Programming in Ruby On Rails

Please follow the below steps to i nstall RVM RUBY RAILS and Postgres in MAC yosemite. Step 1. Install Homebrew Homebrew is a package manager for the Mac. Installing Homebrew by issuing the following command: ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install) " To make sure Homebrew is installed correctly run: brew doctor Step 2: Install GPG Package. Download and install the GPG package from the link https://gpgtools.org Step 3: Install RVM gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 and \curl -sSL https://get.rvm.io | bash -s stable Reload your bash_profile, so it can initialize RVM. ~/.bashrc Run RVM requirements to install basic required packages with Homebrew. Accept the license agreement and install Xcode Tools. After installing the tools continue the rvm requirements installation. rvm requirements Step 4. Install Requir

In Rails we create simple form and also sometimes we need nested form. In Rails we can easily do that using  gem “nested_form”. let's create a project using “nested_form”. Before that I would like to ask you to have a look on nested_attribute_documentation(http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html#method-i-accepts_nested_attributes_for). 1) Create a new Rails 4 Project.     rails new nested_app 2) Include the gem in your gem file.   gem "nested_form" 3) run bundle install  bundle install 4) Generate the necessary javascript file.   rails g nested_form:install 5) Include the javascript file in the asset pipeline. in the application.js add the below line.   //= require jquery_nested_form 6) Let say we have a Exam model and one Exam can have multiple Questions.So lets create the Exam model. class Exam < ActiveRecord::Base   has_many :questions, dependent: :destroy   accepts_nested_attributes_for :questions,

Postgres is a great open source database management system. It's pretty easy to use postgres with Ruby on Rails. Step 1: Install postgress in your system. If you already have postgres installed in your system then skip it else follow the  link . Step 2: Create new project rails new pg_demo You can also create using rails new pg_demo --database=postgresql Step 3: include the pg gem in your gem file gem 'pg' Step 4: run bundle command bundle Step 5: It will give you some error like An error occurred while installing pg (0.17.1), and Bundler cannot continue. Make sure that `gem install pg -v '0.17.1'` succeeds before bundling. So let's try to install the  pg gem first gem install pg It will again throw an error  :( Building native extensions.  This could take a while... ERROR:  Error installing pg: ERROR: Failed to build gem native extension.     /home/sabyasachi/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb checking for pg_config... y

Step 1: Before postgres install, we should quick perform a quick update. apt-get update Step 2: Now install Postgres using the command line.   sudo apt-get install postgresql postgresql-contrib This will install the latest version available in your Ubuntu. Step 3: Install the client   sudo apt-get install postgresql-client Step 4:  For a handy GUI for PostgreSQL install pgAdmin III.  sudo apt-get install pgadmin3 Step 5:  We need to change the PostgreSQL postgres user password; sudo -u postgres psql postgres Set a password for the "postgres" database role using the command: \password postgres Step 6: Exit from Postgres   \q That's it we are done with the installation.  

Neo4j is a graph database, using neo4j gem( https://github.com/neo4jrb/neo4 j) we can easily use neo4j database in our ruby on rails application ( http://programminginrubyonrails.blogspot.in/2014/12/neo-4j-with-rails.html ). Till now neo4j gem does not support rake db tasks. You can check all the supported task by typing rake -T in your console. Now we can create our own custom rake task to seed some  data in neo4j . Step 1: Create a file under lib/tasks name it seed.rake Step 2: Put the below code in seed.rake. namespace :db do   desc 'Load the seed data from db/seeds.rb'   task :seed => :environment do     seed_file = File.join(Rails.root, 'db', 'seeds.rb')     load(seed_file) if File.exist?(seed_file)   end end That's it. now you can run rake db:seed from your terminal.. Simple :) 

How to setup new 4j database with Rails 4. Step 1: Install Neo4j Database in ubuntu.   login as Admin  sudo -i  wget -O - http://debian.neo4j.org/neotechnology.gpg.key | apt-key add -  Add Neo4J to the Apt sources list:   echo 'deb http://debian.neo4j.org/repo stable/' > /etc/apt/sources.list.d/neo4j.list  Update the package manager:  exit as admin  apt-get update  Install Neo4J:  apt-get install neo4j  sudo /etc/init.d/neo4j-service restart Step 2: Create a new rails project.  Rails new neo4j Step 3:  Add neo4j Gem in your gem file   gem 'neo4j', github: 'andreasronge/neo4j' Step 4: Go to application.rb require File.expand_path('../boot', __FILE__) require "rails" %w(   neo4j   action_controller   action_mailer   sprockets ).each do |framework|   begin     require "#{framework}/railtie"   rescue LoadError   end end # Require the gems listed in Gemfile, including any gems # you've

We can create a RESTful API using Grape and RABL in Rails4. Step 1: Add this GEMS in your Gem file, And do Bundle install.  gem 'grape'  gem 'rabl-rails'  gem 'grape-rabl'  gem 'rack-cors', :require => 'rack/cors' Step 2: Create a file under lib directory called api.rb, and create a folder inside the view named as api. # lib/api/v1/root.rb class API < Grape::API end Step 3: Add this line to your application.rb file    config.paths.add "app/api", glob: "**/*.rb"     config.autoload_paths += %W(#{config.root}/lib #{config.root}/app/api/*)     config.middleware.use Rack::Cors do       allow do         origins '*'         # location of your API         resource '/*', :headers => :any, :methods => [:get, :post, :options, :put, :delete]       end     end     config.middleware.use(Rack::Config) do |env|       env['api.tilt.root'] = Rails.root.join "app", "