scRUBYt! Hpricot and Mechanize (or FireWatir) on steroids

scRUBYt! - Hpricot and Mechanize (or FireWatir) on steroids

A simple to learn and use, yet very powerful web extraction framework
written in Ruby. Navigate through the Web, Extract, query, transform and
save relevant data from the Web page of your interest by the concise and
easy to use DSL.

Do you think that Mechanize and Hpricot are powerful libraries? You’re
right, they are, indeed - hats off to their authors: without these libs
scRUBYt! could not exist now! I have been wondering whether their
functionality could be still enhanced further - so I took these two
powerful ingredients, threw in a handful of smart heuristics, wrapped them
around with a chunky DSL coating and sprinkled the whole stuff with a lots
of convention over configuration(tm) goodies

Wait… why do we need one more web-scraping toolkit?

After all, we have HPricot, and Rubyful-soup, and Mechanize, and scrAPI,
and ARIEL and scrapes and … Well, because scRUBYt! is different. It has
an entirely different philosophy, underlying techniques, theoretical
background, use cases, todo list, real-life scenarios etc. - shortly it
should be used in different situations with different requirements than
the previosly mentioned ones.

If you need something quick and/or would like to have maximal control over
the scraping process, I recommend HPricot. Mechanize shines when it comes
to interaction with Web pages. Since scRUBYt! is operating based on XPaths,
sometimes you will chose scrAPI because CSS selectors will better suit
your needs. The list goes on and on, boiling down to the good old mantra:
use the right tool for the right job!

I hope there will be also times when you will want to experiment with
Pandora’s box and reach after the power of scRUBYt! :-)

Sounds fine - show me an example!

Let’s apply the “show don’t tell” principle. Okay, here we go:

ebay_data = Scrubyt::Extractor.define do

fetch 'http://www.ebay.com/'
fill_textfield 'satitle', 'ipod'
submit
click_link 'Apple iPod'
record do
  item_name 'APPLE NEW IPOD MINI 6GB MP3 PLAYER SILVER'
  price '$71.99'
end
next_page 'Next >', :limit => 5

end

output:

<root>

<record>
  <item_name>APPLE IPOD NANO 4GB - PINK - MP3 PLAYER</item_name>
  <price>$149.95</price>
</record>
<record>
  <item_name>APPLE IPOD 30GB BLACK VIDEO/PHOTO/MP3 PLAYER</item_name>
  <price>$172.50</price>
</record>
<record>
  <item_name>NEW APPLE IPOD NANO 4GB PINK MP3 PLAYER</item_name>
  <price>$171.06</price>
</record>
<!-- another 200+ results -->

</root>

This was a relatively beginner-level example (scRUBYt knows a lot more than
this and there are much complicated extractors than the above one) - yet
it did a lot of things automagically. First of all, it automatically loaded
the page of interest (by going to ebay.com, automatically searching for
ipods and narrowing down the results by clicking on ‘Apple iPod’), then
it extracted all the items that looked like the specified example
(which btw described also how the output structure should look like) - on
the first 5 result pages. Not so bad for about 10 lines of code, eh?

OK, OK, I believe you, what should I do?

You can find everything you will need at these addresses (or if not, I
doubt you will find it elsewhere…). See the next section about
installation, and after installing be sure to check out these URLs:

at web scraping in general and/or you would like to understand what’s
going on under the hood, check out <a href=‘http://scrubyt.orgscrubyt.org’>http://scrubyt.org>
- your source of tutorials, howtos, news etc.

<a href=‘scrubyt.rubyforge.org’>scrubyt.rubyforge.org>
- for an up-to-date, online Rdoc

<a href=‘projects.rubyforge.org/scrubyt’>projects.rubyforge.org/scrubyt>
- for developer info, including

open and closed bugs, files etc.

the features of scRUBYt!

have a community, and people will upload their extractors for whatever
reason

If you still can’t find something here, drop a mail to the guys at
scrubyt@/NO-SPAM/scrubyt.org!

How to install

scRUBYt! requires these packages to be installed:

I assume you have ruby any rubygems installed. To install WWW::Mechanize
0.6.3 or higher, just run

sudo gem install mechanize

Hpricot 0.5 is just hot off the frying pan - perfect timing, _why! -
install it with

sudo gem install hpricot

Once all the dependencies (Mechanize and Hpricot) are up and running, you
can install scrubyt with

sudo gem install scrubyt

If you encounter any problems, drop a mail to the guys at
scrubyt@/NO-SPAM/scrubyt.org!

Author

Copyright © 2006 by Peter Szinek (peter@/NO-SPAM/rubyrailways.com)

Copyright

This library is distributed under the GPL. Please see the LICENSE file.

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