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##============================================================= -*-Perl-*- # # Template::Document # # DESCRIPTION # Module defining a class of objects which encapsulate compiled # templates, storing additional block definitions and metadata # as well as the compiled Perl sub-routine representing the main # template content. # # AUTHOR # Andy Wardley <abw@wardley.org> # # COPYRIGHT # Copyright (C) 1996-2007 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::Document; use strict; use warnings; use base 'Template::Base'; use Template::Constants; our $VERSION = '3.100'; our $DEBUG = 0 unless defined $DEBUG; our $ERROR = ''; our ($COMPERR, $AUTOLOAD, $UNICODE); BEGIN { # UNICODE is supported in versions of Perl from 5.008 onwards if ($UNICODE = $] > 5.007 ? 1 : 0) { if ($] > 5.008) { # utf8::is_utf8() available from Perl 5.8.1 onwards *is_utf8 = \&utf8::is_utf8; } elsif ($] == 5.008) { # use Encode::is_utf8() for Perl 5.8.0 require Encode; *is_utf8 = \&Encode::is_utf8; } } } #======================================================================== # ----- PUBLIC METHODS ----- #======================================================================== #------------------------------------------------------------------------ # new(\%document) # # Creates a new self-contained Template::Document object which # encapsulates a compiled Perl sub-routine, $block, any additional # BLOCKs defined within the document ($defblocks, also Perl sub-routines) # and additional $metadata about the document. #------------------------------------------------------------------------ sub new { my ($class, $doc) = @_; my ($block, $defblocks, $variables, $metadata) = @$doc{ qw( BLOCK DEFBLOCKS VARIABLES METADATA ) }; $defblocks ||= { }; $metadata ||= { }; # evaluate Perl code in $block to create sub-routine reference if necessary unless (ref $block) { local $SIG{__WARN__} = \&catch_warnings; $COMPERR = ''; # DON'T LOOK NOW! - blindly untainting can make you go blind! { no warnings 'syntax'; $block = each %{ { $block => undef } } if ${^TAINT}; #untaint } $block = eval $block; return $class->error($@) unless defined $block; } # same for any additional BLOCK definitions @$defblocks{ keys %$defblocks } = # MORE BLIND UNTAINTING - turn away if you're squeamish map { ref($_) ? $_ : ( /(.*)/s && eval($1) or return $class->error($@) ) } values %$defblocks; bless { %$metadata, _BLOCK => $block, _DEFBLOCKS => $defblocks, _VARIABLES => $variables, _HOT => 0, }, $class; } #------------------------------------------------------------------------ # block() # # Returns a reference to the internal sub-routine reference, _BLOCK, # that constitutes the main document template. #------------------------------------------------------------------------ sub block { return $_[0]->{ _BLOCK }; } #------------------------------------------------------------------------ # blocks() # # Returns a reference to a hash array containing any BLOCK definitions # from the template. The hash keys are the BLOCK name and the values # are references to Template::Document objects. Returns 0 (# an empty hash) # if no blocks are defined. #------------------------------------------------------------------------ sub blocks { return $_[0]->{ _DEFBLOCKS }; } #----------------------------------------------------------------------- # variables() # # Returns a reference to a hash of variables used in the template. # This requires the TRACE_VARS option to be enabled. #----------------------------------------------------------------------- sub variables { return $_[0]->{ _VARIABLES }; } #------------------------------------------------------------------------ # process($context) # # Process the document in a particular context. Checks for recursion, # registers the document with the context via visit(), processes itself, # and then unwinds with a large gin and tonic. #------------------------------------------------------------------------ sub process { my ($self, $context) = @_; my $defblocks = $self->{ _DEFBLOCKS }; my $output; # check we're not already visiting this template return $context->throw( Template::Constants::ERROR_FILE, "recursion into '$self->{ name }'" ) if $self->{ _HOT } && ! $context->{ RECURSION }; ## RETURN ## $context->visit($self, $defblocks); $self->{ _HOT } = 1; eval { my $block = $self->{ _BLOCK }; $output = &$block($context); }; $self->{ _HOT } = 0; $context->leave(); die $context->catch($@) if $@; return $output; } #------------------------------------------------------------------------ # meta() # # Return the META items, i.e. anything that isn't prefixed with a _, e.g. # _BLOCKS, or the name or modtime items. #------------------------------------------------------------------------ sub meta { my $self = shift; return { map { $_ => $self->{ $_ } } grep { ! /^(_|modtime$|name$)/ } keys %$self }; } #------------------------------------------------------------------------ # AUTOLOAD # # Provides pseudo-methods for read-only access to various internal # members. #------------------------------------------------------------------------ sub AUTOLOAD { my $self = shift; my $method = $AUTOLOAD; $method =~ s/.*:://; return if $method eq 'DESTROY'; # my ($pkg, $file, $line) = caller(); # print STDERR "called $self->AUTOLOAD($method) from $file line $line\n"; return $self->{ $method }; } #======================================================================== # ----- CLASS METHODS ----- #======================================================================== #------------------------------------------------------------------------ # as_perl($content) # # This method expects a reference to a hash passed as the first argument # containing 3 items: # METADATA # a hash of template metadata # BLOCK # string containing Perl sub definition for main block # DEFBLOCKS # hash containing further subs for addional BLOCK defs # It returns a string containing Perl code which, when evaluated and # executed, will instantiate a new Template::Document object with the # above data. On error, it returns undef with an appropriate error # message set in $ERROR. #------------------------------------------------------------------------ sub as_perl { my ($class, $content) = @_; my ($block, $defblocks, $metadata) = @$content{ qw( BLOCK DEFBLOCKS METADATA ) }; $block =~ s/\s+$//; $defblocks = join('', map { my $code = $defblocks->{ $_ }; $code =~ s/\s*$//; " '$_' => $code,\n"; } keys %$defblocks); $defblocks =~ s/\s+$//; $metadata = join( '', map { my $x = $metadata->{ $_ }; $x =~ s/(['\\])/\\$1/g; " '$_' => '$x',\n"; } keys %$metadata ); $metadata =~ s/\s+$//; return <<EOF #------------------------------------------------------------------------ # Compiled template generated by the Template Toolkit version $Template::VERSION #------------------------------------------------------------------------ $class->new({ METADATA => { $metadata }, BLOCK => $block, DEFBLOCKS => { $defblocks }, }); EOF } #------------------------------------------------------------------------ # write_perl_file($filename, \%content) # # This method calls as_perl() to generate the Perl code to represent a # compiled template with the content passed as the second argument. # It then writes this to the file denoted by the first argument. # # Returns 1 on success. On error, sets the $ERROR package variable # to contain an error message and returns undef. #------------------------------------------------------------------------ sub write_perl_file { my ($class, $file, $content) = @_; my ($fh, $tmpfile); return $class->error("invalid filename: $file") unless defined $file && length $file; eval { require File::Temp; require File::Basename; ($fh, $tmpfile) = File::Temp::tempfile( DIR => File::Basename::dirname($file) ); my $perlcode = $class->as_perl($content) || die $!; if ($UNICODE && is_utf8($perlcode)) { $perlcode = "use utf8;\n\n$perlcode"; binmode $fh, ":utf8"; } print $fh $perlcode; close($fh); }; return $class->error($@) if $@; return rename($tmpfile, $file) || $class->error($!); } #------------------------------------------------------------------------ # catch_warnings($msg) # # Installed as #------------------------------------------------------------------------ sub catch_warnings { $COMPERR .= join('', @_); } 1; __END__ =head1 NAME Template::Document - Compiled template document object =head1 SYNOPSIS use Template::Document; $doc = Template::Document->new({ BLOCK => sub { # some perl code; return $some_text }, DEFBLOCKS => { header => sub { # more perl code; return $some_text }, footer => sub { # blah blah blah; return $some_text }, }, METADATA => { author => 'Andy Wardley', version => 3.14, } }) || die $Template::Document::ERROR; print $doc->process($context); =head1 DESCRIPTION This module defines an object class whose instances represent compiled template documents. The L<Template::Parser> module creates a C<Template::Document> instance to encapsulate a template as it is compiled into Perl code. The constructor method, L<new()>, expects a reference to a hash array containing the C<BLOCK>, C<DEFBLOCKS> and C<METADATA> items. The C<BLOCK> item should contain a reference to a Perl subroutine or a textual representation of Perl code, as generated by the L<Template::Parser> module. This is then evaluated into a subroutine reference using C<eval()>. The C<DEFBLOCKS> item should reference a hash array containing further named C<BLOCK>s which may be defined in the template. The keys represent C<BLOCK> names and the values should be subroutine references or text strings of Perl code as per the main C<BLOCK> item. The C<METADATA> item should reference a hash array of metadata items relevant to the document. The L<process()> method can then be called on the instantiated C<Template::Document> object, passing a reference to a L<Template::Context> object as the first parameter. This will install any locally defined blocks (C<DEFBLOCKS>) in the C<BLOCKS> cache in the context (via a call to L<visit()|Template::Context#visit()>) so that they may be subsequently resolved by the context. The main C<BLOCK> subroutine is then executed, passing the context reference on as a parameter. The text returned from the template subroutine is then returned by the L<process()> method, after calling the context L<leave()|Template::Context#leave()> method to permit cleanup and de-registration of named C<BLOCKS> previously installed. An C<AUTOLOAD> method provides access to the C<METADATA> items for the document. The L<Template::Service> module installs a reference to the main C<Template::Document> object in the stash as the C<template> variable. This allows metadata items to be accessed from within templates, including C<PRE_PROCESS> templates. header: <html> <head> <title>[% template.title %] </head> ... C<Template::Document> objects are usually created by the L<Template::Parser> but can be manually instantiated or sub-classed to provide custom template components. =head1 METHODS =head2 new(\%config) Constructor method which accept a reference to a hash array containing the structure as shown in this example: $doc = Template::Document->new({ BLOCK => sub { # some perl code; return $some_text }, DEFBLOCKS => { header => sub { # more perl code; return $some_text }, footer => sub { # blah blah blah; return $some_text }, }, METADATA => { author => 'Andy Wardley', version => 3.14, } }) || die $Template::Document::ERROR; C<BLOCK> and C<DEFBLOCKS> items may be expressed as references to Perl subroutines or as text strings containing Perl subroutine definitions, as is generated by the L<Template::Parser> module. These are evaluated into subroutine references using C<eval()>. Returns a new C<Template::Document> object or C<undef> on error. The L<error()|Template::Base#error()> class method can be called, or the C<$ERROR> package variable inspected to retrieve the relevant error message. =head2 process($context) Main processing routine for the compiled template document. A reference to a L<Template::Context> object should be passed as the first parameter. The method installs any locally defined blocks via a call to the context L<visit()|Template::Context#visit()> method, processes its own template, (passing the context reference as a parameter) and then calls L<leave()|Template::Context#leave()> in the context to allow cleanup. print $doc->process($context); Returns a text string representing the generated output for the template. Errors are thrown via C<die()>. =head2 block() Returns a reference to the main C<BLOCK> subroutine. =head2 blocks() Returns a reference to the hash array of named C<DEFBLOCKS> subroutines. =head2 variables() Returns a reference to a hash of variables used in the template. This requires the L<TRACE_VARS|Template::Manual::Config#TRACE_VARS> option to be enabled. =head2 meta() Return a reference to a hash of any META items defined in the template. =head2 AUTOLOAD An autoload method returns C<METADATA> items. print $doc->author(); =head1 CLASS METHODS These methods are used internally. =head2 as_perl($content) This method generate a Perl representation of the template. my $perl = Template::Document->as_perl({ BLOCK => $main_block, DEFBLOCKS => { foo => $foo_block, bar => $bar_block, }, METADATA => { name => 'my_template', } }); =head2 write_perl_file(\%config) This method is used to write compiled Perl templates to disk. If the C<COMPILE_EXT> option (to indicate a file extension for saving compiled templates) then the L<Template::Parser> module calls this subroutine before calling the L<new()> constructor. At this stage, the parser has a representation of the template as text strings containing Perl code. We can write that to a file, enclosed in a small wrapper which will allow us to subsequently C<require()> the file and have Perl parse and compile it into a C<Template::Document>. Thus we have persistence of compiled templates. =head1 INTERNAL FUNCTIONS =head2 catch_warnings() This is a simple handler used to catch any errors that arise when the compiled Perl template is first evaluated (that is, evaluated by Perl to create a template subroutine at compile, rather than the template being processed at runtime). =head2 is_utf8() This is mapped to C<utf8::is_utf8> for versions of Perl that have it (> 5.008) or to C<Encode::is_utf8> for Perl 5.008. Earlier versions of Perl are not supported. =head1 AUTHOR Andy Wardley E<lt>abw@wardley.orgE<gt> L<http://wardley.org/> =head1 COPYRIGHT Copyright (C) 1996-2013 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. =head1 SEE ALSO L<Template>, L<Template::Parser> =cut # Local Variables: # mode: perl # perl-indent-level: 4 # indent-tabs-mode: nil # End: # # vim: expandtab shiftwidth=4: