1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
require 'active_support/dependencies'
module AbstractController
module Helpers
extend ActiveSupport::Concern
include RenderingController
def self.next_serial
@helper_serial ||= 0
@helper_serial += 1
end
included do
extlib_inheritable_accessor(:_helpers) { Module.new }
extlib_inheritable_accessor(:_helper_serial) do
AbstractController::Helpers.next_serial
end
end
module ClassMethods
# When a class is inherited, wrap its helper module in a new module.
# This ensures that the parent class's module can be changed
# independently of the child class's.
def inherited(klass)
helpers = _helpers
klass._helpers = Module.new { include helpers }
super
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 -%>
#
# ==== Parameters
# meths<Array[#to_s]>:: The name of a method on the controller
# to be made available on the view.
def helper_method(*meths)
meths.flatten.each do |meth|
_helpers.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1
def #{meth}(*args, &blk)
controller.send(%(#{meth}), *args, &blk)
end
ruby_eval
end
end
# The +helper+ class method can take a series of helper module names, a block, or both.
#
# ==== Parameters
# *args<Array[Module, Symbol, String, :all]>
# block<Block>:: A block defining helper methods
#
# ==== Examples
# When the argument is a module it will be included directly in the template class.
# helper FooHelper # => includes FooHelper
#
# 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
#
# 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)
self._helper_serial = AbstractController::Helpers.next_serial + 1
_modules_for_helpers(args).each do |mod|
add_template_helper(mod)
end
_helpers.module_eval(&block) if block_given?
end
private
# Makes all the (instance) methods in the helper module available to templates
# rendered through this controller.
#
# ==== Parameters
# mod<Module>:: The module to include into the current helper module
# for the class
def add_template_helper(mod)
_helpers.module_eval { include mod }
end
# Returns a list of modules, normalized from the acceptable kinds of
# helpers with the following behavior:
#
# String or Symbol:: :FooBar or "FooBar" becomes "foo_bar_helper",
# and "foo_bar_helper.rb" is loaded using require_dependency.
#
# Module:: No further processing
#
# After loading the appropriate files, the corresponding modules
# are returned.
#
# ==== Parameters
# args<Array[String, Symbol, Module]>:: A list of helpers
#
# ==== Returns
# Array[Module]:: A normalized list of modules for the list of
# helpers provided.
def _modules_for_helpers(args)
args.flatten.map! do |arg|
case arg
when String, Symbol
file_name = "#{arg.to_s.underscore}_helper"
require_dependency(file_name, "Missing helper file helpers/%s.rb")
file_name.camelize.constantize
when Module
arg
else
raise ArgumentError, "helper must be a String, Symbol, or Module"
end
end
end
end
end
end
|
