Ruby On Rails Classroom
Neha Jaggi /
Professional /
Web Technology
- Foreword to the First Edition
- Acknowledgments
- About the Author
- From Zero to Deploy
- Development Environments
- Ruby RubyGems Rails and Git
- The First Application
- rails server
- Model-view-controller MVC
- Version Control with Git
- What Good Does Git Do You
- GitHub
- Branch Edit Commit Merge
- Deploying
- Heroku Setup
- Conclusion
- A Demo App
- Planning the Application
- Modeling Demo Users
- Modeling Demo Microposts
- The Users Resource
- A User Tour
- MVC in Action
- Weaknesses of this Users Resource
- The Microposts Resource
- A Micropost Microtour
- Putting the micro in Microposts
- A User has many Microposts
- Inheritance Hierarchies
- Deploying the Demo App
- Conclusion
- Static Page
- Mostly Static Pages
- Truly Static Pages
- Static Pages with Rails
- Our First Tests
- Test-driven Development
- Adding a Page
- Testing a Title Change
- Passing Title Tests
- Embedded Ruby
- Eliminating Duplication with Layouts
- Conclusion
- Advanced Setup
- Eliminating bundle exec
- Automated Tests with Guard
- Speeding up Tests with Spork
- Tests inside Sublime Text
- Rails-Flavored Ruby
- Strings and Methods
- Objects and Message Passing
- Method Definitions
- Other Data Structures
- Blocks
- Hashes and Symbols
- CSS revisited
- Ruby Classes-Constructors
- Class Inheritance
- Modifying Built-in Classes -A Controller Class
- A User Class
- Conclusion-Exercises
- Adding Some Structure
- Site Navigation
- Bootstrap and Custom CSS
- Partials
- Sass and the Asset Pipeline
- Syntactically Awesome Stylesheets
- Layout Links
- Route Tests
- Rails Routes
- Named Routes
- Pretty RSpec
- User Signup A First Step
- Signup URI
- Conclusion-Exercises
- Modeling Users
- User Model
- Database Migrations
- The Model File
- Creating User Objects
- Finding User Objects
- Updating User Objects
- User Validations
- Validating Presence
- Length Validation-Format Validation
- Uniqueness Validation
- Adding a Secure Password
- An Encrypted Password
- Password and Confirmation
- User Authentication
- User Has Secure Password
- Creating a User
- Conclusion-Exercises
- Showing Users
- Debug and Rails Environments
- A Users Resource
- Testing the User Show Page with Factories
- A Gravatar Image and a Sidebar
- Signup Form
- Tests for User Signup
- Using form for
- The Form HTML
- Signup Failure
- Signup Error Messages
- The Finished Signup Form
- The Flash
- Deploying to Production with SSL
- Conclusion-Exercises
- Sessions and Signin Failure
- Sessions Controller
- Signin Tests
- Signin Form
- Reviewing Form Submission
- Rendering with a Flash Message
- Signin Success
- Remember Me
- A Working sign in Method
- Current User
- Changing the Layout Links
- Signin upon Signup
- Signing Out
- Introduction to Cucumber Optional
- Installation and Setup
- Features and Steps
- Counterpoint RSpec Custom Matchers
- Conclusion-Exercises
- Updating Users
- Edit Form
- Unsuccessful Edits
- Successful Edits
- Authorization
- Requiring Signed-in Users
- Requiring the Right User
- Friendly Forwarding
- Showing All Users
- User Index
- Sample Users
- Pagination
- Partial Refactoring
- Deleting Users-Administrative Users
- The destroy Action
- Conclusion-Exercises
- A Micropost Model
- The Basic Model
- Accessible Attributes and the First Validation
- User Micropost Associations
- Micropost Refinements
- Content Validations
- Showing Microposts
- Augmenting the User Show Page
- Sample Microposts
- Manipulating Microposts
- Access Control
- Creating Microposts
- A Proto-feed
- Destroying Microposts
- Conclusion-Exercises
- Following Users
- The Relationship Model
- A Problem with the Data Model and a Solution
- User Relationship Associations
- Validations
- Followed users
- Followers
- Sample Following Data
- Stats and a Follow Form
- Following and Followers Pages
- A Working Follow Button the Standard Way
- A Working Follow Button with Ajax
- Making the output of find readable in shell
- CRUD Operation-Create
- The Status Feed
- Motivation and Strategy
- A First Feed Implementation
- Subselects
- The New Status Feed
- Conclusion
- Exercises
Ruby On Rails Lesson
Class Inheritance
When learning about classes, it’s useful to find out the class hierarchy using the superclass method:
A diagram of this inheritance hierarchy appears in Figure 4.1. We see here that the superclass of String is Object and the superclass of Object is BasicObject, but BasicObject has no superclass. This pattern is true of every Ruby object: Trace back the class hierarchy far enough and every class in Ruby ultimately inherits from BasicObject, which has no superclass itself. This is the technical meaning of ‘‘everything in Ruby is an object.’’
To understand classes a little more deeply, there’s no substitute for making one of our own. Let’s make a Word class with a palindrome? method that returns true if the word is the same spelled forward and backward:
>> def palindrome? (string)
>> string == string. reverse
>> end
>> end
=> nil
We can use it as follows:
=> #<Word:0x22d0b20>
>> w.palindrome? ("foobar")
=> false
>> w.palindrome? ("level")
=> true
If this example strikes you as a bit contrived, good; this is by design. It’s odd to create a new class just to create a method that takes a string as an argument. Since a word is a string, it’s more natural to have our Word class inherit from String, as seen in Listing 4.8. (You should exit the console and re-enter it to clear out the old definition of Word.)
Listing 4.8 Defining a Word class in the console
Here Word < String is the Ruby syntax for inheritance (discussed briefly in Section 3.1.2), which ensures that, in addition to the new palindrome? method, words also have all the same methods as strings:
=> "level"
>> s.palindrome? # Words have the palindrome? method.
=> true
>> s.length # Words also inherit all the normal string methods.
=> 5
Since the Word class inherits from String, we can use the console to see the class hierarchy explicitly:
=> Word
>> s.class.superclass
=> String
>> s.class.superclass.superclass
=> Object
This hierarchy is illustrated in Figure 4.2.
In Listing 4.8, note that checking that the word is its own reverse involves accessing the word inside the Word class. Ruby allows us to do this using the self keyword: Inside the Word class, self is the object itself, which means we can use
to check if the word is a palindrome.11
Neha Jaggi
Skills Ruby On Rails
Qualifications :- High School - , College/University - Graphic Era Hill University, Dehradun, College/University - ,Location :-Dehradun,Dehradun,UTTARAKHAND,India
Description:-
Experienced Software Developer with a demonstrated history of working in the Information Technology and services industry. Skilled in Web Technologies (Ruby on Rails, PostgreSQL, php, Laravel and AJAX).
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