7600aef48b
As a side benefit, fix an (non-user-visible) bug in display_s5(). Also fixed a bug where removing orphaned pages did not expire cached summary pages.
90 lines
2.8 KiB
Plaintext
90 lines
2.8 KiB
Plaintext
== Create a migration generator ==
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When you created the plugin above, you specified the --with-generator option, so you already have the generator stubs in your plugin.
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We'll be relying on the built-in rails generate template for this tutorial. Going into the details of generators is beyond the scope of this tutorial.
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Type:
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script/generate
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You should see the line:
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Plugins (vendor/plugins): yaffle
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When you run `script/generate yaffle` you should see the contents of your USAGE file. For this plugin, the USAGE file looks like this:
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------------------------------------------------------------------
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Description:
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Creates a migration that adds yaffle squawk fields to the given model
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Example:
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./script/generate yaffle hickwall
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This will create:
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db/migrate/TIMESTAMP_add_yaffle_fields_to_hickwall
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------------------------------------------------------------------
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Now you can add code to your generator:
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[source, ruby]
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------------------------------------------------------------------
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# File: vendor/plugins/yaffle/generators/yaffle/yaffle_generator.rb
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class YaffleGenerator < Rails::Generator::NamedBase
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def manifest
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record do |m|
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m.migration_template 'migration:migration.rb', "db/migrate", {:assigns => yaffle_local_assigns,
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:migration_file_name => "add_yaffle_fields_to_#{custom_file_name}"
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}
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end
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end
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private
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def custom_file_name
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custom_name = class_name.underscore.downcase
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custom_name = custom_name.pluralize if ActiveRecord::Base.pluralize_table_names
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end
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def yaffle_local_assigns
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returning(assigns = {}) do
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assigns[:migration_action] = "add"
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assigns[:class_name] = "add_yaffle_fields_to_#{custom_file_name}"
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assigns[:table_name] = custom_file_name
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assigns[:attributes] = [Rails::Generator::GeneratedAttribute.new("last_squawk", "string")]
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assigns[:attributes] << Rails::Generator::GeneratedAttribute.new("last_squawked_at", "datetime")
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end
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end
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end
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------------------------------------------------------------------
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Note that you need to be aware of whether or not table names are pluralized.
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This does a few things:
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* Reuses the built in rails `migration_template` method.
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* Reuses the built-in rails migration template.
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When you run the generator like
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script/generate yaffle bird
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You will see a new file:
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[source, ruby]
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------------------------------------------------------------------
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# File: db/migrate/20080529225649_add_yaffle_fields_to_birds.rb
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class AddYaffleFieldsToBirds < ActiveRecord::Migration
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def self.up
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add_column :birds, :last_squawk, :string
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add_column :birds, :last_squawked_at, :datetime
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end
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def self.down
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remove_column :birds, :last_squawked_at
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remove_column :birds, :last_squawk
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end
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end
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------------------------------------------------------------------
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