=data_miner

Mine remote data into your ActiveRecord models.

==Quick start

Put this in <tt>config/environment.rb</tt>:

  config.gem 'seamusabshere-data_miner', :lib => 'data_miner', :source => 'http://gems.github.com'

Put this in <tt>lib/tasks/data_miner_tasks.rake</tt>: (unfortunately I don't know a way to automatically include gem tasks, so you have to do this manually for now)

  namespace :data_miner do
    task :mine => :environment do
      DataMiner.mine :class_names => ENV['CLASSES'].to_s.split(/\s*,\s*/).flatten.compact
    end
  end

You need to specify what order to mine data. For example, in <tt>config/initializers/data_miner_config.rb</tt>:

  DataMiner.enqueue do |queue|
    queue << Country  # class whose data should be mined 1st
    queue << Airport  # class whose data should be mined 2nd
    # etc
  end

You need to define <tt>mine_data</tt> blocks. For example, in <tt>app/models/country.rb</tt>:

  class Country < ActiveRecord::Base
    mine_data do |step|
      # import country names and country codes
      step.import :url => 'http://www.cs.princeton.edu/introcs/data/iso3166.csv' do |attr|
        attr.key :iso_3166, :name_in_source => 'country code'
        attr.store :iso_3166, :name_in_source => 'country code'
        attr.store :name, :name_in_source => 'country'
      end
    end
  end

To complete the example, in <tt>app/models/airport.rb</tt>:

  class Airport < ActiveRecord::Base
    belongs_to :country
  
    mine_data do |step|
      # import airport iata_code, name, etc.
      step.import(:url => 'http://openflights.svn.sourceforge.net/viewvc/openflights/openflights/data/airports.dat', :headers => false) do |attr|
        attr.key :iata_code, :field_number => 3
        attr.store :name, :field_number => 0
        attr.store :city, :field_number => 1
        attr.store :country, :field_number => 2, :foreign_key => :name       # will use Country.find_by_name(X)
        attr.store :iata_code, :field_number => 3
        attr.store :latitude, :field_number => 5
        attr.store :longitude, :field_number => 6
      end
    end
  end

Once you have (1) set up the order of data mining and (2) defined <tt>mine_data</tt> blocks in your classes, you can:

  $ rake data_miner:mine

==Complete example

  ~ $ rails testapp
  ~ $ cd testapp/
  ~/testapp $ ./script/generate model Airport iata_code:string name:string city:string country_id:integer latitude:float longitude:float
  ~/testapp $ ./script/generate model Country iso_3166:string name:string
  ~/testapp $ rake db:migrate
  ~/testapp $ touch lib/tasks/data_miner_tasks.rb
  [...edit per quick start...]
  ~/testapp $ touch config/initializers/data_miner_config.rake
  [...edit per quick start...]
  ~/testapp $ rake data_miner:mine

Now you should have

  ~/testapp $ ./script/console 
  Loading development environment (Rails 2.3.3)
  >> Airport.first.iata_code
  => "GKA"
  >> Airport.first.country.name
  => "Papua New Guinea"

==Copyright

Copyright (c) 2009 Brighter Planet. See LICENSE for details.