vendor/rails/railties/doc/guides/source/creating_plugins/generator_method.txt

   1 == Add a custom generator command ==
   2
   3 You may have noticed above that you can used one of the built-in rails migration commands `migration_template`.  If your plugin needs to add and remove lines of text from existing files you will need to write your own generator methods.
   4
   5 This section describes how you you can create your own commands to add and remove a line of text from 'routes.rb'.  This example creates a very simple method that adds or removes a text file.
   6
   7 To start, add the following test method:
   8
   9 *vendor/plugins/yaffle/test/generator_test.rb*
  10
  11 [source, ruby]
  12 -----------------------------------------------------------
  13 def test_generates_definition
  14   Rails::Generator::Scripts::Generate.new.run(["yaffle", "bird"], :destination => fake_rails_root)
  15   definition = File.read(File.join(fake_rails_root, "definition.txt"))
  16   assert_match /Yaffle\:/, definition
  17 end
  18 -----------------------------------------------------------
  19
  20 Run `rake` to watch the test fail, then make the test pass add the following:
  21
  22 *vendor/plugins/yaffle/generators/yaffle/templates/definition.txt*
  23
  24 -----------------------------------------------------------
  25 Yaffle: A bird
  26 -----------------------------------------------------------
  27
  28 *vendor/plugins/yaffle/lib/yaffle.rb*
  29
  30 [source, ruby]
  31 -----------------------------------------------------------
  32 require "yaffle/commands"
  33 -----------------------------------------------------------
  34
  35 *vendor/plugins/yaffle/lib/commands.rb*
  36
  37 [source, ruby]
  38 -----------------------------------------------------------
  39 require 'rails_generator'
  40 require 'rails_generator/commands'
  41
  42 module Yaffle #:nodoc:
  43   module Generator #:nodoc:
  44     module Commands #:nodoc:
  45       module Create
  46         def yaffle_definition
  47           file("definition.txt", "definition.txt")
  48         end
  49       end
  50
  51       module Destroy
  52         def yaffle_definition
  53           file("definition.txt", "definition.txt")
  54         end
  55       end
  56
  57       module List
  58         def yaffle_definition
  59           file("definition.txt", "definition.txt")
  60         end
  61       end
  62
  63       module Update
  64         def yaffle_definition
  65           file("definition.txt", "definition.txt")
  66         end
  67       end
  68     end
  69   end
  70 end
  71
  72 Rails::Generator::Commands::Create.send   :include,  Yaffle::Generator::Commands::Create
  73 Rails::Generator::Commands::Destroy.send  :include,  Yaffle::Generator::Commands::Destroy
  74 Rails::Generator::Commands::List.send     :include,  Yaffle::Generator::Commands::List
  75 Rails::Generator::Commands::Update.send   :include,  Yaffle::Generator::Commands::Update
  76 -----------------------------------------------------------
  77
  78 Finally, call your new method in the manifest:
  79
  80 *vendor/plugins/yaffle/generators/yaffle/yaffle_generator.rb*
  81
  82 [source, ruby]
  83 -----------------------------------------------------------
  84 class YaffleGenerator < Rails::Generator::NamedBase
  85   def manifest
  86     m.yaffle_definition
  87   end
  88 end
  89 -----------------------------------------------------------