Controll
¶ ↑
Some nice and nifty utilities to help you manage complex controller logic.
Requirements¶ ↑
This gem is designed for Rails 3+ and currently only supports (has been tested with) Ruby 1.9+. The gem is under development but stable releases will be pushed to rubygems. Note that older versions may not support the same API described in the README. Go back in history and/or browse the code for that specific version.
Enjoy :)
Install¶ ↑
in Gemfile:
gem 'imperator-ext' gem 'controll'
Bundle it!
$ bundle
Usage: See below, incl. the Generators section ;)
Background¶ ↑
This gem contains logic extracted from my oauth_assist gem (and engine) which was a response to this article oauth pure tutorial.
Note that the oauth_assist gem is not yet fully functional and done, as it “awaits” a stable release of this gem. Please feel free to help out in this effort!
Justification¶ ↑
As you can see, the following #create
REST action is a nightmare of complexity and flow control leading to various different flash messages and redirect/render depending on various outcomes…
Then I naturally thought: There MUST be a better way!
def create # get the service parameter from the Rails router params[:service] ? service_route = params[:service] : service_route = 'No service recognized (invalid callback)' # get the full hash from omniauth omniauth = request.env['omniauth.auth'] # continue only if hash and parameter exist if omniauth and params[:service] # map the returned hashes to our variables first - the hashes differs for every service # create a new hash @authhash = Hash.new extract_auth_data! if unknown_auth? # debug to output the hash that has been returned when adding new services render :text => omniauth.to_yaml return end if @authhash[:uid] != '' and @authhash[:provider] != '' auth = Service.find_by_provider_and_uid(@authhash[:provider], @authhash[:uid]) # if the user is currently signed in, he/she might want to add another account to signin if user_signed_in? if auth flash[:notice] = 'Your account at ' + @authhash[:provider].capitalize + ' is already connected with this site.' redirect_to services_path else current_user.services.create!(:provider => @authhash[:provider], :uid => @authhash[:uid], :uname => @authhash[:name], :uemail => @authhash[:email]) flash[:notice] = 'Your ' + @authhash[:provider].capitalize + ' account has been added for signing in at this site.' redirect_to services_path end else if auth # signin existing user # in the session his user id and the service id used for signing in is stored session[:user_id] = auth.user.id session[:service_id] = auth.id flash[:notice] = 'Signed in successfully via ' + @authhash[:provider].capitalize + '.' redirect_to root_url else # this is a new user; show signup; @authhash is available to the view and stored in the sesssion for creation of a new user session[:authhash] = @authhash render signup_services_path end end else flash[:error] = 'Error while authenticating via ' + service_route + '/' + @authhash[:provider].capitalize + '. The service returned invalid data for the user id.' redirect_to signin_path end else flash[:error] = 'Error while authenticating via ' + service_route.capitalize + '. The service did not return valid data.' redirect_to signin_path end end
Using the tools contained in controll
the above logic can be encapsulated like this:
class ServicesController < ApplicationController include Controll::Enabler def create execute # action.perform end end
A Flow
can use Executors
to encapsulate execution logic, which again can execute Commands that encapsulate business logic related to the user Session or models (data).
The Flow takes the last event on the event stack and consults the ActionPaths registered, usually a Redirecter and Renderer. An ActionPath is a type of Action which can return a path. The Flow initiates an Executor which iterates the ActionPaths to find the first one which can match the event.
The first one with a match is returned as the Action, which the controller can then perform in order to either render or redirect.
If none of the ActionPaths can match the event, a Fallback Action is returned. The controller should then be configured to handle a Fallback Action appropriately.
Controll
has built in Notification Management which work both for flash messages (or other types of notifications) and as return codes for use in flow-control logic.
All events in the event stack are processed and can fx be put on the flash hash according to event type, fx flash[:error]
for an :error
event etc.
The Notification system works by mapping events to messages in a central location, similar to mapping events to paths.
Using these Controll
artifacts/systems, you can avoid the typical Rails anti-pattern of Thick controllers, without bloating your Models with unrelated model logic or pulling in various Helper modules which pollute the space of the Controller!
Usage¶ ↑
The recommended approach to handle complex Controller logic using Controll:
-
Enable
Controll
on Controller -
Configure Controller with Flow, Commander and Notifier
-
Create Commands for Commander
-
Define events corresponding to commands
-
Configure Commander with Command methods
-
Create Flow
-
Configure Flow with Render and Redirect event mappings
-
Create Notifier
-
Configure Notifier with Event handlers and event -> message mappings
Controll
enabling a Controller¶ ↑
In your controller include the Controll::Enabler
module.
class ServicesController < ApplicationController before_filter :authenticate_user!, :except => accessible_actions protect_from_forgery :except => :create # see 'controll' gem include Controll::Enabler end
Better yet, to make it available for all controllers, include it in your ApplicationController or any base controller of your choice.
class ApplicationController include Controll::Enabler end
You can also include the Controll::Macros
module in a base Controller class of your choosing, fx:
class ApplicationController include Controll::Macros end
Then you can use the #enable_controll
macro in any subclass Controller class:
class ServicesController < ApplicationController enable_controll end
Controll
configuration¶ ↑
In your Controller you should define a Notifier and Commander to be used.
class ServicesController < ApplicationController enable_controll ... protected notifier :services commander :services # or simply (using naming convention) controll :notifier, :commander def create create_action.perform end protected def create_action @create_action ||= Flows::CreateService.new(self) end fallback do |event| event == :no_auth ? render(:text => omniauth.to_yaml) : fallback_action end def fallback_action redirect_to root_url end end
Focused Controller config¶ ↑
In case you use Focused Controller, this can be strutctured even better like this:
class ServicesController # could be extracted into "global" namespace for reuse across controllers... module ControllAction extend ActiveSupport::Concern included do controll :notifier, :commander, :flow end def fallback_action redirect_to root_url end end class Create < FocusedAction include ControllAction run do execute end protected fallback do |event| event == :no_auth ? render(:text => omniauth.to_yaml) : fallback_action end end end
Wow! Now we’re talking!!!!
Creating a Commander¶ ↑
The Commander is your command center for a group of related commands. Typically you will want to define a Commander for a specific controller if the controller has more than 3 commands. If you put your Commander under the Commanders
namespace (module) you get direct access to the Commander constant to be used as subclass.
The Commander should contain a group of command methods that are conceptually in the same “category”, fx all the command for a particular controller.
module Commanders class Services < Commander # create basic command methods command_methods :cancel_commit, :create_account, :signout # create custom command method with custom argument hash def sign_in_command @sign_in_command ||= SignInCommand.new auth_hash: auth_hash, user_id: user_id, service_id: service_id, service_hash: service_hash, initiator: self end command_method :sign_out do @sign_out_command ||= SignOutCommand.new user_id: user_id, service_id: service_id, service_hash: service_hash, initiator: self end # delegations (alias for initiator_methods ) controller_methods :auth_hash, :user_id, :service_id, :service_hash end end
The Commander class extends
Imperator::Command::MethodFactorymaking
#command_methodand
#command_methods` available. These class macros can be used to create command methods that only take the initiator (in this case the controller) as argument.
For how to implement the Commands themselves, see the imperator-ext gem.
Flows
¶ ↑
For Controller actions that require complex flow control, use a Flow:
module Flows class CreateService < Flow # event method that returns the event to be processed by the flow handler event do Executors::Authenticator.new(controller).execute end # configuration of the Renderer ActionHandler # will return a Renderer Action if it matches the event renderer :simple do events :signed_in_new_user, :signed_in do signup_services_path end end # configuration of the Redirecter ActionHandler # will return a Redirecter Action if it matches the event redirecter :complex do # redirection mappings for :notice events event_map :notice do { signup_services_path: :signed_in_new_user services_path: [:signed_in_connect, :signed_in_new_connect] root_url: [:signed_in_user, :other] } end # redirection mappings for :error events event_map :error, signin_path: [:error, :invalid, :auth_error] end end end
The #renderer
and #redirector
macros will each create a Class of the same name that inherit from Controll::Flow::ActionMapper::Simple
or Controll::Flow::ActionMapper::Complex
. You can also define these classes directly yourself instead of using the macros. The simple action mapper maps a list of events to a single path and otherwise falls back. The complex action mapper maps the event to an event hash for each registered event type.
In the Redirecter
class we are setting up a mapping for various paths, for each path specifying which events should cause a redirect to that path.
If you are rendering or redirecting to paths that take arguments, you can either extend the #action
class method of your Redirect or Render class implementation or you can define a #use_alternatives
method in your Flow
that contains this particular flow logic.
Note: For mapping paths that take arguments, there should be an option to take a block (closure) to be late-evaluated on the controller context ;)
The Executor¶ ↑
The Authenticator
class shown below inherits from Executor::Notificator
which uses #method_missing
in order to delegate any missing method back to the controller of the Executor. The Flow passed in the controller. This means that calls can be executed directly on the controller, such as making notifications etc.
The #result
call at the end of #execute
ensures that the last notification event is returned, to be used for deciding what to render or where to redirect (see Flow).
module Executors class Authenticator < Controlled # ensures pattern: # - perform validations and only execute command if no error def execute super result end protected controller_methods :omniauth, :service, :auth_hash, :auth_valid? def do_command command! :sign_in end def validations # creates an error notification named :error error and return unless valid_params? # creates an error notification named :auth_invalid error(:auth_invalid) and return unless auth_valid? end def valid_params? omniauth and service and auth_hash end end end
Alternatively you can use the execute block macro to generate the #execute
instance method and ensure that it ends by returning result.
execute do # error/validation checks? ... command! :sign_in end
To encapsulate more complex busines logic affecting the user Session or Model data, we execute an Imperator Command (see imperator
gem) called :sign_in that we registered in the Commander of the Controller.
Notifier¶ ↑
Now we are finally ready to define the notifier to handle the different types of notification events.
The example below demonstrates several different ways you can define messages for events:
-
using the
#messages
method to return a hash of mappings. -
define a method for the event name that returns a String (handles argument replacement)
-
i18n locale mapping
[handler class path].[notification type].[event name]
.
module Notifiers class Services < Typed handler :error do messages do { must_sign_in: 'You need to sign in before accessing this page!', auth_service_error: %q{There was an error at the remote authentication service. You have not been signed in.}, cant_delete_current_account: 'You are currently signed in with this account!', user_save_error: 'This is embarrassing! There was an error while creating your account from which we were not able to recover.', } end msg :auth_error! do "Error while authenticating via #{service_name}. The service did not return valid data." end msg :auth_invalid! do 'Error while authenticating via {{full_route}}. The service returned invalid data for the user id.' end end handler :notice do # for :signed_in and :signed_out - defined in locale file under: # notifiers: # services: # notice: # signed_in: 'Your account has been created and you have been signed in!' # signed_out: 'You have been signed out!' msg :already_connected do 'Your account at {{provider_name}} is already connected with this site.' end msg :account_added do 'Your {{provider_name}} account has been added for signing in at this site.' end msg :sign_in_success do 'Signed in successfully via {{provider_name}}.' end end end end
Rails Generators¶ ↑
Setup generator¶ ↑
$ rails g controll:setup
Generate only specific controll folders
$ rails g controll:setup commanders notifiers
Controll
artifact generators¶ ↑
-
assistant
-
executor
-
flow
-
notifier
Example usage:
$ rails g controll:flow create_service
Use -h
for help on any specific controller for more usage options and info.
Notice¶ ↑
Due to a lot of recent API changes in order to simplify and improve usage, the README docs for the API might potentially contain a few inconsistencies with the code. Please notify me if you spot one. Thanks. See the specs and/or code in order to see the real API in this case.
Contributing to controll¶ ↑
-
Check out the latest master to make sure the feature hasn’t been implemented or the bug hasn’t been fixed yet.
-
Check out the issue tracker to make sure someone already hasn’t requested it and/or contributed it.
-
Fork the project.
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Start a feature/bugfix branch.
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Commit and push until you are happy with your contribution.
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Make sure to add tests for it. This is important so I don’t break it in a future version unintentionally.
-
Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.
Copyright¶ ↑
Copyright © 2012 Kristian Mandrup. See LICENSE.txt for further details.