Add installer support for webpack/webpacker

.prettierignore

@@ -1,4 +1,5 @@
 coverage
+lib/generators/rails_admin/templates
 spec/dummy_app/public
 spec/dummy_app/tmp
 spec/support/jquery.simulate.drag-sortable.js

app/helpers/rails_admin/application_helper.rb

@@ -195,5 +195,17 @@ def flash_alert_class(flash_key)
       else "alert-#{flash_key}"
       end
     end
+
+    def handle_asset_dependency_error
+      yield
+    rescue LoadError => e
+      if e.message =~ /sassc/
+        e = e.exception <<-MSG.gsub(/^\s{10}/, '')
+          #{e.message}
+          RailsAdmin requires the gem sassc-rails, make sure to put `gem 'sassc-rails'` to Gemfile.
+        MSG
+      end
+      raise e
+    end
   end
 end

app/views/layouts/rails_admin/_head.html.erb

@@ -3,10 +3,15 @@
 <meta content="width=device-width, initial-scale=1" name="viewport; charset=utf-8"/>
 <meta content="NONE,NOARCHIVE" name="robots"/>
 <%= csrf_meta_tag %>
-<% if RailsAdmin::config.asset_source == :webpacker %>
-  <%= javascript_pack_tag "rails_admin" %>
+<% case RailsAdmin::config.asset_source
+   when :webpacker %>
   <%= stylesheet_pack_tag "rails_admin" %>
-<% else %>
-  <%= stylesheet_link_tag "rails_admin.css", media: :all %>
-  <%= javascript_include_tag "rails_admin.js" %>
-<% end %>
+  <%= javascript_pack_tag "rails_admin" %>
+<% when :webpack, :sprockets %>
+  <% handle_asset_dependency_error do %>
+    <%= stylesheet_link_tag "rails_admin.css", media: :all %>
+    <%= javascript_include_tag "rails_admin.js", defer: true %>
+  <% end %>
+<% else
+     raise "Unknown asset_source: #{RailsAdmin::config.asset_source}"
+   end %>

lib/generators/rails_admin/install_generator.rb

@@ -7,12 +7,56 @@ class InstallGenerator < Rails::Generators::Base
     include Generators::Utils::InstanceMethods
 
     argument :_namespace, type: :string, required: false, desc: 'RailsAdmin url namespace'
+    class_option :asset, type: :string, required: false, default: nil, desc: 'Asset delivery method [options: webpack, webpacker, sprockets]'
     desc 'RailsAdmin installation generator'
 
     def install
       namespace = ask_for('Where do you want to mount rails_admin?', 'admin', _namespace)
       route("mount RailsAdmin::Engine => '/#{namespace}', as: 'rails_admin'")
       template 'initializer.erb', 'config/initializers/rails_admin.rb'
+      display "Using [#{asset}] for asset delivery method"
+      case asset
+      when 'webpack'
+        configure_for_webpack
+      when 'webpacker'
+        configure_for_webpacker5
+      when 'sprockets'
+        configure_for_sprockets
+      end
+    end
+
+  private
+
+    def asset
+      return options['asset'] if options['asset']
+
+      if Rails.root.join('webpack.config.js').exist?
+        'webpack'
+      elsif defined?(Webpacker)
+        'webpacker'
+      else
+        'sprockets'
+      end
+    end
+
+    def configure_for_sprockets
+      gem 'sassc-rails'
+    end
+
+    def configure_for_webpacker5
+      run "yarn add rails_admin@#{RailsAdmin::Version.js}"
+      @scss_relative_dir = '../stylesheets/'
+      template 'rails_admin.js.erb', 'app/javascript/packs/rails_admin.js'
+      template 'rails_admin.scss', 'app/javascript/stylesheets/rails_admin.scss'
+      template 'environment.js', 'config/webpack/environment.js'
+    end
+
+    def configure_for_webpack
+      run "yarn add rails_admin@#{RailsAdmin::Version.js} css-loader mini-css-extract-plugin sass sass-loader"
+      @scss_relative_dir = './'
+      template 'rails_admin.js.erb', 'app/javascript/rails_admin.js'
+      template 'rails_admin.scss', 'app/javascript/rails_admin.scss'
+      template 'webpack.config.js', 'webpack.config.js'
     end
   end
 end

lib/generators/rails_admin/templates/environment.js

@@ -0,0 +1,6 @@
+const webpack = require('webpack');
+const { environment } = require('@rails/webpacker')
+
+environment.plugins.append('ProvidePlugin-jQuery', new webpack.ProvidePlugin({jQuery: 'jquery'}));
+
+module.exports = environment

lib/generators/rails_admin/templates/initializer.erb

@@ -1,4 +1,5 @@
 RailsAdmin.config do |config|
+  config.asset_source = :<%= asset %>
 
   ### Popular gems integration
 

lib/generators/rails_admin/templates/rails_admin.js.erb

@@ -0,0 +1,2 @@
+import "rails_admin/src/rails_admin/base";
+import "<%= @scss_relative_dir %>rails_admin.scss";

lib/generators/rails_admin/templates/rails_admin.scss

@@ -0,0 +1 @@
+@import "~rails_admin/src/rails_admin/styles/base";

lib/generators/rails_admin/templates/webpack.config.js

@@ -0,0 +1,32 @@
+const path    = require("path")
+const webpack = require('webpack')
+const MiniCssExtractPlugin = require("mini-css-extract-plugin")
+
+module.exports = {
+  mode: "production",
+  entry: {
+    application: "./app/javascript/application.js",
+    rails_admin: "./app/javascript/rails_admin.js",
+  },
+  output: {
+    filename: "[name].js",
+    path: path.resolve(__dirname, "app/assets/builds"),
+  },
+  module: {
+    rules: [
+      {
+        test: /.s?css$/,
+        use: [MiniCssExtractPlugin.loader, "css-loader", "sass-loader"],
+      },
+    ],
+  },
+  plugins: [
+    new webpack.optimize.LimitChunkCountPlugin({
+      maxChunks: 1
+    }),
+    new webpack.ProvidePlugin({
+      jQuery: "jquery"
+    }),
+    new MiniCssExtractPlugin(),
+  ]
+}

lib/rails_admin/version.rb

@@ -10,6 +10,10 @@ class << self
       def to_s
         [MAJOR, MINOR, PATCH, PRE].compact.join('.')
       end
+
+      def js
+        JSON.parse(File.read("#{__dir__}/../../package.json"))['version']
+      end
     end
   end
 end

spec/rails_admin/install_generator_spec.rb

@@ -7,6 +7,7 @@
 
   before do
     prepare_destination
+    FileUtils.touch File.join(destination_root, 'Gemfile')
   end
 
   it 'mounts RailsAdmin as Engine and generates RailsAdmin Initializer' do
@@ -23,6 +24,22 @@
           end
         end
       end
+      case CI_ASSET
+      when :webpacker
+        file 'app/javascript/packs/rails_admin.js' do
+          contains 'import "rails_admin/src/rails_admin/base"'
+        end
+        file 'app/javascript/stylesheets/rails_admin.scss' do
+          contains '@import "~rails_admin/src/rails_admin/styles/base"'
+        end
+        file 'config/webpack/environment.js' do
+          contains 'ProvidePlugin({jQuery'
+        end
+      when :sprockets
+        file 'Gemfile' do
+          contains 'sassc-rails'
+        end
+      end
     }
   end
 end