Simple DSL web scraper using Nibbler + Nokogiri + Faraday (less 35 LOC)

example.rb

require 'webfetch'

rails = WebFetch.parse("http://rubygems.org/gems/rails") do
  element :title
  element '#markup p' => :description
end

puts rails.title

#=> "rails | RubyGems.org | your community gem host"

puts rails.description

#=> "Ruby on Rails is a full-stack web framework optimized for programmer happiness and sustainable productivity. It encourages beautiful code by favoring convention over configuration."

Gemfile

source :rubygems

gem 'nokogiri'
gem 'faraday'
gem 'nibbler'

webfetch.rb

require 'rubygems'
require 'bundler/setup'
require 'nibbler'
require 'nokogiri'
require 'faraday'

class WebFetch
  attr_accessor :uri, :document, :klass

  def self.parse(uri, &block)
    new(uri, &block)
  end

  def initialize(uri, &block)
    @document, @uri = fetch uri
    @klass = Class.new(Nibbler) { instance_eval(&block) }.parse(@document.body)
  end

  def method_missing(m)
    @klass.send(:"#{m}")
  end

  private
   def fetch(uri)
     response = Faraday.get uri
     if [301,302].include?(response.status)
       uri = response.headers['location']
       response = fetch(uri).first
     end
     [response, uri]
   end
end