Nested Pundit policies? - ruby-on-rails-4

Say I have a Document model that belongs to a User model. A User has_many documents. DocumentPolicy might include this...
def edit?
document.user_id == user.id
end
But, what if...to edit a document you must also be able to edit that documents parent (User). Then, the policy might look like this.
def edit?
document.user_id == user.id &&
policy(user).edit?
end
This results in the error:
undefined method `policy' for #<DocumentPolicy
I'm curious if there is a better way to do this. Am I approaching it incorrectly? It seems like something that others would have thought to do...so, Im hoping to get insight on how others have approached this.

You had the right idea, you just needed to call it through the pundit class explicitly:
def edit?
# I am assuming that a user can edit themselves, so the "or" is in there, if not, go back to using and
document.user_id == user.id or UserPolicy.new(user, User.find(document.user_id)).edit?
end
That should give you what you wanted.

In your Document Controller, declare the user variable and authorize that user.
def edit
#document = Document.find(params[:id])
#user = User.find(#document.user_id) #or how you define it
authorize #user
end
Then pundit will look in your User Policy for the edit? method.
**edit regarding the error message, it is saying that your Document model has no policy file associated to it. If you look in your policies folder you should see user_policy.rb but not document_policy.rb (app/controllers/policies)

Related

How to customize Devise Invitable for different use cases

I am trying to follow the documentation for Devise Invitable here to send different email for different user types, in my case partners and clients.
So it says to add in your Devise model, which in my case is User.rb, the following code.
....
attr_accessor :invitation_instructions
....
def self.invite_partner!(attributes={}, invited_by=nil)
self.invite!(attributes, invited_by) do |invitable|
invitable.invitation_instructions = :partner_invitation_instructions
end
end
def self.invite_client!(attributes={}, invited_by=nil)
self.invite!(attributes, invited_by) do |invitable|
invitable.invitation_instructions = :client_invitation_instructions
end
end
Then from my controller, when a new user signs up I am calling
....
if current_user.is_client?
user.invite_client!(user, current_user)
else
user.invite_partner!(user, current_user)
end
When I do that the error I get back is
undefined method 'invite_client!' for #<User:0x007ffbcdfabd08>
Which is a little confusing because the method is defined in the user model, so I would think that, at least, it was defined.
Any help on fixing this and getting this setup to work would be greatly appreciated!
I think those are class methods and you should call it like User.invite_client! and also pass your arguments in method.
Same goes for invite_partner!

Overriding Devise::RegistratoinsController

So I am trying to override Devise::RegistrationsController which they do have wiki for and tons of tutorial out there. The one thing that I can not find is the best implementation of how to override the controller whilst implementing the require admin approval feature as well.
I think I got the hang of it but before I go any further (from all the reading on the Devise's source code) I want to know, on the registrations controller there's a line that does:
resource.active_for_authentication?
However, on the Sessions controller it's just this:
def create
self.resource = warden.authenticate!(auth_options)
set_flash_message(:notice, :signed_in) if is_flashing_format?
sign_in(resource_name, resource)
yield resource if block_given?
respond_with resource, location: after_sign_in_path_for(resource)
end
What I want to know is, if it's not confirmed or the active_for_authentication returns false, where or how does the session controller check this? I tried tracing back the source code but no luck.
So anyone who's very familiar with Devise perhaps you could answer my question? Thank you.
After authenticating a user and in each request, Devise checks if your model is active by calling model.active_for_authentication?. This method is overwritten by other devise modules. For instance, :confirmable overwrites .active_for_authentication? to only return true if your model was confirmed.
You can overwrite this method yourself, but if you do, don't forget to call super:
def active_for_authentication?
super && special_condition_is_valid?
end
Whenever active_for_authentication? returns false, Devise asks the reason why your model is inactive using the inactive_message method. You can overwrite it as well:
def inactive_message
special_condition_is_valid? ? super : :special_condition_is_not_valid
end

How to use pundit scopes?

I have just made the switch to Pundit from CanCan. I am unsure about a couple of things, and how Pundit is best used.
For example:
If you have a resource that can have multiple parent objects, for instance lets say a Goal belongs to a student and instructor. Therefor, a student can have many goals and an instructor can have many goals. In a controller index action you might do:
if params[:student_id].present?
#account = Student.find(params[:student_id])
#goals = #account.goals
elsif params[:instructor_id].present?
#account Instructor.find(params[:instructor_id])
#goals = #account.goals
end
params are not usable inside policies, so the logic needs to be done here. I think. For what I can tell, if you skip the policy_scope you will get an unauthorized error when viewing the index page for goals.
Would you:
#goals = policy_scope(#account.goals)
OR
#goals = policy_scope(Goal.scoped).where( account_id: #account.id)
What happens when you throw a bunch of includes in the mix?
#example = policy_scoped(#school.courses.includes(:account => :user, :teacher ))
Or when needed to order...is this correct?
policy_scope(Issue.scoped).order("created_at desc")
When using scopes: What is :scope here? Is :scope an instance of the model being evaluated? I've tried accessing its attributes via :scope, but didn't work.
class Scope < Struct.new(:user, :scope)
Reading through this from a security perspective I can see a couple things that bear mentioning. For example, if you are allowing users to specify the student_id and instructor_id param fields, what's to stop them from passing in an ID for someone other than themselves? You don't ever want to let a user specify who they are, especially when you are basing policies on the users type.
For starters, I would implement Devise and add an additional boolean field called instructor that would be true when the user was an instructor but default to false for students.
Then your Users would automatically have an instructor? method defined, which will return true if the value in the instructor column is true.
You could then add a helper for students:
def student?
!instructor?
end
Now using Devise (which gives us access to a current_user variable) we can do things like current_user.instructor? which will return true if they are an instructor.
Now on to the policy itself. I just started using Pundit a few weeks ago, but this is what I'd do in your situation:
class GoalPolicy < ApplicationPolicy
class Scope < GoalPolicy
attr_reader :user, :scope
def initialize(user, scope)
#user = user
#scope = scope
end
def resolve
#scope.where(user: #user)
end
end
end
Then your (I'm assuming GoalsController class and index method) method can look like:
def index
policy_scope(Goal) # To answer your question, Goal is the scope
end
If you wanted to order you could also do
def index
policy_scope(Goal).order(:created_at)
end
I just realized that you asked this question half a year ago, but hey! Maybe it'll answer some questions other people have and maybe I'll get some feedback on my own budding Pundit skills.
Follow #Saul's recommendation on adding devise or other means of authentication.
Then you'll want to do this (Entity is Goal in your case):
#entities = policy_scope(Entity).where(...)
In entity_policy.rb:
class EntityPolicy < ApplicationPolicy
class Scope < ApplicationPolicy::Scope
def resolve
# Here you have access to `scope == Entity` and `user == current_user`
scope.where(entity: user.entity)
end
end
end
You might wonder why is where duplicated. The answer is (and here is the answer to your question): they serve different purposes. Although currently they are identical, but consider this:
You now have an admin user who has access to everything. Your policy changes:
class EntityPolicy < ApplicationPolicy
class Scope < ApplicationPolicy::Scope
def resolve
if user.admin?
scope.all
else
scope.where(entity: user.entity)
end
end
end
end
If you have organizations with goals and the following restful endpoint:
/organizations/:organization_id/goals
When a user visits /organizations/1/goals you want to make sure the user is only allowed access to goals when the user is part of the organization:
scope.where(organization: user.organization) in the policy
And you also want to make sure that when an admin visits they can only see the goals related to that organization:
policy_scope(Goal).where(organization_id: params[:organization_id]) in the controller.

Understanding Rails/Twitter On-click tweet on behalf of user

As preface, I've followed through some tutorials (i.e. Michael Hartl's) though I'm still fairly novice. Forgive any cloudy terminology.
I am trying to build a simple application in Rails 4 that does the following:
User logs into application (currently working with sign-in-with-twitter link and routing)
get "/auth/:provider/callback" => "sessions#create"
get "/signout" => "sessions#destroy", :as => :signout
Once <% if current_user %> is true, I have the view rendering a partial where there will be a list of simple buttons. When the user clicks a button I want the application to tweet on behalf of the current_user a preset string. Ideally, I'd do this all in ruby/rails.
These button functions are where I'm getting hung up. I've read a fistful of documents but there seem to be a lot of conflicting and old answers. Here's a quick list of the ones I think are closest, though not explicit about sending a tweet from a simple button/link in a view:
http://www.sitepoint.com/ruby-social-gems-twitter/
http://richonrails.com/articles/sending-a-tweet-to-twitter
Some call for controllers, a more robust oauth setup (which I have bundle installed and connected to the dev.twitter application, though not fleshed out beyond keys), and whatever else. It's got me turned around and I'm not yet good enough to synthesize all the information. Any help and direction would be great. Below are some other files in the app that might be helpful.
class SessionsController < ApplicationController
def create
auth = request.env["omniauth.auth"]
user = User.find_by_provider_and_uid(auth["provider"], auth["uid"]) || User.create_with_omniauth(auth)
session[:user_id] = user.id
redirect_to root_url, :notice => "Hi!"
end
def destroy
session[:user_id] = nil
redirect_to root_url, :notice => "Bye!"
end
end
And omniauth.rb
Rails.application.config.middleware.use OmniAuth::Builder do
provider :twitter, '_priv', '_priv'
end
Eep! I'm the author of the second link (RichOnRails). Did you take a look at the example app included with the tutorial? It does almost exactly what you want. If the tweets are hard coded you could approach it in a couple of different ways. If you take a look at the tweets controller, you'll see it takes a parameter called 'message'. Any message passed to that create method will tweet as the current user.
def create
current_user.tweet(twitter_params[:message])
end
The easiest (but not necessarily best) way to adapt this to fit your needs is to have a form for each tweet, and do a hidden field with the message you wish to tweet. The button becomes a submit for that particular form (you can add remote: true if you want to keep the page from refreshing, then use a bit of javascript to update the UI elements). Hope this helps.

Generating a unique URL with tokens in Rails 4 for an external form response

I have a 'Feedback' model whereby a user should be able to request feedback on his/her job performance. I have written basic actions for creating a new feedback request, and the mailer for sending the request to the provider (person who will respond with feedback).
I would like advice from the community on implementing the following:
Once a new feedback request is created, the email that is sent should contain a link to a form where the provider can input his feedback on the users performance.
The feedback provider should not be required to log-in or sign-up in any way (i.e. completely external to the application).
Once submitted, feedback from the provider should be captured in the
system.
Now, I have the following ideas to implement it, but am not sure if this is the best way to proceed:
Generate a unique token upon the creation of a new feedback request. Something like this: Best way to create unique token in Rails?.
The token should then be entered into 'feedbacks' table.
Mailer should then generate variable (e.g. #url) which generates link to another controller (let's say 'external_feedback' and action which does not require log-in (e.g. no before_filter :authenticate_user! from Devise).
That URL should contain a parameter with the token for the specific feedback request.
The action should be to update the 'feedback' request and a form generated with simple_form.
The whole thing is similar to responding to a questionnaire or survey (like Survey Monkey).
After some research I believe the Friendly ID gem may be useful here. I was also reading Section 8 of http://guides.rubyonrails.org/form_helpers.html and perhaps I need to implement an authenticity_token in the formal sense. What I am really looking for is:
Is the above approach the generally correct way to go about doing this?
If so, any specifics on how you would implement it (with or without Friendly ID)?
Do you know of any gems that exist for generating such URLs/tokens?
Thank you in advance. I am now including the current state of model and controller details:
feedback.rb
# == Schema Information
#
# Table name: feedbacks
#
# id :integer not null, primary key
# user_id :integer
# p_first_name :string(255)
# p_last_name :string(255)
# p_email :string(255)
# goal_id :integer
# u_comment :text
# p_comment :text
# created_at :datetime
# updated_at :datetime
#
class Feedback < ActiveRecord::Base
belongs_to :user
belongs_to :goal
has_many :feedback_attributes
validates_presence_of :p_first_name, :p_last_name, :p_email, :goal_id
end
And this is my mailer:
class FeedbackMailer < ActionMailer::Base
def feedback_request(user, feedback)
#user = user
#feedback = feedback
#url = 'http://thisistheexampleurlforfeedback'
mail(to: #feedback.p_email, subject: "#{#user.first_name} #{#user.last_name} has requested your feedback", from: #user.email)
end
end
Add a token field to the feedback model with an index and add a callback to populate it on create e.g.
feedback.rb
before_create :add_token
private
def add_token
begin
self.token = SecureRandom.hex[0,10].upcase
end while self.class.exists?(token: token)
end
now add a new route for the providers feedback
resources :feedbacks do
get 'provider'
put 'provider_update' # you might not need this one, if you are happy to use update
end
In your controller make sure they don't get rejected by devise
before_filter :authenticate_user!, except: [:provider, :provider_update]
...
def provider
#feedback = Feedback.find_by token: params[:token]
end
then in the app/views/feedback/provider.html.haml you can use url in simple_form to send it to the correct update location and only provide the input that they should see.
f.inputs :p_comment
Now update your mailer.
#url = provider_feedback_url(#feedback, token: #feedback.token)
You could do something similar to this using friendly id but you would still need to create some sort of unique slug and then use Feedback.friendly.find instead. I think you would want to combine it with a token to ensure it's still the provider giving the feedback - so the only benefit would really be hiding the true id/count. I think you should update p_* fields to provider_* so that the next dev knows what's in it - it's not the 90s!