twndl.rb

#-*- coding:utf-8 -*-
require 'open-uri'
require 'json'
require 'sru'
require 'pry'
require 'nokogiri'

class Twitter
  # Twitterのトレンドワードを配列で返す
  def trends
    url    = 'https://api.twitter.com/1/trends/23424856.json'
    trends = JSON.parse(open(url).read).first["trends"]
    raise if trends.nil?
    words = trends.map{|h| h["name"] }.reject{|s| s=~/#.*/ }
    words
  end
end

module NdlSearch
  module SRU
    class Client
      SRU_AP = 'http://iss.ndl.go.jp/api/sru'

      def initialize(opts={})
	@client = ::SRU::Client.new SRU_AP
      end

      #input: query(String)
      #output: Array of Record instances
      def search(query, opts={})
	defaults = {:version=>1.2, :maximumRecords=>10, :operation=>'searchRetrieve', :onlyBib=>'true', :recordSchema=>'dcndl', :recordPacking=>'xml'}
	opts     = defaults.update opts
	response = @client.search_retrieve(query, opts)
	::NdlSearch::Record.load(response)
      end
    end
  end

  # Data Model about bibliobraphic data of NDL
  class Record
    attr_accessor :doc

    #load response of NDLSearch API with SRU, and generate array of Record instances
    #input: response(instance of SRU::Response)
    #output: Array of Record instances
    def self.load(response)
      records = Array.new
      response.doc.elements.each('//record/recordData') do |el| 
        records << self.new(el)
      end
      records
    end

    #input: source(String)
    #output: a Record instance
    def initialize(source, opts={})
      @doc = ::Nokogiri::XML.parse(source.to_s)
      @namespaces = @doc.collect_namespaces
    end

    def title
      @title ||= @doc.xpath('//dc:title/rdf:Description/rdf:value/text()', @namespaces).map(&:text)
    end

    def title_transcription
      @title_transcription ||= @doc.xpath('//dc:title/rdf:Description/dcndl:transcription/text()', @namespaces).map(&:text)
    end

  end

end

class TwNdl
  def initialize
    @tw = Twitter.new
    @ns = NdlSearch::SRU::Client.new
    @trends = []
  end

  # update trend words of Twitter, and search related resources from NDLSearch
  def update!
    @trends = @tw.trends
    @resources = @ns.search(@trends.map{|t| "anywhere=\"#{t}\"" }.join(' OR '))
    @result = {:terms=>@trends, :resources=>@resources}
  end

  def result
    update! if @result.nil?
    @result
  end

  def terms
    result[:terms]
  end

  def resources
    result[:resources]
  end

  def result_s
    "#{terms.join(',')}\n\n"+resources.map(&:title).join("\n")
  end
end

if __FILE__ == $0 then
  tw_ndl = TwNdl.new
  puts tw_ndl.result_s
end

Twitterのトレンドワードに関連した書誌をNDLSearchから引っ張ってくるプログラムです。