RESTful API Overview

RESTful API

What is RESTful APIs?

• Definition: API (Application Programming Interface) is a set of rules enabling communication between programs.

• Creation: Developed by server-side developers, allowing clients to interface with the server.

• REST: Stands for Representational State Transfer, a framework guiding how APIs should be structured.

• Requests and Responses:

  • Data can be fetched via specific URLs (requests).

  • Each URL corresponds to a response.

Traditional HTML Model

• Components:

  • Client (Browser): Sends request to server.

  • Server: Processes request and sends back response.

Mass Server Model

• Components:

  • Various clients (Mobile App, Code, SPA) communicating with the server:

  • Client (Mobile App)

  • Client (Code)

  • Client (Single Page Application)

  • Server (for users and data)

Action and Resource Based URL

• Action Based URLs:

  • Centered on the action performed.

  • Usually include a verb in the URL.

  • Example: GET /returnItem/item?id=123

• Resource Based URLs:

  • Focus on the resource itself.

  • Typically consist of nouns.

  • Uses HTTP verbs (GET, PUT, POST, DELETE) to define action.

  • Example: GET /item/123/

Why Representation?

• State Management:

  • Partial representation of resource state transferred between client and server.

  • States typically sent as JSON or XML.

Recommendations and Constraints

• Key Principles of RESTful APIs:

  • Uniform interface (HTTP)

  • Resource identification in requests

  • Client-server architecture: Separation of concerns

  • Stateless nature: No client-context stored on server

  • Layered systems using intermediate servers

Ilities from REST

• Long-lasting Web Service Attributes:

  • Scalability

  • Simplicity

  • Modifiability

  • Visibility

  • Portability

  • Reliability

The Request

• Components of a Request: Consists of four parts:

  • Endpoint: The URL being requested.

  • Method: The type of request (GET, POST, etc.).

  • Headers: Additional information exchanged.

  • Data/Body: Information sent to the server.

Endpoint

• Definition: The URL where requests are directed.

• Path Configuration: Paths are defined in API documentation.

  • Use of symbols like : or {} to indicate variables.

• Query Parameters:

  • Not part of REST standard but often included, starting with ? and separated by &.

  • Example: GET /users/:username/repos

Method

• Request Types: Serve different purposes:

  • GET: Retrieve data.

  • POST: Create a new resource.

  • PUT/PATCH: Update existing resource.

  • DELETE: Remove a resource.

Calling CRUD Methods

• GET (Read):

  • Request: Fetch data.

  • Response: Returns the requested data.

• POST (Create):

  • Request: Adds a new entry in the database.

  • Response: Confirmation of creation.

• PUT/PATCH (Update):

  • Request: Modifies existing database entry.

  • Response: Status of the update.

• DELETE (Delete):

  • Request: Removes an entry from the database.

  • Response: Confirmation of deletion.

Header

• Definition: Used to communicate additional information to the client/server.

• Uses:

  • Authentication, type of content being sent, etc.

  • Format: HTTP headers in property-value pairs.

Data/Body

• Definition: Contains the payload sent to the server.

• Example Usage:

  • Command: curl -X POST <URL> -d name=value.

Known Challenges for REST

• Challenges Include:

  • Endpoint consensus and declaration consistency.

  • API versioning and full system updates.

  • Handling security concerns including DDoS attacks.

  • Managing multiple requests and unnecessary data transfers.

Summary

• Key Takeaways:

  • Understanding of APIs and RESTful services.

  • Importance of action vs resource-based URLs.

  • Basics of making a RESTful request and executing it.