->{ FILTERS } = $params->{ FILTERS } || { };
$self->{ TOLERANT } = $params->{ TOLERANT } || 0;
$self->{ DEBUG } = ( $params->{ DEBUG } || 0 )
& Template::Constants::DEBUG_FILTERS;
return $self;
}
#========================================================================
# -- STATIC FILTER SUBS --
#========================================================================
#------------------------------------------------------------------------
# uri_filter() and url_filter() below can match using either RFC3986 or
# RFC2732. See https://github.com/abw/Template2/issues/13
#-----------------------------------------------------------------------
our $UNSAFE_SPEC = {
RFC2732 => q{A-Za-z0-9\-_.~!*'()},
RFC3986 => q{A-Za-z0-9\-_.~},
};
our $UNSAFE_CHARS = $UNSAFE_SPEC->{ RFC3986 };
our $URI_REGEX;
our $URL_REGEX;
our $URI_ESCAPES;
sub use_rfc2732 {
$UNSAFE_CHARS = $UNSAFE_SPEC->{ RFC2732 };
$URI_REGEX = $URL_REGEX = undef;
}
sub use_rfc3986 {
$UNSAFE_CHARS = $UNSAFE_SPEC->{ RFC3986 };
$URI_REGEX = $URL_REGEX = undef;
}
sub uri_escapes {
return {
map { ( chr($_), sprintf("%%%02X", $_) ) } (0..255),
};
}
#------------------------------------------------------------------------
# uri_filter() [% FILTER uri %]
#
# URI escape a string. This code is borrowed from Gisle Aas' URI::Escape
# module, copyright 1995-2004. See RFC2396, RFC2732 and RFC3986 for
# details.
#-----------------------------------------------------------------------
sub uri_filter {
my $text = shift;
$URI_REGEX ||= qr/([^$UNSAFE_CHARS])/;
$URI_ESCAPES ||= uri_escapes();
if ($] >= 5.008 && utf8::is_utf8($text)) {
utf8::encode($text);
}
$text =~ s/$URI_REGEX/$URI_ESCAPES->{$1}/eg;
$text;
}
#------------------------------------------------------------------------
# url_filter() [% FILTER uri %]
#
# NOTE: the difference: url vs uri.
# This implements the old-style, non-strict behaviour of the uri filter
# which allows any valid URL characters to pass through so that
# http://example.com/blah.html does not get the ':' and '/' characters
# munged.
#-----------------------------------------------------------------------
sub url_filter {
my $text = shift;
$URL_REGEX ||= qr/([^;\/?:@&=+\$,$UNSAFE_CHARS])/;
$URI_ESCAPES ||= uri_escapes();
if ($] >= 5.008 && utf8::is_utf8($text)) {
utf8::encode($text);
}
$text =~ s/$URL_REGEX/$URI_ESCAPES->{$1}/eg;
$text;
}
#------------------------------------------------------------------------
# html_filter() [% FILTER html %]
#
# Convert any '<', '>' or '&' characters to the HTML equivalents, '<',
# '>' and '&', respectively.
#------------------------------------------------------------------------
sub html_filter {
my $text = shift;
for ($text) {
s/&/&/g;
s/</</g;
s/>/>/g;
s/"/"/g;
}
return $text;
}
#------------------------------------------------------------------------
# xml_filter() [% FILTER xml %]
#
# Same as the html filter, but adds the conversion of ' to ' which
# is native to XML.
#------------------------------------------------------------------------
sub xml_filter {
my $text = shift;
for ($text) {
s/&/&/g;
s/</</g;
s/>/>/g;
s/"/"/g;
s/'/'/g;
}
return $text;
}
#------------------------------------------------------------------------
# html_paragraph() [% FILTER html_para %]
#
# Wrap each paragraph of text (delimited by two or more newlines) in the
# <p>...</p> HTML tags.
#------------------------------------------------------------------------
sub html_paragraph {
my $text = shift;
return "<p>\n"
. join("\n</p>\n\n<p>\n", split(/(?:\r?\n){2,}/, $text))
. "</p>\n";
}
#------------------------------------------------------------------------
# html_para_break() [% FILTER html_para_break %]
#
# Join each paragraph of text (delimited by two or more newlines) with
# <br><br> HTML tags.
#------------------------------------------------------------------------
sub html_para_break {
my $text = shift;
$text =~ s|(\r?\n){2,}|$1<br />$1<br />$1|g;
return $text;
}
#------------------------------------------------------------------------
# html_line_break() [% FILTER html_line_break %]
#
# replaces any newlines with <br> HTML tags.
#------------------------------------------------------------------------
sub html_line_break {
my $text = shift;
$text =~ s|(\r?\n)|<br />$1|g;
return $text;
}
#========================================================================
# -- DYNAMIC FILTER FACTORIES --
#========================================================================
#------------------------------------------------------------------------
# html_entity_filter_factory(\%options) [% FILTER html %]
#
# Dynamic version of the static html filter which attempts to locate the
# Apache::Util or HTML::Entities modules to perform full entity encoding
# of the text passed. Returns an exception if one or other of the
# modules can't be located.
#------------------------------------------------------------------------
sub use_html_entities {
require HTML::Entities;
return ($AVAILABLE->{ HTML_ENTITY } = \&HTML::Entities::encode_entities);
}
sub use_apache_util {
require Apache::Util;
Apache::Util::escape_html(''); # TODO: explain this
return ($AVAILABLE->{ HTML_ENTITY } = \&Apache::Util::escape_html);
}
sub html_entity_filter_factory {
my $context = shift;
my $haz;
# if Apache::Util is installed then we use escape_html
$haz = $AVAILABLE->{ HTML_ENTITY }
|| eval { use_apache_util() }
|| eval { use_html_entities() }
|| -1; # we use -1 for "not available" because it's a true value
return ref $haz eq 'CODE'
? $haz
: (undef, Template::Exception->new(
html_entity => 'cannot locate Apache::Util or HTML::Entities' )
);
}
#------------------------------------------------------------------------
# indent_filter_factory($pad) [% FILTER indent(pad) %]
#
# Create a filter to indent text by a fixed pad string or when $pad is
# numerical, a number of space.
#------------------------------------------------------------------------
sub indent_filter_factory {
my ($context, $pad) = @_;
$pad = 4 unless defined $pad;
$pad = ' ' x $pad if $pad =~ /^\d+$/;
return sub {
my $text = shift;
$text = '' unless defined $text;
$text =~ s/^/$pad/mg;
return $text;
}
}
#------------------------------------------------------------------------
# format_filter_factory() [% FILTER format(format) %]
#
# Create a filter to format text according to a printf()-like format
# string.
#------------------------------------------------------------------------
sub format_filter_factory {
my ($context, $format) = @_;
$format = '%s' unless defined $format;
return sub {
my $text = shift;
$text = '' unless defined $text;
return join("\n", map{ sprintf($format, $_) } split(/\n/, $text));
}
}
#------------------------------------------------------------------------
# repeat_filter_factory($n) [% FILTER repeat(n) %]
#
# Create a filter to repeat text n times.
#------------------------------------------------------------------------
sub repeat_filter_factory {
my ($context, $iter) = @_;
$iter = 1 unless defined $iter and length $iter;
return sub {
my $text = shift;
$text = '' unless defined $text;
return join('\n', $text) x $iter;
}
}
#------------------------------------------------------------------------
# replace_filter_factory($s, $r) [% FILTER replace(search, replace) %]
#
# Create a filter to replace 'search' text with 'replace'
#------------------------------------------------------------------------
sub replace_filter_factory {
my ($context, $search, $replace) = @_;
$search = '' unless defined $search;
$replace = '' unless defined $replace;
return sub {
my $text = shift;
$text = '' unless defined $text;
$text =~ s/$search/$replace/g;
return $text;
}
}
#------------------------------------------------------------------------
# remove_filter_factory($text) [% FILTER remove(text) %]
#
# Create a filter to remove 'search' string from the input text.
#------------------------------------------------------------------------
sub remove_filter_factory {
my ($context, $search) = @_;
return sub {
my $text = shift;
$text = '' unless defined $text;
$text =~ s/$search//g;
return $text;
}
}
#------------------------------------------------------------------------
# truncate_filter_factory($n) [% FILTER truncate(n) %]
#
# Create a filter to truncate text after n characters.
#------------------------------------------------------------------------
sub truncate_filter_factory {
my ($context, $len, $char) = @_;
$len = $TRUNCATE_LENGTH unless defined $len;
$char = $TRUNCATE_ADDON unless defined $char;
# Length of char is the minimum length
my $lchar = length $char;
if ($len < $lchar) {
$char = substr($char, 0, $len);
$lchar = $len;
}
return sub {
my $text = shift;
return $text if length $text <= $len;
return substr($text, 0, $len - $lchar) . $char;
}
}
#------------------------------------------------------------------------
# eval_filter_factory [% FILTER eval %]
#
# Create a filter to evaluate template text.
#------------------------------------------------------------------------
sub eval_filter_factory {
my $context = shift;
return sub {
my $text = shift;
$context->process(\$text);
}
}
#------------------------------------------------------------------------
# perl_filter_factory [% FILTER perl %]
#
# Create a filter to process Perl text iff the context EVAL_PERL flag
# is set.
#------------------------------------------------------------------------
sub perl_filter_factory {
my $context = shift;
my $stash = $context->stash;
return (undef, Template::Exception->new('perl', 'EVAL_PERL is not set'))
unless $context->eval_perl();
return sub {
my $text = shift;
local($Template::Perl::context) = $context;
local($Template::Perl::stash) = $stash;
my $out = eval <<EOF;
package Template::Perl;
\$stash = \$context->stash();
$text
EOF
$context->throw($@) if $@;
return $out;
}
}
#------------------------------------------------------------------------
# redirect_filter_factory($context, $file) [% FILTER redirect(file) %]
#
# Create a filter to redirect the block text to a file.
#------------------------------------------------------------------------
sub redirect_filter_factory {
my ($context, $file, $options) = @_;
my $outpath = $context->config->{ OUTPUT_PATH };
return (undef, Template::Exception->new('redirect',
'OUTPUT_PATH is not set'))
unless $outpath;
$context->throw('redirect', "relative filenames are not supported: $file")
if $file =~ m{(^|/)\.\./};
$options = { binmode => $options } unless ref $options;
sub {
my $text = shift;
my $outpath = $context->config->{ OUTPUT_PATH }
|| return '';
$outpath .= "/$file";
my $error = Template::_output($outpath, \$text, $options);
die Template::Exception->new('redirect', $error)
if $error;
return '';
}
}
#------------------------------------------------------------------------
# stdout_filter_factory($context, $binmode) [% FILTER stdout(binmode) %]
#
# Create a filter to print a block to stdout, with an optional binmode.
#------------------------------------------------------------------------
sub stdout_filter_factory {
my ($context, $options) = @_;
$options = { binmode => $options } unless ref $options;
sub {
my $text = shift;
binmode(STDOUT) if $options->{ binmode };
print STDOUT $text;
return '';
}
}
1;
__END__
=head1 NAME
Template::Filters - Post-processing filters for template blocks
=head1 SYNOPSIS
use Template::Filters;
$filters = Template::Filters->new(\%config);
($filter, $error) = $filters->fetch($name, \@args, $context);
if ($filter) {
print &$filter("some text");
}
else {
print "Could not fetch $name filter: $error\n";
}
=head1 DESCRIPTION
The C<Template::Filters> module implements a provider for creating subroutines
that implement the standard filters. Additional custom filters may be provided
via the L<FILTERS> configuration option.
=head1 METHODS
=head2 new(\%params)
Constructor method which instantiates and returns a reference to a
C<Template::Filters> object. A reference to a hash array of configuration
items may be passed as a parameter. These are described below.
my $filters = Template::Filters->new({
FILTERS => { ... },
});
my $template = Template->new({
LOAD_FILTERS => [ $filters ],
});
A default C<Template::Filters> module is created by the L<Template> module
if the L<LOAD_FILTERS> option isn't specified. All configuration parameters
are forwarded to the constructor.
$template = Template->new({
FILTERS => { ... },
});
=head2 fetch($name, \@args, $context)
Called to request that a filter of a given name be provided. The name
of the filter should be specified as the first parameter. This should
be one of the standard filters or one specified in the L<FILTERS>
configuration hash. The second argument should be a reference to an
array containing configuration parameters for the filter. This may be
specified as 0, or undef where no parameters are provided. The third
argument should be a reference to the current L<Template::Context>
object.
The method returns a reference to a filter sub-routine on success. It
may also return C<(undef, STATUS_DECLINE)> to decline the request, to allow
delegation onto other filter providers in the L<LOAD_FILTERS> chain of
responsibility. On error, C<($error, STATUS_ERROR)> is returned where $error
is an error message or L<Template::Exception> object indicating the error
that occurred.
When the C<TOLERANT> option is set, errors are automatically downgraded to
a C<STATUS_DECLINE> response.
=head2 use_html_entities()
This class method can be called to configure the C<html_entity> filter to use
the L<HTML::Entities> module. An error will be raised if it is not installed
on your system.
use Template::Filters;
Template::Filters->use_html_entities();
=head2 use_apache_util()
This class method can be called to configure the C<html_entity> filter to use
the L<Apache::Util> module. An error will be raised if it is not installed on
your system.
use Template::Filters;
Template::Filters->use_apache_util();
=head2 use_rfc2732()
This class method can be called to configure the C<uri> and C<url> filters to
use the older RFC2732 standard for matching unsafe characters.
=head2 use_rfc3986()
This class method can be called to configure the C<uri> and C<url> filters to
use the newer RFC3986 standard for matching unsafe characters.
=head1 CONFIGURATION OPTIONS
The following list summarises the configuration options that can be provided
to the C<Template::Filters> L<new()> constructor. Please see
L<Template::Manual::Config> for further information about each option.
=head2 FILTERS
The L<FILTERS|Template::Manual::Config#FILTERS> option can be used to specify
custom filters which can then be used with the
L<FILTER|Template::Manual::Directives#FILTER> directive like any other. These
are added to the standard filters which are available by default.
$filters = Template::Filters->new({
FILTERS => {
'sfilt1' => \&static_filter,
'dfilt1' => [ \&dyanamic_filter_factory, 1 ],
},
});
=head2 TOLERANT
The L<TOLERANT|Template::Manual::Config#TOLERANT> flag can be set to indicate
that the C<Template::Filters> module should ignore any errors and instead
return C<STATUS_DECLINED>.
=head2 DEBUG
The L<DEBUG|Template::Manual::Config#DEBUG> option can be used to enable
debugging messages for the Template::Filters module by setting it to include
the C<DEBUG_FILTERS> value.
use Template::Constants qw( :debug );
my $template = Template->new({
DEBUG => DEBUG_FILTERS | DEBUG_PLUGINS,
});
=head1 STANDARD FILTERS
Please see L<Template::Manual::Filters> for a list of the filters provided
with the Template Toolkit, complete with examples of use.
=head1 AUTHOR
Andy Wardley E<lt>abw@wardley.orgE<gt> L<http://wardley.org/>
=head1 COPYRIGHT
Copyright (C) 1996-20202Andy Wardley. All Rights Reserved.
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
=head1 SEE ALSO
L<Template::Manual::Filters>, L<Template>, L<Template::Context>
=cut
# Local Variables:
# mode: perl
# perl-indent-level: 4
# indent-tabs-mode: nil
# End:
#
# vim: expandtab shiftwidth=4: