Downloads and installs chromedriver for use in rails tests, using capybara.

get-chromedriver.rb

#!/usr/bin/env ruby

require 'fileutils'
require 'json'
require 'net/http'
require 'tmpdir'

class ChromedriverDownloader
  def self.download
    new.download
  end

  def download
    return if File.exist?("~/bin/chromedriver-#{major_version}")

    Dir.mktmpdir do |dir|
      Dir.chdir(dir) do
        fetch
        unzip
        install
        symlink
      end
    end
  end

  private

  def fetch
    `curl #{latest_platform_uri} > chromedriver.zip`
  end

  def unzip
    `unzip chromedriver.zip`
  end

  def install
    FileUtils.mv("./chromedriver-#{platform}/chromedriver", install_file)
  end

  def symlink
    File.unlink(symlink_name) if File.exist?(symlink_name)
    File.symlink(install_file.to_s, symlink_name)
  end

  def symlink_name
    "#{ENV["HOME"]}/bin/chromedriver"
  end

  def chrome_version
    @chrome_version ||= (`'/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome' --version`).gsub(/[^0-9\.]/, '')
  end

  def platform
    if RUBY_PLATFORM.include?("arm") || RUBY_PLATFORM.include?("aarch64")
      "mac-arm64"
    elsif RUBY_PLATFORM.include?("x86") || RUBY_PLATFORM.include?("amd64")
      "mac-x64"
    else
      raise "Unsupported platform: #{RUBY_PLATFORM}"
    end
  end

  def major_version
    chrome_version.split('.')[0]
  end

  def latest_platform_uri
    response = Net::HTTP.get(URI(download_json_api_url))
    parsed = JSON.parse(response)
    urls = parsed.dig("milestones", "#{major_version}", "downloads", "chromedriver")
    urls.find { |i| i["platform"] == platform }["url"]
  end

  def download_json_api_url
    "https://googlechromelabs.github.io/chrome-for-testing/latest-versions-per-milestone-with-downloads.json"
  end

  def install_file
    "#{ENV["HOME"]}/bin/chromedriver-#{major_version}"
  end
end

ChromedriverDownloader.download if __FILE__ == $PROGRAM_NAME