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Improve documentation for ActionController::Helpers [jardeon] Closes #…

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git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7363 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
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1 parent 5cbc782 commit 43ef688d7405628972d72d4aa127b9d016feacaa @NZKoz NZKoz committed Aug 28, 2007
Showing with 73 additions and 26 deletions.
  1. +73 −26 actionpack/lib/action_controller/helpers.rb
@@ -18,27 +18,51 @@ class << self
end
end
- # The template helpers serve 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.
+ # The Rails framework provides a large number of helpers for working with +assets+, +dates+, +forms+,
+ # +numbers+ and <tt>Active Record objects</tt>, to name a few. These helpers are 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.
+ # 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.
#
- # module MyHelper
- # def hello_world() "hello world" end
+ # ==== 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="&nbsp;")
+ # time.blank? ? blank_message : time.to_s(format)
+ # end
# end
#
- # MyHelper can now be included in a controller, like this:
+ # +FormattedTimeHelper+ can now be included in a controller, using the +helper+ class method:
#
- # class MyController < ActionController::Base
- # helper :my_helper
+ # class EventsController < ActionController::Base
+ # helper FormattedTimeHelper
+ # def index
+ # @events = Event.find(:all)
+ # end
# end
#
- # ...and, same as above, used in any template rendered from MyController, like this:
+ # 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
#
- # 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
@@ -47,22 +71,41 @@ def add_template_helper(helper_module) #:nodoc:
master_helper_module.send(:include, helper_module)
end
- # Declare a helper:
+ # The +helper+ class method can take a series of helper module names, a block, or both.
#
- # helper :foo
- # requires 'foo_helper' and includes FooHelper in the template class.
+ # * <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
#
- # helper FooHelper
- # includes FooHelper in the template class.
+ # When the argument is a +Module+, it will be included directly in the template class.
+ # helper FooHelper # => includes FooHelper
#
- # helper { def foo() "#{bar} is the very best" end }
- # evaluates the block in the template class, adding method #foo.
+ # When the argument is the symbol <tt>:all</tt>, the controller will includes all helpers from
+ # <tt>app/views/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 invokved with a mix of
+ # +symbols+, +strings+, +modules+ and blocks.
# helper(:three, BlindHelper) { def mice() 'mice' end }
- # does all three.
#
- # helper :all
- # includes all helpers from app/views/helpers/**/*.rb under RAILS_ROOT
def helper(*args, &block)
args.flatten.each do |arg|
case arg
@@ -97,9 +140,13 @@ def helper(*args, &block)
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.
+ # class ApplicationController < ActionController::Base
+ # helper_method :current_user
+ # def current_user
+ # @current_user ||= User.find(session[:user])
+ # end
+ # end
+ # makes the +current_user+ controller method available in the view.
def helper_method(*methods)
methods.flatten.each do |method|
master_helper_module.module_eval <<-end_eval

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