Rails - ActiveAdmin & CanCan custom override method for initialize_cancan_ability - ruby-on-rails

I am attempting to pass thru request data to the Ability model as suggested here:
class ApplicationController < ActionController::Base
#...
private
def current_ability
#current_ability ||= Ability.new(current_user, request.remote_ip)
end
end
and here:
class Ability
include CanCan::Ability
def initialize(user, ip_address=nil)
can :create, Comment unless BLACKLIST_IPS.include? ip_address
end
end
See: https://github.com/ryanb/cancan/wiki/Accessing-request-data
However, I am using ActiveAdmin with the CancanAdapter, and it uses a separate initialize call via:
def initialize_cancan_ability
klass = resource.namespace.cancan_ability_class
klass = klass.constantize if klass.is_a? String
klass.new user
end
See: https://github.com/activeadmin/activeadmin/blob/master/lib/active_admin/cancan_adapter.rb
So how/where can I redefine initialize_cancan_ability so that I can pass in request data similar to the current_ability example?
Basically I'm hoping to just replace the last line as such:
klass.new user, request
Thanks.

You can create a file under lib/monkey_patches/active_admin.rb and put your overridden method there:
require 'cancan'
# Add a setting to the application to configure the ability
ActiveAdmin::Application.inheritable_setting :cancan_ability_class, "Ability"
module ActiveAdmin
private
def initialize_cancan_ability
klass = resource.namespace.cancan_ability_class
klass = klass.constantize if klass.is_a? String
klass.new user, request
end
end
end

If you use Devise, you can access the the Ip from the User model user.current_sign_in_ip

Related

How can you use a setup method in ActionMailer Previews?

I would like to avoid duplicating the setup for multiple mailer previews. What is the best way to clean this up?
class MyMailerPreview < ActionMailer::Preview
def email1
setup
mailer.email1
end
def email2
setup
mailer.email2
end
def email3
setup
mailer.email3
end
end
Here are two possible solutions I found:
There is something called preview_interceptors that are used when generating mailer previews, you could add your own like this:
config/environments/development.rb
config.action_mailer.preview_interceptors = :my_setup
test/mailers/previews/my_setup.rb
class MySetup
def self.previewing_email(message)
message.subject = "New subject"
end
end
test/mailers/previews/user_mailer_preview.rb
class UserMailerPreview < ActionMailer::Preview
include ActionMailer::Previews
register_preview_interceptor :my_setup
def welcome_email
UserMailer.with(user: User.first).welcome_email
end
end
The message parameter is an instance of ActionMailer::Parameterized::MessageDelivery, I am not sure everything you can do with it, but you can set some attributes on the email itself.
I couldn't find much documentation on preview interceptors, but here is a link to how they are used in Rails.
# Previews can also be intercepted in a similar manner as deliveries can be by registering
# a preview interceptor that has a <tt>previewing_email</tt> method:
#
# class CssInlineStyler
# def self.previewing_email(message)
# # inline CSS styles
# end
# end
#
# config.action_mailer.preview_interceptors :css_inline_styler
#
# Note that interceptors need to be registered both with <tt>register_interceptor</tt>
# and <tt>register_preview_interceptor</tt> if they should operate on both sending and
# previewing emails.
I tried to include Rails before_action in the class, but it wouldn't hook the methods in the previewer, so the second option I found is to build your own before_action like this:
module MySetup
def before_action(*names)
UserMailer.instance_methods(false).each do |method|
alias_method "old_#{method}", method
define_method method do
names.each do |name|
send(name)
end
send("old_#{method}")
end
end
end
end
class UserMailerPreview < ActionMailer::Preview
extend MySetup
def welcome_email
UserMailer.with(user: User.first).welcome_email
end
before_action :setup
private
def setup
puts "Setting up"
end
end
Use an initialize method.
Just override the parent initialize method, call super and then run your setup:
class MyMailerPreview < ActionMailer::Preview
def initialize( params = {} )
super( params )
#email_address = "jules#verne.com"
end
def email1
mailer.email1( #email_address )
end
end
You can view the ActionMailer::Preview.new method here as a reference.
Based on my understanding of what you're asking maybe you could add it into one single method that takes the mailer method as a param
class MyMailerPreview < ActionMailer::Preview
def email_for(emailx) # (Pass the method(email1, etc) as an argument where you're calling it
setup
mailer.send(emailx.to_sym) # Call the method param as a method on the mailer
end
end
Would that work for you?

Accessing current_user variable in another controller

I am trying to access Devise's current_user variable inside a new instance of another controller. Here is my definition of GetsInterfaceController
class GetsInterfaceController < ApplicationController
def select_current_signed_in_user
#signed_in_user_here = current_user
end
end
Then I instantiate a new instance of GetsInterfaceController in ClientsController
class ClientsController < ApplicationController
def get_current_user
#gets_interface_controller = GetsInterfaceController.new
find_signed_in_user = #gets_interface_controller.select_current_signed_in_user
end
end
But I get null error on the #signed_in_user_here = current_user line in GetsInterfaceController when I try this. Anyway to get to the current_user attribute from inside GetsInterfaceController ?
I solved this by moving my code into a Module in lib directory. Works like a charm
current_user is not a variable - it is a helper method. Thus it is already available in all your helpers and views.
Additionally you never instantiate controllers in Rails. The router does that for you.
The only public methods in your controllers should be the actions which respond to HTTP requests.
If you want to reuse a method in several controllers you should be using inheritance, modules (concerns) or helpers. Never by calling a method on another controller.
To call an external service you want to create an API client class:
# adapted from https://github.com/jnunemaker/httparty
require 'httparty'
class StackExchangeClient
include HTTParty
base_uri 'api.stackexchange.com'
def initialize(service, page, user = nil)
#user = user
#options = { query: {site: service, page: page} }
end
def questions
self.class.get("/2.2/questions", #options)
end
def users
self.class.get("/2.2/users", #options)
end
end
Or if you need to call an external service and for example create several models with the data a Service Object:
class SomeService
def initialize(user, client: SomeClient)
#user = user
#client = client # for mocking
end
def call
response = #client.get('/foo')
response.each do |d|
#user.baz << d[:woo]
end
end
end
SomeService.new(current_user).call

Pundit: undefined method `authorize'

I am trying to use Pundit to authenticate access to some static views that require no database interaction:
class StaticController < ApplicationController
include Pundit
authorize :splash, :home?
def home end
end
Below is my static policy. The home? policy always returns true, so I should be able to access the home view.
class StaticPolicy < Struct.new(:user, :static)
def initialize(user, resource)
#user = user
#resource = resource
end
def home?
true
end
end
Instead I get this:
undefined method `authorize' for StaticController:Class
Pundit works perfectly if I'm authorizing a model:
def forums_index
#forums = Forum.all
authorize #forums
end
However, if I try to use the authorize method outside of an action that doesn't make use of a model I get:
undefined method `authorize' for StaticController:Class
Well, AFAIK you'll always have to authorize against either an object or a class, while CanCan already "load_and_authorize_resource", when using Pundit you already know that you have to load and authorize something yourself (sorry if I'm being too obvious here).
That said and considering that your view doesn't have DB interation, it seems to me that the best solution for your case is make some custom authorization against your user, something like
class StaticPolicy < Struct.new(:user, :static)
def initialize(user, resource)
#user = user
#resource = resource
end
def home?
authorize #user, :admin # or suppress the second parameter and let the Policy use the 'home?' method
true
end
end
and in your UserPolicy something like
class UserPolicy < ApplicationPolicy
def admin # or def home?, it's up to you
user.admin?
end
end
I didn't test it, but that's the main idea, does it make any sense? Is it clear?
Please give it a try and post any impressions, hope it helps :)

How to get Devise's current_user in ActiveRecord callback in Rails?

I'm using Devise and Rails 3.2.16. I want to automatically insert who created a record and who updated a record. So I have something like this in models:
before_create :insert_created_by
before_update :insert_updated_by
private
def insert_created_by
self.created_by_id = current_user.id
end
def insert_updated_by
self.updated_by_id = current_user.id
end
Problem is that I get the error undefined local variable or method 'current_user' because current_user is not visible in a callback. How can I automatically insert who created and updated this record?
If there's an easy way to do it in Rails 4.x I'll make the migration.
Editing #HarsHarl's answer would probably have made more sense since this answer is very much similar.
With the Thread.current[:current_user] approach, you would have to make this call to set the User for every request. You've said that you don't like the idea of setting a variable for every single request that is only used so seldom; you could chose to use skip_before_filter to skip setting the User or instead of placing the before_filter in the ApplicationController set it in the controllers where you need the current_user.
A modular approach would be to move the setting of created_by_id and updated_by_id to a concern and include it in models you need to use.
Auditable module:
# app/models/concerns/auditable.rb
module Auditable
extend ActiveSupport::Concern
included do
# Assigns created_by_id and updated_by_id upon included Class initialization
after_initialize :add_created_by_and_updated_by
# Updates updated_by_id for the current instance
after_save :update_updated_by
end
private
def add_created_by_and_updated_by
self.created_by_id ||= User.current.id if User.current
self.updated_by_id ||= User.current.id if User.current
end
# Updates current instance's updated_by_id if current_user is not nil and is not destroyed.
def update_updated_by
self.updated_by_id = User.current.id if User.current and not destroyed?
end
end
User Model:
#app/models/user.rb
class User < ActiveRecord::Base
...
def self.current=(user)
Thread.current[:current_user] = user
end
def self.current
Thread.current[:current_user]
end
...
end
Application Controller:
#app/controllers/application_controller
class ApplicationController < ActionController::Base
...
before_filter :authenticate_user!, :set_current_user
private
def set_current_user
User.current = current_user
end
end
Example Usage: Include auditable module in one of the models:
# app/models/foo.rb
class Foo < ActiveRecord::Base
include Auditable
...
end
Including Auditable concern in Foo model will assign created_by_id and updated_by_id to Foo's instance upon initialization so you have these attributes to use right after initialization, and they are persisted into the foos table on an after_save callback.
another approach is this
class User
class << self
def current_user=(user)
Thread.current[:current_user] = user
end
def current_user
Thread.current[:current_user]
end
end
end
class ApplicationController
before_filter :set_current_user
def set_current_user
User.current_user = current_user
end
end
current_user is not accessible from within model files in Rails, only controllers, views and helpers. Although , through class variable you can achieve that but this is not good approach so for that you can create two methods inside his model. When create action call from controller then send current user and field name to that model ex:
Contoller code
def create
your code goes here and after save then write
#model_instance.insert_created_by(current_user)
end
and in model write this method
def self.insert_created_by(user)
update_attributes(created_by_id: user.id)
end
same for other methods
just create an attribute accessor in the model and initialize it when your record is being saved in controller as below
# app/models/foo.rb
class Foo < ActiveRecord::Base
attr_accessor :current_user
before_create :insert_created_by
before_update :insert_updated_by
private
def insert_created_by
self.created_by_id = current_user.id
end
def insert_updated_by
self.updated_by_id = current_user.id
end
end
# app/controllers/foos_controller.rb
class FoosController < ApplicationController
def create
#foo = Foo.new(....)
#foo.current_user = current_user
#foo.save
end
end

Remove .xml extension from ActiveResource request

I am trying to use ActiveResource to consume xml data from a third party API. I can use the RESTClient app to successfully authenticate and make requests. I coded my app and when I make a request I get a 404 error. I added:
ActiveResource::Base.logger = Logger.new(STDERR)
to my development.rb file and figured out the problem. The API responds with xml data to requests that do NOT end in xml. EG, this works in RESTClient:
https://api.example.com/contacts
but ActiveResource is sending this request instead
https://api.example.com/contacts.xml
Is there anyway "nice" way to strip the extension from the request being generated by ActiveResource?
Thanks
You can exclude the format string from paths with:
class MyModel < ActiveResource::Base
self.include_format_in_path = false
end
You probably need to override the element_path method in your model.
According to the API, the current defintion looks like this:
def element_path(id, prefix_options = {}, query_options = nil)
prefix_options, query_options = split_options(prefix_options) if query_options.nil?
"#{prefix(prefix_options)}#{collection_name}/#{id}.#{format.extension}#{query_string(query_options)}"
end
Removing the .#{format.extension} part might do what you need.
You can override methods of ActiveResource::Base
Add this lib in /lib/active_resource/extend/ directory don't forget uncomment
"config.autoload_paths += %W(#{config.root}/lib)" in config/application.rb
module ActiveResource #:nodoc:
module Extend
module WithoutExtension
module ClassMethods
def element_path_with_extension(*args)
element_path_without_extension(*args).gsub(/.json|.xml/,'')
end
def new_element_path_with_extension(*args)
new_element_path_without_extension(*args).gsub(/.json|.xml/,'')
end
def collection_path_with_extension(*args)
collection_path_without_extension(*args).gsub(/.json|.xml/,'')
end
end
def self.included(base)
base.class_eval do
extend ClassMethods
class << self
alias_method_chain :element_path, :extension
alias_method_chain :new_element_path, :extension
alias_method_chain :collection_path, :extension
end
end
end
end
end
end
in model
class MyModel < ActiveResource::Base
include ActiveResource::Extend::WithoutExtension
end
It's far simpler to override the _path accessors mentioned in this answer on a class-by-class basis, rather than monkey-patching ActiveResource application-wide which may interfere with other resources or gems which depend on ActiveResource.
Just add the methods directly to your class:
class Contact < ActiveResource::Base
def element_path
super.gsub(/\.xml/, "")
end
def new_element_path
super.gsub(/\.xml/, "")
end
def collection_path
super.gsub(/\.xml/, "")
end
end
If you're accessing multiple RESTful resources within the same API, you should define your own base class where common configuration can reside. This is a far better place for custom _path methods:
# app/models/api/base.rb
class Api::Base < ActiveResource::Base
self.site = "http://crazy-apis.com"
self.username = "..."
self.password = "..."
self.prefix = "/my-api/"
# Strip .xml extension off generated URLs
def element_path
super.gsub(/\.xml/, "")
end
# def new_element_path...
# def collection_path...
end
# app/models/api/contact.rb
class Api::Contact < Api::Base
end
# app/models/api/payment.rb
class Api::Payment < Api::Base
end
# Usage:
Api::Contact.all() # GET http://crazy-apis.com/my-api/contacts
Api::Payment.new().save # POST http://crazy-apis.com/my-api/payments

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