module ActionMailer module Helpers #:nodoc: def self.included(base) #:nodoc: # Initialize the base module to aggregate its helpers. base.class_inheritable_accessor :master_helper_module base.master_helper_module = Module.new # Extend base with class methods to declare helpers. base.extend(ClassMethods) base.class_eval do # Wrap inherited to create a new master helper module for subclasses. class << self alias_method_chain :inherited, :helper end # Wrap initialize_template_class to extend new template class # instances with the master helper module. alias_method_chain :initialize_template_class, :helper end end 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) #:nodoc: master_helper_module.module_eval "include #{helper_module}" end # Declare a helper: # 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 = arg.to_s.underscore + '_helper' class_name = file_name.camelize begin require_dependency(file_name) rescue LoadError => load_error requiree = / -- (.*?)(\.rb)?$/.match(load_error.message).to_a[1] msg = (requiree == file_name) ? "Missing helper file helpers/#{file_name}.rb" : "Can't load file: #{requiree}" raise LoadError.new(msg).copy_blame!(load_error) end add_template_helper(class_name.constantize) else raise ArgumentError, 'helper expects String, Symbol, or Module argument' end end # Evaluate block in template class if given. master_helper_module.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) methods.flatten.each do |method| master_helper_module.module_eval <<-end_eval def #{method}(*args, &block) controller.send!(%(#{method}), *args, &block) end end_eval end 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_with_helper(child) inherited_without_helper(child) begin child.master_helper_module = Module.new child.master_helper_module.send! :include, master_helper_module child.helper child.name.to_s.underscore rescue MissingSourceFile => e raise unless e.is_missing?("helpers/#{child.name.to_s.underscore}_helper") end end end private # Extend the template class instance with our controller's helper module. def initialize_template_class_with_helper(assigns) returning(template = initialize_template_class_without_helper(assigns)) do template.extend self.class.master_helper_module end end end end