/ 
HTML-Manipulator-0.01
River stage zero No dependents
/ HTML::Manipulator

NAME

HTML::Manipulator - Perl extension for manipulating HTML files

SYNOPSIS

use HTML::Manipulator;

my $html = <<HTML;
  <h1 id=title>Old news</h1>
  <a href='http://www.google.com' id=link>Google</a>....
HTML

# replace a tag content
my $new = HTML::Manipulator::replace($html, title => 'New news');

# replace a tag attribute and content
my $new = HTML::Manipulator::replace($html, link => { 
  _content => 'Slashdot',
   href=>'http://www.slashdot.org/' }
  );

# extract a tag content
my $content = HTML::Manipulator::extract_content($html, 'link');

# extract a tag content and attributes
my $tag =  HTML::Manipulator::extract($html, 'link');
  # returns a hash ref like
  # { href => 'http://www.google.com', id => 'link', _content => 'Google' }

DESCRIPTION

This module manipulates of the contents of HTML files. It can query and replace the content or attributes of any HTML tag.

The advertised usage pattern is to update static HTML files.

ANOTHER TEMPLATE ENGINE ?

HTML::Manipulator is NOT yet another templating module. There are, for example, no template files. It works on normal HTML files without any special markup (you only have to give element IDs to tags you are interested in).

ABOUT THE INPUT HTML FILES

HTML::Manipulator is meant to work on real-life HTML files (in all their non-standards-compliant ugliness). It uses the HTML::Parser module to find elements (tags) inside those files, which you can then replace or modify. All you have to do is give those elements a DOM ID, for example

<h3 id=headline77>Headline</h3>

No other markup is necessary.

HTML::Manipulator tries to cope with malformed input data. All you have to ensure is that you properly close the element you are working on (any other tags can be unbalanced) and that the IDs are unique. It will also preserve the content outside the element you asked it to operate on. It does not rewrite your HTML any more than it has to.

Case insensitivity

HTML is case insensitive in its tag and attribute names. This means that

<h3 id=headline77>Headline</h3>

and

<H3 iD=headline77>Headline</h3>

are treated as identical.

However, HTML::Manipulator respects case when comparing the IDs of elements (not sure about the HTML standard here), so that you could NOT address above h3 element as HeadLine77.

FUNCTIONS TO CHANGE CONTENT

You can change the content or attributes of any HTML element with an attached ID.

Replace the content of one element

my $new = HTML::Manipulator::replace($html, title => 'New news');

The function takes as input the HTML data and returns the modified data (as a long scalar).

Replace the content of many elements

my $new = HTML::Manipulator::replace($html, 
   title => 'New news', headline77=>'All clear?');

You can just pass many IDs and new contents to the function as well. The caveat here is that if those elements are nested, only the outermost will be applied: The complete content of the outermost element will be replaced with the new content, eliminating any nested tags. Even if the new content contains nested elements, these will not be evaluated. No recursion today.

Replace attribute values

If you want to replace attribute values (such as a link href), you use the same function described above, but pass a hashref instead of the string with the new content:

my $new = HTML::Manipulator::replace($html, link => { 
     href=>'http://www.slashdot.org/' }
);

The hashref can contain as many key/value pairs as you want. Any attributes that you specify here will appear in the output HTML. Any attributes that you do not specify will retain their old value.

Replace attribute values and content

You can also change content and attributes at the same time, by adding the special "attribute" _content to the attribute hashref.

 my $new = HTML::Manipulator::replace($html, link => { 
     _content => 'Slashdot',
    href=>'http://www.slashdot.org/' }
);

FUNCTIONS TO EXTRACT CONTENT

In addition to replacing parts of the HTML document, you can also query it for the current content.

Extract the content of an element

  my $content = HTML::Manipulator::extract_content($html, 'link');

gives you a scalar containing the content of the tag with the ID 'link'.

Extract the content of all elements

my $content = HTML::Manipulator::extract_all_content($html);

gives you a hashref with all element IDs as keys and their contents as values.

Extract the content and attributes

my $content = HTML::Manipulator::extract($html, 'link');

gives you a hashref with information about the tag with the ID 'link'. There is a key for every attribute in the tag, and the special key '_content' which contains the content. The structure of the hashref is identical to what you would use when calling the replace function.

There is also a function to get information about all elements (that have an ID):

my $content = HTML::Manipulator::extract_all($html);

This returns a hashref of hashrefs, so that you could get the href of the "link" element like $content->{link}{href}.

Extract some elements

You can selectively use the extract_all* functions by passing in the IDs you are interested in. This is optional. The default returns data for all elements with IDs.

my $content = HTML::Manipulator::extract_all_content
    ($html, 'one', 'two', 'three');

USING FILEHANDLES

You can also call all of the above functions with a file handle instead of the string holding the HTML. HTML::Manipulator (or HTML::Parser deeper down the line) will read from the file.

use FileHandle;
my $new = HTML::Manipulator::replace(new FileHandle('myfile.html'), title => 'New news');

open IN, 'myfile.html';
my $new = HTML::Manipulator::replace(*IN, title => 'New news');
close IN;

HTML::Manipulator will only read from the file handles you give it. It does not change them.

EXPORT

The module exports none of its functions. You have to prefix the full module name to use them.

SEE ALSO

Like I said before, this is not a templating module. If you want one of those take a look at

HTML::Manipulator uses HTML::Parser for parsing the input file. If you find yourself in the unfortunate situation of having to process HTML, have a look at that module, too.

BUGS

This is a young module. It works for me, but it has not been extensively tested in the wild. Handle with care. Report bugs to get them fixed.

AUTHOR

Thilo Planz, <planz@epost.de>

COPYRIGHT AND LICENSE

Copyright 2004 by Thilo Planz

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.