Adding initial intro to railtie

1 files changed, 76 insertions, 0 deletions

diff --git a/railties/lib/rails/railtie.rb b/railties/lib/rails/railtie.rb
index 43a0303c5b..cba18a5196 100644
--- a/railties/lib/rails/railtie.rb
+++ b/railties/lib/rails/railtie.rb
@@ -1,7 +1,83 @@
 module Rails
+  # Railtie is the core of the Rails Framework and provides all the hooks and
+  # methods you need to link your plugin into Rails.
+  # 
+  # What Railtie does is make every component of Rails a "plugin" and creates 
+  # an API that exposes all the powers that the builtin components need
+  # to any plugin author.
+  # 
+  # In fact, every major component of Rails (Action Mailer, Action Controller,
+  # Action View, Active Record and Active Resource) are all now just plain
+  # old plugins.
+  # 
+  # Developing a plugin for Rails does not _require_ any implementation of
+  # Railtie, there is no fixed rule, but as a guideline, if your plugin works
+  # by just being required before Rails boots, then there is no need for you
+  # to hook into Railtie, but if you need to interact with the Rails framework
+  # during boot, or after boot, then Railtie is what you need to do that
+  # interaction.
+  # 
+  # For example, the following would need you to implement Railtie in your
+  # plugin:
+  # 
+  # * creating initializers (including route insertion)
+  # * modifying the render path (think HAML et al)
+  # * adding Rails config.* keys to the environment
+  # * setting up a subscriber to the Rails +ActiveSupport::Notifications+
+  # * adding global Rake tasks into rails
+  # * setting up a default configuration for the Application
+  # 
+  # Railtie gives you a central place to connect into the Rails framework.  If you
+  # find yourself writing plugin code that is having to monkey patch parts of the
+  # Rails framework to achieve something, there is probably a better, more elegant
+  # way to do it through Railtie, if there isn't, then you have found a lacking
+  # feature of Railtie, please lodge a ticket.
+  # 
+  # Implementing Railtie in your plugin is done with the following:
+  # 
+  # * Create a class Railtie which inherits from Rails::Railtie and is namespaced
+  #   to your plugin
+  #
+  #   module MyPlugin
+  #     class Railtie < Rails::Railtie
+  #     end
+  #   end
+  # 
+  # * Require your own plugin as well as rails in this file.
+  # 
+  #   require 'my_plugin'
+  #   require 'rails'
+  # 
+  #   module MyPlugin
+  #     class Railtie < Rails::Railtie
+  #     end
+  #   end
+  #   
+  # * Give your plugin a unique name
+  # 
+  #   require 'my_plugin'
+  #   require 'rails'
+  # 
+  #   module MyPlugin
+  #     class Railtie < Rails::Railtie
+  #       plugin_name :my_plugin
+  #     end
+  #   end
+  # 
+  # * Then start implementing the components of Railtie you need to
+  #   get your plugin working!
+  # 
+  # 
   class Railtie
     include Initializable
 
+    # Pass in the name of your plugin.  This is passed in as an underscored symbol.
+    # 
+    #   module MyPlugin
+    #     class Railtie < Rails::Railtie
+    #       plugin_name :my_plugin
+    #     end
+    #   end
     def self.plugin_name(plugin_name = nil)
       @plugin_name ||= name.demodulize.underscore
       @plugin_name = plugin_name if plugin_name