Building a Robust ASP.NET Core Web API with PostgreSQL

Replace your username and your password with your PostgreSQL credentials.

7. Configure Dependency Injection

In the Startup.cs file, configure dependency injection for the database context.

// Startup.cs

using CSharpCornerApi.Data;

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<AppDbContext>(options =>
        options.UseNpgsql(Configuration.GetConnectionString("DefaultConnection")));
    
    // ...
}

8. Create CRUD Endpoints

In the Controllers folder, create a controller to handle CRUD operations.

// Controllers/CSharpCornerArticlesController.cs

using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using CSharpCornerApi.Data;
using CSharpCornerApi.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;


[Route("API/[controller]")]
[ApiController]
public class CSharpCornerArticlesController: ControllerBase
{
    private readonly AppDbContext _context;

    public CSharpCornerArticlesController(AppDbContext context)
    {
        _context = context;
    }

    [HttpGet]
    public async Task<ActionResult<IEnumerable<CSharpCornerArticle>>> GetArticles()
    {
        return await _context.Articles.ToListAsync();
    }

    [HttpGet("{id}")]
    public async Task<ActionResult<CSharpCornerArticle>> GetArticle(int id)
    {
        var article = await _context.Articles.FindAsync(id);

        if (article == null)
        {
            return NotFound();
        }

        return article;
    }

    [HttpPost]
    public async Task<ActionResult<CSharpCornerArticle>> PostArticle(CSharpCornerArticle article)
    {
        article.CreatedAt = DateTime.Now;
        _context.Articles.Add(article);
        await _context.SaveChangesAsync();

        return CreatedAtAction("GetArticle", new { id = article.Id }, article);
    }

    [HttpPut("{id}")]
    public async Task<IActionResult> PutArticle(int id, CSharpCornerArticle article)
    {
        if (id != article.Id)
        {
            return BadRequest();
        }

        _context.Entry(article).State = EntityState.Modified;

        try
        {
            await _context.SaveChangesAsync();
        }
        catch (DbUpdateConcurrencyException)
        {
            if (!ArticleExists(id))
            {
                return NotFound();
            }
            else
            {
                throw;
            }
        }

        return NoContent();
    }

    [HttpDelete("{id}")]
    public async Task<IActionResult> DeleteArticle(int id)
    {
        var article = await _context.Articles.FindAsync(id);

        if (article == null)
        {
            return NotFound();
        }

        _context.Articles.Remove(article);
        await _context.SaveChangesAsync();

        return NoContent();
    }

    private bool ArticleExists(int id)
    {
        return _context.Articles.Any(e => e.Id == id);
    }
}

9. Run Migrations

Generate and apply migrations to create the database schema.

dotnet ef migrations add InitialCreate
dotnet ef database update

Run your ASP.NET Core Web API project, and you can use Postman or any other API testing tool to test the CRUD operations on the CSharpCornerArticle model.

• To create a new article, make a POST request to https://localhost:5001/api/CSharpCornerArticles.
• To retrieve all articles, make a GET request to https://localhost:5001/api/CSharpCornerArticles.
• To retrieve a specific article, make a GET request to https://localhost:5001/api/CSharpCornerArticles/{id}.
• To update an article, make a PUT request to https://localhost:5001/api/CSharpCornerArticles/{id}.
• To delete an article, make a DELETE request to https://localhost:5001/api/CSharpCornerArticles/{id}.

CRUD API with a PostgreSQL database in ASP.NET Core, complete with a real-world use case model named CSharpCornerArticle. You can now build upon this foundation to create more advanced features for your application.