/ 
HTML-TokeParser-Simple-1.4
River stage two • 30 direct dependents • 92 total dependents
3 ++
/ HTML::TokeParser::Simple

NAME

HTML::TokeParser::Simple - easy to use HTML::TokeParser interface

SYNOPSIS

 use HTML::TokeParser::Simple;
 my $p = HTML::TokeParser::Simple->new( $somefile );

 while ( my $token = $p->get_token ) {
     # This prints all text in an HTML doc (i.e., it strips the HTML)
     next unless $token->is_text;
     print $token->as_is;
 }

DESCRIPTION

HTML::TokeParser is a fairly common method of parsing HTML. However, the tokens returned are not exactly intuitive to parse:

 ["S",  $tag, $attr, $attrseq, $text]
 ["E",  $tag, $text]
 ["T",  $text, $is_data]
 ["C",  $text]
 ["D",  $text]
 ["PI", $token0, $text]

To simplify this, HTML::TokeParser::Simple allows the user ask more intuitive (read: more self-documenting) questions about the tokens returned. Specifically, there are 7 is_foo type methods and 5 return_bar type methods. The is_ methods allow you to determine the token type and the return_ methods get the data that you need.

Since this is a subclass of HTML::TokeParser, all HTML::TokeParser methods are available. To truly appreciate the power of this module, please read the documentation for HTML::TokeParser and HTML::Parser.

The following will be brief descriptions of the available methods followed by examples.

is_ Methods

  • is_start_tag

    Use this to determine if you have a start tag. An optional "tag type" may be passed. This will allow you to match if it's a particular start tag. The supplied tag is case-insensitive.

     if ( $token->is_start_tag( 'font' ) ) { ... }

  • is_end_tag.

    Use this to determine if you have an end tag. An optional "tag type" may be passed. This will allow you to match if it's a particular end tag. The supplied tag is case-insensitive.

    When testing for an end tag, the forward slash on the tag is optional.

     while ( $token = $p->get_token ) {
   if ( $token->is_end_tag( 'form' ) ) { ... }
 }

    Or:

     while ( $token = $p->get_token ) {
   if ( $token->is_end_tag( '/form' ) ) { ... }
 }

  • is_tag

    Use this to determine if you have any tag. An optional "tag type" may be passed. This will allow you to match if it's a particular tag. The supplied tag is case-insensitive.

     if ( $token->is_tag ) { ... }

  • is_text

    Use this to determine if you have text. Note that this is not to be confused with the return_text (deprecated) method described below! is_text will identify text that the user typically sees display in the Web browser.

  • is_comment

    Are you still reading this? Nobody reads POD. Don't you know you're supposed to go to CLPM, ask a question that's answered in the POD and get flamed? It's a rite of passage.

    Really.

    is_comment is used to identify comments. See the HTML::Parser documentation for more information about comments. There's more than you might think.

  • is_declaration

    This will match the DTD at the top of your HTML. (You do use DTD's, don't you?)

  • is_process_instruction

    Process Instructions are from XML. This is very handy if you need to parse out PHP and similar things with a parser.

The return_ methods

Note:

In case it's not blindingly obvious (I've been bitten by this myself when writing the tests), you should generally test what type of token you have before you call some return_ methods. For example, if you have an end tag, there is no point in calling the return_attrseq method. Calling an innapropriate method will return an empty string.

As noted for the is_ methods, these methods are case-insensitive after the return_ part.

  • return_tag

    Do you have a start tag or end tag? This will return the type (lower case).

  • return_attr

    If you have a start tag, this will return a hash ref with the attribute names as keys and the values as the values.

  • return_attrseq

    For a start tag, this is an array reference with the sequence of the attributes, if any.

  • return_text

    This method has been deprecated in favor of as_is. Programmers were getting confused over the difference between is_text, return_text, and some parser methods such as HTML::TokeParser::get_text and friends. This confusion stems from the fact that your author is a blithering idiot when it comes to choosing methods names :)

    This method will hang around for a while, but no guarantees (but hey, that's what deprecation is, yes?).

  • as_is

    This is the exact text of whatever the token is representing.

  • return_token0

    For processing instructions, this will return the token found immediately after the opening tag. Example: For <?php, "php" will be the start of the returned string.

Important note:

Some people get confused and try to call parser methods on tokens and token methods (those described above) on methods. To prevent this, HTML::TokeParser::Simple versions 1.4 and above now bless all tokens into a new class which inherits nothing. Please keep this in mind while using this module (and many thanks to PodMaster http://www.perlmonks.org/index.pl?node_id=107642 for pointing out this issue to me.

Examples

Finding comments

For some strange reason, your Pointy-Haired Boss (PHB) is convinced that the graphics department is making fun of him by embedding rude things about him in HTML comments. You need to get all HTML comments from the HTML.

 use strict;
 use HTML::TokeParser::Simple;

 my @html_docs = glob( "*.html" );

 open PHB, "> phbreport.txt" or die "Cannot open phbreport for writing: $!";

 foreach my $doc ( @html_docs ) {
     print "Processing $doc\n";
     my $p = HTML::TokeParser::Simple->new( $doc );
     while ( my $token = $p->get_token ) {
         next if ! $token->is_comment;
         print PHB $token->as_is, "\n";
     }
 }

 close PHB;

Stripping Comments

Uh oh. Turns out that your PHB was right for a change. Many of the comments in the HTML weren't very polite. Since your entire graphics department was just fired, it falls on you need to strip those comments from the HTML.

 use strict;
 use HTML::TokeParser::Simple;

 my $new_folder = 'no_comment/';
 my @html_docs  = glob( "*.html" );

 foreach my $doc ( @html_docs ) {
     print "Processing $doc\n";
     my $new_file = "$new_folder$doc";

     open PHB, "> $new_file" or die "Cannot open $new_file for writing: $!";

     my $p = HTML::TokeParser::Simple->new( $doc );
     while ( my $token = $p->get_token ) {
         next if $token->is_comment;
         print PHB $token->as_is;
     }
     close PHB;
 }

Changing form tags

Your company was foo.com and now is bar.com. Unfortunately, whoever wrote your HTML decided to hardcode "http://www.foo.com/" into the action attribute of the form tags. You need to change it to "http://www.bar.com/".

 use strict;
 use HTML::TokeParser::Simple;

 my $new_folder = 'new_html/';
 my @html_docs  = glob( "*.html" );

 foreach my $doc ( @html_docs ) {
     print "Processing $doc\n";
     my $new_file = "$new_folder$doc";

     open FILE, "> $new_file" or die "Cannot open $new_file for writing: $!";

     my $p = HTML::TokeParser::Simple->new( $doc );
     while ( my $token = $p->get_token ) {
         if ( $token->is_start_tag( 'form' ) ) {
             my $form_tag = new_form_tag( 
                $token->return_attr, 
                $token->return_attrseq 
             );
             print FILE $form_tag;
         }
         else {
             print FILE $token->as_is;
         }
     }
     close FILE;
 }

 sub new_form_tag {
     my ( $attr, $attrseq ) = @_;
     if ( exists $attr->{ action } ) {
         $attr->{ action } =~ s/www\.foo\.com/www.bar.com/;
     }
     my $tag = '';
     foreach ( @$attrseq ) {
         $tag .= "$_=\"$attr->{ $_ }\" ";
     }
     $tag = "<form $tag>";
     return $tag;
 }

COPYRIGHT

Copyright (c) 2001 Curtis "Ovid" Poe. All rights reserved. This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself

TODO

Considering overloading some methods to allow multiple parameters to be tested. May add support for regexen. For example:

  if ( $token->is_start_tag( qw/ h1 h2 h3 h4 h5 h6 / ) {...}
  if ( $token->is_start_tag( qr/h[1..6]/ ) {...}

AUTHOR

Curtis "Ovid" Poe poec@yahoo.com

BUGS

Use of $HTML::Parser::VERSION which is less than 3.25 may result in incorrect behavior as older versions do not always handle XHTML correctly. It is the programmer's responsibility to verify that the behavior of this code matches the programmer's needs.

Address bug reports and comments to: poec@yahoo.com. When sending bug reports, please provide the version of HTML::Parser, HTML::TokeParser, HTML::TokeParser::Simple, the version of Perl, and the version of the operating system you are using.