Lecture on Building RESTful APIs with .NET Core

Jul 4, 2024

Lecture on Building RESTful APIs with .NET Core 🌐

Introduction

Instructor: Progen

  • API: Application Programming Interface
  • Purpose: Transmitting data and communication between multiple applications
  • Course includes real-world project and database integration
  • Common error messages and resolutions included

API Basics

Definition and Example

  • API: A way for multiple applications to communicate with each other
  • Example: Ordering food at a restaurant
    • Menu (API documentation)
    • Server (API) takes the order (request) to the chef and returns the prepared food (response)

Real-World Scenario

  • Websites like Kayak or Expedia use APIs from airlines and hotels to display rates
  • Client Request and API Response model

HTTP Requests and Responses

Request Components

  1. Verb: Action like GET, POST, PUT, DELETE, PATCH
  2. Headers: Metadata about the request (Content-Type, Authorization, etc.)
  3. Content: Optional data like JSON objects

Response Components

  1. Status Code: e.g., 200 OK, 404 Not Found, 500 Internal Server Error
  2. Headers: Metadata about the response (Content-Type, etc.)
  3. Content: Data like JSON, blobs, etc.

Common HTTP Verbs

  • GET: Fetch data
  • POST: Create new resource
  • PUT: Update an existing resource
  • PATCH: Partially update a resource
  • DELETE: Remove a resource

Building API with .NET Core

Setting Up

  • Use Visual Studio 2022
  • Create a new project using ASP.NET Core Web API template
  • Configure for HTTPS and enable OpenAPI support

Source Control

  • Add project to GitHub for version control

Creating API Endpoints

  • GET: Retrieve all items (Villas)
  • GET by ID: Retrieve item by ID
  • POST: Create new item
  • PUT: Update an item
  • PATCH: Partially update item
  • DELETE: Remove item

Return Types

  • Use ActionResult to return different types
  • ProducesResponseType to document possible responses

Data Transfer Objects (DTOs)

  • DTOs act as a wrapper between database models and exposed API
  • Create VillaDTO class

Temporary Data Store

  • Create a static list to store data temporarily before using a database

Data Validations

  • Use data annotations like Required and MaxLength for validation

Logging

  • Dependency Injection for logger implementation

Database Integration

  • Use Entity Framework Core
  • Create DBContext for managing entities
  • Add NuGet packages: Microsoft.EntityFramework.Core, Microsoft.EntityFrameworkCore.SqlServer, Microsoft.EntityFrameworkCore.Tools
  • Configure connection strings

Migrations

  • Create migrations for database updates
  • Use commands Add-Migration and Update-Database

Testing with Postman and Swagger

  • Used for visually interacting with API endpoints and testing functionalities

Key Concepts in EF Core

  • DbContext: Managing entities
  • AsNoTracking: Optimize for read-only operations

Summary

  • RESTful API basics and CRUD operations
  • Dependency Injection, logging, and database integration
  • Practical steps for using Swagger, Postman, DTOs, and EF Core

[Music] thank you for attending