Getting Started with .NET Core: Creating Your First Web API

Creating a .NET Core Web API from scratch involves several steps. Here’s a step-by-step guide to help you get started:

1. Set Up Your Development Environment

Install .NET SDK: Download and install the latest .NET SDK from the .NET website. This will include the .NET Core runtime and CLI tools.

Install a Code Editor: Use Visual Studio (Community Edition) or Visual Studio Code. Visual Studio provides more features out of the box for .NET Core development.

2. Create a New Web API Project

1. Open Command Line or Terminal:
2. Create a New Project:

dotnet new webapi -o MyFirstWebApi
cd MyFirstWebApi

3. Explore the Project Structure

• Controllers/WeatherForecastController.cs: Contains a sample API controller.
• Program.cs: The entry point for the application.
• Startup.cs: Contains configuration and services setup.

4. Run the Application

Build and Run:

dotnet run

This will start the application and you can access it at http://localhost:5000 by default.

5. Create a Custom API Controller

Create a new file in the Controllers folder named ProductsController.cs with the following code:

using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;

namespace MyWebApi.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class ProductsController : ControllerBase
    {
        private static readonly List<string> Products = new List<string>
        {
            "Product1",
            "Product2",
            "Product3"
        };

        [HttpGet]
        public ActionResult<IEnumerable<string>> Get()
        {
            return Products;
        }

        [HttpGet("{id}")]
        public ActionResult<string> Get(int id)
        {
            if (id < 0 || id >= Products.Count)
            {
                return NotFound();
            }

            return Products[id];
        }

        [HttpPost]
        public ActionResult Post([FromBody] string product)
        {
            Products.Add(product);
            return CreatedAtAction(nameof(Get), new { id = Products.Count - 1 }, product);
        }

        [HttpDelete("{id}")]
        public ActionResult Delete(int id)
        {
            if (id < 0 || id >= Products.Count)
            {
                return NotFound();
            }

            Products.RemoveAt(id);
            return NoContent();
        }
    }
}

6. How to Test the API?

Unit Testing: Use xUnit or NUnit for unit testing your API controllers and services.

Integration Testing: Test the entire application flow using tools like Postman or integration test libraries.

7. Test the API:

Use tools like Postman or Swagger URL to test your new endpoints:

• GET /api/products – Retrieve all products.
• GET /api/products/{id} – Retrieve a specific product.
• POST /api/products – Add a new product.
• DELETE /api/products/{id} – Remove a product.

8. Deploy Your API

Publish: Use the dotnet publish command to prepare your application for deployment.

Deploy to Cloud or Server: Deploy your API to a cloud provider (like Azure) or an on-premises server.

dotnet publish -c Release -o ./publish

This guide covers the basic steps to create and deploy a .NET Core Web API. You can further enhance your application with advanced features such as authentication, authorization, and database integration.

Have any questions or thoughts on getting started with .NET Core or building your first Web API? Drop a comment below and join the conversation!

Thanks for reading! Cheers and happy coding!