Representational State Transfer

Learning Goals

• Explain CRUD in the context of web applications.
• Explain what is REST
• Be able to distinguish between a RESTful vs non-RESTful route.

Vocabulary

• CRUD
• REST
• HTTP Verbs
• URI

Warm Up

Based on your Task Manager App:

• What does CRUD stand for?
• Look at your Task Manager routes: what are the eight different method/path/controller#action combinations contained there?
• What does each one do?

CRUD

• C - Create
• R - Read
• U - Update
• D - Delete

This is a list of the operations we can perform on a resource.

In this context, resource is a generic term for something that we have in our application (e.g. tasks, people, movies). Generally, each table we create in our database holds specific instances of a particular resource. We create, read, update and destroy resources in our database.

Often, our applications will have a separate controller and model for each resource.

REST

• Representational State Transfer (ReST) is a web architecture style
• Coined by Roy Fielding in doctoral dissertation (2000)
• REST is a simple way to organize interactions between independent systems
• A map between HTTP verb/path combinations and CRUD actions users want to perform on a resource
• RESTful applications typically treat the web like a resource

HTTP Verbs

• GET: retrieve a resource from a url
• POST: create a new resource
• PUT: update an entire resource
• PATCH: update part of a resource
• DELETE: remove/destroy a resource

Additional information from the W3C.

URI

• Uniform Resource Identifier

In this context, the portion of the URL after the domain.

For the URL https://en.wikipedia.org/wiki/Uniform_Resource_Identifier, the URI would be /wiki/Uniform_Resource_Identifier.

Think to yourself

What is the URI for this address? http://www.tatteredcover.com/book/9781626722934

Seven RESTful Routes

Pull up the routes and TaskController from Task Manager. Let’s see if you can create a table for seven RESTful routes allowing us to perform all CRUD actions on a Task. Include the following:

• Method (verb)
• Path/URI
• Controller
• Controller action
• What does it do?

Complete the table. You can either make a copy of the spreadsheet, or diagram this in your notebook.

Is there a command you can run from your terminal to help with the diagram? (HINT)

Not So RESTful Routes

• Do research. What is an example of a non-RESTful route?
  • /tasks/add
  • /tasks/show_all
  • etc

CFU

• What is each part of CRUD?
• What is REST?
• How do we combine CRUD and REST in web applications?
• Record a version of the restful routes table in your notes

Additional Resources

• Representational State Transfer on Wikipedia
• What is REST? from REST API Tutorial
• Another Video