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diff --git a/railties/guides/source/generators.textile b/railties/guides/source/generators.textile index c0d3116fe4..6945f6f9bb 100644 --- a/railties/guides/source/generators.textile +++ b/railties/guides/source/generators.textile @@ -1,4 +1,4 @@ -h2. Creating and Customizing Rails Generators +h2. Creating and Customizing Rails Generators & Templates Rails generators are an essential tool if you plan to improve your workflow. With this guide you will learn how to create generators and customize existing ones. @@ -10,6 +10,7 @@ In this guide you will: * Customize your scaffold by creating new generators * Customize your scaffold by changing generator templates * Learn how to use fallbacks to avoid overwriting a huge set of generators +* Learn how to create an application template endprologue. @@ -45,6 +46,8 @@ class InitializerGenerator < Rails::Generators::Base end </ruby> +NOTE: +create_file+ is a method provided by +Thor::Actions+ and the documentation for it and its brethren can be found at "rdoc.info":http://rdoc.info/github/wycats/thor/master/Thor/Actions. + Our new generator is quite simple: it inherits from +Rails::Generators::Base+ and has one method definition. Each public method in the generator is executed when a generator is invoked. Finally, we invoke the +create_file+ method that will create a file at the given destination with the given content. If you are familiar with the Rails Application Templates API, you'll feel right at home with the new generators API. To invoke our new generator, we just need to do: @@ -92,7 +95,7 @@ class InitializerGenerator < Rails::Generators::NamedBase end </ruby> -First, notice that we are inheriting from +Rails::Generators::NamedBase+ instead of +Rails::Generators::Base+. This means that our generator expects at least one argument, which will be the name of the initializer. +First, notice that we are inheriting from +Rails::Generators::NamedBase+ instead of +Rails::Generators::Base+. This means that our generator expects at least one argument, which will be the name of the initializer, and will be available in our code in the variable +name+. We can see that by invoking the description of this new generator (don't forget to delete the old generator file): @@ -131,6 +134,8 @@ $ rails generate initializer core_extensions We can see that now a initializer named core_extensions was created at +config/initializers/core_extensions.rb+ with the contents of our template. That means that +copy_file+ copied a file in our source root to the destination path we gave. The method +file_name+ is automatically created when we inherit from +Rails::Generators::NamedBase+. +The methods that are available for generators are covered in the "final section":#generator-methods of this guide. + h3. Generators Lookup When you run +rails generate initializer core_extensions+ Rails requires these files in turn until one is found: @@ -201,18 +206,18 @@ config.generators do |g| end </ruby> -If we generate another resource with the scaffold generator, we can notice that neither stylesheets nor fixtures are created anymore. If you want to customize it further, for example to use DataMapper and RSpec instead of Active Record and TestUnit, it's just a matter of adding their gems to your application and configuring your generators. +If we generate another resource with the scaffold generator, we can see that neither stylesheets nor fixtures are created anymore. If you want to customize it further, for example to use DataMapper and RSpec instead of Active Record and TestUnit, it's just a matter of adding their gems to your application and configuring your generators. -To demonstrate this, we are going to create a new helper generator that simply adds some instance variable readers. First, we create a generator: +To demonstrate this, we are going to create a new helper generator that simply adds some instance variable readers. First, we create a generator within the rails namespace, as this is where rails searches for generators used as hooks: <shell> -$ rails generate generator my_helper +$ rails generate generator rails/my_helper </shell> After that, we can delete both the +templates+ directory and the +source_root+ class method from our new generators, because we are not going to need them. So our new generator looks like the following: <ruby> -class MyHelperGenerator < Rails::Generators::NamedBase +class Rails::MyHelperGenerator < Rails::Generators::NamedBase def create_helper_file create_file "app/helpers/#{file_name}_helper.rb", <<-FILE module #{class_name}Helper @@ -265,7 +270,7 @@ Since Rails 3.0, this is easy to do due to the hooks concept. Our new helper doe To do that, we can change the generator this way: <ruby> -class MyHelperGenerator < Rails::Generators::NamedBase +class Rails::MyHelperGenerator < Rails::Generators::NamedBase def create_helper_file create_file "app/helpers/#{file_name}_helper.rb", <<-FILE module #{class_name}Helper @@ -278,7 +283,7 @@ end end </ruby> -Now, when the helper generator is invoked and TestUnit is configured as the test framework, it will try to invoke both +MyHelper::Generators::TestUnitGenerator+ and +TestUnit::Generators::MyHelperGenerator+. Since none of those are defined, we can tell our generator to invoke +TestUnit::Generators::HelperGenerator+ instead, which is defined since it's a Rails generator. To do that, we just need to add: +Now, when the helper generator is invoked and TestUnit is configured as the test framework, it will try to invoke both +Rails::TestUnitGenerator+ and +TestUnit::MyHelperGenerator+. Since none of those are defined, we can tell our generator to invoke +TestUnit::Generators::HelperGenerator+ instead, which is defined since it's a Rails generator. To do that, we just need to add: <ruby> # Search for :helper instead of :my_helper @@ -361,8 +366,258 @@ $ rails generate scaffold Comment body:text Fallbacks allow your generators to have a single responsibility, increasing code reuse and reducing the amount of duplication. +h3. Application templates + +Now that you've seen how generators can be used _inside_ an application, did you know they can also be used to _generate_ applications too? This kind of generator is referred as a "template". + +<ruby> + gem("rspec-rails", :group => "test") + gem("cucumber-rails", :group => "test") + + if yes?("Would you like to install Devise?") + gem("devise") + generate("devise:install") + model_name = ask("What would you like the user model to be called? [user]") + model_name = "user" if model_name.blank? + generate("devise", model_name) + end +</ruby> + +In the above template we specify that the application relies on the +rspec-rails+ and +cucumber-rails+ gem so these two will be added to the +test+ group in the +Gemfile+. Then we pose a question to the user about whether or not they would like to install Devise. If the user replies "y" or "yes" to this question, then the template will add Devise to the +Gemfile+ outside of any group and then runs the +devise:install+ generator. This template then takes the users input and runs the +devise+ generator, with the user's answer from the last question being passed to this generator. + +Imagine that this template was in a file called +template.rb+. We can use it to modify the outcome of the +rails new+ command by using the +-m+ option and passing in the filename: + +<shell> + rails new thud -m template.rb +</shell> + +This command will generate the +Thud+ application, and then apply the template to the generated output. + +Templates don't have to be stored on the local system, the +-m+ option also supports online templates: + +<shell> + rails new thud -m https://gist.github.com/722911 +</shell> + +Whilst the final section of this guide doesn't cover how to generate the most awesome template known to man, it will take you through the methods available at your disposal so that you can develop it yourself. These same methods are also available for generators. + +h3. Generator methods + +The following are methods available for both generators and templates for Rails. + +NOTE: Methods provided by Thor are not covered this guide and can be found in "Thor's documentation":http://rdoc.info/github/wycats/thor/master/Thor/Actions.html + +h4. +plugin+ + ++plugin+ will install a plugin into the current application. + +<ruby> + plugin("dynamic-form", :git => "git://github.com/rails/dynamic-form.git") +</ruby> + +Available options are: + +* +:git+ - Takes the path to the git repository where this plugin can be found. +* +:branch+ - The name of the branch of the git repository where the plugin is found. +* +:submodule+ - Set to +true+ for the plugin to be installed as a submodule. Defaults to +false+. +* +:svn+ - Takes the path to the svn repository where this plugin can be found. +* +:revision+ - The revision of the plugin in an SVN repository. + +h4. +gem+ + +Specifies a gem dependency of the application. + +<ruby> + gem("rspec", :group => "test", :version => "2.1.0") + gem("devise", "1.1.5") +</ruby> + +Available options are: + +* +:group+ - The group in the +Gemfile+ where this gem should go. +* +:version+ - The version string of the gem you want to use. Can also be specified as the second argument to the method. +* +:git+ - The URL to the git repository for this gem. + +Any additional options passed to this method are put on the end of the line: + +<ruby> + gem("devise", :git => "git://github.com/plataformatec/devise", :branch => "master") +</ruby> + +The above code will put the following line into +Gemfile+: + +<ruby> + gem "devise", :git => "git://github.com/plataformatec/devise", :branch => "master" +</ruby> + + +h4. +add_source+ + +Adds a specified source to +Gemfile+: + +<ruby> + add_source "http://gems.github.com" +</ruby> + +h4. +application+ + +Adds a line to +config/application.rb+ directly after the application class definition. + +<ruby> + application "config.asset_host = 'http://example.com'" +</ruby> + +This method can also take a block: + +<ruby> + application do + "config.asset_host = 'http://example.com'" + end + end +</ruby> + +Available options are: + +* +:env+ - Specify an environment for this configuration option. If you wish to use this option with the block syntax the recommended syntax is as follows: + +<ruby> + application(nil, :env => "development") do + "config.asset_host = 'http://localhost:3000'" + end +</ruby> + +h4. +git+ + +Runs the specified git command: + +<ruby> + git :init + git :add => "." + git :commit => "-m First commit!" + git :add => "onefile.rb", :rm => "badfile.cxx" +</ruby> + +The values of the hash here being the arguments or options passed to the specific git command. As per the final example shown here, multiple git commands can be specified at a time, but the order of their running is not guaranteed to be the same as the order that they were specified in. + +h4. +vendor+ + +Places a file into +vendor+ which contains the specified code. + +<ruby> + vendor("sekrit.rb", '#top secret stuff') +</ruby> + +This method also takes a block: + +<ruby> + vendor("seeds.rb") do + "puts 'in ur app, seeding ur database'" + end +</ruby> + +h4. +lib+ + +Places a file into +lib+ which contains the specified code. + +<ruby> + lib("special.rb", 'p Rails.root') +</ruby> + +This method also takes a block: + +<ruby> + lib("super_special.rb") do + puts "Super special!" + end +</ruby> + +h4. +rakefile+ + +Creates a Rake file in the +lib/tasks+ directory of the application. + +<ruby> + rakefile("test.rake", 'hello there') +</ruby> + +This method also takes a block: + +<ruby> + rakefile("test.rake") do + %Q{ + task :rock => :environment do + puts "Rockin'" + end + } + end +</ruby> + +h4. +initializer+ + +Creates an initializer in the +config/initializers+ directory of the application: + +<ruby> + initializer("begin.rb", "puts 'this is the beginning'") +</ruby> + +This method also takes a block: + +<ruby> + initializer("begin.rb") do + puts "Almost done!" + end +</ruby> + +h4. +generate+ + +Runs the specified generator where the first argument is the generator name and the remaining arguments are passed directly to the generator. + +<ruby> + generate("scaffold", "forums title:string description:text") +</ruby> + + +h4. +rake+ + +Runs the specified Rake task. + +<ruby> + rake("db:migrate") +</ruby> + +Available options are: + +* +:env+ - Specifies the environment in which to run this rake task. +* +:sudo+ - Whether or not to run this task using +sudo+. Defaults to +false+. + +h4. +capify!+ + +Runs the +capify+ command from Capistrano at the root of the application which generates Capistrano configuration. + +<ruby> + capify! +</ruby> + +h4. +route+ + +Adds text to the +config/routes.rb+ file: + +<ruby> + route("resources :people") +</ruby> + +h4. +readme+ + +Output the contents of a file in the template's +source_path+, usually a README. + +<ruby> + readme("README") +</ruby> + h3. Changelog +* December 1, 2010: Documenting the available methods and options for generators and templates by "Ryan Bigg":http://ryanbigg.com +* December 1, 2010: Addition of Rails application templates by "Ryan Bigg":http://ryanbigg.com + * August 23, 2010: Edit pass by "Xavier Noria":credits.html#fxn * April 30, 2010: Reviewed by José Valim |