Install npm dependencies on Gem.pre_install

Author: glebm

.gitignore

@@ -17,3 +17,4 @@ test/version_tmp
 tmp
 
 .DS_Store
+/node_modules/

Gemfile

@@ -1,4 +1,10 @@
-# A sample Gemfile
-source "https://rubygems.org"
+source 'https://rubygems.org'
 
-gem 'rubocop', require: false
+gemspec
+
+gem 'rubocop', require: false
+
+# Gem hooks are not triggered for the gemspec gem
+# https://github.com/bundler/bundler/issues/2354
+# Work around this by requiring the hooks here
+require_relative './lib/rubygems_plugin'

Rakefile

@@ -0,0 +1,41 @@
+desc 'Update the vendored version of penthouse'
+task :update_penthouse do # rubocop:disable Metrics/BlockLength
+  require 'net/http'
+  require 'uri'
+  fetch = lambda do |url|
+    uri = URI.parse(url)
+    response = Net::HTTP.start(uri.host, uri.port, use_ssl: true) do |http|
+      http.request(Net::HTTP::Get.new(uri.path, 'User-Agent' => 'Ruby'))
+    end
+    case response
+      when Net::HTTPSuccess
+        response.body
+      when Net::HTTPRedirection
+        # unpkg.com returns a relative URL in the `location` field.
+        location = uri.clone
+        location.path = URI.parse(response['location']).path
+        location
+      else
+        response.error!
+    end
+  end
+  local_root = 'lib/penthouse'
+  remote_root = "#{fetch['https://unpkg.com/penthouse']}/lib"
+
+  File.write File.join(local_root, 'timeago.js'),
+             fetch["#{remote_root}/dist/timeago.js"]
+  File.write File.join(local_root, 'timeago.locales.js'),
+             fetch["#{remote_root}/dist/timeago.locales.min.js"]
+  src = fetch.call.body
+  # Remove the source mapping comment as this gem does not bundle source maps:
+  src.sub!(%r{^//# sourceMappingURL=.*\n\z}, '')
+  File.write(File.join('lib/penthouse/penthouse.js'), src)
+
+  version_path = File.join('lib/popper_js/version.rb')
+  File.write version_path,
+             File.read(version_path)
+                 .sub(/VERSION = '.*?'/,
+                      "VERSION = '#{uri.path.split('@')[-1]}'")
+
+  STDERR.puts "Updated from #{uri}"
+end

lib/npm_commands.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+# NPM wrapper with helpful error messages
+class NpmCommands
+
+  # @return [Boolean] whether the installation succeeded
+  def install # rubocop:disable Metrics/MethodLength
+    return false unless check_nodejs_installed
+    STDERR.puts
+    install_status = system('npm install')
+    STDERR.puts(
+      *if install_status
+         ['npm dependencies installed']
+       else
+         ['-' * 60,
+          'Error: npm dependencies installation failed',
+          '-' * 60]
+       end
+    )
+    install_status
+  end
+
+  private
+
+  def check_nodejs_installed # rubocop:disable Metrics/MethodLength
+    return true if executable?('node')
+    STDERR.puts(
+      '-' * 60,
+      'Error: critical-path-css-rails requires NodeJS and NPM.',
+      *if executable?('brew')
+         ['  To install NodeJS and NPM, run:',
+          '  brew install node']
+       elsif Gem.win_platform?
+         ['  To install NodeJS and NPM, we recommend:',
+          '  https://github.com/coreybutler/nvm-windows/releases']
+       else
+         ['  To install NodeJS and NPM, we recommend:',
+          '  https://github.com/creationix/nvm']
+       end,
+      '-' * 60
+    )
+  end
+
+  def executable?(cmd)
+    exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
+    ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
+      exts.each do |ext|
+        exe = File.join(path, "#{cmd}#{ext}")
+        return exe if File.executable?(exe) && !File.directory?(exe)
+      end
+    end
+    nil
+  end
+end

lib/rubygems_plugin.rb

@@ -0,0 +1,4 @@
+Gem.pre_install do
+  require_relative './npm_commands'
+  NpmCommands.new.install
+end