Fullstack Javascript
Course Notes
06 - HTTP Methods and RESTful APIs
2. REST and RESTful APIs

2. REST and RESTful APIs

What is REST?

  • REST (or Representational State Transfer) is a way of designing APIs in web applications
    • Essentially, REST defines a set of rules to help create scalable, flexible and maintainable web services
  • REST Rules
    1. Statelessness
    • Each request from the client to the server must contain all necessary infomration
    • The server doesn’t store any client context between requests
    • Note: Many real-world systems slightly bend this rule when managing user sessions.
      • Often times, when a user logs into a site (assuming the login is successful) the server will send them back a session id (usually stored in a cookie)
      • On each subsequent request, the user will send along their session ID to indicate who they are
      • The server (usually) has a cache containing all active session IDs, then when the user makes a request they can lookup the provided session ID to see who it belongs to and if it should be active
      • Technically storing that cache means the server isn’t actually stateless
      • However, managing some state on the server (especially for user sessions) means we can avoid things like sending the user’s password along with every request
    • The goal in REST should be to minimize the state stored on the server wherever possible
  1. Resource-Oriented: Resources (like books, users, etc.) are represented by URLs. You interact with resources using HTTP methods.
  2. Uniform Interface: Resources are accessed and manipulated in a standard way, typically using HTTP methods (GET, POST, etc.).
  3. Layered System: Due to REST APIs being stateless, there can be multiple layers or even multiple servers running the same REST API and the client shouldn’t have to know

What Does it Mean to Have a RESTful API?

  • A RESTful API is an API that follows the principles of REST.

    • It exposes resources (like books) via URLs.
    • It uses HTTP methods to perform actions on those resources.

  • Example (Library System):

    • Resources: Books in the library are treated as resources.
    • URLs:
      • /books: Represents the entire collection of books.
      • /books/1: Represents a specific book.
    • HTTP Methods:
      • GET /books: Retrieves all books.
      • POST /books: Adds a new book (with data in the request body as JSON).
      • PUT /books/1: Updates book details.
      • DELETE /books/1: Deletes a book.