Ruby on Rails - Ruby Rails Session - ruby on rails tutorial - rails guides - rails tutorial - ruby rails

• To save data across multiple requests, you can use either the session or the flash hashes.
• A flash stores a value (normally text) until the next request, while a session stores data during the complete session.
• A session usually consists of a hash of values and a session ID, usually a 32-character string, to identify the hash.
• Every cookie sent to the client's browser includes the session ID. And the other way round: the browser will send it to the server on every request from the client.
• In Rails, you can save and retrieve values using the session method.

session[:user] = @user
flash[:message] = "Data was saved successfully"

<%= link_to "login", :action => 'login' unless session[:user] %>
<% if flash[:message] %>
<div><%= h flash[:message] %></div>
<% end %>

It's possible to turn off session management

session :off                           # turn session management off
session :off, :only => :action      # only for this :action
session :off, :except => :action    # except for this action

session :only => :foo,              # only for :foo when doing HTTPS
        :session_secure => true 

session :off, :only=>:foo, # off for foo,if uses as Web Service
        :if => Proc.new { |req| req.parameters[:ws] }

In Rails, data can be save and retrieve using session method:

session[:user_id] = @current_user.id User.find(session[:user_id])  

class LoginsController < ApplicationController  
  # "Create" a login, aka "log the user in"  
  def create  
    if user = User.authenticate(params[:username], params[:password])  
      # Save the user ID in the session so it can be used in  
      # subsequent requests  
      session[:current_user_id] = user.id  
      redirect_to root_url  
 end  
end  
end  
To remove data from the session, assign that key to be nil.
class LoginsController < ApplicationController  
# "Delete" a login, aka "log the user out"  
def destroy  
# Remove the user id from the session  
@_current_user = session[:current_user_id] = nil  
redirect_to root_url  
end  
end  

To reset the entire session, use reset_session.

Step 1 Create an application log

rails new log  

Step 2 Change your directory to log

cd log  

Step 3

Step 4 Now run the bundle

bundle  

Step 5 Create a controller.

rails g controller Page index  

Step 6 Change the config/routes.rb file.

Rails.application.routes.draw do  
get 'page/index'  
root 'page#index'  
end  

Step 7 Generate a user scaffold.

rails g scaffold User first_name last_name email password:digest  

Step 8 Migrate your database.

rake db:migrate  

Step 9 Go to app/models/user.rb file and write following code.

class User < ActiveRecord::Base  
  has_secure_password  
  validates :first_name,  
            presence: true  
            validates :last_name,  
            presence: true  
           validates :email,  
            presence: true,  
            uniqueness: true,  
            format: {  
              with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i  
            }  
  def to_s  
    "#{first_name} #{last_name}"  
  end  
end  

Step 10 We need a session mechanism to create a login and logout procedure.

rails g controller sessions new create destroy

Step 11 Go to config/routes.rb file and change the following data.

Rails.application.routes.draw do  
resources :sessions, only: [:new, :create, :destroy]  
  get 'signup', to: 'users#new', as: 'signup'  
  get 'login', to: 'sessions#new', as: 'login'  
  get 'logout', to: 'sessions#destroy', as: 'logout'  
  resources :users  
  get 'page/index'  
  root 'page#index'  
end  

Step 12 Create a login form in app/views/sessions/new.html.erb file.

<h1>Log In</h1>   
<%= form_tag sessions_path do %>   
<div>   
<%= label_tag :email %><br>   
<%= text_field_tag :email %>   
</div>   
<div>   
<%= label_tag :password %><br>   
<%= password_field_tag :password %>   
</div>   
<div>   
<%= submit_tag "Log In" %>   
</div>   
<% end %>  

Step 13 Go to app/controllers/sessions_controller.rb file and write the following code.

class SessionsController < ApplicationController   
 def new   
 end   
  def create   
    user = User.find_by_email(params[:email])   
    if user && user.authenticate(params[:password])   
      session[:user_id] = user.id   
      redirect_to root_url, notice: 'Logged in!'   
    else   
      render :new   
    end   
  end   
  def destroy   
    session[:user_id] = nil   
    redirect_to root_url, notice: 'Logged out!'   
  end   
end  

Step 14 We need to create a current_user method to access current user in the application. Go to the app/controllers/application_controller.rb file and write the following code.

class ApplicationController < ActionController::Base   
 # Prevent CSRF attacks by raising an exception.   
 # For APIs, you may want to use :null_session instead.   
  protect_from_forgery with: :exception   
  private   
  def current_user   
    User.where(id: session[:user_id]).first   
  end   
  helper_method :current_user   
end  

Step 15 Go to the app/views/layouts/application.html.erb file and write the following code in the body.

<div id="user_header">  
 <% if current_user %>  
   Logged in as <%= current_user.email %>.  
    <%= link_to "Log Out", logout_path %>  
  <% else %>  
    <%= link_to "Sign Up", signup_path %> or  
    <%= link_to "Log In", login_path %>  
  <% end %>  
</div>  
<% flash.each do |key, value| %>  
  <%= content_tag(:div, class: "alert alert-#{key}") do %>  
    <p><%= value %></p>  
  <% end %>  
<% end %>  

Step 16 Delete following line from app/views/users/show.html.erb and app/views/layouts/index.html.erb files.

<p id="notice"><%= notice %></p>  

Step 17 When a new user sign up, he/she will be auto login. For this, we need to set session in the app/controllers/users_controller.rb file.

def create   
    @user = User.new(user_params)   
    if @user.save   
      session[:user_id] = @user.id   
      redirect_to root_url, notice: 'User successfully created.'   
    else   
      render :new   
    end   
  end  

Step 18 Start your Rails server in the console.

rails s  

Step 19 Go to the browser.

Localhost:3000  

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