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NAME
pQuery - A port of jQuery.js to Perl
SYNOPSIS
use pQuery;
pQuery("http://google.com/search?q=pquery")
->find("h2")
->each(sub {
my $i = shift;
print $i + 1, ") ", pQuery($_)->text, "\n";
});
DESCRIPTION
pQuery is a pragmatic attempt to port the jQuery JavaScript framework to
Perl. It is pragmatic in the sense that it switches certain JavaScript
idioms for Perl ones, in order to make the use of it concise. A primary
goal of jQuery is to "Find things and do things, concisely". pQuery has
the same goal.
pQuery exports a single function called "pQuery". (Actually, it also
exports the special "PQUERY" function. Read below.) This function acts a
constructor and does different things depending on the arguments you
give it. This is discussed in the CONSTRUCTORS section below.
A pQuery object acts like an array reference (because, in fact, it is).
Typically it is an array of pQuery::DOM elements, but it can be an array
of anything.
pQuery::DOM is roughly an attempt to duplicate JavaScript's DOM in Perl.
It subclasses HTML::TreeBuilder/HTML::Element so there are a few
differences to be aware of. See the pQuery::DOM documentation for
details.
Like jQuery, pQuery methods return a pQuery object; either the original
object or a new derived object. All pQuery METHODS are described below.
THE ROYAL PQUERY
The power of jQuery is that single method calls can apply to many DOM
objects. pQuery does the exact same thing but can take this one step
further. A single PQUERY object can contain several DOMs!
Consider this example:
> perl -MpQuery -le 'PQUERY(\
map "http://search.cpan.org/~$_/", qw(ingy gugod miyagawa))\
->find("table")->eq(1)->find("tr")\
->EACH(sub{\
printf("%40s - %s Perl distributions\n", $_->url, $_->length - 1)\
})'
http://search.cpan.org/~ingy/ - 88 Perl distributions
http://search.cpan.org/~gugod/ - 86 Perl distributions
http://search.cpan.org/~miyagawa/ - 138 Perl distributions
The power lies in "PQUERY", a special constructor that creates a wrapper
object for many pQuery objects, and applies all methods called on it to
all the pQuery objects it contains.
CONSTRUCTORS
The pQuery constructor is an exported function called "pQuery". It does
different things depending on the arguments you pass it.
URL
If you pass pQuery a URL, it will attempt to get the page and use its
HTML to create a pQuery::DOM object. The pQuery object will contain the
top level pQuery::DOM object.
pQuery("http://google.com");
It will also set the global variable $pQuery::document to the resulting
DOM object. Future calls to pQuery methods will use this document if
none other is supplied.
HTML
If you already have an HTML string, pass it to pQuery and it will create
a pQuery::DOM object. The pQuery object will contain the top level
pQuery::DOM object.
pQuery("<p>Hello <b>world</b>.</p>");
FILE
If you pass pQuery a string that ends with .html and contains no
whitespace, pQuery will assume it is the name of a file containing html
and will read the contents and parse the HTML into a new DOM.
pQuery("my/webpage.html");
Selector String
You can create a pQuery object with a selector string just like in
jQuery. The problem is that Perl doesn't have a global document object
lying around like JavaScript does.
One thing you can do is set the global variable, $pQuery::document, to a
pQuery::DOM document. This will be used by future selectors.
Another thing you can do is pass the document to select on as the second
parameter. (jQuery also has this second, context parameter).
pQuery("table.mygrid > td:eq(7)", $dom);
pQuery Object
You can create a new pQuery object from another pQuery object. The new
object will be a shallow copy.
my $pquery2 = pQuery($pquery1);
Array Reference
You can create a pQuery object as an array of anything you want; not
just pQuery::DOM elements. This can be useful to use the "each" method
to iterate over the array.
pQuery(\ @some_array);
No Arguments
Calling pQuery with no arguments will return a pQuery object that is
just an empty array reference. This is useful for using it to call class
methods that don't need a DOM object.
my $html = pQuery->get("http://google.com")->content;
PQUERY(@list_of_pQuery_constructor_args)
The PQUERY constructor takes a list of any of the above pQuery forms and
creates a PQUERY object with one pQuery object per argument.
METHODS
This is a reference of all the methods you can call on a pQuery object.
They are almost entirely ported from jQuery.
pquery()
Returns the version number of the pQuery module.
size()
Returns the number of elements in the pQuery object.
length()
Also returns the number of elements in the pQuery object.
each($sub)
This method takes a subroutine reference and calls the subroutine once
for each member of the pQuery object that called "each". When the
subroutine is called it is passed an integer count starting at 0 at
incremented once for each call. It is also passed the current member of
the pQuery object in $_.
pQuery("td", $dom)->each(sub {
my $i = shift;
print $i, " => ", pQuery($_)->text(), "\n";
});
The "each" method returns the pQuery object that called it.
EACH($sub)
This method can only be called on PQUERY objects. The sub is called once
for every pQuery object within the PQUERY object. If you call "each()"
on a PQUERY object, it iterates on all the DOM objects of each pQuery
object (as you would expect).
find($selector)
This method will search all the pQuery::DOM elements of the its caller
for all sub elements that match the selector string. It will return a
new pQuery object containing all the elements found.
my $pquery2 = $pquery1->find("h1,h2,h3");
html() html($html)
This method is akin to the famous JavaScript/DOM function "innerHTML".
If called with no arguments, this will return the the inner HTML string
of the first DOM element in the pQuery object.
If called with an HTML string argument, this will set the inner HTML of
all the DOM elements in the pQuery object.
toHtml()
This extremely handy method is not ported from jQuery. Maybe jQuery will
port it back some day. :)
This function takes no arguments, and returns the outer HTML of the
first DOM object in the pQuery object. Outer HTML means the HTML of the
current object and its inner HTML.
For example:
pQuery('<p>I <b>like</b> pie</p>')->toHtml;
returns:
<p>I <b>like</b> pie</p>
while:
pQuery('<p>I <b>like</b> pie</p>')->html();
returns:
I <b>like</b> pie
end()
Revert the most recent 'destructive' operation, changing the set of
matched elements to its previous state (right before the destructive
operation). This method is useful for getting back to a prior context
when chaining pQuery methods.
pQuery("table", $dom) # Select all the tables
->find("td") # Select all the tds
->each(sub { ... }) # Do something with the tds
->end() # Go back to the tables selection
->each(sub { ... }); # Do something with the tables
get($index) get($url)
If this method is passed an integer, it will return that specific
element from the array of elements in the pQuery object.
Givn a URL, this method will fetch the HTML content of the URL and
return a HTML::Response object.
my $html = pQuery->get("http://google.com")->content;
index($elem)
This method returns the index number of its argument if the elem is in
the current pQuery object. Otherwise it returns -1.
UNDER CONSTRUCTION
This module is still being written. The documented methods all work as
documented (but may not be completed ports of their jQuery counterparts
yet).
The selector syntax is still very limited. (Single tags, IDs and classes
only).
Version 0.02 added the pQuery::DOM class which is a huge improvement,
and should facilitate making the rest of the porting easy.
But there is still much more code to port. Stay tuned...
AUTHOR
Ingy döt Net <ingy@cpan.org>
COPYRIGHT AND LICENSE
Copyright (c) 2008, 2011. Ingy döt Net.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See http://www.perl.com/perl/misc/Artistic.html
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