I have a transaction in one of my model. When something go wrong, I want to be notified.
If it would be transaction in controller, I would simply do:
begin
(my transaction...)
rescue => exception
ExceptionNotifier.deliver_exception_notification(exception, self, request, data)
end
But I want to do similar thing in my model, passing nils as self and request does not help. What can I do about it?
In our project, we use it differently:
For model, we create an initializer in project_directory/config/initializers to add it to
ActiveRecord::Base.
class ActiveRecord::Base
include ExceptionNotifiable
end
Doing this, all models exception will invoke ExceptionNotifier email as per our configuration.
For controllers, we include it in our ApplicationController so if there is an exception in any controllers, we will receive an email.
class ApplicationController < ActionController::Base
include ExceptionNotifiable
.....
end
For transaction in the controller, i will do:
class MyController < ApplicationController
.....
def create
MyModel.transaction do
.....
end
end
end
Without rescuing the exception, the ExceptionNotifier will be called automatically.
Hopefully it helps.
Related
I have a requirement to need to validate presence of some params in certain situations. Here is the example of that :
In my user controller, for update action, I am required to validate the presence of these params. Same deal for car controller, update action as well, you could see recurring theme here. Params are additional_info.
My base controller provides additional_info_params which pulls the right data from the request.
Here is what I tried so far. I created a AR controller concern and included it in the controller, here is some code:
module ClassMethods
def require_additional_info_for(*methods)
binding.pry
return unless methods.include?(action_name)
if additional_info_params.empty?
head 400
end
end
end
My idea was to be able to define methods that require these params on the top of controller file, just like before_action from rails or skip_authorization_check from cancan. Like so:
MyController < BaseController
include Concerns::AdditionalInformation
require_additional_info_for :update
def update
...
end
end
This code above however does not work as I intended, mainly because this fires on the request class without much knowledge about the request (where I need to derive action name from via action_name).
So how can I do something like this?
Yes, you can, but i suggest you to use the before_action callback!
In a 'abstract' controller, register your method like this:
class SameController < ApplicationController
...
protected
def require_additional_params
render status: :unprocessable_entity if additional_info_params.empty?
end
end
After this, all the controllers who will use this methods, must extends SameController, and runs before_action passing the above method for the wanted actions, for example:
class UserController < SameController
before_action :require_additional_params, only: [:action1, :action2]
end
Note: You can put the require_additional_params in a module and include in your controller, or just put it in the ApplicationController
You might also look at making these regular strong params in the respective controller. It looks something like this:
def update_params
params.require(:car).permit(:engine, :wheels, :rims).tap do |car_params|
car_params.require(:engine)
end
end
This would expect a top-level :car key params (which it strips), and require an :engine param, but allow the other 2 (:wheels and :rims). If :engine isn't present, it will raise a ActionController::ParameterMissing (just like if :cars was missing)
This is straight from the action controller strong params docs (last example at bottom)
I'll sometimes throw these into separate private methods on the respective controller, so there would also possibly be a create_params method with different requirements. I prefer this method over using a custom method as a before_action.
I need to create a controller instance from another controller for using its methods. When I creating
c = SomeController.new
c.some_method
some_method use params[], and then I have an error NoMethodError: undefined method 'parameters' for nil:NilClass.
How can I pass params to the controller?
The thing you are trying to do it not recommended any framework. You probable have some code that you wanted in multiple controllers. To achieve your desired behavior, extract the common code to library can call that in any controller you want.
You don't instantiate controllers in Rails - its done by the router when it matches a request to a route.
Its just not done because it violates the way MVC in Rails works - one request = one controller. You also need to pass the entire env hash from rack into the controller for it even work properly.
But really - don't. There are much better ways.
If you need to share a method between controllers there are better ways such as using inheritance:
class ApplicationController
def some_method
end
end
class FooController < ApplicationController
end
class BarController < ApplicationController
end
Or mixins:
# app/controllers/concerns/foo.rb
module Foo
def some_method
end
end
class BarController < ApplicationController
include Foo
end
class BazController < ApplicationController
include Foo
end
If you instead need to move a request from one controller action to another you should be redirecting the user.
class UsersController < ApplicationController
def create
# call the action do_something from ImagesController
# continue in the normal flow
end
end
class ImagesController < ApplicationController
def do_something
...
end
end
I want to call the action do_something in the ImagesController from UsersController but after it is executed I want to continue in the normal flow of the create action, few questions:
Is it a bad practice?
How can I do that? Do I have to create an instance of the ImagesController and then call the action or is there another way?
You could technically create an instance of the other controller and call methods on that, but it is tedious, error prone and highly not recommended.
If that function is common to both controllers, you should probably have it in ApplicationController or another superclass controller of your creation.
class ApplicationController < ActionController::Base
def common_to_all_controllers
# some code
end
end
class SuperController < ApplicationController
def common_to_some_controllers
# some other code
end
end
class MyController < SuperController
# has access to common_to_all_controllers and common_to_some_controllers
end
class MyOtherController < ApplicationController
# has access to common_to_all_controllers only
end
another method is
# lib/common_stuff.rb
module CommonStuff
def common_thing
# code
end
end
# app/controllers/my_controller.rb
require 'common_stuff'
class MyController < ApplicationController
include CommonStuff
# has access to common_thing
end
source - Calling a method from another controller
this is possible actually. And not that hard.
That said. It is bad practice. Very bad practice.
What you want to do is extract the logic you do in the controller you want to invoke into a service object or move it into a model. Alternativly you could also make your first controller inherit from the one you are trying to invoke.
So, how to call a controller?
TheController.new.dispatch(:index, request)
If I've got a method in a different controller to the one I'm writing in, and I want to call that method, is it possible, or should I consider moving that method to a helper?
You could technically create an instance of the other controller and call methods on that, but it is tedious, error prone and highly not recommended.
If that function is common to both controllers, you should probably have it in ApplicationController or another superclass controller of your creation.
class ApplicationController < ActionController::Base
def common_to_all_controllers
# some code
end
end
class SuperController < ApplicationController
def common_to_some_controllers
# some other code
end
end
class MyController < SuperController
# has access to common_to_all_controllers and common_to_some_controllers
end
class MyOtherController < ApplicationController
# has access to common_to_all_controllers only
end
Yet another way to do it as jimworm suggested, is to use a module for the common functionality.
# lib/common_stuff.rb
module CommonStuff
def common_thing
# code
end
end
# app/controllers/my_controller.rb
require 'common_stuff'
class MyController < ApplicationController
include CommonStuff
# has access to common_thing
end
Try and progressively move you methods to your models, if they don't apply to a model then a helper and if it still needs to be accessed elsewhere put in the ApplicationController
If you requirement has to Do with some DB operations, then you can write a common function (class method) inside that Model. Functions defined inside model are accessible across to all the controllers. But this solution does to apply to all cases.
I don't know any details of your problem, but maybe paths could be solution in your case (especially if its RESTful action).
http://guides.rubyonrails.org/routing.html#path-and-url-helpers
I'm new to rails and don't even know if this is the correct way of solving my situation.
I have a "Club" ActiveRecords model which has a "has_many" association to a "Member" model. I want the logged in "Club" to only be able to administrate it's own "Member" so in the beginning of each action in the "Member" model I did something similar to the following:
def index
#members = Club.find(session[:club_id]).members
to access the right members. This did not however turn out very DRY as I did the same in every action. So I thought of using something equivalent to what would be called a constructor in other languages. The initialize method as I've understood it. This was however not working, this told me why, and proposed an alternative. The after_initialize.
def after_initialize
#club = Club.find(session[:club_id])
end
def index
#members = #club.members
....
does not seem to work anyway. Any pointers to why?
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.members
Makes me think that the #club var isn't set at all.
Also, is this solution really a good one? This makes it hard to implement any kind of "super admin" who can manage the members in all of the clubs. Any ideas on where I am missing something?
You can use a before_filter.
Define the filter in your ApplicationController (so that you can access it from any controller).
class ApplicationController < ActionController::Base
# ..
protected
def load_members
#members = if session[:club_id]
Club.find(session[:club_id]).members
else
[]
end
end
end
Then, load the filter before any action where you need it.
For example
class ClubController < ApplicationController
before_filter :load_members, :only => %w( index )
def index
# here #members is set
end
end
Otherwise, use lazy loading. You can use the same load_members and call it whenever you need it.
class ClubController < ApplicationController
def index
# do something with members
load_members.each { ... }
end
end
Of course, you can customize load_member to raise an exception, redirect the client if #members.empty? or do whatever you want.
You want to use a before_filter for this.
class MembersController < ApplicationController
before_filter :find_club
def index
#members = #club.members
end
private
def find_club
#club = Club.find(session[:club_id])
end
end
I'm a fan of a plugin called Rolerequirement. It allows you to make custom roles and apply them by controller: http://code.google.com/p/rolerequirement/