inject method - API extension request [rt.cpan.org #... | libwww-perl/HTML-Parser

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Migrated from rt.cpan.org#5941 (status was 'open')

Requestors:

talby@trap.mtview.ca.us

Attachments:

inject.diff

From on 2004-04-05 23:25:04
:

Perl version: v5.8.3 built for i386-linux-thread-multi
HTML::Parser version: 3.36
on Linux 2.4.25, Debian testing dist

I am working with emulation of web browsers and found I need to have some level of preprocessing in the HTML parser.  A primitive I could use for this is the ability to inject input immediately after the current parse token.

As best I can tell, when a browser hits a chunk of content such as:
<script>
document.write('<a href="http://www.perl.org/">the stuff</a>');
</script>
it essentially injects that text immediately after the </script> element in the input parse buffer.

The attached patch adds an ->inject(chunk) method to an HTML::Parser object, and is far from a clean patch, but shows my intent.

Here is a sample use of the inject method to do simple preprocessing:

#!/usr/bin/perl
use strict;
use warnings;
use lib 'blib/lib';
use lib 'blib/arch';
use HTML::Parser qw();
use URI::Escape qw();
use IO::String qw();
use IO::Handle qw();

my $h = <<EOF;
<deftag name="foo">bar</deftag>
<deftag name="navbar">
  <foo>
  <table>
  <tr><td><a href="http://www.perl.org/">perl</a>
  <tr><td><a href="http://www.apache.org/">apache</a>
  <tr><td><a href="http://www.mozilla.org/">mozilla</a>
  </table>
</deftag>
<html><head><title>foo</title></head><body>
<navbar>
Testing 1... 2... 3...
</body></html>
EOF

my %special = ();
my $cdt = undef;
my $p;
my @out = (\*STDOUT);
$p = new HTML::Parser(
    'start_h' => [ sub { my($tag, $attr, $txt) = @_;
        if(exists $special{$tag}) {
            $p->inject($special{$tag});
        } elsif($tag eq 'deftag') {
            $cdt = $attr->{'name'};
            unshift @out, IO::String->new();
        } else {
            $out[0]->print($txt);
        }
    }, 'tag,attr,text' ],
    'text_h' => [ sub { $out[0]->print(shift) }, 'text' ],
    'end_h'  => [ sub { my($tag, $txt) = @_;
        if($tag eq '/deftag') {
            $special{$cdt} = ${$out[0]->string_ref()};
            shift @out;
        } else {
            $out[0]->print($txt);
        }
    }, 'tag,text' ],
) or die "No parser: $!";
$p->parse($h);

From on 2006-06-18 15:01:07
:

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. Also [url]http://www.insurance-top.com/car/[/url] and [link=http://www.insurance-top.com]insurance quote[/link] from site .

From on 2006-06-18 15:01:13
:

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. Also [url=http://www.insurance-top.com]cars insurance[/url] from website .

From on 2006-06-18 15:01:17
:

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. from website .

From on 2006-06-18 15:01:21
:

From on 2006-06-18 15:01:25
:

Start with the HTML::Parser API and the attached inject.diff, then trace how parsing advances through the current token. Define and implement injection immediately after the current parse token, and verify it supports the preprocessing example shown in the issue.

Written by the indexing model from the issue text.

inject method - API extension request [rt.cpan.org #5941]

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