I'm creating a gem to create an around_filter on my ApplicationController in all projects that the gem is in. This is my first gem and I'm having a few concerns.
I included rails as a dependency in the gemspec file, but how would I reference anything in rails?
Would I do something like require 'rails' at the top of my file, then do something like
Rails::Path::To::ApplicationController? I understand I could do something like:
Module MyGem
def self.included(klass)
klass.class_eval do
around_filter do |controller, action|
#insert code here
end
end
end
end
Then, in my Rails app I would include it in my Rails ApplicationController, but I don't want to have to include it. Of course, I might have to do some additional config for even that to work, but that is the gist of my crux. How would I reference ApplicationController in my gem? Do I just assume I have Rails since it is a dependency now and I should be able to freely call upon it in my ruby files?
Related
The title is my question.
devise provide us many useful methods like current_user, authenticate_user!, and so on. I want to know why is it possible to use them without including any module like below.
class ApplicationController < ActionController::Base
before_action :authenticate_user!
end
Those method's definition is here
Somebody please help me！
The answer is devise included its helper methods into ActionController on behalf of you when Rails on_load
# devise/rails.rb
module Devise
class Engine < ::Rails::Engine
# ...
initializer "devise.url_helpers" do
Devise.include_helpers(Devise::Controllers)
end
# ...
end
# devise.rb
# ...
def self.include_helpers(scope)
ActiveSupport.on_load(:action_controller) do
include scope::Helpers if defined?(scope::Helpers)
include scope::UrlHelpers
end
ActiveSupport.on_load(:action_view) do
include scope::UrlHelpers
end
end
# ...
I saw many 3rd gems using on_load to include their methods (or themselves) into Rails core, maybe it's a typical way to do that (allows Rails to lazily load a lot of components and thus making the app boot faster). If you install some gems and you could use their methods on your model/controller/view then those gems did the same thing devise did above.
About those methods current_user, authenticate_user! ... they are dynamic methods devise will generate when it did include scope::Helpers into Rails (see code above and the link).
So one very good thing about rails is the fact that you get a lot of things for free out of the box. One of these things at the top level is autoloading.
So in the case of Devise. When you install Devise and run the generate command, you get a devise.rb file inside of your config/initializers/ folder. This file is always autoloaded by rails on server startup and reload. That's how all these methods are able to be use these devise methods without importing anything.
Read more at rails docs
I have spree gem installed successfully. I don't need spree_frontend. Here is the Gemfile
gem 'spree_core', '4.2.0.rc2'
gem 'spree_backend', '4.2.0.rc2'
gem 'spree_sample', '4.2.0.rc2'
gem 'spree_cmd', '4.2.0.rc2'
gem 'spree_auth_devise', '~> 4.2'
So I want to extend my ApplicationController from Spree's BaseController. Here is the code:
class ApplicationController < Spree::BaseController
include Spree::Core::ControllerHelpers::Order
end
But I get following errors:
uninitialized constant Spree::BaseController (NameError)
How can I extend my controller from installed Spree gem's controller?
The problem you're running into is that Spree::BaseController already inherits from ApplicationController; see https://github.com/spree/spree/blob/master/core/app/controllers/spree/base_controller.rb. This is to allow your ApplicationController to define things like current_user and similar basic functions before Spree sees it.
Declaring them the other way around as well creates a circular dependency, and the class loading fails as a result. Without changing Spree itself, the only fix is to do something else.
Instead, to have your controllers use Spree::BaseController as a superclass, first define ApplicationController in the more usual fashion e.g.:
# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
# ...
end
then invent a new abstract controller, for your own use, that inherits from Spree, e.g. let's name it StoreBaseController:
# app/controllers/store_base_controller.rb
class StoreBaseController < Spree::BaseController
include Spree::Core::ControllerHelpers::Order
# ...
end
This StoreBaseController can now be used in place of ApplicationController when defining more specific controllers. It works because it doesn't create a loop in the inheritance tree, which now looks like this:
Note: if you're also using the rails generator command to produce controllers or scaffolds from templates, be aware that the generator has ApplicationController hard-coded in the templates, so you'll need to amend them once created.
Is there any reason why you need to extend strictly ApplicationController?
I advise you alternative approach to create a new Base controller class, and then inherit all the children from it and leave ApplicationController to basic rails
app/controller/my_base_controller.rb
class MyBaseController < Spree::BaseController
def foo
# ...
end
end
app/controller/my_resources_controller.rb
class MyResourcesController < MyBaseController
def bar
# ...
end
end
As the errors states, Spree::BaseController is not defined within your app - it is defined in the spree-core gem. If you re-create the filepath to the base controller locally, that is app/controllers/spree/, and copy and paste the code from the controller into a local base_controller.rb, you can edit it and add custom functionality.
Note that it will still inherit from the ApplicationController, but you can place any of the code you wanted to put in the ApplicationController into here and have your classes inherit from Spree::BaseContoller and the effect will be the same.
hmmm, I tried what you want to do but I succeeded (?)
class PagesController < Spree::BaseController
include Spree::Core::ControllerHelpers::Order
end
in the console
2.6.5 :006 > pp PagesController.ancestors
[PagesController,
Spree::Core::ControllerHelpers::Order,
#<Module:0x00007fca27610410>,
Spree::BaseController,
Spree::Core::ControllerHelpers::CurrencyHelpers,
Spree::Core::ControllerHelpers::StrongParameters,
...
I'm using
ruby 2.6.5
rails 6.0.3.4
run bundle update after adding the your spree's gems in the Gemfile
So I think its the requiring or auto-loading problem
what's your rails version? 6? spree >= 4.1 should use rails >= 6
Does Spree::BaseController exist in rails console?
Is Bundler.require(*Rails.groups) in config/application.rb?
Does the gems included in the right group of the Gemfile? ex: spree gems are in :production group.
Does it have config.load_defaults 6.0 in config/application.rb?
I'm working on a gem that does some general string manipulations I'd like to expose as helper methods to rails 4+ apps.
Not all consumers of my gem are rails apps so i'd like to safely expose helper methods to rails apps.
Two questions:
How do I add view helper methods to Rails from a gem and where should it live within the gem directory structure?
What can i do to prevent a blow up when the consumer is NOT a rails app? i.e. the gem can't find rails when it's included
Thanks
In your lib/my_gem.rb, you typically want to do something along these lines:
require 'my_gem/action_methods' if defined? ActionView
And lib/my_gem/action_view_methods.rb would contain all if your methods that require Rails/ActionView.
You can add these helpers to Rails with:
module ActionMethods
# ...
end
ActionView::Base.send :include, ActionMethods
Also see this question, and this one.
The rails way is by creating an engine and as it gets loaded with your gem it gets processed by rails
module MyGem
class Engine < ::Rails::Engine
isolate_namespace MyGem
initializer "my_gem.include_view_helpers" do |app|
ActiveSupport.on_load :action_view do
include MyViewHelper
end
end
end
end
Another way you can go is to not include the helper by default so that consumers don't get unexpected side-effects from your gem. Create the helper as a module and document that it should be added to ApplicationController or any needed controller.
I'm making a gem for Rails. I need access to the ApplicationController because I'll toy with it. Absolutely nothing online gives information about what to do with gemspec and then somehow manage to get Rails accessible in my gem.
I imagine the goal is eventually to be able to talk to Rails like:
module Rails
module ActionController
#code
end
end
If you are developing a gem exclusively for Rails I strongly recommend you generate the initial scaffold using rails plugin new gem_name. There's a ton of info on developing rails plugins.
The initial structure generated looks like this:
gem_name
gem_name.gemspec
lib/
gem_name.rb
gem_name/
version.rb
engine.rb # if generated using --mountable
The whole rails environment becomes available [edit: after your gem is loaded] so extending ApplicationController can be done like this:
# lib/gem_name.rb
require 'gem_name/controller_extensions'
module GemName
end
# lib/gem_name/controller_extensions.rb
module GemName::ControllerExtensions
# bleh
end
# dummy_application/app/application_controller.rb
class ApplicationController < ActionController::Base
include GemName::ControllerExtensions
end
Look at this question.
I am upgrading my Rails plugin to be an engine that works with the latest 3.0RC1 release and I'm having a bit of trouble figuring out the best (and most correct) way to extend ActionController. I've seen this post by DHH and this question here on SO, but my question is more about how to properly call code within the ActionController.
For instance, I need to call the following within my engine's controller:
class ApplicationController < ActionController::Base
helper :all
before_filter :require_one_user
after_filter :store_location
private
def require_one_user
# Code goes here
end
def store_location
# Code goes here
end
end
I know how to properly include my two private functions, but I can't find a way to get it to properly call helper, before_filter and after_filter.
I would greatly appreciate some links or a way to make this work. I have tried naming my controller something other than ApplicationController and having the real ApplicationController extend it, but that doesn't seem to work either. I'm really up for any solution that makes the life of the engine user as easy as possible. Ideally, they wouldn't have to extend my class, but they'd have all of the functionality built into their own ApplicationController.
You may also want to look into the initializers inside your engine subclass, so you don't have to include view helpers inside your controller class. And this will give you control over the load order of these modules.
Here is what I have been using:
module MyEngine
class Engine < Rails::Engine
initializer 'my_engine.helper' do |app|
ActionView::Base.send :include, MyEngineHelper
end
initializer 'my_engine.controller' do |app|
ActiveSupport.on_load(:action_controller) do
include MyEngineActionControllerExtension
end
end
end
end
Also, another option for the action controller extension is using a mixin module. This will let you use the before_filter, after_filter, etc..
module MyEngineActionControllerExtension
def self.included(base)
base.send(:include, InstanceMethods)
base.before_filter :my_method_1
base.after_filter :my_method_2
end
module InstanceMethods
#...........
end
end
One other thing... if you create the default rails directories at the top level of your gem, you don't have to worry about requiring the helpers or controllers. Your engine subclass has access to them. So I add my application controller and application helper extensions here:
/myengine/app/helpers/myengine_application_helper_extension.rb
/myengine/app/controllers/my_engine_action_controller_extension.rb
I like this setup because it looks similar to the application_controller and application_helper in your rails app. Again, this is just personal preference, but I try to keep anything that is directly rails related, such as controllers, helpers and models inside /my_engine/app and anything that is related to the plugin in general inside /my_engine/lib
Check out this tutorial by Jose Valim for more info on initializers:
https://gist.github.com/e139fa787aa882c0aa9c (engine_name is deprecated now, but most of this doc seems up-to-date)
So, I finally figured out the solution and I hope it helps someone else.
You need to create a file in your lib directory because you are actually going to extend the class. I did myplugin/lib/extensions/action_controller_base.rb.
Then, inside of your myplugin/lib/myplugin.rb file, do the following:
require 'extensions/action_controller_base.rb'
Inside of myplugin/lib/extensions/action_controller_base.rb put the following:
require 'action_controller' # Make sure ActionController::Base is defined
ActionController::Base.class_eval {
private
def my_method_1
# Code Goes Here
end
def my_method_2
# Code Goes Here
end
}
ActionController::Base.instance_eval {
helper_method :my_method_1, :my_method_2
before_filter :my_method_1
after_filter :my_method_2
}
If you need to have view helpers, create them in the myplugin/lib/helpers directory (or anything inside of lib, the name "helpers" doesn't matter) also and add the following to the bottom of myplugin/lib/extensions/action_controller_base.rb:
require 'helpers/helper_file_1'
require 'helpers/helper_file_2'
ActionView::Base.send :include, MyHelper1
ActionView::Base.send :include, MyHelper2