Rail3 intro 29th_sep_surendran

Rails3 – Introduction-I - Surendran S http://www.Spritle.com Copyright: Spritle Software Private Limited Please note that some of the images or content might have been taken from Internet and we don’t own copyright on them. If you have any objection in the content, please let us know at info@spritle.com

About Me http://www.Spritle.com Copyright: Spritle Software Private Limited

Rails is a web application development framework written in the Ruby language.
DRY – “Don’t Repeat Yourself”
REST is the best pattern for web applications
Rails Introduction

Rails is the Model, View, Controller architecture, usually just called MVC.
Rails Architecture

A model represents the information (data) of the application and the rules to manipulate that data.
In the case of Rails, models are primarily used for managing the rules of interaction with a corresponding database table.
In most cases, one table in your database will correspond to one model in your application.
The bulk of your application’s business logic will be concentrated in the models
MODEL

Views represent the user interface of your application.
In Rails, views are often HTML files with embedded Ruby code that perform tasks related solely to the presentation of the data.
Views handle the job of providing data to the web browser or other tool that is used to make requests from your application.
VIEW

Controllers provide the “glue” between models and views.
In Rails, controllers are responsible for processing the incoming requests from the web browser, interrogating the models for data, and passing that data on to the views for presentation.
CONTROLLER

Rest stands for Representational State Transfer and is the foundation of the RESTful architecture.
For example, to a Rails application a request such as this:DELETE /photos/17
REST

$rails new sample Creates a new rails project CREATING NEW RAILS APP

$rails new sample
Creates a new rails project
Configuring a Database
The database to use is specified in a configuration file, config/database.yml
he file contains sections for three different environments in which Rails can run by default:
The development environment is used on your development computer as you interact manually with the application
The test environment is used to run automated tests
The production environment is used when you deploy your application for the world to use.

The database to use is specified in a configuration file, config/database.yml
The file contains sections for three different environments in which Rails can run by default:
The development environment is used on your development computer as you interact manually with the application
The test environment is used to run automated tests
The production environment is used when you deploy your application for the world to use.

CONFIGURING DATABASE

$ rake db:create $ rails server This will fire up an instance of the Mongrel web server by default To see your application in action, open a browser window and navigate to http://localhost:3000 . You should see Rails’ default information page: STARING SERVER

Brand new router
New Active Record chainable query language built on top of relational algebra
Unobtrusive JavaScript helpers with drivers for Prototype, jQuery, and more coming (end of inline JS)
Action controller respond_with
Explicit dependency management with Bundler
Whats new in rails3

Old New script/generate rails g script/console rails c script/server rails s script/dbconsole rails db

$ rails generate scaffold Post name:string title:string content:text

Old New script/generate rails g script/console rails c script/server rails s script/dbconsole rails db rake db:migrate creates a table and add the 3 columns in the table MODEL AND MIGRATION

$ rails generate model Comment commenter:string body:text post:references

Rails 2 config/routes.rb TestApp::Application.routes.draw do |map| map.resources :posts end Rails 3 TestApp::Application.routes.draw do resources :posts end ROUTES

creates seven different routes in your application, all mapping to the Posts controller ROUTES

Rails 2 resources :posts do |post| post.resources :comments end Rails 3 resources :posts do resources :comments end This creates comments as a nested resource within posts. This is another part of capturing the hierarchical relationship that exists between posts and comments ROUTES

Rails 2 @posts = Post.find(:all, :conditions => {:published => true}) immediately queries the db returns an Array of Posts Rails 3@posts = Post.where(:published => true) doesn’t query the db returns an ActiveRecord::Relation ActiveRelation

Old New script/generate rails g script/console rails c script/server rails s script/dbconsole rails db @posts.each do |p| ... end ActiveRelation Query runs here this is Lazy loading

@published = Post.published will return you the posts whose ppublished column is true Class Post < ActiveRecord::Base default_scope order('title') scope :published, where(:published => true) scope :unpublished, where(:published => false) end ActiveRelation

Rails 2 Post.find(:all, :conditions => {:author => "Joe"}, :includes => :comments,:order => "title", :limit => 10) Rails 3 Post.where(:author=>Joe").include(:comments).order(:title).limit(10) ActiveRelation

BUNDLER $bundle install Will ensure all gems are installed, including webrat (but it’s only included in test mode). $bundle --without test Will install everything except webrat. gemfile

HTML 5 custom data attributes data-* Custom data attributes are intended to store custom data private to the page or application, for which there are no more appropriate attributes or elements data-remote data-method data-confirm data-disable-with Adopting Unobtrusive Javascript

Rails 2 <%= link_to_remote 'Show', :url => post %> <a href="#" onclick="new Ajax.Request('/posts/1', {asynchronous:true, evalScripts:true, parameters:'authenticity_token=' + encodeURIComponent('9sk..44d')}); return false;">Show</a> Rails 3 <%= link_to 'Show', post, :remote => true %> <a href="/posts/1" data-remote="true">Show</a> Adopting Unobtrusive Javascript

Adopting Unobtrusive Javascript

Adopting Unobtrusive Javascript document.observe("dom:loaded", function() { $(document.body).observe("click", function(event) { var message = event.element().readAttribute('data-confirm'); if (message) { // ... Do a confirm box } var element = event.findElement("a[data-remote=true]"); if (element) { // ... Do the AJAX call } var element = event.findElement("a[data-method]"); if (element) { // ... Create a form } })

http://github.com/rails/jquery-uj $('a[data-confirm],input[data-confirm]').live('click', function () { // ... Do a confirm box }); $('form[data-remote="true"]').live('submit', function (e) { // ... Do an AJAX call }); jQuery in Rails?

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Rail3 intro 29th_sep_surendran

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