How to add this specific authorization feature to my rails app? - ruby-on-rails

My rails app has a few cab operators and they have a few cabs associated with them, and they are related as follows:
class Operator < ActiveRecord::Base
has_many :cabs
end
I have used Devise as my authentication gem. It authenticates users, admins and super admins in my app. I have created separate models for users, admins and super admins (and have not assigned roles to users per se).
I now wish to add the authorization feature to the app, so that an admin (who essentially would be the cab operator in my case) can CRUD only its own cabs. For e.g., an admins belonging to operator# 2 can access only the link: http://localhost:3000/operators/2/cabs and not the link: http://localhost:3000/operators/3/cabs.
My admin model already has an operator_id that associates it to an operator when an admin signs_up. I tried to add the authorization feature through CanCan, but I am unable to configure CanCan to provide restriction such as the one exemplified above.
I also tried to extend my authentication feature in the cabs_controller, as follows:
class CabsController < ApplicationController
before_action :authenticate_admin!
def index
if current_admin.operator_id != params[:operator_id]
redirect_to new_admin_session_path, notice: "Unauthorized access!"
else
#operator = Operator.find(params[:operator_id])
#cabs = Operator.find(params[:operator_id]).cabs
end
end
But this redirects me to the root_path even if the operator_id of the current_admin is equal to the params[:operator_id]. How should I proceed?
EDIT:
Following is my routes.rb file:
Rails.application.routes.draw do
devise_for :super_admins
devise_for :users
resources :operators do
resources :cabs
end
scope "operators/:operator_id" do
devise_for :admins
end
end
I have three tables: users, admins and super_admins. I created these coz I wanted my admins to hold operator_ids so that the admins corresponding to an operator can be identified. Also, I wanted the admin sign_in paths to be of the type /operators/:operator_id/admins/sign_in, hence the tweak in the routes file.

Unfortunately, initially I didn't understand that you actually have 3 different tables for users and (super)admins... Not sure that Pundit can help you in this case, but I'll keep the old answer for future visitors.
Coming back to your problem, let's try to fix just the unexpected redirect.
Routes seems fine, so the problem can be one of this:
You're getting redirected because you're currently not logged in as an admin, so you don't pass the :authenticate_admin! before_action.
You say "even if the operator_id of the current_admin is equal to the params[:operator_id]", but this condition is probably not true. Can you debug or print somewhere the value of both current_admin.operator_id and params[:operator_id] to see if they're actually equals?
Another interesting thing, is that you have a redirect for new_admin_session_path in your code, but then you say "this redirects me to the root_path". Can you please double check this?
OLD ANSWER
If you want to setup a good authorization-logic layer, I advice you to use pundit.
You've probably heard about cancan, but it's not supported anymore...
Leave Devise managing only the authentication part and give it a try ;)
PUNDIT EXAMPLE
First of all, follow pundit installation steps to create the app/policies folder and the base ApplicationPolicy class.
Then, in your case, you'll need to create a CabPolicy class in that folder:
class CabPolicy < ApplicationPolicy
def update?
user.is_super_admin? or user.cabs.include?(record)
end
end
This is an example for the update action. The update? function have to return true if the user has the authorisation to update the cab (You'll see later WHICH cab), false otherwise. So, what I'm saying here is "if the user is a super_admin (is_super_admin? is a placeholder function, use your own) is enough to return true, otherwise check if the record (which is the cab your checking) is included in the cabs association of your user".
You could also use record.operator_id == record.id, but I'm not sure the association for cab is belongs_to :operator. Keep in mind that in CabPolicy, record is a Cab object, and user is the devise current_user, so implement the check that you prefer.
Next, in your controller, you just need to add a line in your update function:
def update
#cab = Cab.find(params[:id]) # this will change based on your implementation
authorize #cab # this will call CabPolicy#update? passing current_user and #cab as user and record
#cab.update(cab_params)
end
If you want to make things even better, I recommend you to use a before_action
class CabsController < ApplicationController
before_action :set_cab, only: [:show, :update, :delete]
def update
#cab.update(cab_params)
end
#def delete and show...
private
def set_cab
#cab = Cab.find(params[:id])
authorize #cab
end
And of course, remember to define also show? and delete? methods in your CabPolicy.

Related

Using devise for user registration/login redirect user to a different form page based on their response

I am using devise for user registration/login, after the user has successfully signed up, I want to show a page/a dialog box and redirect to another page based on user response. How can I do that?
User Model (By devise)
username
password
Student Model
name
student_id
Teacher Model
name
grade
First_page:
signup signin links
Signup link will show the devise views/devise/registrations/new.html.erb page.
After successful signup, it takes the user to root page. I have defined the root page in routes.rb:
` Rails.application.routes.draw do
devise_for :users
resources :students, :teachers
# For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
root to: "students#index"
end `
At this point, the application doesn't have any idea who the user is.
So, I want to get the identity information(student/teacher) from the user.
How will I get this information?
Student/Teacher controller:
`class StudentsController < ApplicationController
before_action :authenticate_user!, only: [:new, :create]
def index
#students = Student.all
end
def new
#student = Student.new
end
def create
current_user.create_student(student_params)
redirect_to root_path
end
private
def student_params
params.require(:student).permit(:name, :skypid)
end
end`
After the user has successfully signed in, I want to ask if the user is a student or teacher. Based on what they select, redirect them to a student form page or teacher form page.
How can I do that in rails?
Thank you
You can write a custom after_sign_in_path_for function in your ApplicationController assuming you're using all the default Devise controllers otherwise. Any named path helper or other route that it returns will be where the user is redirected, so you could do something simple like always redirect to a selection page that presents the options and handles the choice on a subsequent action:
def after_sign_in_path_for(resource)
user_type_selection_path # whatever route in your app manages the selection
end
Alternately, you could invoke a custom method on the user model in that function to make a choice right there:
def after_sign_in_path_for(resource)
resource.student? ? student_path : teacher_path
end
You could hybridize these of course as well to do the latter when the selection has already been made and redirect otherwise, with something similar to the following:
def after_sign_in_path_for(resource)
if resource.user_type_chosen?
resource.student? ? student_path : teacher_path
else
user_type_selection_path
end
Bear in mind that none of those functions or paths are real, since I can't be more specific on the information you've provided, but hopefully this gets you headed in the right direction. The after_sign_in_path_for hook is your primary tool here, unless you get into the world of overriding the default devise controllers and interrupting the usual workflow there to accommodate this step, which doesn't seem strictly necessary by your description.

How to make API Controller Actions readonly

I want to design an API in Rails that requires actions like Create, Update and Delete to be readonly for certain controllers, and open to the public for others (eg, comments on an article should be open but editing that article should require API authentication)
I know how to do the authentication part, what I don't know how to do is the "read only" part or the "you have permission to create a comment but not delete it" part.
Does any one have any resources, tips, tricks or github repositories that do this or something similar to this?
You are needing to do authorization. Look at Pundit for a scalable solution https://github.com/elabs/pundit
I had an app for a while that only needed a little bit of control as there were only a few methods on 2 controllers that were limited. For those i just created a before_filter and method to control the authorization.
The code below would allow everyone to do index and only allow users with a role attribute that has a value of "admin" to do any other action in the controller. You can also opt to raise an unauthorized error or raise an error message instead of redirecting. There are articles (probably books) written on the security side of the house for whether you should give users notice if they are not authorized to do something (which means they can infer that there is something there that someone can do at the uri)
SomeController < ApplicationController
before_filter check_authorized, except [:index]
def index
....stuff that everyone can do
end
def delete
....stuff only admin can do
end
private
def check_authorized
redirect_to root_path unless current_user.admin?
end
end
Of course you will need devise or a current_user method and a method on user that checks admin
class User < ActiveRecord::Base
def admin?
if self.role == "admin"
true
else
false
end
end
end

Allow user to edit their own data with device

I know there's probably solutions to this elsewhere, but I'm looking for help that works specifically in my case because I'm having a lot of trouble translating other solutions into my situation.
I currently have a device set up and the database is seeded so an admin is already created. Everyone else that signs up after that is a user.
There are two tables right now, a user table generated by rails and a cadet table. The cadet table stores information such as company, room number, class year and such.
My question is, how do I allow a user to edit/destroy only the cadet record that they've created? I know it seems like a big question but I've been looking all over and still can't find a reasonable way to implement this. Thank you!
Devise is related to authentication (who you are), you need a solution for authorization (who can do what). My suggestion is to go for CanCan (https://github.com/ryanb/cancan), which is a gem very widely use together wide Devise.
For your example, and after install the gem via Gemfile+Bundler:
Initialize the gem for your User model
rails g cancan:ability
it will create a file in app/models/ability.rb to define your restrictions
Define your restrictions, for instance:
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new # guest user (this line it to manage users not logged in yet)
if user
can :manage, Cadet, user_id: user.id
end
end
end
That will allow a user just to read, create, edit and destroy Cadets which user_id matches the id for the User.
Take a look at CanCan github page is wery well documented and with lot of examples; it's very simple to set up and works great.
You can also use a before_filter, something like the following:
class CadetsController < ApplicationController
before_filter :cadet_belongs_to_user, only: [:show, :edit, :update, :destroy]
....
private
def cadet_belongs_to_user
# following will work only on routes with an ID param
# but there are a few ways you could check if the cadet
# belongs to the current user
unless current_user && current_user.cadets.where(id: params[:id]).any?
flash[:notice] = "You are not authorized to view this page."
redirect_to root_path
end
end
end

How to allow only Admin (or some user) to edit the pages in Rails?

I have a scaffold Finances and I just realized that it can be edited by any logged in user by going to /finances/1/edit
I have installed activ_admin gem but I don't think it is what I need. How to make sure other than admin (or may be some users) no one can edit finances resource type- I
EDIT - I found https://github.com/EppO/rolify, is this best option or I still can do something better as it may be overkill ?
EDIT 1 - I went through this https://github.com/EppO/rolify/wiki/Tutorial and have assigned role "admin" to user = User.find(1), everything went well upto "ability.can? :manage, :all" in console, which shows TRUE for user 1 and false for other users. Now I am not able to figure out what to do ? I can still see all users being able to edit the page even though I have added "resourcify" in the finance.rb model. Any help ?
Well, I personally use rolify for my project and love it.. but to be honest this is super easy to achieve by simply adding a column "admin" to your User model and having it default to false. When you want a user to be an admin update the attribute to true and then require the User.admin==true to access the finances edit action... You can do this by redirecting the non-admin user from the controller (within the finances edit action)
By the way if you're using devise for auth check out Devise before_filter authenticate_admin?
I'm not sure how your models are set up, but lets say your User model has an admin column, you can do the following:
FinancesController < ApplicationController
before_filter :must_be_admin, only: :edit
def edit
...
end
private
def must_be_admin
unless current_user && current_user.admin?
redirect_to root_path, notice: "Some message"
end
end
end
You can add any actions needed to the before filter, e.g. before_filter :must_be_admin, only: [:edit, :destroy]
If you're looking to add sensible user authorization without rolling your own solution, definitely check out CanCan. Also helpful is this screencast by its author, Ryan Bates.

Best way to restrict actions (edit/delete) with Ruby on Rails and Devise

I am fairly new to Ruby On Rails and right now I am doing a simple app. In this app a user can create many items and I use devise for authentication. Ofcourse I want to make sure that you are the owner in order to delete items (Teams, Players etc) and the way I do it now is:
def destroy
#team = Team.find(params[:id])
if current_user.id == #team.user_id
#team.destroy
redirect_to(teams_url, :notice => 'The team was deleted.')
else
redirect_to root_path
end
end
Is this the best way? I was thinking about putting a method in the model but I am not sure I can access current_user from there. I was also thinking about a before_filer, something like:
before_filter :check_ownership, :only => [:destroy, :update]
I that case and if I want to code only one method for all objects (all objects this relates to have a "user_id"-field)
In my application controller I put:
before_filter :authorize
def authorize
false # Or use code here to check if user is admin or not
end
Then I override the authorize method in my actual controller to allow access to various actions.
You're looking for an authorization solution on top of your authentication (devise)
You can't access current user in the model no. I've had a fair amount of success using Makandra's Aegis for authorization. It allows you to create roles specify permissions attributed to each role. The docs are pretty good and I know it works fine with Devise, it's pretty agnostic that way, I've also used it with Clearance. It also passes an implicit "current_user" to your permissions so you can specify and check that your current user can take appropriate actions.

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