To develop an HTTP API with minimal dependencies prior to .NET Core 6.0, you can follow these steps:

  1. Choose a Lightweight Framework
    Use ASP.NET Core (preferably version 2.1 or higher). It’s lightweight and designed for building HTTP APIs.
  2. Set Up Your Project
    Create a new ASP.NET Core Web API project:
    dotnet new webapi -n YourApiName
    This creates a basic project structure with minimal dependencies.
  3. Define Your Models
    Create simple data models representing the resources your API will handle. For example:
    public class Product
    {
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
    }
  4. Create Controllers
    Create a controller to handle HTTP requests. For example:
    [ApiController]
    [Route(\”api\/[controller]\”)]
    public class ProductsController : ControllerBase
    {
    private static List products = new List();
    [HttpGet]
    public ActionResult> GetProducts()
    {
    1.  return Ok(products);
    }
    [HttpPost]
    public ActionResult CreateProduct(Product product)
    {
    1.  products.Add(product);
    2.  return CreatedAtAction(nameof(GetProducts), new { id = product.Id }, product);
    }
    }
  5. Configure Routing and Middleware
    In Startup.cs, configure routing and any necessary middleware:
    public void ConfigureServices(IServiceCollection services)
    {
    services.AddControllers();
    }
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
    if (env.IsDevelopment())
    {
    1.  app.UseDeveloperExceptionPage();
    }
    app.UseRouting();
    app.UseEndpoints(endpoints =>
    {
    1.  endpoints.MapControllers();
    });
    }
  6. Run and Test Your API
    Run your API using:
    dotnet run
    Use tools like Postman or curl to test the endpoints.
  7. Document Your API
    Consider using Swagger for API documentation. Add the following NuGet package:
    dotnet add package Swashbuckle.AspNetCore
    Configure Swagger in Startup.cs to generate documentation.
  8. Deployment
    Choose your hosting environment (e.g., Azure, AWS, or on-premises) and deploy your application as needed.