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Diffstat (limited to 'actionpack/lib/action_controller/helpers.rb')
| -rw-r--r-- | actionpack/lib/action_controller/helpers.rb | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/helpers.rb b/actionpack/lib/action_controller/helpers.rb new file mode 100644 index 0000000000..9c88582288 --- /dev/null +++ b/actionpack/lib/action_controller/helpers.rb @@ -0,0 +1,100 @@ +module ActionController #:nodoc: + module Helpers #:nodoc: + def self.append_features(base) + super + base.class_eval { class << self; alias_method :inherited_without_helper, :inherited; end } + base.extend(ClassMethods) + end + + # The template helpers serves to relieve the templates from including the same inline code again and again. It's a + # set of standardized methods for working with forms (FormHelper), dates (DateHelper), texts (TextHelper), and + # Active Records (ActiveRecordHelper) that's available to all templates by default. + # + # It's also really easy to make your own helpers and it's much encouraged to keep the template files free + # from complicated logic. It's even encouraged to bundle common compositions of methods from other helpers + # (often the common helpers) as they're used by the specific application. + # + # module MyHelper + # def hello_world() "hello world" end + # end + # + # MyHelper can now be included in a controller, like this: + # + # class MyController < ActionController::Base + # helper :my_helper + # end + # + # ...and, same as above, used in any template rendered from MyController, like this: + # + # Let's hear what the helper has to say: <tt><%= hello_world %></tt> + module ClassMethods + # Makes all the (instance) methods in the helper module available to templates rendered through this controller. + # See ActionView::Helpers (link:classes/ActionView/Helpers.html) for more about making your own helper modules + # available to the templates. + def add_template_helper(helper_module) + template_class.class_eval "include #{helper_module}" + end + + # Declare a helper. If you use this method in your controller, you don't + # have to do the +self.append_features+ incantation in your helper class. + # helper :foo + # requires 'foo_helper' and includes FooHelper in the template class. + # helper FooHelper + # includes FooHelper in the template class. + # helper { def foo() "#{bar} is the very best" end } + # evaluates the block in the template class, adding method #foo. + # helper(:three, BlindHelper) { def mice() 'mice' end } + # does all three. + def helper(*args, &block) + args.flatten.each do |arg| + case arg + when Module + add_template_helper(arg) + when String, Symbol + file_name = Inflector.underscore(arg.to_s.downcase) + '_helper' + class_name = Inflector.camelize(file_name) + begin + require_or_load(file_name) + rescue LoadError + raise LoadError, "Missing helper file helpers/#{file_name}.rb" + end + raise ArgumentError, "Missing #{class_name} module in helpers/#{file_name}.rb" unless Object.const_defined?(class_name) + add_template_helper(Object.const_get(class_name)) + else + raise ArgumentError, 'helper expects String, Symbol, or Module argument' + end + end + + # Evaluate block in template class if given. + template_class.module_eval(&block) if block_given? + end + + # Declare a controller method as a helper. For example, + # helper_method :link_to + # def link_to(name, options) ... end + # makes the link_to controller method available in the view. + def helper_method(*methods) + template_class.controller_delegate(*methods) + end + + # Declare a controller attribute as a helper. For example, + # helper_attr :name + # attr_accessor :name + # makes the name and name= controller methods available in the view. + # The is a convenience wrapper for helper_method. + def helper_attr(*attrs) + attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") } + end + + private + def inherited(child) + inherited_without_helper(child) + begin + child.helper(child.controller_name) + rescue LoadError + # No default helper available for this controller + end + end + end + end +end |