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45137795e8
git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@990 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
101 lines
4 KiB
Ruby
101 lines
4 KiB
Ruby
module ActionController #:nodoc:
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module Helpers #:nodoc:
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def self.append_features(base)
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super
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base.class_eval { class << self; alias_method :inherited_without_helper, :inherited; end }
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base.extend(ClassMethods)
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end
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# The template helpers serves to relieve the templates from including the same inline code again and again. It's a
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# set of standardized methods for working with forms (FormHelper), dates (DateHelper), texts (TextHelper), and
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# Active Records (ActiveRecordHelper) that's available to all templates by default.
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#
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# It's also really easy to make your own helpers and it's much encouraged to keep the template files free
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# from complicated logic. It's even encouraged to bundle common compositions of methods from other helpers
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# (often the common helpers) as they're used by the specific application.
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#
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# module MyHelper
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# def hello_world() "hello world" end
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# end
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#
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# MyHelper can now be included in a controller, like this:
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#
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# class MyController < ActionController::Base
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# helper :my_helper
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# end
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#
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# ...and, same as above, used in any template rendered from MyController, like this:
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#
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# Let's hear what the helper has to say: <tt><%= hello_world %></tt>
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module ClassMethods
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# Makes all the (instance) methods in the helper module available to templates rendered through this controller.
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# See ActionView::Helpers (link:classes/ActionView/Helpers.html) for more about making your own helper modules
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# available to the templates.
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def add_template_helper(helper_module) #:nodoc:
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template_class.class_eval "include #{helper_module}"
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end
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# Declare a helper:
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# helper :foo
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# requires 'foo_helper' and includes FooHelper in the template class.
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# helper FooHelper
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# includes FooHelper in the template class.
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# helper { def foo() "#{bar} is the very best" end }
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# evaluates the block in the template class, adding method #foo.
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# helper(:three, BlindHelper) { def mice() 'mice' end }
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# does all three.
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def helper(*args, &block)
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args.flatten.each do |arg|
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case arg
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when Module
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add_template_helper(arg)
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when String, Symbol
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file_name = arg.to_s.underscore + '_helper'
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class_name = file_name.camelize
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begin
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require_dependency(file_name)
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rescue LoadError => load_error
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requiree = / -- (.*?)(\.rb)?$/.match(load_error).to_a[1]
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msg = (requiree == file_name) ? "Missing helper file helpers/#{file_name}.rb" : "Can't load file: #{requiree}"
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raise LoadError.new(msg).copy_blame!(load_error)
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end
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add_template_helper(class_name.constantize)
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else
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raise ArgumentError, 'helper expects String, Symbol, or Module argument'
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end
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end
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# Evaluate block in template class if given.
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template_class.module_eval(&block) if block_given?
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end
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# Declare a controller method as a helper. For example,
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# helper_method :link_to
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# def link_to(name, options) ... end
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# makes the link_to controller method available in the view.
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def helper_method(*methods)
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template_class.controller_delegate(*methods)
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end
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# Declare a controller attribute as a helper. For example,
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# helper_attr :name
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# attr_accessor :name
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# makes the name and name= controller methods available in the view.
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# The is a convenience wrapper for helper_method.
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def helper_attr(*attrs)
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attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") }
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end
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private
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def inherited(child)
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inherited_without_helper(child)
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begin child.helper(child.controller_path)
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rescue MissingSourceFile => e
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raise unless e.is_missing?("helpers/#{child.controller_path}_helper")
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end
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end
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end
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end
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end
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