ping.rb

module DataMapper
  module Search
    module SearchMethods
      # Used in a DM model to provide o search method like SearchLogic
      # class BlogPost
      #   include DataMapper::Resource
      #   extend DataMapper::Search::SearchMethods
      #   property :id, Serial
      #   property :created_on, Date
      # end
      # 
      # BlogPost.search('created_at.gt' => 2.days.ago, 'created_at.lte' => 1.day.ago)
      #
      # This seems generally useless, unless we consider the case of a form.
      # - form_for @search do |f|
      #   f.date_select "created_on.gt", :include_blank => true
      #   f.date_select "created_on.lte", :inclued_blank => true
      #   f.submit "Filter"
      # 
      # Then, in the controller:
      #
      # class BlogPostsController < ApplicationController
      #   def index
      #     @search = BlogPost.search(params[:search])
      #     @blog_posts = @search.all
      #   end
      # end
      # 
      # Now that's pretty stylin'
      def self.search(params={})
        SearchObject.new self, SearchMethods.parse_query_operators(params)
      end
      
      def self.parse_query_operators(params)
        params.inject({}) do |memo, (key, value)|
          memo[parse_query_operator(key)] = value
          memo
        end
      end
      
      def self.parse_query_operator(key)
        property, operator = key.split('.')
        operator ? property.to_sym.send(operator) : property
      end
    end
    
    class SearchObject
      def initialize(model, query_conditions)
        @model, @query_conditions =  model, query_conditions
      end
      
      def all
        @model.all(@query_conditions)
      end
      
      def first
        @model.first(@query_conditions)
      end
    end
  end
end