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https://github.com/miyagawa/web-scraper

Perl web scraping toolkit
https://github.com/miyagawa/web-scraper

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Perl web scraping toolkit

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README 

        
# NAME



Web::Scraper - Web Scraping Toolkit using HTML and CSS Selectors or XPath expressions



# SYNOPSIS



    use URI;

    use Web::Scraper;

    use Encode;



    # First, create your scraper block

    my $authors = scraper {

        # Parse all TDs inside 'table[width="100%]"', store them into

        # an array 'authors'.  We embed other scrapers for each TD.

        process 'table[width="100%"] td', "authors[]" => scraper {

          # And, in each TD,

          # get the URI of "a" element

          process "a", uri => '@href';

          # get text inside "small" element

          process "small", fullname => 'TEXT';

        };

    };



    my $res = $authors->scrape( URI->new("http://search.cpan.org/author/?A") );



    # iterate the array 'authors'

    for my $author (@{$res->{authors}}) {

        # output is like:

        # Andy Adler      http://search.cpan.org/~aadler/

        # Aaron K Dancygier       http://search.cpan.org/~aakd/

        # Aamer Akhter    http://search.cpan.org/~aakhter/

        print Encode::encode("utf8", "$author->{fullname}\t$author->{uri}\n");

    }



The structure would resemble this (visually)

  {

    authors => \[

      { fullname => $fullname, link => $uri },

      { fullname => $fullname, link => $uri },

    \]

  }



# DESCRIPTION



Web::Scraper is a web scraper toolkit, inspired by Ruby's equivalent

Scrapi. It provides a DSL-ish interface for traversing HTML documents and

returning a neatly arranged Perl data structure.



The _scraper_ and _process_ blocks provide a method to define what segments

of a document to extract.  It understands HTML and CSS Selectors as well as

XPath expressions.



# METHODS



## scraper



    $scraper = scraper { ... };



Creates a new Web::Scraper object by wrapping the DSL code that will be fired when _scrape_ method is called.



## scrape



    $res = $scraper->scrape(URI->new($uri));

    $res = $scraper->scrape($html_content);

    $res = $scraper->scrape(\$html_content);

    $res = $scraper->scrape($http_response);

    $res = $scraper->scrape($html_element);



Retrieves the HTML from URI, HTTP::Response, HTML::Tree or text

strings and creates a DOM object, then fires the callback scraper code

to retrieve the data structure.



If you pass URI or HTTP::Response object, Web::Scraper will

automatically guesses the encoding of the content by looking at

Content-Type headers and META tags. Otherwise you need to decode the

HTML to Unicode before passing it to _scrape_ method.



You can optionally pass the base URL when you pass the HTML content as

a string instead of URI or HTTP::Response.



    $res = $scraper->scrape($html_content, "http://example.com/foo");



This way Web::Scraper can resolve the relative links found in the document.



## process



    scraper {

        process "tag.class", key => 'TEXT';

        process '//tag[contains(@foo, "bar")]', key2 => '@attr';

        process '//comment()', 'comments[]' => 'TEXT';

    };



_process_ is the method to find matching elements from HTML with CSS

selector or XPath expression, then extract text or attributes into the

result stash.



If the first argument begins with "//" or "id(" it's treated as an

XPath expression and otherwise CSS selector.



    # 2008/12/21

    # date => "2008/12/21"

    process ".date", date => 'TEXT';



    # 
foo


    # link => URI->new("http://example.com/")

    process ".body > a", link => '@href';



    # 
foo


    # comment => " HTML Comment here "

    #

    # NOTES: A comment nodes are accessed when installed

    # the HTML::TreeBuilder::XPath (version >= 0.14) and/or

    # the HTML::TreeBuilder::LibXML (version >= 0.13)

    process "//div[contains(@class, 'body')]/comment()", comment => 'TEXT';



    # 
foo


    # link => URI->new("http://example.com/"), text => "foo"

    process ".body > a", link => '@href', text => 'TEXT';



    # 
    

  • foo
    • 

  • bar
    • 



    # list => [ "foo", "bar" ]

    process "li", "list[]" => "TEXT";



    # 
    

  • foo
    • 

  • bar
    • 



    # list => [ { id => "1", text => "foo" }, { id => "2", text => "bar" } ];

    process "li", "list[]" => { id => '@id', text => "TEXT" };



## process\_first



`process_first` is the same as `process` but stops when the first matching

result is found.



    # 2008/12/21

    # 2008/12/22

    # date => "2008/12/21"

    process_first ".date", date => 'TEXT';



## result



`result` allows to return not the default value after processing but a single

value specified by a key or a hash reference built from several keys.



    process 'a', 'want[]' => 'TEXT';

    result 'want';



# EXAMPLES



There are many examples in the `eg/` dir packaged in this distribution.

It is recommended to look through these.



# NESTED SCRAPERS



Scrapers can be nested thus allowing to scrape already captured data.



    # 


    # friends => [ {href => 'foo1'}, {href => 'foo2'} ];

    process 'li', 'friends[]' => scraper {

      process 'a', href => '@href',

    };



# FILTERS



Filters are applied to the result after processing. They can be declared as

anonymous subroutines or as class names.



    process $exp, $key => [ 'TEXT', sub { s/foo/bar/ } ];

    process $exp, $key => [ 'TEXT', 'Something' ];

    process $exp, $key => [ 'TEXT', '+MyApp::Filter::Foo' ];



Filters can be stacked



    process $exp, $key => [ '@href', 'Foo', '+MyApp::Filter::Bar', \&baz ];



More about filters you can find in [Web::Scraper::Filter](https://metacpan.org/pod/Web::Scraper::Filter) documentation.



# XML backends



By default [HTML::TreeBuilder::XPath](https://metacpan.org/pod/HTML::TreeBuilder::XPath) is used, this can be replaces by

a [XML::LibXML](https://metacpan.org/pod/XML::LibXML) backend using [Web::Scraper::LibXML](https://metacpan.org/pod/Web::Scraper::LibXML) module.



    use Web::Scraper::LibXML;



    # same as Web::Scraper

    my $scraper = scraper { ... };



# AUTHOR



Tatsuhiko Miyagawa 



# LICENSE



This library is free software; you can redistribute it and/or modify

it under the same terms as Perl itself.



# SEE ALSO



[http://blog.labnotes.org/category/scrapi/](http://blog.labnotes.org/category/scrapi/)



[HTML::TreeBuilder::XPath](https://metacpan.org/pod/HTML::TreeBuilder::XPath)