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rails--rails/actionpack/lib/abstract_controller/callbacks.rb
Zachary Wasserman 9c6b3204d4 Add cancellation info to before filter docs
It is important for users to know that a render or redirect in a "before"
filter causes the action to be cancelled. This was addressed in the guide, but
not the API docs
(http://guides.rubyonrails.org/action_controller_overview.html#filters).

[ci skip]
2018-03-14 12:18:10 -07:00

224 lines
7.7 KiB
Ruby

# frozen_string_literal: true
module AbstractController
# = Abstract Controller Callbacks
#
# Abstract Controller provides hooks during the life cycle of a controller action.
# Callbacks allow you to trigger logic during this cycle. Available callbacks are:
#
# * <tt>after_action</tt>
# * <tt>append_after_action</tt>
# * <tt>append_around_action</tt>
# * <tt>append_before_action</tt>
# * <tt>around_action</tt>
# * <tt>before_action</tt>
# * <tt>prepend_after_action</tt>
# * <tt>prepend_around_action</tt>
# * <tt>prepend_before_action</tt>
# * <tt>skip_after_action</tt>
# * <tt>skip_around_action</tt>
# * <tt>skip_before_action</tt>
#
# NOTE: Calling the same callback multiple times will overwrite previous callback definitions.
#
module Callbacks
extend ActiveSupport::Concern
# Uses ActiveSupport::Callbacks as the base functionality. For
# more details on the whole callback system, read the documentation
# for ActiveSupport::Callbacks.
include ActiveSupport::Callbacks
included do
define_callbacks :process_action,
terminator: ->(controller, result_lambda) { result_lambda.call; controller.performed? },
skip_after_callbacks_if_terminated: true
end
# Override <tt>AbstractController::Base#process_action</tt> to run the
# <tt>process_action</tt> callbacks around the normal behavior.
def process_action(*args)
run_callbacks(:process_action) do
super
end
end
module ClassMethods
# If +:only+ or +:except+ are used, convert the options into the
# +:if+ and +:unless+ options of ActiveSupport::Callbacks.
#
# The basic idea is that <tt>:only => :index</tt> gets converted to
# <tt>:if => proc {|c| c.action_name == "index" }</tt>.
#
# Note that <tt>:only</tt> has priority over <tt>:if</tt> in case they
# are used together.
#
# only: :index, if: -> { true } # the :if option will be ignored.
#
# Note that <tt>:if</tt> has priority over <tt>:except</tt> in case they
# are used together.
#
# except: :index, if: -> { true } # the :except option will be ignored.
#
# ==== Options
# * <tt>only</tt> - The callback should be run only for this action.
# * <tt>except</tt> - The callback should be run for all actions except this action.
def _normalize_callback_options(options)
_normalize_callback_option(options, :only, :if)
_normalize_callback_option(options, :except, :unless)
end
def _normalize_callback_option(options, from, to) # :nodoc:
if from = options[from]
_from = Array(from).map(&:to_s).to_set
from = proc { |c| _from.include? c.action_name }
options[to] = Array(options[to]).unshift(from)
end
end
# Take callback names and an optional callback proc, normalize them,
# then call the block with each callback. This allows us to abstract
# the normalization across several methods that use it.
#
# ==== Parameters
# * <tt>callbacks</tt> - An array of callbacks, with an optional
# options hash as the last parameter.
# * <tt>block</tt> - A proc that should be added to the callbacks.
#
# ==== Block Parameters
# * <tt>name</tt> - The callback to be added.
# * <tt>options</tt> - A hash of options to be used when adding the callback.
def _insert_callbacks(callbacks, block = nil)
options = callbacks.extract_options!
_normalize_callback_options(options)
callbacks.push(block) if block
callbacks.each do |callback|
yield callback, options
end
end
##
# :method: before_action
#
# :call-seq: before_action(names, block)
#
# Append a callback before actions. See _insert_callbacks for parameter details.
#
# If the callback renders or redirects, the action will not run. If there
# are additional callbacks scheduled to run after that callback, they are
# also cancelled.
##
# :method: prepend_before_action
#
# :call-seq: prepend_before_action(names, block)
#
# Prepend a callback before actions. See _insert_callbacks for parameter details.
#
# If the callback renders or redirects, the action will not run. If there
# are additional callbacks scheduled to run after that callback, they are
# also cancelled.
##
# :method: skip_before_action
#
# :call-seq: skip_before_action(names)
#
# Skip a callback before actions. See _insert_callbacks for parameter details.
##
# :method: append_before_action
#
# :call-seq: append_before_action(names, block)
#
# Append a callback before actions. See _insert_callbacks for parameter details.
#
# If the callback renders or redirects, the action will not run. If there
# are additional callbacks scheduled to run after that callback, they are
# also cancelled.
##
# :method: after_action
#
# :call-seq: after_action(names, block)
#
# Append a callback after actions. See _insert_callbacks for parameter details.
##
# :method: prepend_after_action
#
# :call-seq: prepend_after_action(names, block)
#
# Prepend a callback after actions. See _insert_callbacks for parameter details.
##
# :method: skip_after_action
#
# :call-seq: skip_after_action(names)
#
# Skip a callback after actions. See _insert_callbacks for parameter details.
##
# :method: append_after_action
#
# :call-seq: append_after_action(names, block)
#
# Append a callback after actions. See _insert_callbacks for parameter details.
##
# :method: around_action
#
# :call-seq: around_action(names, block)
#
# Append a callback around actions. See _insert_callbacks for parameter details.
##
# :method: prepend_around_action
#
# :call-seq: prepend_around_action(names, block)
#
# Prepend a callback around actions. See _insert_callbacks for parameter details.
##
# :method: skip_around_action
#
# :call-seq: skip_around_action(names)
#
# Skip a callback around actions. See _insert_callbacks for parameter details.
##
# :method: append_around_action
#
# :call-seq: append_around_action(names, block)
#
# Append a callback around actions. See _insert_callbacks for parameter details.
# set up before_action, prepend_before_action, skip_before_action, etc.
# for each of before, after, and around.
[:before, :after, :around].each do |callback|
define_method "#{callback}_action" do |*names, &blk|
_insert_callbacks(names, blk) do |name, options|
set_callback(:process_action, callback, name, options)
end
end
define_method "prepend_#{callback}_action" do |*names, &blk|
_insert_callbacks(names, blk) do |name, options|
set_callback(:process_action, callback, name, options.merge(prepend: true))
end
end
# Skip a before, after or around callback. See _insert_callbacks
# for details on the allowed parameters.
define_method "skip_#{callback}_action" do |*names|
_insert_callbacks(names) do |name, options|
skip_callback(:process_action, callback, name, options)
end
end
# *_action is the same as append_*_action
alias_method :"append_#{callback}_action", :"#{callback}_action"
end
end
end
end