Class: Securities::Scraper

Inherits:
Object
  • Object
show all
Defined in:
lib/securities/scraper.rb

Overview

Main class to communicate with Yahoo! Finance

Defined Under Namespace

Classes: ScraperException

Class Method Summary collapse

Class Method Details

.get(type, url) ⇒ Object 



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# File 'lib/securities/scraper.rb', line 16

def self.get type, url
  results = Array.new
  
  # Encoding for bad characters in index names.
  clean_url = URI::encode(url)
  uri = URI.parse(clean_url)

  # Check connection.
  begin
    get = Net::HTTP.get(uri)
  rescue => error
    raise ScraperException, "Connection error: #{error.message}"
  end

  case type
  #
  # Scraping for lookup.
  when :lookup
    doc = Nokogiri::HTML(get)

    table = doc.at('div#yfi_sym_results tbody')

    if table.nil?
      raise ScraperException, 'There were no results for this lookup.'
    end

    # Symbol  Name  Last Trade  Type  Industry/Category Exchange
    table.xpath('tr').each do |tr|
      row = tr.xpath('td')
      results << {:symbol => row[0].text,
                  :name => row[1].text, 
                  :last_trade => row[2].text, 
                  :type => row[3].text, 
                  :industry_category => row[4].text, 
                  :exchange => row[5].text}
    end
  #
  # Scraping for history
  when :history
    # Skip first line because it contains headers with Date,Open,High,Low,Close,Volume,Adj Close.
    # Check for errors during CSV parsing.
    begin
      csv = CSV.parse(get, :headers => true)
    rescue => error
      # Probably an invalid symbol specified or there was some other way the parser couldn't read a CSV.
      raise ScraperException, 'Stock symbol does not exist.'
    end

    csv.each_with_index do |row, index|
      line = Hash.new
      csv.headers.each_with_index do |header, i|
        # Set headers as keys for the data hash.
        line[header.parameterize.underscore.to_sym] = row[i]
        results[index] = line
      end
    end

    if results.empty?
      raise ScraperException, 'There were no results for this symbol.'
    end

    # Reversing results to return from the oldest to the newest.
    results = results.reverse
  end

  return results
end