cityofhypes.rb

require 'json'
require 'open-uri'
require 'digest'

class BackType
  def self.requires_key?; true; end
  def initialize(key)
    @key = key
  end
  def said_about(url)    
    api = "http://api.backtype.com/comments/search.json?q=#{url}&key=#{@key}"
    begin
      h = JSON.parse(open(api).read) 
    rescue
      return {:num => 1, :dates => [Time.at(0)]}
    end
    dates = h['comments'].map{|comment| Time.parse(comment['comment']['date'])}
    { :num => h['totalresults'].to_i, :dates => dates}
  end
end

class Delicious
  def self.requires_key?; false; end
  def initialize
  end
  def said_about(url)
    api = "http://feeds.delicious.com/v2/json/url/#{Digest::MD5.hexdigest(url)}?count=100"
    arr = JSON.parse(open(api).read)
    dates = arr.map{|bkmk| Time.parse(bkmk['dt'])}
    { :num => arr.length, :dates => dates}
  end
end

class Hatebu
  def self.requires_key?; false; end
  def initialize
  end
  def said_about(url)
    api = "http://b.hatena.ne.jp/entry/jsonlite/#{url}"
    data = open(api).read
    return { :num => 1,:dates => [Time.at(0)]} if (data = open(api).read) == "null"
    h = JSON.parse(open(api).read)
    dates = h['bookmarks'].map{|bkmk| Time.parse(bkmk['timestamp'])}
    { :num => h['count'].to_i, :dates => dates}
  end
end

class CityOfHypes
  # Sources below are expected to return a hash like this:
  # { :dates => Array of DateTime the URL was mentioned
  #   :num => A number of mentions
  # }
  # You can add other sources within writing a class keeping above interface
  @@sources = [BackType, Delicious, Hatebu]
  @@keys = ['BackType API Key'] # will be pop when treating a source requiring API key

  def self.search(url) 
   h = { :num => 0, :dates => []}
    @@sources.each do |interface|
      obj = ( interface.requires_key? ? interface.new( @@keys.shift) : interface.new)
      result = obj.said_about(url)
      h[:num] += result[:num]
      h[:dates].concat( result[:dates])
    end
    h
  end

  def self.score_of(url)
    # Determines a score by the result of self.search
    # fomura of score is  (Time.now - avg of bookmarks)/(86400 * number of bookmarks)
    # 86400 = 24 hours ( 60 * 60 *24)
    # it could be 604800
    info = self.search(url)
    if info[:dates] != []
      date_avg = info[:dates].inject(0) {  |result, item| result + item.to_i } /info[:dates].size
    end
    (Time.now.to_i - date_avg.to_i)/(86400*info[:num])
  end
end