Rails - CRUD for user and admin, how many controllers? - ruby-on-rails

My model holds expenses, including user and project references..
class Expense < ActiveRecord::Base
attr_accessible :amount, :expense_date, :description, :project_id, :user_id
belongs_to :project
belongs_to :user
end
The ExpensesController handles basic CRUD operations for the expenses.
I now am needing to build an administrators version of this same page, a new view preferably, which can include the different views of the data, by user, by project, etc, and can also edit data that the user cannot.
My question is: Do a build a second controller to handle the administrative perspective of the data, -- or do I setup conditions inside of every method, to detect the originating view and form, and then conditions to redirect them back to where they belong?
If I do build a second controller, how do I properly setup the form_for so that it knows what controller to go to?
Thanks!
PS - If anyone has any books about how to properly put together a rails app, I feel like I know the pieces ant parts, but I'm getting stuck on the big picture implementation. I learned rails with Michael Hartl's guide, prior to that I was a PHP developer.

IMHO, if security is a big concern for your app then using an admin namespace and separate controllers is the best way to make sure you don't leave any gaps. It's also just simpler and lower stress.
I would have a directory structure like so:
/app/controllers/application_controller.rb
/app/controllers/admin_controller.rb - inherits from application_controller
/app/controllers/expenses_controller.rb - non-admin, inherits from application_controller
/app/controllers/admin/expenses_controller.rb - inherits from admin_controller
Your views would be similarly separated/duplicated:
/app/views/expenses/* - non-admin expenses views
/app/views/admin/expenses/* - admin expenses views
In application_controller you'd put the Devise methods to authenticate_user and CanCan method to check_authorization (which throws an exception if authorization is not checked at some point in the controller action). In admin_controller you have more strict filters to make sure the user is an admin. Then you can get even more fine-grained in the specific controllers and their actions.
Of course each controller only has to define the actions it really needs and you don't have to duplicate views. Maybe the non-admin expenses_controller has index, show, new, create, while the admin one has only edit, update, and destroy. Then in the 'show' view you'd still have code that add links to the 'edit' action if the user is an admin.
Edit - Routes
With the above example, your routes.rb would look something like:
resources :expenses, :only => [:index, :show, :new, :create]
namespace :admin do
resources :expenses, :only => [:edit, :update, :destroy]
end
So you still use expenses_path() for the index and expense_path(foo) for show. A form on the admin page, however, would post to admin_expense_path(#expense).

If you wish to add another Controller I would suggest having common code in a module and importing them in each Controller. Each controller would also have an adequate before filter to check for adequate rights.
But I would prefer having one controller and one set of views since I think it avoids code duplication and/or confusion. Pass the user as a local variable to the view and check for administrator rights when you need to decide the URL for the form_for or whether to hide or show some part.
If the views differ significantly, check for admin rights in the controller and render either the user view or the admin view.
You can even create a special partial for the admin part of the view and decide whether to render it in the view or not, sending the appropriate data in the params or not.

You can use Devise gem for authentication.
You can create somekind of "namespace" for administrative part of your application.
I my opinion, creating another controller depends on how many views and actions your admin will access.
About the doubt about form_for action, it will be managed by your routes and paths that you configure in your form_for params.

Related

Rails 4 user roles and permissions

I am writing a rails application for an organization. Every user may have 1 or more roles and can only access certain controller actions depending on those roles.
For example, only admins can create, destroy and update certain fields of Users. Also, there are Teams which each have a team leader, and only the team leader can update certain information about the Team (like the member list, for example). However, Admins are the one who assign the team leader in the first place.
The specific details of my scenario are not important, I merely hope I described the situation where there are many different roles and permissions.
My question is: what gem to use? My first thought was CanCan, but the last commit was almost a year ago and there is no mention of Rails 4 compatibility. Is there a currently maintained alternative?
Your first guess was right, use cancancan and you'll be good with it.
EDIT Jul 24, 2015
I've been using cancancan for a long time now and it was always working great. I've recently started working on a project where Pundit is used for authorization.
It is awesome. It prompts you to define the policy for each resource and it feels more natural than one bloated Ability class.
For bigger projects, I would definitely recommend Pundit.
To control access to actions I'd recommend Action Access, it boils down to this:
class UsersController < ApplicationController
let :admin, :all
let :user, [:index, :show]
# ...
end
This will automatically lock the controller, allowing admins to access every action, users only to show or index users and anyone else will be rejected and redirected with an alert.
If you need more control, you can use not_authorized! inside actions to check and reject access.
It's completely independent of the authentication system and it can work without User models or predefined roles. All you need is to set the clearance level for the current request:
class ApplicationController < ActionController::Base
def current_clearance_level
session[:role] || :guest
end
end
You can return whatever you app needs here, like current_user.role for example.
Although it isn't required, it bundles a set of handy model additions that allow to do things like:
<% if current_user.can? :edit, :team %>
<%= link_to 'Edit team', edit_team_path(#team) %>
<% end %>
Here :team refers to TeamsController, so the link will only be displayed if the current user is authorized to access the edit action in TeamsController. It also supports namespaces.
You can lock controllers by default, customize the redirection path and the alert message, etc.
It's very straightforward and easy, I hope you find it useful.
Something that was suggested to me that we are now using is the petergate gem. Easy to use and very clean looking with a great rails feel.
Works well with devise.
Here is some examples from the readme.
If you're using devise you're in luck, otherwise you'll have to add following methods to your project:
user_signed_in?
current_user
after_sign_in_path_for(current_user)
authenticate_user!
This comes in your User.rb. Adding more roles is as easy as adding them to the array.
petergate(roles: [:admin, :editor], multiple: false)
Instance Methods
user.role => :editor
user.roles => [:editor, :user]
user.roles=(v) #sets roles
user.available_roles => [:admin, :editor]
user.has_roles?(:admin, :editors) # returns true if user is any of roles passed in as params.
Controller access syntax.
access all: [:show, :index], user: {except: [:destroy]}, company_admin: :all

Custom Rails action and forms

I'm still trying to get my head around actions and routes. I more or less understand how to user forms with the build-in controller actions like create, show, etc. What I want to do for a demo app is imitate a school's class schedule, where I have Courses and Students with a has_and_belongs_to_many relationship.
I'm using Mongoid, and I can add students to a course and vice versa using the console, but I can't figure out how to do it with a form. Would adding students to a course even be a controller action, or can I write and call a setter in the model somehow? If a controller action is better, what would the route look like?
If anyone knows of an example that does something similar, I'd love to examine it.
Thanks
It can be a controller action. If adding students to a course is a simple logic, you could add /courses/:course_id/Students/add. This means creating a courses folder, and a students_controller within it, with an add action.
Example (in your routes.rb)
resources :courses, :except => [:destroy] do
resources :students
end
More info: https://gist.github.com/jhjguxin/3074080
Is this what you are looking for?

Rails RESTful website vs user experience and less clicks

Situation: I have a team model, a user model and a teamate model for the users of a team.
Say I want to have a view that contains the information of a team team/show
and that I wish (to simplify the user's experience) to add a list of the users, an add user to team and the possibility to remove a user from that team.
To be perfectly restful, I would need a controller (let's call it Teamates), it would handle the users of a team.
I would have all the CRUD needed.
Is it clean to have the team/show view call the teamates controller for the following actions: adduser, removeuser, listusers.
What I am trying to achieve is less clicks for the users.
In other words, I would like the user to be able to manage the users of a team from the team view instead if requireing him to navigate even further.
I don't think you need a controller for teamates.
And you really should not have adduser/removeuser/etc actions in your team controller!
You could set up your routes like that:
resources :teams do
scope :module => "team_scope" do
resources :users
end
end
Then you would have a UsersController in app/controllers/team_scope/users_controller.rb
To create a new user for a team, you would post to: /team/1-team-a/users and it would hit the create action in the UsersController above.
When you use scope in your routes, it does not change the route helpers like with namespace. The new action would just be accessible via new_team_user_path(#team).
Hum... so yeah, in this case I would have a TeamatesController, and maybe set up my routes like that:
resources :teams do
resources :teamates, :only => [] do
collection do
get :edit
put :update
end
end
end
And then you could edit the associations between a team and its players...
Your form would post the users id to team_teamates_path(team)...
But I'm really not sure it's the best way, I'd have to think about it. This is not really restful as well.

Why would you want to use the same controller to handle a singular and a plural route?

I'm working on a rails app and using a singular resource. However the controller name for the singular resource is plural.
Eg map.resource activity_report expectes the activity_reports_controller.
The explanation given in the rails 3 guide is: "... you might want to use the same controller for a singular route and a plural route..." That is a reasonable explanation, but what is the use case for using the same controller to handle a singular route and a plural route?
In a RESTful Rails application there is usually a mapping of one controller per RESTful resource. For example, let's say we wanted a controller to process user logins (/session) but also to provide a list of users who are currently logged in (/sessions). Logically we could put both of those responsibilities within a SessionsController:
class SessionsController < ApplicationController
# GET /sessions
# Display a list of logged in users
def index
...
end
# GET /session/new
# Display the login form
def new
...
end
# POST /session
# Authenticate a user
def create
...
end
end
An alternative would be to split the functionality for listing logged in users out into a separate administration controller.
You can use it.
class UsersController < Application
end
map.resource :user
map.resources :users
Another situation in which I can imagine using it would be, let's say (and this isn't necessarily the business model you'd want, but stay with me for a moment) you are going to make a site of film reviews, and film information. So, on the one hand you'd have the link to your list of the latest reviews be a plural resource route, something like this:
http://yoursite.com/reviews?count=5
So, in this case, you have a controller for the collection, right? But you're only going to review each movie once. So what if you wanted to provide an easy access to a movie's review?
http://yoursite.com/movies/pirates_of_the_carribean_2/review
Well, there's a nested single resource route, because a movie has_one review, right?

Multiple controllers with a single model

I'm setting up a directory application for which I need to have two separate interfaces for the same Users table. Basically, administrators use the Users controller and views to list, edit, and add users, while non-admins need a separate interface which lists users in a completely different manner. To do this, would I be able to just set up another controller with different views but which accesses the Users model?
Sorry if this is a simple question, but I've had a hard time finding how to do this.
Why not put the admin part into a separate namespace - you would have Admin::UsersController with views in app/views/admin/users/. And your users would go to UsersController with its own views in app/views/users/.
The routing is defined like this:
map.namespace :admin do |admin|
admin.resources :users
end
map.resources :users
And can be got to via admin_users_path and users_path

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