Clears up all existing helpers in this class, only keeping the helper with the same name as this class.
# File lib/abstract_controller/helpers.rb, line 104 104: def clear_helpers 105: inherited_helper_methods = _helper_methods 106: self._helpers = Module.new 107: self._helper_methods = Array.new 108: 109: inherited_helper_methods.each { |meth| helper_method meth } 110: default_helper_module! unless anonymous? 111: end
The helper class method can take a series of helper module names, a block, or both.
*args - Module, Symbol, String, :all
block - A block defining helper methods
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 }
# File lib/abstract_controller/helpers.rb, line 94 94: def helper(*args, &block) 95: modules_for_helpers(args).each do |mod| 96: add_template_helper(mod) 97: end 98: 99: _helpers.module_eval(&block) if block_given? 100: 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 -%>
method[, method] - A name or names of a method on the controller to be made available on the view.
# File lib/abstract_controller/helpers.rb, line 46 46: def helper_method(*meths) 47: meths.flatten! 48: self._helper_methods += meths 49: 50: meths.each do |meth| 51: _helpers.class_eval def #{meth}(*args, &blk) controller.send(%(#{meth}), *args, &blk) end, __FILE__, __LINE__ + 1 52: end 53: end
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.
# File lib/abstract_controller/helpers.rb, line 19 19: def inherited(klass) 20: helpers = _helpers 21: klass._helpers = Module.new { include helpers } 22: klass.class_eval { default_helper_module! unless anonymous? } 23: super 24: 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.
args - An array of helpers
Array - A normalized list of modules for the list of helpers provided.
# File lib/abstract_controller/helpers.rb, line 130 130: def modules_for_helpers(args) 131: args.flatten.map! do |arg| 132: case arg 133: when String, Symbol 134: file_name = "#{arg.to_s.underscore}_helper" 135: require_dependency(file_name, "Missing helper file helpers/%s.rb") 136: file_name.camelize.constantize 137: when Module 138: arg 139: else 140: raise ArgumentError, "helper must be a String, Symbol, or Module" 141: end 142: end 143: end
Makes all the (instance) methods in the helper module available to templates rendered through this controller.
module - The module to include into the current helper module for the class
# File lib/abstract_controller/helpers.rb, line 152 152: def add_template_helper(mod) 153: _helpers.module_eval { include mod } 154: end
# File lib/abstract_controller/helpers.rb, line 156 156: def default_helper_module! 157: module_name = name.sub(/Controller$/, '') 158: module_path = module_name.underscore 159: helper module_path 160: rescue MissingSourceFile => e 161: raise e unless e.is_missing? "helpers/#{module_path}_helper" 162: rescue NameError => e 163: raise e unless e.missing_name? "#{module_name}Helper" 164: end
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