Program.cs

using System.Security.Claims;
using Microsoft.EntityFrameworkCore;
using NSwag.AspNetCore;

var MyAllowSpecificOrigins = "_myAllowSpecificOrigins";
var builder = WebApplication.CreateBuilder(args);

builder.Services.AddCors(options =>
{
    options.AddPolicy(name: MyAllowSpecificOrigins,
                      policy =>
                      {
                          policy.WithOrigins("http://localhost:5173").AllowAnyHeader().AllowAnyMethod();
                      });
});

// Requires Microsoft.AspNetCore.Authentication.JwtBearer
builder.Services.AddCors();
builder.Services.AddAuthentication("Bearer").AddJwtBearer();
builder.Services.AddAuthorization();

builder.Services.AddDbContext<TodoDbContext>(opt => opt.UseInMemoryDatabase("TodoList"));
builder.Services.AddDatabaseDeveloperPageExceptionFilter();

// Swagger middleware
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddOpenApiDocument(config =>
{
    config.DocumentName = "TodoAPI";
    config.Title = "TodoAPI v1";
    config.Version = "v1";
});

var app = builder.Build();

app.UseCors(MyAllowSpecificOrigins);
app.UseAuthentication();
app.UseAuthorization();

app.Logger.LogInformation("The app started");

if (app.Environment.IsDevelopment())
{
    app.UseOpenApi();
    app.UseSwaggerUi(config =>
    {
        config.DocumentTitle = "TodoAPI";
        config.Path = "/swagger";
        config.DocumentPath = "/swagger/{documentName}/swagger.json";
        config.DocExpansion = "list";
    });
}

// root entry point with link to swagger
app.MapGet("/", () => TypedResults.Text("<h1>Todo API</h1><a href='/swagger'>Swagger Documentation</a>", "text/html"));

var todoItems = app.MapGroup("/todoitems");
todoItems.MapGet("/", GetAllTodos);
todoItems.MapGet("/complete", GetCompleteTodos);
todoItems.MapGet("/{id}", GetTodo);
todoItems.MapPost("/", CreateTodo);
todoItems.MapPut("/{id}", UpdateTodo);
todoItems.MapDelete("/{id}", DeleteTodo);

// test authorized endpoint with JWT token via curl
app.MapGet("/secret", (ClaimsPrincipal user) => $"Hello {user.Identity?.Name}. My secret")
    .RequireAuthorization();

app.Logger.LogInformation("Registered routes");
app.Run();

static async Task<IResult> GetAllTodos(TodoDbContext db)
{
    return TypedResults.Ok(await db.Todos.Select(x => new TodoItemDTO(x)).ToArrayAsync());
}

static async Task<IResult> GetCompleteTodos(TodoDbContext db)
{
    return TypedResults.Ok(await db.Todos.Where(t => t.IsComplete).Select(x => new TodoItemDTO(x)).ToListAsync());
}

static async Task<IResult> GetTodo(int id, TodoDbContext db)
{
    return await db.Todos.FindAsync(id)
        is Todo todo
            ? TypedResults.Ok(new TodoItemDTO(todo))
            : TypedResults.NotFound();
}

static async Task<IResult> CreateTodo(TodoItemDTO todoItemDTO, TodoDbContext db)
{
    var todoItem = new Todo
    {
        IsComplete = todoItemDTO.IsComplete,
        Name = todoItemDTO.Name
    };

    db.Todos.Add(todoItem);
    await db.SaveChangesAsync();

    todoItemDTO = new TodoItemDTO(todoItem);

    return TypedResults.Created($"/todoitems/{todoItem.Id}", todoItemDTO);
}

static async Task<IResult> UpdateTodo(int id, TodoItemDTO todoItemDTO, TodoDbContext db)
{
    var todo = await db.Todos.FindAsync(id);

    if (todo is null) return TypedResults.NotFound();

    todo.Name = todoItemDTO.Name;
    todo.IsComplete = todoItemDTO.IsComplete;

    await db.SaveChangesAsync();

    return TypedResults.NoContent();
}

static async Task<IResult> DeleteTodo(int id, TodoDbContext db)
{
    if (await db.Todos.FindAsync(id) is Todo todo)
    {
        db.Todos.Remove(todo);
        await db.SaveChangesAsync();
        return TypedResults.NoContent();
    }

    return TypedResults.NotFound();
}