SYNOPSIS
use Web::Query;
wq('http://www.w3.org/TR/html401/')
->find('div.head dt')
->each(sub {
my $i = shift;
printf("%d %s\n", $i+1, $_->text);
});
DESCRIPTION
Web::Query is a yet another scraping framework, have a jQuery like
interface.
Yes, I know Ingy's pQuery. But it's just a alpha quality. It doesn't
works. Web::Query built at top of the CPAN modules,
HTML::TreeBuilder::XPath, LWP::UserAgent, and HTML::Selector::XPath.
So, this module uses HTML::Selector::XPath and only supports the CSS 3
selector supported by that module. Web::Query doesn't support jQuery's
extended queries(yet?). If a selector is passed as a scalar ref, it'll
be taken as a straight XPath expression.
$wq( '<div><p>hello</p><p>there</p></div>' )->find( 'p' ); # css selector
$wq( '<div><p>hello</p><p>there</p></div>' )->find( \'/div/p' ); # xpath selector
THIS LIBRARY IS UNDER DEVELOPMENT. ANY API MAY CHANGE WITHOUT NOTICE.
FUNCTIONS
wq($stuff)
This is a shortcut for Web::Query->new($stuff). This function is
exported by default.
METHODS
CONSTRUCTORS
my $q = Web::Query->new($stuff, \%options )
Create new instance of Web::Query. You can make the instance from
URL(http, https, file scheme), HTML in string, URL in string, URI
object, undef, and either one HTML::Element object or an array ref of
them.
# all valid creators
$q = Web::Query->new( 'http://techblog.babyl.ca' );
$q = Web::Query->new( '<p>foo</p>' );
$q = Web::Query->new( undef );
This method throw the exception on unknown $stuff.
This method returns undefined value on non-successful response with
URL.
Currently, the only two valid options are indent, which will be used
as the indentation string if the object is printed, and
no_space_compacting, which will prevent the compaction of whitespace
characters in text blocks.
my $q = Web::Query->new_from_element($element: HTML::Element)
Create new instance of Web::Query from instance of HTML::Element.
my $q = Web::Query->new_from_html($html: Str)
Create new instance of Web::Query from HTML.
my $q = Web::Query->new_from_url($url: Str)
Create new instance of Web::Query from URL.
If the response is not success(It means /^20[0-9]$/), this method
returns undefined value.
You can get a last result of response, use the $Web::Query::RESPONSE.
Here is a best practical code:
my $url = 'http://example.com/';
my $q = Web::Query->new_from_url($url)
or die "Cannot get a resource from $url: " . Web::Query->last_response()->status_line;
my $q = Web::Query->new_from_file($file_name: Str)
Create new instance of Web::Query from file name.
TRAVERSING
add
Returns a new object augmented with the new element(s).
add($html)
An HTML fragment to add to the set of matched elements.
add(@elements)
One or more @elements to add to the set of matched elements.
@elements that already are part of the set are not added a second
time.
my $group = $wq->find('#foo'); # collection has 1 element
$group = $group->add( '#bar', $wq ); # 2 elements
$group->add( '#foo', $wq ); # still 2 elements
add($wq)
An existing Web::Query object to add to the set of matched elements.
add($selector, $context)
$selector is a string representing a selector expression to find
additional elements to add to the set of matched elements.
$context is the point in the document at which the selector should
begin matching
contents
Get the immediate children of each element in the set of matched
elements, including text and comment nodes.
each
Visit each nodes. $i is a counter value, 0 origin. $elem is iteration
item. $_ is localized by $elem.
$q->each(sub { my ($i, $elem) = @_; ... })
end
Back to the before context like jQuery.
filter
Reduce the elements to those that pass the function's test.
$q->filter(sub { my ($i, $elem) = @_; ... })
find
Get the descendants of each element in the current set of matched
elements, filtered by a selector.
my $q2 = $q->find($selector); # $selector is a CSS3 selector.
NOTE If you want to match the element itself, use "filter".
INCOMPATIBLE CHANGE From v0.14 to v0.19 (inclusive) find() also matched
the element itself, which is not jQuery compatible. You can achieve
that result using filter(), add() and find():
my $wq = wq('<div class="foo"><p class="foo">bar</p></div>'); # needed because we don't have a global document like jQuery does
print $wq->filter('.foo')->add($wq->find('.foo'))->as_html; # <div class="foo"><p class="foo">bar</p></div><p class="foo">bar</p>
first
Return the first matching element.
This method constructs a new Web::Query object from the first matching
element.
last
Return the last matching element.
This method constructs a new Web::Query object from the last matching
element.
match($selector)
Returns a boolean indicating if the elements match the $selector.
In scalar context returns only the boolean for the first element.
For the reverse of not(), see filter().
not($selector)
Returns all the elements not matching the $selector.
# $do_for_love will be every thing, except #that
my $do_for_love = $wq->find('thing')->not('#that');
and_back
Add the previous set of elements to the current one.
# get the h1 plus everything until the next h1
$wq->find('h1')->next_until('h1')->and_back;
map
Creates a new array with the results of calling a provided function on
every element.
$q->map(sub { my ($i, $elem) = @_; ... })
parent
Get the parent of each element in the current set of matched elements.
prev
Get the previous node of each element in the current set of matched
elements.
my $prev = $q->prev;
next
Get the next node of each element in the current set of matched
elements.
my $next = $q->next;
next_until( $selector )
Get all subsequent siblings, up to (but not including) the next node
matched $selector.
MANIPULATION
add_class
Adds the specified class(es) to each of the set of matched elements.
# add class 'foo' to <p> elements
wq('<div><p>foo</p><p>bar</p></div>')->find('p')->add_class('foo');
toggle_class( @classes )
Toggles the given class or classes on each of the element. I.e., if the
element had the class, it'll be removed, and if it hadn't, it'll be
added.
Classes are toggled once, no matter how many times they appear in the
argument list.
$q->toggle_class( 'foo', 'foo', 'bar' );
# equivalent to
$q->toggle_class('foo')->toggle_class('bar');
# and not
$q->toggle_class('foo')->toggle_class('foo')->toggle_class('bar');
after
Insert content, specified by the parameter, after each element in the
set of matched elements.
wq('<div><p>foo</p></div>')->find('p')
->after('<b>bar</b>')
->end
->as_html; # <div><p>foo</p><b>bar</b></div>
The content can be anything accepted by "new".
append
Insert content, specified by the parameter, to the end of each element
in the set of matched elements.
wq('<div></div>')->append('<p>foo</p>')->as_html; # <div><p>foo</p></div>
The content can be anything accepted by "new".
as_html
Returns the string representations of either the first or all elements,
depending if called in list or scalar context.
If given an argument join, the string representations of the elements
will be concatenated with the given string.
wq( '<div><p>foo</p><p>bar</p></div>' )
->find('p')
->as_html( join => '!' );
# <p>foo</p>!<p>bar</p>
attr
Get/set attribute values.
In getter mode, it'll return either the values of the attribute for all
elements of the set, or only the first one depending of the calling
context.
my @values = $q->attr('style'); # style of all elements
my $first_value = $q->attr('style'); # style of first element
In setter mode, it'll set attributes value for all elements, and return
back the original object for easy chaining.
$q->attr( 'alt' => 'a picture' )->find( ... );
# can pass more than 1 element too
$q->attr( alt => 'a picture', src => 'file:///...' );
The value passed for an attribute can be a code ref. In that case, the
code will be called with $_ set to the current attribute value. If the
code modifies $_, the attribute will be updated with the new value.
$q->attr( alt => sub { $_ ||= 'A picture' } );
id
Get/set the elements's id attribute.
In getter mode, it behaves just like attr().
In setter mode, it behaves like attr(), but with the following
exceptions.
If the attribute value is a scalar, it'll be only assigned to the first
element of the set (as ids are supposed to be unique), and the returned
object will only contain that first element.
my $first_element = $q->id('the_one');
It's possible to set the ids of all the elements by passing a sub to
id(). The sub is given the same arguments as for each(), and its return
value is taken to be the new id of the elements.
$q->id( sub { my $i = shift; 'foo_' . $i } );
name
Get/set the elements's 'name' attribute.
my $name = $q->name; # equivalent to $q->attr( 'name' );
$q->name( 'foo' ); # equivalent to $q->attr( name => 'foo' );
data
Get/set the elements's 'data-*name*' attributes.
my $data = $q->data('foo'); # equivalent to $q->attr( 'data-foo' );
$q->data( 'foo' => 'bar' ); # equivalent to $q->attr( 'data-foo' => 'bar' );
tagname
Get/Set the tag name of elements.
my $name = $q->tagname;
$q->tagname($new_name);
before
Insert content, specified by the parameter, before each element in the
set of matched elements.
wq('<div><p>foo</p></div>')->find('p')
->before('<b>bar</b>')
->end
->as_html; # <div><b>bar</b><p>foo</p></div>
The content can be anything accepted by "new".
clone
Create a deep copy of the set of matched elements.
detach
Remove the set of matched elements from the DOM.
has_class
Determine whether any of the matched elements are assigned the given
class.
html
Get/Set the innerHTML.
my @html = $q->html();
my $html = $q->html(); # 1st matching element only
$q->html('<p>foo</p>');
insert_before
Insert every element in the set of matched elements before the target.
insert_after
Insert every element in the set of matched elements after the target.
prepend
Insert content, specified by the parameter, to the beginning of each
element in the set of matched elements.
remove
Delete the elements associated with the object from the DOM.
# remove all <blink> tags from the document
$q->find('blink')->remove;
remove_class
Remove a single class, multiple classes, or all classes from each
element in the set of matched elements.
replace_with
Replace the elements of the object with the provided replacement. The
replacement can be a string, a Web::Query object or an anonymous
function. The anonymous function is passed the index of the current
node and the node itself (with is also localized as $_).
my $q = wq( '<p><b>Abra</b><i>cada</i><u>bra</u></p>' );
$q->find('b')->replace_with('<a>Ocus</a>);
# <p><a>Ocus</a><i>cada</i><u>bra</u></p>
$q->find('u')->replace_with($q->find('b'));
# <p><i>cada</i><b>Abra</b></p>
$q->find('i')->replace_with(sub{
my $name = $_->text;
return "<$name></$name>";
});
# <p><b>Abra</b><cada></cada><u>bra</u></p>
size
Return the number of elements in the Web::Query object.
wq('<div><p>foo</p><p>bar</p></div>')->find('p')->size; # 2
text
Get/Set the text.
my @text = $q->text();
my $text = $q->text(); # 1st matching element only
$q->text('text');
If called in a scalar context, only return the string representation of
the first element
OTHERS
Web::Query->last_response()
Returns last HTTP response status that generated by new_from_url().
HOW DO I CUSTOMIZE USER AGENT?
You can specify your own instance of LWP::UserAgent.
$Web::Query::UserAgent = LWP::UserAgent->new( agent => 'Mozilla/5.0' );
FAQ AND TROUBLESHOOTING
How to find XML processing instructions in a document?
It's possible with Web::Query::LibXML and by using an xpath expression
with find():
# find <?xml-stylesheet ... ?>
$q->find(\"//processing-instruction('xml-stylesheet')");
However, note that the support for processing instructions in
HTML::TreeBuilder::LibXML::Node is sketchy, so there are methods like
attr() that won't work.
Can't get the content of script elements
The <script> tag is treated differently by HTML::TreeBuilder, the
parser used by Web::Query. To retrieve the content, you can use either
the method html() (with the caveat that the content will be escaped),
or use Web::Query::LibXML, which parse the 'script' element
differently.
my $node = "<script>var x = '<p>foo</p>';</script>";
say Web::Query::wq( $node )->text;
# nothing is printed!
say Web::Query::wq( $node )->html;
# var x = '<p>foo</p>';
say Web::Query::LibXML::wq( $node )->text;
# var x = '<p>foo</p>';
say Web::Query::LibXML::wq( $node )->html;
# var x = '<p>foo</p>';
INCOMPATIBLE CHANGES
0.10
new_from_url() is no longer throws exception on bad response from
HTTP server.
AUTHOR
Tokuhiro Matsuno <tokuhirom AAJKLFJEF@ GMAIL COM>
SEE ALSO
pQuery
XML::LibXML::jQuery
LICENSE
Copyright (C) Tokuhiro Matsuno
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.