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Diffstat (limited to 'actionpack/lib/action_controller/base/helpers.rb')
| -rw-r--r-- | actionpack/lib/action_controller/base/helpers.rb | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/base/helpers.rb b/actionpack/lib/action_controller/base/helpers.rb new file mode 100644 index 0000000000..ba65032f6a --- /dev/null +++ b/actionpack/lib/action_controller/base/helpers.rb @@ -0,0 +1,225 @@ +require 'active_support/dependencies' + +# FIXME: helper { ... } is broken on Ruby 1.9 +module ActionController #:nodoc: + module Helpers #:nodoc: + 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 + + # Set the default directory for helpers + base.class_inheritable_accessor :helpers_dir + base.helpers_dir = (defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/app/helpers" : "app/helpers") + + # 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 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 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)?$/.match(load_error.message).to_a[1] + if requiree == file_name + msg = "Missing helper file helpers/#{file_name}.rb" + raise LoadError.new(msg).copy_blame!(load_error) + else + raise + end + end + + add_template_helper(class_name.constantize) + else + raise ArgumentError, "helper expects String, Symbol, or Module argument (was: #{args.inspect})" + end + end + + # Evaluate block in template class if given. + master_helper_module.module_eval(&block) if block_given? + end + + # Declare a controller method as a helper. For example, the following + # makes the +current_user+ controller method available to the view: + # class ApplicationController < ActionController::Base + # helper_method :current_user, :logged_in? + # + # def current_user + # @current_user ||= User.find_by_id(session[:user]) + # end + # + # def logged_in? + # current_user != nil + # end + # end + # + # In a view: + # <% if logged_in? -%>Welcome, <%= current_user.name %><% end -%> + def helper_method(*methods) + methods.flatten.each do |method| + master_helper_module.module_eval <<-end_eval + def #{method}(*args, &block) # def current_user(*args, &block) + controller.send(%(#{method}), *args, &block) # controller.send(%(current_user), *args, &block) + end # end + end_eval + end + end + + # Declares helper accessors for controller attributes. For example, the + # following adds new +name+ and <tt>name=</tt> instance methods to a + # controller and makes them available to the view: + # helper_attr :name + # attr_accessor :name + def helper_attr(*attrs) + attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") } + end + + # Provides a proxy to access helpers methods from outside the view. + def helpers + unless @helper_proxy + @helper_proxy = ActionView::Base.new + @helper_proxy.extend master_helper_module + else + @helper_proxy + end + end + + private + def default_helper_module! + unless name.blank? + module_name = name.sub(/Controller$|$/, 'Helper') + module_path = module_name.split('::').map { |m| m.underscore }.join('/') + require_dependency module_path + helper module_name.constantize + end + rescue MissingSourceFile => e + raise unless e.is_missing? module_path + rescue NameError => e + raise unless e.missing_name? module_name + end + + def inherited_with_helper(child) + inherited_without_helper(child) + + begin + child.master_helper_module = Module.new + child.master_helper_module.__send__ :include, master_helper_module + child.__send__ :default_helper_module! + rescue MissingSourceFile => e + raise unless e.is_missing?("helpers/#{child.controller_path}_helper") + end + end + + # Extract helper names from files in app/helpers/**/*.rb + def all_application_helpers + extract = /^#{Regexp.quote(helpers_dir)}\/?(.*)_helper.rb$/ + Dir["#{helpers_dir}/**/*_helper.rb"].map { |file| file.sub extract, '\1' } + end + end + end +end |