NAME
Markup::Content - Extract content markup information from a markup document
SYNOPSIS
my $content = Markup::Content->new(
target => 'noname.html',
template => 'noname.xml',
target_options => {
no_squash_whitespace => [qw(script style pi code pre textarea)]
},
template_options => {
callbacks => {
title => sub {
print shift()->get_text();
}
}
});
$content->extract();
$content->tree->save_as(\*STDOUT);
DESCRIPTION
This modules uses a description of another markup page (template) to match against a specified markup document (target). The point is to extract formatted content from a markup page. While this module in itself lends a good deal of flexibility and reuse, the script [to be] written around this module is probably a better choice. See <http://sourceforge.net/projects/content-x>.
ARGUMENTS
template
This can be a file name, glob or internet address, or if you already
have a Markup::MatchTree you want to use as the template, you may
set this argument to the tree. This argument will be passed directly
to the "set_template" method. See the section "TEMPLATES" for more
information on what is meant by "template".
template_options
This HASHREF will be sent directly to Markup::MatchTree as the
"parser_options" option.
target
This can be a file name, glob or internet address, or if you already
have a Markup::Tree you want to use as the target, you may set this
argument to the tree. This argument will be passed directly to the
"set_target" method.
target_options
This HASHREF will be sent directly to Markup::Tree as the
"parser_options" option.
template_name
The name of the template. This is unused right now, but will
eventually be a nice-to-have-if-set option.
METHODS
set_template(FILE|"Markup::MatchTree")
Makes a template tree from the FILE or "Markup::MatchTree". See the
section "TEMPLATES" for more information on what is meant by
"template".
set_target(FILE|"Markup::Tree")
Makes a target tree from the FILE or "Markup::Tree".
extract
Based on the "template" and "target" it will build a Markup::Tree,
with just the content, accessible as $content->tree.
TEMPLATES
A template, as wanted by this module, is nothing more than a simple XML document. I will try to outline the document structure below.
The XML root node should be template.
<template>
There are only two kinds of tags - "match" or "section".
<match />
<section />
There are four known attributes: "tagname", "options", "element_type", and "text".
<match element_type = "-->text" tagname = "-->text" options = "text_not_null" text = "{!!}" />
Section elements are only used to mark off sections (as you may have guessed). The name of the section is specified in the tag by the "tagname" known attribute.
<section tagname = "nav1">
<match tagname = "a" _href = "{!!}" />
</section>
Generally section elements will only be used to mark off content. This, of course does not require children, and the tagname must be CONTENT.
<section tagname = "CONTENT" />
Match elements are used to match elements of the target.
Attributes are defined with a leading underscore.
<match tagname ="a" _href = "{!^http://!}" _title = "outside link" />
These are unknown or unnamed attributes. Known attributes are a short list of pre-defined keywords. It is perfectly fine to have an unknown attribute the same as a known attribute, such as:
<match tagname = "tagname" tagname = "thetag_name" />
This is unlikely to be encountered in the wild, as HTML tags don't have any validity to the known attributes. We will describe our known attributes more clearly below.
Known Attributes
tagname
This represents the name of the element. Likely it will correspond
to an HTML tag.
element_type
This will be directly mapped into Markup::MatchTree as the elements
element_type. See the "element_type" description under Markup::Tree
for a list of meaningful values.
text
Useful only if element_type is "-->text". Note that text need not be
specified only with <match element_type = "-->text" /> elements. It
could also be betwen <match> tags, like so:
<match tagname = "p">some text</p>
options
This is a comma-seperated (,) list of options. Options may be one or
more of the following:
call_filter(CALLBACK)
CALLBACK is the name of a key of the HASHREF option whose value
is a CODEREF of Markup::MatchTrees "callback" arguments. An
example will do nicely here.
my $content = Markup::Content->new( target => 'http://foobar/',
template => '~/sites/foobar/foobar.xml',
template_options => {
callbacks => {
my_callback_filter => sub {
my $node = shift();
print $node->drop()->{'tagname'}, "\n";
},
another_callback_filter => sub {
my $node = shift();
do {
if ($node->{'element_type'} eq '-->text') {
print $node->{'text'};
}
} while ($node = $node->next_node());
}
}
});
text_not_null
If the "text" or next text element of the specified element
contains more than whitespace, this option will not mark it as
an error.
ignore_children
If this option is specified, all children of the element will be
ignored, but not the element itself.
optional
This option marks the element as optional. That is to say, if
the element does not appear in the target document, it will not
be marked as an error.
ignore_attrs
Attributes will not be considered if this option is specified.
In addition to the above knowledge, there is only one more property to consider. All text or attributes need not be an exact match. By surrounding text or attribute values with {! and !} you are saying, "use the perl5 regular expression specified between {! and !} to match the target element". Luckily you don't have to actually say all that!
Please see "noname.html", "noname.xml" and "noname.pl" in this distribution for a small example of this module, what it does, and a bit on how to use it.
CAVEATS
This module is HIGHLY experimental. It may save your life, job or carrer. It is also liable to get you fired, get you divorced, or put sugar in your gastank. I would love to hear your success/horror stories.
SEE ALSO
Markup::Tree, Markup::MatchTree,
<http://sourceforge.net/projects/content-x>
AUTHOR
BPrudent (Brandon Prudent)
Email: xlacklusterx@hotmail.com