NAME
Markup::Tree - Unified way to easily access XML or HTML markup locally or remotly.
SYNOPSIS
use Markup::Tree;
my @preserve = qw(pre style script code);
my $tree = Markup::Tree->new ( markup => 'html', no_squash_whitespace => \@preserve,
no_indent => \@preserve );
$tree->parse_file('http://lackluster.tzo.com:1024');
$tree->save_as('ltzo.com.xml', 'xml');
# or
my $tree = Markup::Tree->new ( markup => 'xml', no_squash_whitespace => \@preserve,
no_indent => \@preserve );
$tree->parse_file('http://lackluster.tzo.com:1024/index.php.xml');
$tree->foreach_node(\&start, \&end);
DESCRIPTION
I wanted a module to allow one to access either XML or HTML input, locally or remotely, easily transform it, and save it as HTML or XML (or some user-defined format). So I quit whining and wrote one. It's not 100% finished, but it's a good start and the groundwork for the Markup::Content module.
CONVENTIONS
I will be reopening certain terms to save myself keystrokes and you confusion (or does that just create confusion?).
FILE
When I mention FILE, what I really mean is either a local or
remotely mounted file "(i.e - /home/bprudent/this_xml_file.xml)", an
already opened filehandle, or a remote file location of which
LWP::Simple's get is capable of, well, getting.
Note that if you pass an open filehandle to a method that wants to
read from it, you should open it for reading, and if the method
wants to write to it, you should open it for writing. Also, we
cannot write to a remote location (at least, the functionality does
not exist in this module to do so) so please don't pass a remote
location to a method that wants to write something (such as the
save_as method).
pi I see alot of people using pi or (p)rocessing (i)nstruction to mean
a local procressing directive. I am using here and in "TreeNode" to
mean also server-side instructions, which are often found in the
wild. Please remember that you will not see these from a remote URL.
ARGUMENTS
These are the arguments you can specify upon instantiation. In most cases you can also set them yourself after you have an object of this class via $tree->{'the_option'} = $whatever.
markup
Valid options are 'xml' or 'html'. This just specifies which parser
to use. I would like to, in the future, add more parsers to this
list. The default is 'html', which is much more forgiving.
parser_options
This parameters requests an anonymous hash with parser-specific
options. If you specified 'xml' for markup then the "parser_options"
argument will be passed to XML::Parser. Otherwise it will go to
HTML::TreeBuilder.
no_squash_whitespace
There are three modes to this argument:
mode 0
Squash all whitespace. This is the default mode.
mode 1
Set "no_squash_whitespace" to a true value to keep the tree as
close to the original document as possible.
mode 2
Set "no_squash_whitespace" to an anonymous array containing
tagnames of which you want to preserve. This is handy when
re-creating or transforming HTML documents containing
pre-formatted text, such as "script", "style", "pre", or,
sometimes, "code". It is also wise to include the fabricated
tag, pi. This is the tag that is made up when either <% or <? is
encountered, except when within quotes. See Also
Markup::TreeNode for a bit more on this.
Example:
my $tree = Markup::Tree->new ( no_squash_whitespace => [qw(script style pre code)] );
no_indent
It's all in the name. This value affects only (as of now) the
save_as method. Again, there are three operating modes:
mode 0
Leave indentation on. This is the default mode.
mode 1
Setting "no_indent" to a true value will never indent.
mode 2
Set "no_indent" to an anonymous array containing tagnames of
which you want to not indent. This is normally the same value as
no_squash_whitespace.
METHODS
get_node (description)
description
Description must be one of the following: "first", "last",
"start", "end", "copy-of", "copy", "copy_of", or "root".
first
Causes the method to return the first node in the tree, not
including the "root" node. This is the first actual element
found in the markup source.
last
Causes the method to return the last node in the tree.
start
An alias for "first".
end An alias for "last".
copy-of
Returns a copy of the entire tree. This allows you to have
two copies in memory. One that you can chop to bits and
another that you can preserve.
copy
An alias for "copy-of".
copy_of
An alias for "copy-of".
root
Causes the method to return the root node. This is
equivalant to $tree->tree.
Example:
my $first_node = $tree->get_node('first');
print "The first node in the tree is a ".$first_node->{'tagname'}." node.\n";
parse_file (FILE)
FILE to be parsed
$tree->parse_file ('http://lackluster.tzo.com:1024');
# or
$tree->parse_file (\*INPUT);
# or
$tree->parse_file ('/home/lackluster/public_html/index.html');
Returns: a refrence to the parser so that you can say things like
$tree = Markup::Tree->new()->parse_file('noname.html');
Note that this will close the file(handle).
parse (DATA)
Just the same as HTML or XML ::Parse's parse method. Pass in markup
data. For HTML you will need to call eof().
Returns: a refrence to the parser
eof ( )
Signals the end of HTML markup. Calling eof on XML data will not
generate an error, it just won't do anything.
Returns: a refrence to the parser
save_as (FILE [, type])
Saves the tree to FILE as type, if specified.
FILE
This is the filename or handle to write the information in. If
this argument is textual, the method will try to guess, based on
the file extension, the second argument if not present.
type
Valid values are 'html' or 'xml'. Will also accept 'xhtml'.
Default is 'html'.
Example: $tree->save_as
('/home/lackluster/public_html/transformed.html.xml', 'xml');
foreach_node (start_CODE [, end_CODE] [, start_from])
Loops through each node in the syntax tree, calling "start_CODE"
and, if present, end_CODE. This method makes looping through the
tree really quite simple and lends itself well to saving files to
your own format.
Arguments:
start_CODE
This CODE ref will be called when a node is encounted and before
its children have been processed. A Markup::TreeNode element
will be passed to your sub.
end_CODE
If this parameter is present, then the CODE ref will be called
after a node is encountered and after its children have been
processed. If end_CODE is not a CODE ref, but instead a
Markup::TreeNode, the method will interpret "end_CODE" as
"start_from".
start_from
Instead of looping over the whole tree, this value can be a
Markup::TreeNode start point. (See "BUGS" section)
Example: $tree->foreach_node( sub { my $node = shift();
indent($node->{'level'}); print $node->{'tagname'}."\n"; }, sub
{ my $node = shift(); indent($node->{'level'}); print
$node->{'tagname'}."\n"; } );
RETURN VALUES MATTER!
Returning a false value will end the iterations and cause the method
to return. Return true to keep processing.
copy_of
Returns a copy, not a reference, of the tree.
CAVEATS
This module isn't really the best for people who don't often use markup. It requires quite a few modules (I actually feed bad about the module requirements), and "HTML::TreeBuilder" or "XML::Parser" is probably a better choice for most things you want to do. On the upside, if you already have these modules, it is a comparativly easy way to use markup.
BUGS || UNFINISHED
"Wide character in print" warnings are abound. I haven't taken the time to look into this. Something about UNICODE?
The "foreach_node" method doesn't behave properly when passed the start_from parameter. That's what I thought, at least. The behaviour may work for you in your situation. Just know that it may change in the future unless anyone requests otherwise.
Please inform me of other bugs.
SEE ALSO
Markup::TreeNode, XML::Parser, HTML::TreeBuilder, LWP::Simple
AUTHOR
BPrudent (Brandon Prudent)
Email: xlacklusterx@hotmail.com