How to call helper method from model? - ruby-on-rails

I use MongoDB as a database in my Rails application with MongoID gem. I want to call the helper method from the model within after_create callback method. How is it possible?My model code is:
class Department
include ApplicationHelper
after_create :create_news
private
def create_news
#user = ApplicationHelper.get_current_users
end
end
And my helper code is:
module ApplicationHelper
def get_current_users
current_user
end
end
When I create new department then following error occur.
undefined method `get_current_users' for ApplicationHelper:Module
How to remove error? Thanks in advance.

I also use mongoid and use this all the time. Shouldn't be unique to mongoid though.
ApplicationController.helpers.my_helper_method

If you want a helper method that you can use in your views to return the current user, you can do so in your ApplicationController, something like this for example:
private
def current_user
#current_user ||= User.find(session[:user_id]) if session[:user_id]
end
helper_method :current_user
Then you can use this in any view.
If you want some arbitrary method in a model to know what user it's dealing with, pass #current_user in as an argument to the method when you call it in your controller.
Your code seems incomplete so I can't really see what you're trying to accomplish, but this is pretty standard practice.

Make sure the module file is named properly, meaning in your case application_helper.rb and it's located on the helpers library.
You can also try to include the helper in the ApplicationController (app/controller/application_controller.rb).

Related

Devise methods in helper file?

I have a helper module ModelHelper. I want to use user_signed_in? method inside that helper module. But it shows error. How can I call this method inside helper file.
Method user_signed_in? defined in the Devise::Controllers::Helpers::ClassModule module. Long story short it just checks if scope authenticated in warden. So you can try to check it without Devise helpers
def #{mapping}_signed_in?
!!current_#{mapping}
end
def current_#{mapping}
#current_#{mapping} ||= warden.authenticate(scope: :#{mapping})
end
I think that you can use current_user.present?
Anyway, rails helpers are very ugly and I advise to don't use it at all

How do I pass params to Rails controller's callback

The callback is like below.
class User
include UserSettable
before_action :set_user
def show
[Something with #user]
end
end
class Group
include UserSettable
before_action :set_user
...
end
And the set_user is like below. And this method is defined in the controller concern.
module UserSettable
extend ActiveSupport::Concern
def set_user
#user = User.find(params[:id])
end
end
I have three questions.
How do I pass params to callback method?
Can the instance variable defined in concern be used in controller?
Does this implementation deviate from the usual usage of rails?
How do I pass params to callback method?
params of request will automatically be available to action. You don't need to pass it explicitly. Your code snippet is perfect use case of how it should be used.
Can the instance variable defined in concern be used in controller?
You mean controller's concern. I think the instance variable defined there should be available. Can you give an example of what you are trying to achieve?
Does this implementation deviate from the usual usage of rails?
No

Helper method called upon in model file, not working

In a create method in a controller I have:
if logged_in_admin?
#invitation.set_ids
In the Invitation model:
def set_ids
self.person_one_id = current_user.id
end
current_user is a method in app/helpers/sessions_helper.rb and defines the currently logged in user. I use this method successfully in many controller methods. However, for the use case above I get the error message undefined local variable or method 'current_user' for #<Invitation:0x007f699086bf40>.
Why do I get this error message? Is this because this time I'm using the helper method in a model file and is this not allowed? If such is not allowed, what would be the best way to securely set person_one_id for #invitation equal to the id of the currently logged in user?
current_user not available in a model layer(it's MVC, your helpers on the CV layer and model know nothing about the current_user helper). Pass user_id from your helper as argument:
some_helper.rb
def my_helper
if logged_in_admin?
#invitation.set_ids(current_user.id)
# .....
model.rb:
def set_ids(user_id)
self.person_one_id = user_id
end
You have to add the following line to your ApplicationController:
class ApplicationController < ActionController::Base
protect_from_forgery with: :exception
include SessionsHelper
end
Now you should be able to use the methods inside your controllers / models.

Ruby on Rails: Common method available for controllers and views?

I have been working with Ruby on Rails for a short time. Recently I implemented an authentication system for my application. I made a method available on 'application_helper.rb' to retrieve the current logged user (method called current_user).
The method just retrieves my User object if the session[:user_id] variable is present.
However I face the following problem.
If I place the current_user method in 'application_helper.rb', my controllers can't make use of it
If I place the current_user method in 'application_controller.rb', my views can't make use of it
What's the best approach to solve this problem? The easy way would be duplicate my code in both controller and helper, but I know there is a better and more correct way.
Thanks in advance
This is a common and well-solved problem.
Rails doesn't allow controllers to access helper methods. If you want to share a method between your views and controllers, you need to define the method in your controller, and then make it available to your views with helper_method:
class ApplicationController < ActionController::Bbase
# Let views access current_user
helper_method :current_user
def current_user
# ...
end
end
You can pass more than one method name to helper_method to make additional methods in your controller available to your views:
helper_method :current_user, :logged_in?
def current_user
# ...
end
def logged_in?
!current_user.nil?
end

Rails-way - where to put this kind of helper method?

I'm struggling a bit to find the right place for a helper method. The method basicly 'inspects' a User-model object and should return some information about the 'progress' of the user, eg. "You need to add pictures", "Fill out your address" or "Add your e-mail-adress". None of the conditions I'm checking for are required, it's just like a "This is your profile completeness"-functionality as seen on LinkedIn etc.
Each of these 'actions' have a URL, where the user can complete the action, eg. a URL to the page where they can upload a profile photo if that is missing.
Since I need access to my named routes helpers (eg. new_user_image_path) I'm having a hard time figuring out the Rails-way of structuring the code.
I'd like to return an object with a DSL like this:
class UserCompleteness
def initialize(user)
end
def actions
# Returns an array of actions to be completed
end
def percent
# Returns a 'profile completeness' percentage
end
end
And user it with something like: #completeness = user_completeness(current_user)
However, if I'm adding this to my application_helper I don't have access to my named routes helpers. Same goes if I add it to my User-model.
Where should I place this kind of helper method?
This is a similar problem to that of Mailers. They are models, and should not cross the MVC boundaries, but need to generate views. Try this:
class UserCompleteness
include ActionController::UrlWriter
def initialize(user)
end
def actions
# Returns an array of actions to be completed
new_user_image_path(user)
end
def percent
# Returns a 'profile completeness' percentage
end
end
But be aware you are breaking MVC encapsulation, which might make testing more difficult. If you can get away with some methods in the users helper instead of a class that might be better.
From the little i got your question i think you want a method which you can used in Controller as well as Views.
To Accomplish this simple add method in application_controller.rb and named it hepler_method
Example:-
class ApplicationController < ActionController::Base
helper_method :current_user
def current_user
#current_user ||= User.find_by_id(session[:user])
end
end
you can use method current_user in both Controller as well as views

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