# Allow your controllers to inherit their views from parent controllers, or from
# specified view paths.
#
# === Example
#
# class FooController < ApplicationController
# inherit_views
# end
#
# class BarController < FooController
# ... # will look for views in 'views/bar' and 'views/foo'
# end
#
# In the example above, If BarController, or any of the views in views/bar, renders 'bar/view'
# and it is not found then 'foo/view' is rendered (if it can be found)
#
# You can also specify an inherit path other than the default (it does not have to be the default controller path)
# If your controller inherits from a controller with inherit_views then that controller
# gets the inherited view paths as well.
#
# class FooController < ApplicationController
# inherit_views 'far', 'faz' # will look for views in 'foo', then 'far', then 'faz'
# end
#
# class BarController < FooController
# # will look for views in 'bar', 'foo', 'far', 'faz'
# end
#
# If you want to turn off inherited views for a controller that has inherit_views in its
# ancestors use self.inherit_views=
#
# class BarController < FooController
# self.inherit_views = false
# end
#
# You can completely override the inherited view paths in a subclass controller using
# inherit_view_paths=
#
# class BarController < FooController
# self.inherit_view_paths = ['you_can_go', 'your_own_way']
# # will look for views in 'bar', 'you_can_go', and 'your_own_way'
# # (not 'far' or 'faz' from FooController)
# end
module InheritViews
# class extension which enables specification of inherit_views
module ActMethod
# Specify this to have your controller or mailer inherit its views from the specified path
# or the current controller/mailer's default path if no argument is given
def inherit_views(*paths)
class_eval do
extend PathsContainer unless respond_to?(:inherit_views_paths)
self.inherit_views = true
self.inherit_view_paths = paths if paths.any?
end
end
end
# class extension that enables inherit_view_paths to be calculated/set
#
# requires a class method called 'controller_path' (ActionController::Base & ActionMailer::Base have this)
module PathsContainer
def self.extended(base)
base.class_eval do
delegate :inherit_views?, :inherit_view_paths, :to => 'self.class'
end
end
# Return true if the class is inheriting views
def inherit_views?
read_inheritable_attribute('inherit_views') ? true : false
end
# Instruct the class that it is, or is not, inheriting views
def inherit_views=(bool)
write_inheritable_attribute('inherit_views', bool)
end
# Return the inherit view paths, in order of self to ancestor.
# Takes inherit_view_paths from the superclass when first read, and prepends the current controller_path
def inherit_view_paths
instance_variable_get('@inherit_view_paths') || instance_variable_set('@inherit_view_paths', [controller_path] + (superclass.inherit_view_paths rescue []))
end
# Set the inherit view paths, in order of self to ancestor.
# The controller_path for self is always prepended to the front, no matter what the arguments.
def inherit_view_paths=(new_paths)
new_paths -= [controller_path]
old_paths = inherit_view_paths - [controller_path] - new_paths
instance_variable_set('@inherit_view_paths', [controller_path] + new_paths + old_paths)
end
end
# just like a normal path set, but can have an optional array of inherit_view_paths
# which will be used to look for a matching template if the original template is missing
class PathSet < ::ActionView::PathSet
attr_accessor :inherit_view_paths
alias_method :orig_find_template, :find_template
# look for a parent template if a standard one can't be found
def find_template(template_path, format = nil, html_fallback = true)
super
rescue ::ActionView::MissingTemplate
find_parent_template(template_path, format)
end
# given a template_path and format, returns a parent template, or raise ActionView::MissingTemplate
def find_parent_template(template_path, format = nil, html_fallback = true)
# first, we grab the inherit view paths that are 'above' the given template_path
if inherit_view_paths.present? && (starting_path = inherit_view_paths.detect {|path| template_path.starts_with?("#{path}/")})
parent_paths = inherit_view_paths.slice(inherit_view_paths.index(starting_path)+1..-1)
# then, search through each path, substituting the inherit view path, returning the first found
parent_paths.each do |path|
begin
return orig_find_template(template_path.sub(/^#{starting_path}/, path), format, html_fallback)
rescue ::ActionView::MissingTemplate
next
end
end
end
raise ::ActionView::MissingTemplate.new(self, template_path, format)
end
end
# Mixin for ActionView::Base to enable inherit views functionality. There are two
# enhancements
#
# * view_paths are set to an InheritViews::PathSet object, and any inherit_view_paths
# are passed from the view's controller to the view_paths
#
# * render is extended to include support for render :parent, see render_with_parent
module ActionView
def self.included(base)
base.class_eval do
def self.process_view_paths(value)
InheritViews::PathSet.new(Array(value))
end
alias_method_chain :view_paths=, :inherit_views
alias_method_chain :render, :parent
end
end
# set the view_paths, and afterwards pass it my controller's inherit_view_paths
def view_paths_with_inherit_views=(value)
returning self.view_paths_without_inherit_views=(value) do
@view_paths.inherit_view_paths = controller.inherit_view_paths if (controller.inherit_views? rescue false)
end
end
# Extension for render which enables the following (in partials as well as top-level tenplates)
#
# <%= render :parent %>
# <%= render :parent, :locals => {:foo => @foo} %>
#
# These calls will render the template that is 'above' the current template according to the#
# current controller's inherit_view_paths.
def render_with_parent(*args, &block)
if args.first == :parent
args.shift
args.first[:file] = view_paths.find_parent_template(template.to_s, template.format)
end
render_without_parent(*args, &block)
end
end
end
