I'm running into problems defining user permissions in my cancan controller:
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new # guest user
if user.role? :admin
can :manage, :all
else
can :read, :all
can :update, User do |user|
user.try(:user) == user
end
end
end
end
This results in a NoMethodError:
undefined method `user' for #<User:0x000001050914c8>
When I try and edit / update a user. Everything else seems just fine.
Any help appreciated
Bob
The problem is that
user.try(:user) == user
is basically trying to execute user.user == user
Looks like you're trying to only let users update the User model attributes if the User instance in question is the logged-in user.
Try this instead:
can :update, User, :id => user.id
Which is saying "Can update the User model when #user.id is the same as the current_user.id."
Your block notation is ambiguous since your block variable |user| is the same as the user passed in to the Ability model.
As a side-note for those still getting a grip on Ruby,
can :update, User, :id => user.id
is the same as:
can(:update, User, { id: user.id })
Related
Having trouble figuring out how to set up my different roles with cancancan abilities. I have a model "Business" which has many users with a role of either :owner, :manager or :employee.
Im trying to make it first that if they don't belong_to that business they can't see anything for that business. And second I want to limit functionality based on which role they have.
I guess I could do this within the views by using if statements and only showing them the things they have access to, but wondering if there is a better way with cancan
inside your ability.rb
class Ability
include CanCan::Ability
def initialize(user)
alias_action :create, :read, :update, :destroy, :to => :crud
if user
if user.role == "manager"
can :crud, Business, :id => user.business_id
# this will cek whether user can access business instance (id)
elsif user.role == "owner"
can :manage, :all
end
end
end
end
inside your controller you can do checking with 2 ways
step 1: with load_and_authorize_resource, this will automatically check all 7 rails method
class BookingsController < ApplicationController
load_and_authorize_resource
# this before filter will automatically check between users and resource
# rails method here
def show
end
end
step 2: check manually with authorize inside each method
def show
#business = Business.find(params[:id])
authorize! :read, #business
end
Definitely read through cancan's wiki as I'm not 100% on this, but I think the solution will look something like this:
def initialize(user)
user ||= User.new
if user.has_role?(:owner)
can :read, Business, Business.all do |business|
business.id == user.business_id
end
elsif user.has_role?(:whatever)
# etc
end
end
Then just check authorize! in the controller in the normal cancan way. As for showing them appropriate functionality in views, you can either do a bunch of if statements in the view any maybe try to use partials to make it all look palatable, or check in the controller and render different views based on role, but yeah, there's gotta be if statements somewhere.
The best way is to always use "incremental" permissions. Consider that cancancan starts already with the assumption that your users have no right on Business, so you can give them "incremental" permissions based on their role.
An example would be:
# give read access if they have any role related to the business
can :read, Business, users: { id: user.id }
# give write access if they are manager
can [:edit, :update], Business, business_users: { role: 'manager', user: { id: user.id } }
# give destroy permissions to owners
can [:destroy], Business, business_users: { role: 'owner', user: { id: user.id } }
I'm making a rails project, and I'm trying to implement CanCanCan. I installed the gem and the ran the commands. I then added this to ability.rb:
class Ability
include CanCan::Ability
def initialize(user)
# Define abilities for the passed in user here. For example:
user ||= User.new # guest user (not logged in)
if user.admin?
can :manage, :all
else
can :update, Post do |post|
post.user == user
end
can :destroy, Post do |post|
post.user == user
end
can :create, Post
can :read, :all
end
end
end
However, now in my project, if I sign into a different user, I can still edit other users posts.
Any help with what I'm missing will be greatly appreciated.
The error was solved by adding load_and_authorize_resource to my posts_controller
According to CanCanCan documentation,
The block is only evaluated when an actual instance object is present.
It is not evaluated when checking permissions on the class (such as in
the index action). This means any conditions which are not dependent
on the object attributes should be moved outside of the block.
don't do this
can :update, Project do |project|
user.admin? # this won't always get called
end
do this
can :update, Project if user.admin?
So instead of
can :update, Post do |post|
post.user == user
end
can :destroy, Post do |post|
post.user == user
end
Change that do
can :update, Post if post.user == user
can :destroy, Post if post.user == user
Try something like can :manage, Post, :user_id => user.id
As you can see at https://github.com/ryanb/cancan/wiki/defining-abilities
I have it set up the same way as nersoh, and that method works for me. Have you tried authorizing the Posts resource in the controller? For example,
class PostsController < ActionController::Base
load_and_authorize_resource
end
I am a little confused about how to configure CanCanCan properly.
For starters, do I have to add load_and_authorize_resource to every controller resource I want to restrict access to?
This is what I would like to do:
Admin can manage and access all controllers and actions
Editor can read all, manage :newsroom, and can manage all Posts
Member can read every Post and can create & update Posts (not edit/delete/anything else), cannot access the newsroom. The difference between an update & edit post in our business rules is that an update is creating a new post that is a child post of the current post. So it isn't an edit. Just a new record with an ancestry association.
Guest can read every Post, but cannot create Posts nor access the Newsroom.
This is what my ability.rb looks like:
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new # guest user (not logged in)
#Admin
if user.has_role? :admin
can :manage, :all
can :manage, :newsroom
# Editor
elsif user.has_role? :editor
can :read, :all
can :manage, :newsroom
can :manage, Post
#Member
elsif user.has_role? :member
can :read, :all
can :create, Post
can :status, Post
can :update, Post do |post|
post.try(:user) == user
end
#Guest
else
can :read, :all
can :create, Post
can :status, Post
end
end
end
In my routes.rb I have this:
authenticate :user, lambda { |u| u.has_role? :admin or :editor } do
get 'newsroom', to: 'newsroom#index', as: "newsroom"
get 'newsroom/published', to: 'newsroom#published'
get 'newsroom/unpublished', to: 'newsroom#unpublished'
end
What is happening though, is when I am logged in with a user that has not been assigned any roles (i.e. what I want to be a "Guest"), they can access the Newsroom.
When I try to edit a post with the role of :member, it gives me a "Not authorized to edit post" error (which is correct).
I just can't quite lockdown the Newsroom and I am not sure why.
You do not need to use load_and_authorize_resource in every controller. That is a convenience macro that does two things. First it assigns an instance variable with the record(s) assumed for the current controller and action. It then authorizes the resource. For some controller actions the first step might be wrong, so you want to load your resource and then authorize it manually. An example from the Railscasts episode about CanCan is like this:
def edit
#article = Article.find(params[:id])
unauthorized! if cannot? :edit, #article
end
You can also do it like in the example on the CanCan Wiki for authorizing controllers:
def show
#project = Project.find(params[:project])
authorize! :show, #project
end
Or you can just use authorize_resource and take care of loading it yourself. In the end, you must make sure that CanCan is used for authorization somehow (controller macro or in each action). Regarding your abilities, I think you want something like this:
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new # guest user (not logged in)
#Admin
if user.has_role? :admin
can :manage, :all
# Editor
elsif user.has_role? :editor
can :read, :all
can :manage, :newsroom
can :manage, Post
#Member
elsif user.has_role? :member
can :read, :all
can :create, Post
can :status, Post
can :update, Post do |post|
post.try(:user) == user
end
#Guest
else
can :read, :all
cannot [:index, :published, :unpublished], :newsroom
end
end
end
And here's an example like how you might be able to authorize your newsroom:
class ToolsController < ApplicationController
authorize_resource :class => false
def show
# automatically calls authorize!(:show, :tool)
end
end
A last personal note about CanCan is that I wouldn't suggest it for new projects since it isn't actively maintained anymore and that I found it a bit counterintuitive when defining abilities. That said, CanCan is one of the most well-documented gems that I have worked with, especially the wiki has loads of examples and explanations.
can :read, :all
means user has permission to read all the resources of your app. It should be
can :read, Post
also add
cannot :manage, :newsroom
where you do not want access to newsroom. The order in which you specify permissions matters.
As others have already mentioned, 'load_and_authorize_resource' is optional. Only 'authorize resource' is needed to authorize all actions of a controller. If you skip these then you can 'authorize' individual controller actions.
Avoid using block for ability unless absolutely necessary. For instance if Post has a user_id in it then you could do
can :update, Post, user_id: user.id
Lastly, 'class => false' is used where you do not have a model backing your controller.
i.e you do not have a model called 'Newsroom' but you have a controller called 'NewsroomsController'.
For what it's worth, I had to setup my NewsroomController like this:
class NewsroomController < ApplicationController
authorize_resource :class => false
This is what the working version of my ability.rb looks like after I got it to work with the permissions I needed:
#Roles
#Admin
if user.has_role? :admin
can :manage, :all
# Editor
elsif user.has_role? :editor
can :manage, :newsroom
can :manage, Post
#Member
elsif user.has_role? :member
can [:read, :create, :status], Post
can :update, Post do |post|
post.try(:user) == user
end
#Guest
else
can [:read, :status], Post
end
For starters, do I have to add load_and_authorize_resource to every controller resource I want to restrict access to?
Yes.
What is happening though, is when I am logged in with a user that has
not been assigned any roles (i.e. what I want to be a "Guest"), they
can access the Newsroom.
From the guest role above:
...
#Guest
else
can :read, :all
can :create, Post
can :status, Post
end
This gives a guest read access to everything and the ability to create posts.
If you want your Guests to only be able to read posts it should be:
...
#Guest
else
can :read, Post
# can :status, Post # maybe you want this aswell
end
I am utilizing Devise and Cancan for a rails 3.2.6 application. In the application, I allow users to create a document with some information gathered in a form. I then want to allow the user to list on a Document index page at localhost:3000/users/1/documents only their documents, which this is working. What isn't working, is I am trying to limit the user from being able to see everyone else's documents by replacing the /users/:id/documents with another number.
I am using cancan and have tried both
can :index, Document, :user_id => user.id
can :read, Document, :user_id => user.id
and then on the Document controller index method
if can? :read, Document
#documents = #user.documents
else
redirect_to root_path
end
also tried with :index as well...but this isn't working. I am also using load_and_authorize_resource..
Any thoughts on what I am missing?
I will say, cancan is working for my user management and users controller for an admin to create, list and edit users, so I know cancan is working in general. It is also working for updating and deleting a users documents. It is just the index function not working.
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new # guest user (not logged in)
if user.id
if user.has_role? :user
can :create, Document
can :read, Document, :user_id => user.id
can :update, Document, :user_id => user.id
end
end
end
end
You have to make sure that non-logged in users, as well as users whose user.id isn't the same as the Document's user_id (document owner) don't have permission to read all Documents.
class Ability
include CanCan::Ability
def initialize(account)
user ||= User.new #non-logged-in user
# logged in users
if user.id and user.has_role?(:user)
#content owners
can :manage, Document, :user_id => user.id
#other logged-in users
can [:show, :create], Document
end
end
end
Be careful you don't have any line like can :read, :all or can :read, Document most likely you are giving the permission somewhere if you said cancan is working already.
In your case you should write in your ability class
def initialize(user)
can :manage, Document do |document|
document.user == user
end
end
This will check whether document belongs to logged in user or not. If yes can will return true otherwise false.
For more details on how to handle complex authorization with block,
https://github.com/ryanb/cancan/wiki/Defining-Abilities-with-Blocks
I'm trying to use Devise authorisation with CanCan roles in my rails3+mongoid app.
Now I have to limit users access to edit the events, so only their author could do this. Author of the event is determined by that line:
<%= f.hidden_field (:author, :value =>current_user.email) %>
So, now in CanCan's Ability file i'm trying to use this code:
class Ability
include CanCan::Ability
def initialize(user)
user ||= User.new
if user.role? :admin
can :manage, :all
else
can :read, :all
end
if
user.role?(:normal)
can :create, Event
can :update, Event do |event|
event.try(:author) == current_user.email
end
can :create, Comment
can :update, Comment do |comment|
comment.try(:author) == current_user.email
end
end
end
end
But this results me with this error:
undefined local variable or method `current_user' for #
Then i've tried to change
can :update, Event do |event|
event.try(:author) == current_user.email
to
event.try(:author) == Devise.current_user.email
but that results with this error
undefined method `current_user' for Devise:Module
So, what should I do and how can I call for `current_user' method from ability.rb? Thank you in advance for any tips.
Why are you referring to current_user in your initialize method? Why not just the user that was supplied as an argument to the method?
CanCan will call initialize for the current_user when it needs to.