require 'active_support/core_ext/load_error'
require 'active_support/core_ext/name_error'
require 'active_support/dependencies'
module ActionController
module Helpers
extend ActiveSupport::DependencyModule
depends_on AbstractController::Helpers
included do
# Set the default directory for helpers
class_inheritable_accessor :helpers_dir
self.helpers_dir = (defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/app/helpers" : "app/helpers")
end
module ClassMethods
def inherited(klass)
klass.__send__ :default_helper_module!
super
end
# The +helper+ class method can take a series of helper module names, a block, or both.
#
# * <tt>*args</tt>: One or more modules, strings or symbols, or the special symbol <tt>:all</tt>.
# * <tt>&block</tt>: A block defining helper methods.
#
# ==== Examples
# When the argument is a string or symbol, the method will provide the "_helper" suffix, require the file
# and include the module in the template class. The second form illustrates how to include custom helpers
# when working with namespaced controllers, or other cases where the file containing the helper definition is not
# in one of Rails' standard load paths:
# helper :foo # => requires 'foo_helper' and includes FooHelper
# helper 'resources/foo' # => requires 'resources/foo_helper' and includes Resources::FooHelper
#
# When the argument is a module it will be included directly in the template class.
# helper FooHelper # => includes FooHelper
#
# When the argument is the symbol <tt>:all</tt>, the controller will include all helpers beneath
# <tt>ActionController::Base.helpers_dir</tt> (defaults to <tt>app/helpers/**/*.rb</tt> under RAILS_ROOT).
# helper :all
#
# Additionally, the +helper+ class method can receive and evaluate a block, making the methods defined available
# to the template.
# # One line
# helper { def hello() "Hello, world!" end }
# # Multi-line
# helper do
# def foo(bar)
# "#{bar} is the very best"
# end
# end
#
# Finally, all the above styles can be mixed together, and the +helper+ method can be invoked with a mix of
# +symbols+, +strings+, +modules+ and blocks.
# helper(:three, BlindHelper) { def mice() 'mice' end }
#
def helper(*args, &block)
args.flatten.each do |arg|
case arg
when :all
helper all_application_helpers
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)?$/.match(load_error.message).to_a[1]
if requiree == file_name
msg = "Missing helper file helpers/#{file_name}.rb"
raise LoadError.new(msg).copy_blame!(load_error)
else
raise
end
end
super class_name.constantize
else
super args
end
end
# Evaluate block in template class if given.
master_helper_module.module_eval(&block) if block_given?
end
# Declares helper accessors for controller attributes. For example, the
# following adds new +name+ and <tt>name=</tt> instance methods to a
# controller and makes them available to the view:
# helper_attr :name
# attr_accessor :name
def helper_attr(*attrs)
attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") }
end
# Provides a proxy to access helpers methods from outside the view.
def helpers
unless @helper_proxy
@helper_proxy = ActionView::Base.new
@helper_proxy.extend master_helper_module
else
@helper_proxy
end
end
private
def default_helper_module!
unless name.blank?
module_name = name.sub(/Controller$|$/, 'Helper')
module_path = module_name.split('::').map { |m| m.underscore }.join('/')
require_dependency module_path
helper module_name.constantize
end
rescue MissingSourceFile => e
raise unless e.is_missing? module_path
rescue NameError => e
raise unless e.missing_name? module_name
end
# Extract helper names from files in app/helpers/**/*.rb
def all_application_helpers
extract = /^#{Regexp.quote(helpers_dir)}\/?(.*)_helper.rb$/
Dir["#{helpers_dir}/**/*_helper.rb"].map { |file| file.sub extract, '\1' }
end
end # ClassMethods
end
end
