Module: Ttsttb

Defined in:
lib/ttsttb.rb,
lib/ttsttb/version.rb

Overview

Scrape TTS and TTB data from MURC.

Constant Summary collapse

VERSION = 
'0.0.3'.freeze

Class Method Summary collapse

Class Method Details

.find(date) ⇒ Object

Execute scraping



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# File 'lib/ttsttb.rb', line 7

def self.find(date)
  # TODO
  throw 'Data of today is not supported yet.' if date == Date.today

  # TODO
  throw 'Old data is not supported yet.' if date == Date.new(2006, 1, 1)

  require 'date'
  url = format('http://www.murc-kawasesouba.jp/fx/past/index.php?id=%s', date.strftime('%y%m%d'))

  require 'open-uri'

  doc = Nokogiri::HTML(open(url, redirect: false))
  scrape(doc)
end

.get_ttm(tts, ttb) ⇒ Object

calculate TTM



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# File 'lib/ttsttb.rb', line 54

def self.get_ttm(tts, ttb)
  require 'bigdecimal'

  return nil unless tts && ttb

  (BigDecimal(tts.to_s) + BigDecimal(ttb.to_s) / 2).round(2).to_f
end

.normalize(value) ⇒ Object

normalize string to float



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# File 'lib/ttsttb.rb', line 47

def self.normalize(value)
  value = value.strip
  return nil if value == 'unquoted'
  value.to_f
end

.scrape(doc) ⇒ Object

parse document



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# File 'lib/ttsttb.rb', line 24

def self.scrape(doc)
  rows = {}
  doc.xpath('//table[1]/tr').each do |tr|
    tds = tr.xpath('.//td')

    next unless tds[0]

    rows[tds[2].content] = {
      'currency' => {
        'en' => tds[0].content,
        'ja' => tds[1].content
      },
      'code' => tds[2].content,
      'tts' => normalize(tds[3].content),
      'ttb' => normalize(tds[4].content),
      'ttm' => get_ttm(normalize(tds[3].content), normalize(tds[4].content))
    }
  end

  rows
end