--- /dev/null
+# FIXME: helper { ... } is broken on Ruby 1.9
+module ActionController #:nodoc:
+ module Helpers #:nodoc:
+ HELPERS_DIR = (defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/app/helpers" : "app/helpers")
+
+ def self.included(base)
+ # 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
+ end
+ end
+
+ # The Rails framework provides a large number of helpers for working with +assets+, +dates+, +forms+,
+ # +numbers+ and Active Record objects, to name a few. These helpers are available to all templates
+ # by default.
+ #
+ # In addition to using the standard template helpers provided in the Rails framework, creating custom helpers to
+ # extract complicated logic or reusable functionality is strongly encouraged. By default, the controller will
+ # include a helper whose name matches that of the controller, e.g., <tt>MyController</tt> will automatically
+ # include <tt>MyHelper</tt>.
+ #
+ # Additional helpers can be specified using the +helper+ class method in <tt>ActionController::Base</tt> or any
+ # controller which inherits from it.
+ #
+ # ==== Examples
+ # The +to_s+ method from the Time class can be wrapped in a helper method to display a custom message if
+ # the Time object is blank:
+ #
+ # module FormattedTimeHelper
+ # def format_time(time, format=:long, blank_message=" ")
+ # time.blank? ? blank_message : time.to_s(format)
+ # end
+ # end
+ #
+ # FormattedTimeHelper can now be included in a controller, using the +helper+ class method:
+ #
+ # class EventsController < ActionController::Base
+ # helper FormattedTimeHelper
+ # def index
+ # @events = Event.find(:all)
+ # end
+ # end
+ #
+ # Then, in any view rendered by <tt>EventController</tt>, the <tt>format_time</tt> method can be called:
+ #
+ # <% @events.each do |event| -%>
+ # <p>
+ # <% format_time(event.time, :short, "N/A") %> | <%= event.name %>
+ # </p>
+ # <% end -%>
+ #
+ # Finally, assuming we have two event instances, one which has a time and one which does not,
+ # the output might look like this:
+ #
+ # 23 Aug 11:30 | Carolina Railhawks Soccer Match
+ # N/A | Carolina Railhaws Training Workshop
+ #
+ 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
+
+ # 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 from
+ # <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 Module
+ add_template_helper(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)?$/.match(load_error.message).to_a[1]
+ if requiree == file_name
+ msg = "Missing helper file helpers/#{file_name}.rb"
+ raise LoadError.new(msg).copy_blame!(load_error)
+ else
+ raise
+ end
+ end
+
+ add_template_helper(class_name.constantize)
+ else
+ raise ArgumentError, "helper expects String, Symbol, or Module argument (was: #{args.inspect})"
+ end
+ end
+
+ # Evaluate block in template class if given.
+ master_helper_module.module_eval(&block) if block_given?
+ end
+
+ # Declare a controller method as a helper. For example, the following
+ # makes the +current_user+ controller method available to the view:
+ # class ApplicationController < ActionController::Base
+ # helper_method :current_user, :logged_in?
+ #
+ # def current_user
+ # @current_user ||= User.find_by_id(session[:user])
+ # end
+ #
+ # def logged_in?
+ # current_user != nil
+ # end
+ # end
+ #
+ # In a view:
+ # <% if logged_in? -%>Welcome, <%= current_user.name %><% end -%>
+ def helper_method(*methods)
+ methods.flatten.each do |method|
+ master_helper_module.module_eval <<-end_eval
+ def #{method}(*args, &block)
+ controller.send(%(#{method}), *args, &block)
+ end
+ end_eval
+ end
+ end
+
+ # Declares helper accessors for controller attributes. For example, the
+ # following adds new +name+ and <tt>name=</tt> instance methods to a
+ # controller and makes them available to the view:
+ # helper_attr :name
+ # attr_accessor :name
+ def helper_attr(*attrs)
+ attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") }
+ end
+
+ # Provides a proxy to access helpers methods from outside the view.
+ def helpers
+ unless @helper_proxy
+ @helper_proxy = ActionView::Base.new
+ @helper_proxy.extend master_helper_module
+ else
+ @helper_proxy
+ end
+ end
+
+ private
+ def default_helper_module!
+ unless name.blank?
+ module_name = name.sub(/Controller$|$/, 'Helper')
+ module_path = module_name.split('::').map { |m| m.underscore }.join('/')
+ require_dependency module_path
+ helper module_name.constantize
+ end
+ rescue MissingSourceFile => e
+ raise unless e.is_missing? module_path
+ rescue NameError => e
+ raise unless e.missing_name? module_name
+ end
+
+ def inherited_with_helper(child)
+ inherited_without_helper(child)
+
+ begin
+ child.master_helper_module = Module.new
+ child.master_helper_module.__send__ :include, master_helper_module
+ child.__send__ :default_helper_module!
+ rescue MissingSourceFile => e
+ raise unless e.is_missing?("helpers/#{child.controller_path}_helper")
+ end
+ end
+
+ # Extract helper names from files in app/helpers/**/*.rb
+ def all_application_helpers
+ extract = /^#{Regexp.quote(HELPERS_DIR)}\/?(.*)_helper.rb$/
+ Dir["#{HELPERS_DIR}/**/*_helper.rb"].map { |file| file.sub extract, '\1' }
+ end
+ end
+ end
+end
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