Rails CanCan and Scoped attr_protected - ruby-on-rails

I've got a Rails 3.1 app using CanCan 1.6. I'm protecting a variety of attributes with attr_protected ... :as => :api. I'd like to use load_and_authorize_resource, but also to strip off the protected fields. Any ideas?
EDIT: Here's my current workaround:
In orders#new, I'm skipping the load_resource and just authorizing. I initialize the new order directly, with the appropriate scope:
#order = Order.new(params[:order], :as => :api)
Then setting the user manually:
#order.user = current_user
Certainly not a huge deal to do, but less elegant than just letting CanCan load and authorize natively, as I'm doing elsewhere.

Generally if you only have a few protected fields to submit for, it would just be easier to pull the value out of the parameter hash and manually assign it.
##save the parameter and delete it from the hash
role = params[:employee][:role_id]
params[:employee].delete("role_id")
##create object and assign parameter manually
#employee = Employee.new(params[:employee])
#employee.role_id = role
If you have a lot of attributes, you could automate the manual assignment.
##list protected attributes and create new employee
attr = Employee.protected_attributes ##["id", "type", "name"]
#employee = Employee.new
##loop through params and manually send value
params[:employee].each do |p|
#employee.send("#{p}=", params[:employee]["#{p}"])
end
Didn't have time to fully test the second part, but that should get you in the right direction.

Related

Strong Parameters and Find in Rails 4

I am having trouble with strong parameters in my custom controller. I understand how to use strong parameters in a new or update action. However, I can't seem to figure out if this is an unsecure use of the params[] hash or not in my custom action.
My view redirects to a controller with an order id and an operation number:
link_to 'Confirm', confirmpayment_confirm_path(order: order, operacion: order.operacion), :data => { confirm: 'Are you sure?' }
My confirmpayment controller is as follows:
class ConfirmpaymentController < ApplicationController
before_action :authenticate_user!
def lookup
authorize! :lookup, :confirmpayment
#orders=Order.where(:status => 'PENDING')
end
def confirm
authorize! :confirm, :confirmpayment
#order=Order.find(params[:order])
#order.payment_id = params[:operacion]
#order.confirm_payment_date = DateTime.now()
#order.save
end
def order_params
params.require(:order).permit(:order, :operacion)
end
end
The question is:
I am not using order_params anywhere in my confirm action, since this is not a new order. I am using the parameter to find the proper order and confirm it. Is this secure? Or am I missing something?
So to clear a few things up.
Strong Parameters is responsible for the allowed parameters which are passed to your database. It should prevent the users to modify attributes in the database which they aren't allowed to modify.
For example:
You have the following table with columns:
User:
- firstname
- lastname
- email
- password_digest
- role (user, admin)
You probably want to prevent normal users to change their role. But if you pass a parameters hash as it is to the database, he could also add a role key with value to the hash. Your application would accept it. Strong parameters checks the hash and prevent the change.
In your example above, Strong Parameters brings no advantages. You assign the values directly to the appropriate table columns. It isn't possible to modify any other attributes in the database for the user. If you don't have any other methods in your controller, you could remove the entire #order_params. Strong Parameters just raises an exception if you would try to pass a hash directly through.
However I would recommend you to search for the payment in the database before you assign it. If you assign payment_id directly you have no guarantee that payment exists. So first check for the payment and if you found it assign it to the order.
Here is how I would have done it:
class PaymentConfirmationController < ApplicationController
before_action :authenticate_user!
before_action :authorize_user! # To DRY up your code
def lookup
#orders = Order.where(:status => 'PENDING')
end
def confirm
#order = Order.find(params[:order_id])
#payment = Payment.find(params[:operation_id])
# You should catch the exceptions if an order or payment wasn't found
#order.payment = #payment
#order.payment_confirmation_date = Time.now()
#order.save
end
private
def authorize_user!
authorize! :confirm, :confirmpayment
end
end
I haven't tested the code but it should work.
Here are the Docs of Strong Parameters. They describe everything in more detail.
I hope this helps!
Happy coding :)
About the way of using parameter, I think there is nothing wrong with it. But about the security problem, you may want to think about the case that user can change any Order information by just change the order param to something that doesn't belong to him.
In that case, you will want to limit the query to Order, make he can only confirm the order that belongs to him.
Strong Parameters: prevent accidentally exposing that which shouldn't be exposed. They are generally used when you create or update a model, this to avoid entering parameters have not been allowed.
I have some suggestions:
English preferably encoding: operacion to operation
Check style
in your code ConfirmpaymentController to class
ConfirmPaymentController
you can see: best practices and style prescriptions for Ruby on Rails 4 :)

Ruby - How to define params for require()?

questions_controller.rb
def index
#questions = Question.all(app_params)
end
private
def app_params
params.require(:questions).permit(:question, :answer)
end
end
question.rb
class Question < ActiveRecord::Base
end
I am completely new to ruby-on-rails. I was following a guide and it said I should take care of some "loopholes" or "security issues" and it used attr_accessible, but on Rails 4, they suggest strong parameters, so now I'm trying to use them. I'm confused on how to define the :questions params, because I'm currently getting an error saying that :questions param is not found.
:questions is pretty much something that I will define myself as the web developer.
So for example, I will define questions = "How are you?", "What is your name?". I'm basically starting very simply. I want questions that I have created to be displayed on my webpage. Ultimately, I plan to make a website what is basically a list of questions and, with answer options. After the user clicks "submit" I want to store the information into my database.
Am I supposed to even be requiring this as a param? I'm completely lost..
Do you have a dump of the params we could look at? They are shown when your app encounters an error, and typically shows you the params array which rails will pass through
Strong Params In Rails 4
Strong Params allow you to allow certain parameters for use in the controller, protecting against any malicious assignment client-side. They replaced attr_accessible in Rails 4.0
Strong Params is only for user-submitted content, as it's designed to protect the params hash. To that end, it's mostly used with the create and find functions:
class PeopleController < ActionController::Base
# Using "Person.create(params[:person])" would raise an
# ActiveModel::ForbiddenAttributes exception because it'd
# be using mass assignment without an explicit permit step.
# This is the recommended form:
def create
Person.create(person_params)
end
# This will pass with flying colors as long as there's a person key in the
# parameters, otherwise it'll raise an ActionController::MissingParameter
# exception, which will get caught by ActionController::Base and turned
# into a 400 Bad Request reply.
def update
redirect_to current_account.people.find(params[:id]).tap { |person|
person.update!(person_params)
}
end
private
# Using a private method to encapsulate the permissible parameters is
# just a good pattern since you'll be able to reuse the same permit
# list between create and update. Also, you can specialize this method
# with per-user checking of permissible attributes.
def person_params
params.require(:person).permit(:name, :age)
end
end
params.require
The params.require function works by taking this params hash:
params{:question => {:question => "1", :answer => "5"}}
That's why people asked what your params hash looks like, because the require function can only work if the :question hash is present.
Possible Solutions For You
Question.all(app_params)
Regardless of what you're trying to achieve, don't use all. The where function is better for receiving an array of data based on certain values. I believe all is depreciated anyway.
def index
#questions = Question.where("value = ?", variable)
end
What data is being passed?
I will define questions = "How are you?", "What is your name?"
This is okay, but typically in rails, you'd call data by using an ID in the database. If you're defining these questions in a form, you'd use the strong params system; but you'd need a form to submit the data to
Further Additions
The rails way is to keep all your data in a database, and use the application to manipulate that data, either by showing it, or allowing people to input more.
The "params" variables are basically there to help the rails controllers & models accept & process data from end users, and consequently allow you to keep the system growing. Instead of having to write custom code to accommodate all sorts of different data, the params give you a rigid structure to work with. Here is a good explaination of how MVC (and params) works for you: How does an MVC system work?
I think you're getting confused with how your app should work
Your "questions" should be stored in a questions table / model, and can be accessed by calling their ID's with the find function. This code would be like this:
#app/controllers/questions_controller.rb
def show
#question = Question.find(params[:id])
end
If you want to add new questions, you'll be best to add them to the questions table, like this:
#app/controllers/questions_controller.rb
def new
#question = Question.new
end
def create
#question = Question.new(question_params)
#question.save
end
private
def question_params
params.require(:question).permit(:question)
end
#app/views/questions/new.html.erb
<%= form_for #question do |f| %>
<%= f.text_field :question %>
<% end %>
This will give you a central store of your questions, which you'll then be able to access when you need them, either with a helper or with your ".all" call :)
Give it a shot with question (singular):
params.require(:question).permit(:text, :answer)
Assuming question is your model and text (which I made up) is the wording of the question.

Can I make Rails update_attributes with nested form find existing records and add to collections instead of creating new ones?

Scenario: I have a has_many association (Post has many Authors), and I have a nested Post form to accept attributes for Authors.
What I found is that when I call post.update_attributes(params[:post]) where params[:post] is a hash with post and all author attributes to add, there doesn't seem to be a way to ask Rails to only create Authors if certain criteria is met, e.g. the username for the Author already exists. What Rails would do is just failing and rollback update_attributes routine if username has uniqueness validation in the model. If not, then Rails would add a new record Author if one that does not have an id is in the hash.
Now my code for the update action in the Post controller becomes this:
def update
#post = Post.find(params[:id])
# custom code to work around by inspecting the author attributes
# and pre-inserting the association of existing authors into the testrun's author
# collection
params[:post][:authors_attributes].values.each do |author_attribute|
if author_attribute[:id].nil? and author_attribute[:username].present?
existing_author = Author.find_by_username(author_attribute[:username])
if existing_author.present?
author_attribute[:id] = existing_author.id
#testrun.authors << existing_author
end
end
end
if #post.update_attributes(params[:post])
flash[:success] = 'great!'
else
flash[:error] = 'Urgg!'
end
redirect_to ...
end
Are there better ways to handle this that I missed?
EDIT: Thanks for #Robd'Apice who lead me to look into overriding the default authors_attributes= function that accepts_nested_attributes_for inserts into the model on my behalf, I was able to come up with something that is better:
def authors_attributes=(authors_attributes)
authors_attributes.values.each do |author_attributes|
if author_attributes[:id].nil? and author_attributes[:username].present?
author = Radar.find_by_username(radar_attributes[:username])
if author.present?
author_attributes[:id] = author.id
self.authors << author
end
end
end
assign_nested_attributes_for_collection_association(:authors, authors_attributes, mass_assignment_options)
end
But I'm not completely satisfied with it, for one, I'm still mucking the attribute hashes from the caller directly which requires understanding of how the logic works for these hashes (:id set or not set, for instance), and two, I'm calling a function that is not trivial to fit here. It would be nice if there are ways to tell 'accepts_nested_attributes_for' to only create new record when certain condition is not met. The one-to-one association has a :update_only flag that does something similar but this is lacking for one-to-many relationship.
Are there better solutions out there?
This kind of logic probably belongs in your model, not your controller. I'd consider re-writing the author_attributes= method that is created by default for your association.
def authors_attributes=(authors_attributes)
authors_attributes.values.each do |author_attributes|
author_to_update = Author.find_by_id(author_attributes[:id]) || Author.find_by_username(author_attributes[:username]) || self.authors.build
author_to_update.update_attributes(author_attributes)
end
end
I haven't tested that code, but I think that should work.
EDIT: To retain the other functionality of accepts_nested_Attributes_for, you could use super:
def authors_attributes=(authors_attributes)
authors_attributes.each do |key, author_attributes|
authors_attributes[key][:id] = Author.find_by_username(author_attributes[:username]).id if author_attributes[:username] && !author_attributes[:username].present?
end
super(authors_attributes)
end
If that implementation with super doesn't work, you probably have two options: continue with the 'processing' of the attributes hash in the controller (but turn it into a private method of your controller to clean it up a bit), or continue with my first solution by adding in the functionality you've lost from :destroy => true and reject_if with your own code (which wouldn't be too hard to do). I'd probably go with the first option.
I'd suggest using a form object instead of trying to get accepts_nested_attributes to work. I find that form object are often much cleaner and much more flexible. Check out this railscast

How can I suppress the assignment of one or more fields in a Ruby-On-Rails mass-assignment?

I'm a bit confused about this mass assignment issue. Here's my question
Say I have a user model with the following attributes:
name
login
password
email
During an edit, the update method is triggered:
def update
#user = User.find(params[:id])
if #user.update_attributes(params[:user])
....
end
In my head it makes sense to protect most, if not all, of these attributes as i wouldn't want the password/email/login to be compromised. So I would do this in the model
attr_accessible :name
So every other attribute, asides from name, wouldn't be able to be mass assigned.
If I do this how would the valid edit form work though? Do I need to assign attributes one by one in the update method #user.email = params[:user][:email], etc? Or am I misunderstanding something (probably)?
Thanks!
Edit:
To be more specific:
Usually you see examples with the admin attribute protected. And it makes sense.
But what about the password or email attributes? Those aren't usually protected. Why wouldn't the password be protected or the email? It could mean that potentially somebody could reset the email and do a password reset or reset the password attribute and gain access to the system, no?
Watch this railscasts http://railscasts.com/episodes/26-hackers-love-mass-assignment/
You are thinking about mass assignment security the wrong way. attr_accessbile does not make the password value open to the public (you will use filter_parameter to hide that value).
Think of it this way, you have a user form. You want the user to be able to create an account with a password but you do not want them to be able to add themselves as an admin (they could do this through sql injection or manipulating the POST parameters). To protect against this, you would add :name, :password, :email to attr_accessible and leave out the admin field.
The idea is to filter the params in your controller, as described here.
class PeopleController < ActionController::Base
# This will raise an ActiveModel::ForbiddenAttributes exception because it's using mass assignment
# without an explicit permit step.
def create
Person.create(params[:person])
end
# This will pass with flying colors as long as there's a person key in the parameters, otherwise
# it'll raise a ActionController::MissingParameter exception, which will get caught by
# ActionController::Base and turned into that 400 Bad Request reply.
def update
redirect_to current_account.people.find(params[:id]).tap do |person|
person.update_attributes!(person_params)
end
end
private
# Using a private method to encapsulate the permissible parameters is just a good pattern
# since you'll be able to reuse the same permit list between create and update. Also, you
# can specialize this method with per-user checking of permissible attributes.
def person_params
params.required(:person).permit(:name, :age)
end
end

Adding a parameter to an instance variable in Rails

I am creating a instance variable that gets passed to my view. This variable 'post' has a user_id associated with it and I wanted to add an extra attribute called 'username' so I can also pass that and use it in the view.
Here is an example of what I would like to do.
#post = Post.find(params[:id])
#post.username = User.find(#post.user_id).username
A username column does exist on my Users model but not my Songs model. So it won't let me use
#post.username
I know I can just make an entirely new instance variable and put that information in there but I would like to keep everything nice and neat, in one variable. Which will also make my json rendered code look cleaner.
Any ideas on how I can accomplish this?
Thanks!
Based on the presence of a user_id in your Post model, you probably already have an association set up that can retrieve the username. It will probably save a lot of trouble to simply use the existing association:
#post = Post.find(params[:id])
username = #post.user.username
If you're likely to be querying more than one post at a time (e.g., on an index page, calling .includes to tell Rails to eager-load an association will help you avoid the N+1 problem:
#posts = Post.includes(:user).all
Finally, to include the associated record in your JSON output, pass the :include parameter as you serialize:
# in controller
render :json => #post.to_json(:include => :user)
This question includes a much more comprehensive discussion of serialization options. Well worth a read.
No need to pass a separate instance variable.
1. You can use #post.user.username in view itself.
2. Or you can create a helper and pass #post.user
def username user
user.username
end

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