Ruby On Rails Classroom
Anil Bist /
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
A First Feed Implementation
Now it’s time to implement Micropost.from_users_followed_by, which for simplicity we’ll just refer to as ‘‘the feed.’’ Since the final result is rather intricate, we’ll build up to the final feed implementation by introducing one piece at a time. The first step is to think of the kind of query we’ll need. What we want to do is select from the microposts table all the microposts with ids corresponding to the users being followed by a given user (or the user itself). We might write this schematically as follows:
In writing this code, we’ve guessed that SQL supports an IN keyword that allows us to test for set inclusion. (Happily, it does.)
Recall from the proto-feed in Section 10.3.3 that Active Record uses the where method to accomplish the kind of select shown above, as illustrated in Listing 10.39. There, our select was very simple; we just picked out all the microposts with user id corresponding to the current user:
Here, we expect it to be more complicated, something like
(Here we’ve used the Rails convention of user instead of user.id in the condition; Rails automatically uses the id. We’ve also omitted the leading Micropost. since we expect this method to live in the Micropost model itself.)
We see from these conditions that we’ll need an array of ids corresponding to the users being followed. One way to do this is to use Ruby’s map method, available on any ‘‘enumerable’’ object, i.e., any object (such as an Array or a Hash) that consists of a collection of elements.11 We saw an example of this method in Section 4.3.2; it works like this:
Anil Bist
Skills Ruby On Rails
Qualifications :- High School - SLV, College/University - Graphic Era Deemed Univ University,Location :-Dehradun,Dehradun,Uttarakhand,India
Description:-
I started my Professional Journey in 2006 with one of the Web Development Company in Bangalore and my 1st framework was "Ruby on Rail" as Web development and delivered around 5+ Projects using this platform. Then came another dimension as JEE/Sturst framework, Gradually I realized that I want to build something on my own and give my passion and energy on creating something different a
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