Scrappy(3pm)
NAME
Scrappy - The All Powerful Web Spidering, Scraping, Creeping Crawling Framework
VERSION
version 0.94112090
SYNOPSIS
#!/usr/bin/perl
use Scrappy;
my $scraper = Scrappy->new;
$scraper->crawl('http://search.cpan.org/recent',
'/recent' => {
'#cpansearch li a' => sub {
print $_[1]->{href}, "\n";
}
}
);
And now manually, ... without crawl, the above is similar to the
following ...
#!/usr/bin/perl
use Scrappy;
my $scraper = Scrappy->new;
if ($scraper->get($url)->page_loaded) {
$scraper->select('#cpansearch li a')->each(sub{
print shift->{href}, "\n";
});
}
DESCRIPTION
Scrappy is an easy (and hopefully fun) way of scraping, spidering,
and/or harvesting information from web pages, web services, and more.
Scrappy is a feature rich, flexible, intelligent web automation tool.
Scrappy (pronounced Scrap+Pee) == 'Scraper Happy' or 'Happy Scraper';
If you like you may call it Scrapy (pronounced Scrape+Pee) although
Python has a web scraping framework by that name and this module is not
a port of that one.
FEATURES
Scrappy provides a framework containing all the tools necessary to
create a simple yet powerful web scraper. At its core, Scrappy loads an
array of features for access control, event logging, session handling,
url matching, web request and response handling, proxy management, web
scraping, and downloading.
Furthermore, Scrappy provides a simple Moose-based plugin system that
allows Scrappy to be easily extended.
my $scraper = Scrappy->new;
$scraper->control; # Scrappy::Scraper::Control (access control)
$scraper->parser; # Scrappy::Scraper::Parser (web scraper)
$scraper->user_agent; # Scrappy::Scraper::UserAgent (user-agent tools)
$scraper->logger; # Scrappy::Logger (event logger)
$scraper->queue; # Scrappy::Queue (flow control for loops)
$scraper->session; # Scrappy::Session (session management)
Please see the METHODS section for a more in-depth look at all Scrappy
functionality.
ATTRIBUTES
The following is a list of object attributes available with every
Scrappy instance, attributes always return an instance of the class
they represent.
content
The content attribute holds the HTTP::Response object of the current
request. Returns undef if no page has been successfully fetched.
my $scraper = Scrappy->new;
$scraper->content;
control
The control attribute holds the Scrappy::Scraper::Control object which
is used the provide access conrtol to the scraper.
my $scraper = Scrappy->new;
$scraper->control;
... $scraper->control->restrict('google.com');
... $scraper->control->allow('cpan.org');
... if $scraper->control->is_allowed($url);
debug
The debug attribute holds a boolean which controls whether event logs
are captured.
my $scraper = Scrappy->new;
$scraper->debug(1);
logger
The logger attribute holds the Scrappy::Logger object which is used to
provide event logging capabilities to the scraper.
my $scraper = Scrappy->new;
$scraper->logger;
parser
The parser attribute holds the Scrappy::Scraper::Parser object which is
used to scrape html data from the specified source material.
my $scraper = Scrappy->new;
$scraper->parser;
plugins
The plugins attribute holds the Scrappy::Plugin object which is an
interface used to load plugins.
my $scraper = Scrappy->new;
$scraper->plugins;
queue
The queue attribute holds the Scrappy::Queue object which is used to
provide flow-control for the standard loop approach to crawling.
my $scraper = Scrappy->new;
$scraper->queue;
session
The session attribute holds the Scrappy::Session object which is used
to provide session support and persistent data across executions.
my $scraper = Scrappy->new;
$scraper->session;
user_agent
The user_agent attribute holds the Scrappy::Scraper::UserAgent object
which is used to set and manipulate the user-agent header of the
scraper.
my $scraper = Scrappy->new;
$scraper->user_agent;
worker
The worker attribute holds the WWW::Mechanize object which is used
navigate web pages and provide request and response header information.
my $scraper = Scrappy->new;
$scraper->worker;
METHODS
back
The back method is the equivalent of hitting the "back" button in a
browser, it returns the previous page (response) and returns that URL,
it will not backtrack beyond the first request.
my $scraper = Scrappy->new;
$scraper->get(...);
...
$scraper->get(...);
...
my $last_url = $scraper->back;
cookies
The cookies method returns an HTTP::Cookie object. Note! Cookies can be
made persistent by enabling session-support. Session-support is enable
by simply specifying a file to be used.
my $scraper = Scrappy->new;
$scraper->session->write('session.yml'); # enable session support
$scraper->get(...);
my $cookies = $scraper->cookies;
crawl
The crawl method is very useful when it is desired to crawl an entire
website or at-least partially, it automates the tasks of creating a
queue, fetching and parsing html pages, and establishing simple flow-
control. See the SYNOPSIS for a simplified example, ... the following
is a more complex example.
my $scrappy = Scrappy->new;
$scrappy->crawl('http://search.cpan.org/recent',
'/recent' => {
'#cpansearch li a' => sub {
my ($self, $item) = @_;
# follow all recent modules from search.cpan.org
$self->queue->add($item->{href});
}
},
'/~:author/:name-:version/' => {
'body' => sub {
my ($self, $item, $args) = @_;
my $reviews = $self
->select('.box table tr')->focus(3)->select('td.cell small a')
->data->[0]->{text};
$reviews = $reviews =~ /\d+ Reviews/ ?
$reviews : '0 reviews';
print "found $args->{name} version $args->{version} ".
"[$reviews] by $args->{author}\n";
}
}
);
domain
The domain method returns the domain host of the current page. Local
pages, e.g. file:///this/that/the_other will return undef.
my $scraper = Scrappy->new;
$scraper->get('http://www.google.com');
print $scraper->domain; # print www.google.com
download
The download method is passed a URL, a Download Directory Path and a
optionally a File Path, then it will follow the link and store the
response contents into the specified file without leaving the current
page. Basically it downloads the contents of the request (especially
when the request pushes a file download). If a File Path is not
specified, Scrappy will attempt to name the file automatically
resorting to a random 6-charater string only if all else fails, then
returns to the originating page.
my $scaper = Scrappy->new;
my $requested_url = '...';
$scraper->download($requested_url, '/tmp');
# supply your own file name
$scraper->download($requested_url, '/tmp', 'somefile.txt');
dumper
The dumper method is a convenience feature that passes the passed-in
objects to Data::Dumper which in turn returns a stringified
representation of that object/data-structure.
my $scaper = Scrappy->new;
my $requested_url = '...';
$scraper->get($requested_url);
my $data = $scraper->select('//a[@href]')->data;
# print out the scraped data
print $scraper->dumper($data);
form
The form method is used to submit a form on the current page.
my $scraper = Scrappy->new;
$scraper->form(fields => {
username => 'mrmagoo',
password => 'foobarbaz'
});
# or more specifically, for pages with multiple forms
$scraper->form(form_name => 'login_form', fields => {
username => 'mrmagoo',
password => 'foobarbaz'
});
$scraper->form(form_number => 1, fields => {
username => 'mrmagoo',
password => 'foobarbaz'
});
get
The get method takes a URL or URI object, fetches a web page and
returns the Scrappy object.
my $scraper = Scrappy->new;
if ($scraper->get($new_url)->page_loaded) {
...
}
# $self->content has the HTTP::Response object
log
The log method logs an event with the event logger.
my $scraper = Scrappy->new;
$scraper->debug(1); # unnecessary, on by default
$scraper->logger->verbose(1); # more detailed log
$scraper->log('error', 'Somthing bad happened');
...
$scraper->log('info', 'Somthing happened');
$scraper->log('warn', 'Somthing strange happened');
$scraper->log('coolness', 'Somthing cool happened');
Note! Event logs are always recorded but never automatically written to
a file unless explicitly told to do so using the following:
$scraper->logger->write('log.yml');
page_content_type
The page_content_type method returns the content_type of the current
page.
my $scraper = Scrappy->new;
$scraper->get('http://www.google.com/');
print $scraper->page_content_type; # prints text/html
page_data
The page_data method returns the HTML content of the current page,
additionally this method when passed a string with HTML markup, updates
the content of the current page with that data and returns the modified
content.
my $scraper = Scrappy->new;
$scraper->get(...);
my $html = $scraper->page_data;
page_ishtml
The page_ishtml method returns true/false based on whether our content
is HTML, according to the HTTP headers.
my $scraper = Scrappy->new;
$scraper->get($requested_url);
if ($scraper->is_html) {
...
}
page_loaded
The page_loaded method returns true/false based on whether the last
request was successful.
my $scraper = Scrappy->new;
$scraper->get($requested_url);
if ($scraper->page_loaded) {
...
}
page_match
The page_match method checks the passed-in URL (or URL of the current
page if left empty) against the URL pattern (route) defined. If URL is
a match, it will return the parameters of that match much in the same
way a modern web application framework processes URL routes.
my $url = 'http://somesite.com/tags/awesomeness';
...
my $scraper = Scrappy->new;
# match against the current page
my $this = $scraper->page_match('/tags/:tag');
if ($this) {
print $this->{'tag'};
# ... prints awesomeness
}
.. or ..
# match against a passed url
my $this = $scraper->page_match('/tags/:tag', $url, {
host => 'somesite.com'
});
if ($this) {
print "This is the ", $this->{tag}, " page";
# ... prints this is the awesomeness page
}
page_reload
The page_reload method acts like the refresh button in a browser, it
simply repeats the current request.
my $scraper = Scrappy->new;
$scraper->get(...);
...
$scraper->reload;
page_status
The page_status method returns the 3-digit HTTP status code of the
response.
my $scraper = Scrappy->new;
$scraper->get(...);
if ($scraper->page_status == 200) {
...
}
page_text
The page_text method returns a text representation of the last page
having all HTML markup stripped.
my $scraper = Scrappy->new;
$scraper->get(...);
my $text = $scraper->page_text;
page_title
The page_title method returns the content of the title tag if the
current page is HTML, otherwise returns undef.
my $scraper = Scrappy->new;
$scraper->get('http://www.google.com/');
my $title = $scraper->page_title;
print $title; # print Google
pause
This method sets breaks between your requests in an attempt to simulate
human interaction.
my $scraper = Scrappy->new;
$scraper->pause(20);
$scraper->get($request_1);
$scraper->get($request_2);
$scraper->get($request_3);
Given the above example, there will be a 20 sencond break between each
request made, get, post, request, etc., You can also specify a range to
have the pause method select from at random...
$scraper->pause(5,20);
$scraper->get($request_1);
$scraper->get($request_2);
# reset/turn it off
$scraper->pause(0);
print "I slept for ", ($scraper->pause), " seconds";
Note! The download method is exempt from any automatic pausing.
plugin
The plugin method allow you to load a plugin. Using the appropriate
case is recommended but not necessary. See Scrappy::Plugin for more
information.
my $scraper = Scrappy->new;
$scraper->plugin('foo_bar'); # will load Scrappy::Plugin::FooBar
$scraper->plugin('foo-bar'); # will load Scrappy::Plugin::Foo::Bar
$scraper->plugin('Foo::Bar'); # will load Scrappy::Plugin::Foo::Bar
# more pratically
$scraper->plugin('whois', 'spammer_check');
... somewhere in code
my $var = $scraper->plugin_method();
# example using core plugin Scrappy::Plugin::RandomProxy
my $s = Scrappy->new;
$s->plugin('random_proxy');
$s->use_random_proxy;
$s->get(...);
post
The post method takes a URL, a hashref of key/value pairs, and
optionally an array of key/value pairs, and posts that data to the
specified URL, then returns an HTTP::Response object.
my $scraper = Scrappy->new;
$scraper->post($requested_url, {
input_a => 'value_a',
input_b => 'value_b'
});
# w/additional headers
my %headers = ('Content-Type' => 'multipart/form-data');
$scraper->post($requested_url, {
input_a => 'value_a',
input_b => 'value_b'
}, %headers);
Note! The most common post headers for content-type are
application/x-www-form-urlencoded and multipart/form-data.
proxy
The proxy method will set the proxy for the next request to be tunneled
through.
my $scraper = Scrappy->new;
$scraper->proxy('http', 'http://proxy1.example.com:8000/');
$scraper->get($requested_url);
$scraper->proxy('http', 'ftp', 'http://proxy2.example.com:8000/');
$scraper->get($requested_url);
# best practice when using proxies
use Tiny::Try;
my $proxie = Scrappy->new;
$proxie->proxy('http', 'http://proxy.example.com:8000/');
try {
$proxie->get($requested_url);
} catch {
die "Proxy failed\n";
};
Note! When using a proxy to perform requests, be aware that if they
fail your program will die unless you wrap your code in an eval
statement or use a try/catch mechanism. In the example above we use
Tiny::Try to trap any errors that might occur when using proxy.
request_denied
The request_denied method is a simple shortcut to determine if the page
you requested got loaded or redirected. This method is very useful on
systems that require authentication and redirect if not authorized.
This function return boolean, 1 if the current page doesn't match the
requested page.
my $scraper = Scrappy->new;
$scraper->get($url_to_dashboard);
if ($scraper->request_denied) {
# do login, again
}
else {
# resume ...
}
response
The response method returns the HTTP::Repsonse object of the current
page.
my $scraper = Scrappy->new;
$scraper->get(...);
my $res = $scraper->response;
select
The select method takes XPATH or CSS selectors and returns a
Scrappy::Scraper::Parser object which contains the matching elements.
my $scraper = Scrappy->new;
# return a list of links
my $list = $scraper->select('#profile li a')->data; # see Scrappy::Scraper::Parser
foreach my $link (@{$list}) {
print $link->{href}, "\n";
}
# Zoom in on specific chunks of html code using the following ...
my $list = $scraper
->select('#container table tr') # select all rows
->focus(4) # focus on the 5th row
->select('div div')->data;
# The code above selects the div > div inside of the 5th tr in #container table
# Access attributes html, text and other attributes as follows...
$element = $scraper->select('table')->data->[0];
$element->{html}; # HTML representation of the table
$element->{text}; # Table stripped of all HTML
$element->{cellpadding}; # cellpadding
$element->{height}; # ...
stash
The stash method sets a stash (shared) variable or returns a reference
to the entire stash object.
my $scraper = Scrappy->new;
$scraper->stash(age => 31);
print 'stash access works'
if $scraper->stash('age') == $scraper->stash->{age};
my @array = (1..20);
$scraper->stash(integers => [@array]);
store
The store method stores the contents of the current page into the
specified file. If the content-type does not begin with 'text', the
content is saved as binary data.
my $scraper = Scrappy->new;
$scraper->get($requested_url);
$scraper->store('/tmp/foo.html');
url
The url method returns the complete URL for the current page.
my $scraper = Scrappy->new;
$scraper->get('http://www.google.com/');
print $scraper->url; # prints http://www.google.com/
AUTHOR
Al Newkirk <awncorp@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by awncorp. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
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