Tag: Rails

How to customize Devise authentication in Rails3?

Posted on by Jay

Rails31Devise is an authentication solution for Rails application development. Since devise is an engine and all the files created by it are packaged inside the gem. We need to invoke some generators in order to customize it according to our choice.

Configuring views:

  • If you want to modify the views generated by devise, then you just need to invoke the following generator, and it will copy all views to your application.
rails generate devise:views
  • If you have more than one role in your application (such as “User” and “Admin”), Devise offers an easy way to customize views. Just write the following line inside your “config/initializers/devise.rb”
config.scoped_views = true
  • Now you will be able to have views based on the role like “users/sessions/new” and “admins/sessions/new”. You can also use the generator to generate scoped views like below:
rails generate devise:views users

Configuring controllers:

If the customization at the views level is not enough, you can customize the controller generated by devise using following steps.
Step#1

  • Create a custom controller
class Users::SessionsController < Devise::SessionsController
[Your code goes here]
end

Now you can customize your methods according to the conditions.

Step#2

  • Now tell the route to use this controller in “config/routes.rb”
devise_for :users, :controllers => { :sessions => "users/sessions" }

ustomizing Error Messages:

Devise has its own error messages that are shown when something goes wrong. All of these messages are stored in a locale file (config/locales/devise.en.yml), making it easy to maintain them. Here you can see the list of error messages created by devise and you can customize them according to your choice.

Customizing Registration process:

You can also customize the registration process of devise. Here is an example to explain the customization of Registration process where devise sends an activation email automatically after a new user registration happens.

Step#1

  • Modify the “users” migration file created by devise. Uncomment the block of fields under Confirmable.
t.string   :confirmation_token
t.datetime :confirmed_at
t.datetime :confirmation_sent_at
t.string   :unconfirmed_email

Step#2

  • Customize the “User” model like below:
devise :database_authenticatable, :registerable,:recoverable, :rememberable, :trackable, :validatable, :confirmable

We have added “:confirmable” module for devise to the model. Confirmable is responsible to verify if an account is already confirmed to sign in, and to send emails with confirmation instructions. Confirmation instructions are sent to the user email after creating a record.

Then add the field names that are defined in step#1 to the ‘attr_accessible’.

Step#3

  • Run the migration
rake db:migrate

Step#4

  • Now set the default URL for according to your requirement in “config/enviroments/development.rb”
config.action_mailer.default_url_options = { :host => 'localhost:3000' }

Now if you register for a new user then devise will send a confirmation email with required instructions.

File Uploading Through Paperclip in Rails 3.x

Posted on by Jay

Rails3Paperclip is an easy file attachment library for Rails Applications. Attached files are saved to the file system, database or cloud and referenced in the browser by an easily understandable specification.

Here is an example to explain the image attachment for a user profile in an application. This example narrates about saving the image in the file system. However, the images can be saved in S3 bucket [Amazon Simple Storage Service, S3] or database.

Step#1

ImageMagick must be installed in the system and Paperclip must have access to it. ImageMagick is a software suite to create, edit, compose, or convert bitmap images. It can read and write images in a variety of formats. You can download it by visiting the following URL:

http://www.imagemagick.org/script/index.php

Step#2
Include the paperclip gem in your Gemfile

gem "paperclip"

Then run the bundler to install the gem

bundle install

Step#3
Add the fields for the image processing as below in your migration file

class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :name
t.string :photo_file_name
t.string :photo_content_type
t.string :photo_file_size
t.timestamps
end
end
end

Then run your migration files

rake db:migrate

Step#4

Modify the user model for cropping and save image in your system folder

has_attached_file :photo, :styles => { :small => "150x150>" },
:url => "/system/:attachment/:id/:style/:basename.:extension",
:path => ":rails_root/public/system/:attachment/:id/:style/:basename.:ex

Here you can specify the file path and the image size as per the requirement.

Step#5
Modify your view file to upload an image

<pre class="plain plain">&lt;%= form_for :user,:url =&gt; {:action =&gt; "create"}, :html =&gt; { :multipart =&gt; true } do |f| %&gt;
&lt;%= f.file_field :photo %&gt;
&lt;% end %&gt;</pre>

Step#6
Write the following code to display the image of a user

<%= image_tag @user.photo.url (:small)%>

Please stay connected with us by subscribing our email.
Also feel free to share your opinions in the comments section below:

How to Generate SEO Friendly URL in Rails 3.x

Posted on by Jay

Rails3SEO friendly URLs are more important to make a page popular & search engines to crawl.

FriendlyId is the slugging and permalink plug-in for Ruby on Rails. It allows you to create pretty URLs and work with human-friendly strings.

The URLs created by slug are very useful for SEO. It is designed for generation of URL slug and history maintenance.

Steps to create Pretty URLs:

Step#1

Include gem in your Gem file:

gem 'friendly_id'

Then run bundle install.

Step#2

Modify your model on which you want the pretty URL:

extend FriendlyId
 
friendly_id :title, use: :slugged

Step#3

Add the slug column in your migration file to add it on the table

add_column :articles, :slug, :string

Then run

rake db:migrate

Now if you create an article with Title like “This is a demo title for testing”,
it will create a SEO friendly URL like “this-is-a-demo-title-for-testing” and will
save into the articles table under slug column.

What is the Importance of Filters in Rails

Posted on by Jay

Rails

In Ruby on Rails development, filters play a vital role. They are the methods executed ‘before’, ‘after’  or  ‘around’ a controller action.

For example, one filter might check to see if the user has the credentials to access that particular controller or action.

Filters are inherited, so if you set a filter on ‘ApplicationController’, it would run on every controller in your application.

Below is an example to explain how a filter can be used to restrict a non-logged in user to access specified actions in a controller

Step#1

  • In Application controller write the following block of code according to the requirement.
def user_login_required
 if !session[:username]
 flash[:notice] = "Oops you need to login!"
 redirect_to :controller => "user_sessions", :action => "new"
 end
end

Step#2

  • Now write the before_filter block in the controller you want to restrict the not registered users. You can also restrict particular actions of a controller by writing the action name.
class UsersController < ApplicationController
 before_filter :user_login_required, :only => [:profile]
 def profile
 [Your code block goes here]
 end
end

In the above block the ‘before_filter’ restrict the not registered user to access
the profile page and redirect them to login page. We can also restrict multiple
actions by writing like this

before_filter :user_login_required, :only => [:profile,:edit]

In this case the filter is applied to only these two methods of a particular controller.

before_filter :user_login_required, :except => [:index,:show]

In this case the filter is applied to all other actions except index and show
action of a particular controller.

If you write the before_filter block in the “ApplicationController” then the
filter will be applied to all the controllers.

Planning anything on Ruby on Rails? Talk to Andolasoft’s experts to get a clearer idea.

How to install Devise in Rails 3.x

Posted on by Jay

ror41-150x150Devise is a flexible authentication solution for Rails based on Warden. Devise handles authentication across the entire stack. It has the following features:

  • Rack based
  • MVC based on Rails engines
  • Allows you to have multiple roles (or models/scopes) signed in at the same time
  • Modularity concept: use just what you really need

It is composed of 12 modules:

  • Database Authenticatable
  • Token Authenticatable
  • Omniauthable
  • Confirmable
  • Recoverable
  • Registerable
  • Rememberable
  • Trackable
  • Timeoutable
  • Validatable
  • Lockable

Steps to install the Devise

Step#1

Add the following gem in your Gemfile

gem 'devise'

Then run

bundle install

Step#2

To invoke the Devise in your application, run the devise generator

 rails g devise:install

The generator will install an initialize, which describes all devise’s configuration options.

Step#3

Create a model “User” using devise to handle authentication.

rails g devise User

This generator creates a few interesting things like a file, a migration and a devise_for in route.

Step#4

Run the migration

rake db:migrate

Step#5

Devise provides some helper methods to recognize a user after sign in and default route paths for “sign in”, “sign up” and “sign out”

We can modify our ‘app/views/layout/application.html.erb’ file to allow us to “sign out”, “sign in” and “sign up” by writing the following block

<div>
<% if user_signed_in? %>
Signed in as <%= current_user.email %>. Not you?
<%= link_to "Sign out", destroy_user_session_path,:method => :delete %>
<% else %>
<%= link_to "Sign up", new_user_registration_path %> or
<%= link_to "Sign in", new_user_session_path %>
<% end %>
</div>

Configuring views

Since Devise is an engine, all its views are packaged inside the devise gem.

Get all the view files for devise by running the following generate command

rails generate devise:views

You can also configure the message language, mailer from address and other things by editing the devise config files as located in following locations

devise.en.yml – config/locales
 
devise.rb – config/initializers

Now you are done to use the app with authentication!

How to use Amazon S3 Bucket with Paperclip to store images in Rails3

Posted on by Jay

Amazon_S3_Online_Service-resized200-150x150

“S3 Bucket” is Amazon Simple Storage Service – a “highly durable and available store” and can be used to reliably store graphical and other applications contents such as media files, static assets and user uploads. It allows you to off-load your entire storage infrastructure. This feature facilitates better scalability, reliability, and speed than just storing files on the file-system.

It is an online storage web service offered by Amazon Web Services and provides storage through web services interfaces (REST, SOAP etc.)

Here is an example on how to use Amazon S3 with paperclip in Ruby on Rails applications.

Step#1

  • In rails 3.x

Install aws-s3 gem by adding in Gemfile

gem 'aws-s3'

And run

Run “bundle install”

Step#2

To get AWS S3 bucket ‘Access Key ID’ and ‘Secret Access Key’ go to the “http://aws.amazon.com/s3”

Create s3.yml file under config directory and enter your Amazon S3 credentials

development:
bucket: bucket-dev-name
access_key_id: xxxxx
secret_access_key: xxxxx
test:
bucket: bucket-test-name
access_key_id: xxxxx
secret_access_key: xxxxx
production:
bucket: bucket-prod-name
access_key_id: xxxxx
secret_access_key: xxxxx

Step#3

Open your model file that would hold the attachment and modify it as follows

###Paperclip
has_attached_file :photo,:styles =>{ :thumb => "100x100", :medium => "200x200", :large => "600x400" },:storage => :s3,
:s3_credentials => "#{RAILS_ROOT}/config/s3.yml",:path => ":attachment/:id/:style.:extension",:bucket => 'yourbucket'

Step#4

In view, to display the image