Without Book Interview Questions and Answers | Online Test | Moct Test
Download Android App in your Android Device from Google Play Store
- Search for "Withoutbook Practice Exam Test" in Mobile/Tablet Play Store
Institute Training Search by Name or Email

Exams Attended

Make Homepage

Bookmark this page

Subscribe Email Address

Ruby On Rails Interview Questions and Answers

Ques 46. How can you implement Caching in Ruby on Rails?

Ans.

Rails offers multiple ways to cache content.

Fragment caching is my favorite because it gives you the choice to fragment to pull a portion from the cache and the remaining from a real-time DB call. 

Say you wanted to show all the orders placed on your website in real time and didn’t want to cache that part of the page, but did want to cache the part of the page which lists all products available, you could use this piece of code:

<% Order.find_recent.each do |o| %>
  <%= o.buyer.name %> bought <%= o.product.name %>
<% end %>
<% CACHE DO %>  All available products:
  <% Product.all.each do |p| %>
    <%= link_to p.name, product_url(p) %>
  <% end %>
<% end %>

Another technique that works well for static pages is page caching. This technique is often used for home pages and is super fast.

class ProductsController < ActionController
   CACHES_PAGE:index
  def index
    @products = Products.all
  end
end

Is it helpful? Add Comment View Comments
Ques 47. What is Filter and when is it called in Ruby on Rails?
Ans.

Filters are methods that are called either before/after a controller action is called. 

Say a user requests a controller action such as userdashboard/index

In such a case a filter can be setup so that the UserDashboard/index page is only accessible to loggedin users by adding the following lines towards the beginning of the page:

class UserDashboardController < ApplicationController

  before_filter :confirm_logged_in,  :except => [:login, :attempt_login, :logout]  
def index
....
end

def login
....
end

def attempt_login
....
end

def logout
....
end

end  

In the code above the condition “confirm_logged_in” is checked before all actions, except login, logout & attempt_login. 

After filters (after_filter) are not used too much but they have the effect of executing some code after a particular action has completed. 

Think of them like triggers that get executed automatically — just like a database trigger. 

Is it helpful? Add Comment View Comments
Ques 48. What do Controllers task in Ruby on Rails?
Ans.

Once a request comes into the Rails stack, it goes to the routes table to determine which controller and action should be called. 

Once a controller action is determined the request is routed to the controller and it does the needed processing by connecting with the DB if needed and then it sends control to the View to render the output. 

So, really the flow for Rails goes somewhat like this:

Customer-> Routes-> Controller -> Model(DB) -> Controller -> View -> Customer

Is it helpful? Add Comment View Comments
Ques 49. What is RESTFUL routing in Ruby on Rails?
Ans.

Routing is fun. If you have ever dealt with IIS you will fall in love with RESTful routing. Here’s how it works. 

Say you want your users to have access to certain pages such as:

/photos/new

/photos/1/edit

/photos/1

And, you want the right controller to get called.

And, you want the right view to get rendered.

All this is made possible with a single entry in the routes.rb file.

In Rails, a resourceful route provides a mapping between HTTP verbs and URLs to controller actions. By convention, each action also maps to particular CRUD operations in a database. The single entry in the routing file creates seven different routes in your application, all mapping to the Photos controller:

GET-/photos

GET-/photos/new

POST - /photos

GET -  /photos/:id

GET -  /photos/:id/edit

PUT - /photos/:id

DELETE - /photos/:id

Is it helpful? Add Comment View Comments
Ques 50. How can you routes all routs of an application?
Ans.
rake routes -- will display all routes for an application.
Is it helpful? Add Comment View Comments

Most helpful rated by users:

©2016 WithoutBook