From: MonkeeSage <MonkeeSage@...>
Date: 2006-09-30T09:50:11+09:00
Subject: Re: newbie: how to find & extract a string from a file

Esmail Bonakdarian wrote:
> I would like to extract the filename with the .jpg extension.
> What is the best approach for this?

Hi there,

You could use raw regexps and do it yourself, but you should probably
use an HTML parser to extract HTML data. ;)

A nice HTML parser is Hpricot [1], but it requires an extension (you
cen get it very easily via gems, see the link below). It is very easy
to use, and it's fast.

Using Hpricot, you can do something like this:

require 'hpricot'
require 'open-uri'
soc = open('http://utopia.utexas.edu/maps/ireland.html')
doc = Hpricot(soc)
soc.close
doc.search('//a').each { |elem|
  href = elem.attributes['href']
  if not href.nil? and
     ['.jpg', '.jpeg'].include?(File.extname(href))
    puts href
  end
}

Note that you can also use the built-in REXML parser [2], and do
something like:

require 'rexml/document'
require 'open-uri'
include REXML
soc = open('http://utopia.utexas.edu/maps/ireland.html')
doc = Document.new(soc)
soc.close
doc.elements.each('//a') { |elem|
  href = elem.attributes['href']
  if not href.nil? and
     ['.jpg', '.jpeg'].include?(File.extname(href))
    puts href
  end
}

[1] http://code.whytheluckystiff.net/hpricot/
[2] http://www.germane-software.com/software/rexml/docs/tutorial.html

Regards,
Jordan