require "action_controller/log_subscriber"
module ActionController
# Action Controllers are the core of a web request in \Rails. They are made up of one or more actions that are executed
# on request and then either render a template or redirect to another action. An action is defined as a public method
# on the controller, which will automatically be made accessible to the web-server through \Rails Routes.
#
# By default, only the ApplicationController in a \Rails application inherits from <tt>ActionController::Base</tt>. All other
# controllers in turn inherit from ApplicationController. This gives you one class to configure things such as
# request forgery protection and filtering of sensitive request parameters.
#
# A sample controller could look like this:
#
# class PostsController < ApplicationController
# def index
# @posts = Post.all
# end
#
# def create
# @post = Post.create params[:post]
# redirect_to posts_path
# end
# end
#
# Actions, by default, render a template in the <tt>app/views</tt> directory corresponding to the name of the controller and action
# after executing code in the action. For example, the +index+ action of the PostsController would render the
# template <tt>app/views/posts/index.html.erb</tt> by default after populating the <tt>@posts</tt> instance variable.
#
# Unlike index, the create action will not render a template. After performing its main purpose (creating a
# new post), it initiates a redirect instead. This redirect works by returning an external
# "302 Moved" HTTP response that takes the user to the index action.
#
# These two methods represent the two basic action archetypes used in Action Controllers. Get-and-show and do-and-redirect.
# Most actions are variations on these themes.
#
# == Requests
#
# For every request, the router determines the value of the +controller+ and +action+ keys. These determine which controller
# and action are called. The remaining request parameters, the session (if one is available), and the full request with
# all the HTTP headers are made available to the action through accessor methods. Then the action is performed.
#
# The full request object is available via the request accessor and is primarily used to query for HTTP headers:
#
# def server_ip
# location = request.env["SERVER_ADDR"]
# render :text => "This server hosted at #{location}"
# end
#
# == Parameters
#
# All request parameters, whether they come from a GET or POST request, or from the URL, are available through the params method
# which returns a hash. For example, an action that was performed through <tt>/posts?category=All&limit=5</tt> will include
# <tt>{ "category" => "All", "limit" => "5" }</tt> in params.
#
# It's also possible to construct multi-dimensional parameter hashes by specifying keys using brackets, such as:
#
# <input type="text" name="post[name]" value="david">
# <input type="text" name="post[address]" value="hyacintvej">
#
# A request stemming from a form holding these inputs will include <tt>{ "post" => { "name" => "david", "address" => "hyacintvej" } }</tt>.
# If the address input had been named "post[address][street]", the params would have included
# <tt>{ "post" => { "address" => { "street" => "hyacintvej" } } }</tt>. There's no limit to the depth of the nesting.
#
# == Sessions
#
# Sessions allow you to store objects in between requests. This is useful for objects that are not yet ready to be persisted,
# such as a Signup object constructed in a multi-paged process, or objects that don't change much and are needed all the time, such
# as a User object for a system that requires login. The session should not be used, however, as a cache for objects where it's likely
# they could be changed unknowingly. It's usually too much work to keep it all synchronized -- something databases already excel at.
#
# You can place objects in the session by using the <tt>session</tt> method, which accesses a hash:
#
# session[:person] = Person.authenticate(user_name, password)
#
# And retrieved again through the same hash:
#
# Hello #{session[:person]}
#
# For removing objects from the session, you can either assign a single key to +nil+:
#
# # removes :person from session
# session[:person] = nil
#
# or you can remove the entire session with +reset_session+.
#
# Sessions are stored by default in a browser cookie that's cryptographically signed, but unencrypted.
# This prevents the user from tampering with the session but also allows him to see its contents.
#
# Do not put secret information in cookie-based sessions!
#
# == Responses
#
# Each action results in a response, which holds the headers and document to be sent to the user's browser. The actual response
# object is generated automatically through the use of renders and redirects and requires no user intervention.
#
# == Renders
#
# Action Controller sends content to the user by using one of five rendering methods. The most versatile and common is the rendering
# of a template. Included in the Action Pack is the Action View, which enables rendering of ERB templates. It's automatically configured.
# The controller passes objects to the view by assigning instance variables:
#
# def show
# @post = Post.find(params[:id])
# end
#
# Which are then automatically available to the view:
#
# Title: <%= @post.title %>
#
# You don't have to rely on the automated rendering. For example, actions that could result in the rendering of different templates
# will use the manual rendering methods:
#
# def search
# @results = Search.find(params[:query])
# case @results.count
# when 0 then render :action => "no_results"
# when 1 then render :action => "show"
# when 2..10 then render :action => "show_many"
# end
# end
#
# Read more about writing ERB and Builder templates in ActionView::Base.
#
# == Redirects
#
# Redirects are used to move from one action to another. For example, after a <tt>create</tt> action, which stores a blog entry to the
# database, we might like to show the user the new entry. Because we're following good DRY principles (Don't Repeat Yourself), we're
# going to reuse (and redirect to) a <tt>show</tt> action that we'll assume has already been created. The code might look like this:
#
# def create
# @entry = Entry.new(params[:entry])
# if @entry.save
# # The entry was saved correctly, redirect to show
# redirect_to :action => 'show', :id => @entry.id
# else
# # things didn't go so well, do something else
# end
# end
#
# In this case, after saving our new entry to the database, the user is redirected to the <tt>show</tt> method, which is then executed.
# Note that this is an external HTTP-level redirection which will cause the browser to make a second request (a GET to the show action),
# and not some internal re-routing which calls both "create" and then "show" within one request.
#
# Learn more about <tt>redirect_to</tt> and what options you have in ActionController::Redirecting.
#
# == Calling multiple redirects or renders
#
# An action may contain only a single render or a single redirect. Attempting to try to do either again will result in a DoubleRenderError:
#
# def do_something
# redirect_to :action => "elsewhere"
# render :action => "overthere" # raises DoubleRenderError
# end
#
# If you need to redirect on the condition of something, then be sure to add "and return" to halt execution.
#
# def do_something
# redirect_to(:action => "elsewhere") and return if monkeys.nil?
# render :action => "overthere" # won't be called if monkeys is nil
# end
#
class Base < Metal
abstract!
# Shortcut helper that returns all the ActionController::Base modules except the ones passed in the argument:
#
# class MetalController
# ActionController::Base.without_modules(:ParamsWrapper, :Streaming).each do |left|
# include left
# end
# end
#
# This gives better control over what you want to exclude and makes it easier
# to create a bare controller class, instead of listing the modules required manually.
def self.without_modules(*modules)
modules = modules.map do |m|
m.is_a?(Symbol) ? ActionController.const_get(m) : m
end
MODULES - modules
end
MODULES = [
AbstractController::Layouts,
AbstractController::Translation,
AbstractController::AssetPaths,
Helpers,
HideActions,
UrlFor,
Redirecting,
Rendering,
Renderers::All,
ConditionalGet,
RackDelegation,
Caching,
MimeResponds,
ImplicitRender,
StrongParameters,
Cookies,
Flash,
RequestForgeryProtection,
ForceSSL,
Streaming,
DataStreaming,
RecordIdentifier,
HttpAuthentication::Basic::ControllerMethods,
HttpAuthentication::Digest::ControllerMethods,
HttpAuthentication::Token::ControllerMethods,
# Before callbacks should also be executed the earliest as possible, so
# also include them at the bottom.
AbstractController::Callbacks,
# Append rescue at the bottom to wrap as much as possible.
Rescue,
# Add instrumentations hooks at the bottom, to ensure they instrument
# all the methods properly.
Instrumentation,
# Params wrapper should come before instrumentation so they are
# properly showed in logs
ParamsWrapper
]
MODULES.each do |mod|
include mod
end
# Define some internal variables that should not be propagated to the view.
self.protected_instance_variables = [
:@_status, :@_headers, :@_params, :@_env, :@_response, :@_request,
:@_view_runtime, :@_stream, :@_url_options, :@_action_has_layout
]
ActiveSupport.run_load_hooks(:action_controller, self)
end
end
