NAME

Web::Query - Yet another scraping library like jQuery

VERSION

version 1.01

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 alpha quality. It doesn't work. 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

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.

Get the previous node of each element in the current set of matched elements.

my $prev = $q->prev;

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 = &#39;&lt;p&gt;foo&lt;/p&gt;&#39;;

say Web::Query::LibXML::wq( $node )->text;
    # var x = '<p>foo</p>';
    
say Web::Query::LibXML::wq( $node )->html;
    # var x = '&lt;p&gt;foo&lt;/p&gt;';

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>

LICENSE

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

BUGS

Please report any bugs or feature requests on the bugtracker website https://github.com/tokuhirom/Web-Query/issues

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

To install Web::Query, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Web::Query

CPAN shell

perl -MCPAN -e shell
install Web::Query

For more information on module installation, please visit the detailed CPAN module installation guide.

	Global
`s`	Focus search bar
`?`	Bring up this help dialog

	GitHub
`g` `p`	Go to pull requests
`g` `i`	go to github issues (only if github is preferred repository)

	POD
`g` `a`	Go to author
`g` `c`	Go to changes
`g` `i`	Go to issues
`g` `d`	Go to dist
`g` `r`	Go to repository/SCM
`g` `s`	Go to source
`g` `b`	Go to file browse

	Search terms
module: (e.g. module:Plugin)
distribution: (e.g. distribution:Dancer auth)
author: (e.g. author:SONGMU Redis)
version: (e.g. version:1.00)

NAME

VERSION

SYNOPSIS

DESCRIPTION

FUNCTIONS

METHODS

CONSTRUCTORS

TRAVERSING

add

contents

each

end

filter

find

first

last

match($selector)

not($selector)

and_back

map

parent

prev

next

next_until( $selector )

MANIPULATION

add_class

toggle_class( @classes )

after

append

as_html

attr

id

name

data

tagname

before

clone

detach

has_class

html

insert_before

insert_after

prepend

remove

remove_class

replace_with

size

text

OTHERS

HOW DO I CUSTOMIZE USER AGENT?

FAQ AND TROUBLESHOOTING

How to find XML processing instructions in a document?

Can't get the content of script elements

INCOMPATIBLE CHANGES

AUTHOR

SEE ALSO

LICENSE

BUGS

Module Install Instructions

`attr`

`id`

`name`

`data`

`html`

`prepend`