Download all MS StyleGuides from https://www.microsoft.com/en-us/language/StyleGuides

Gemfile

# frozen_string_literal: true

source 'https://rubygems.org'

gem 'nokogiri'
gem 'rubocop', require: false

msstyleguides_downloader.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'nokogiri'
require 'open-uri'

URL = 'https://www.microsoft.com/en-us/language/StyleGuides'
PDF_FOLDER = 'pdf_files'

html = URI.parse(URL).open.read
doc = Nokogiri::HTML(html)
pdf_list = doc.at_css('#ddlStyleGuideLanguage')
options = pdf_list.css('option')

Dir.mkdir(PDF_FOLDER) unless Dir.exist?(PDF_FOLDER)

mutex = Mutex.new
threads = []

options.each do |option|
  value = option['value']
  next if value.nil? || !value.end_with?('.pdf')

  file_name = "#{option.text.strip}.pdf"
  file_path = File.join(PDF_FOLDER, file_name)

  threads << Thread.new do
    mutex.synchronize do
      URI.parse(value).open do |pdf_file|
        File.open(file_path, 'wb') do |file|
          file.write(pdf_file.read)
        end
      end
    end
    puts "#{file_name} downloaded successfully."
  rescue StandardError => e
    warn "Failed to download #{file_name}: #{e.message}"
  end
end

threads.each(&:join)

puts 'All PDF files downloaded.'