// Build ASP.NET Core 8+ backend services with EF Core, auth, background jobs, and production API patterns.
[HINT] SKILL.mdと関連ファイルを含む完全なスキルディレクトリをダウンロード
| name | dotnet-backend |
| description | Build ASP.NET Core 8+ backend services with EF Core, auth, background jobs, and production API patterns. |
| risk | safe |
| source | self |
| date_added | 2026-02-27 |
You are an expert .NET/C# backend developer with 8+ years of experience building enterprise-grade APIs and services.
Use this skill when the user asks to:
Build ASP.NET Core APIs
Entity Framework Core
Authentication & Authorization
Background Services
Performance
using Microsoft.EntityFrameworkCore;
var builder = WebApplication.CreateBuilder(args);
// Services
builder.Services.AddDbContext<AppDbContext>(options =>
options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection")));
builder.Services.AddAuthentication().AddJwtBearer();
builder.Services.AddAuthorization();
var app = builder.Build();
// Create user endpoint
app.MapPost("/api/users", async (CreateUserRequest request, AppDbContext db) =>
{
// Validate
if (string.IsNullOrEmpty(request.Email))
return Results.BadRequest("Email is required");
// Hash password
var hashedPassword = BCrypt.Net.BCrypt.HashPassword(request.Password);
// Create user
var user = new User
{
Email = request.Email,
PasswordHash = hashedPassword,
Name = request.Name
};
db.Users.Add(user);
await db.SaveChangesAsync();
return Results.Created($"/api/users/{user.Id}", new UserResponse(user));
})
.WithName("CreateUser")
.WithOpenApi();
app.Run();
record CreateUserRequest(string Email, string Password, string Name);
record UserResponse(int Id, string Email, string Name);
[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
private readonly AppDbContext _db;
private readonly ILogger<UsersController> _logger;
public UsersController(AppDbContext db, ILogger<UsersController> logger)
{
_db = db;
_logger = logger;
}
[HttpGet]
public async Task<ActionResult<List<UserDto>>> GetUsers()
{
var users = await _db.Users
.AsNoTracking()
.Select(u => new UserDto(u.Id, u.Email, u.Name))
.ToListAsync();
return Ok(users);
}
[HttpPost]
public async Task<ActionResult<UserDto>> CreateUser(CreateUserDto dto)
{
var user = new User
{
Email = dto.Email,
PasswordHash = BCrypt.Net.BCrypt.HashPassword(dto.Password),
Name = dto.Name
};
_db.Users.Add(user);
await _db.SaveChangesAsync();
return CreatedAtAction(nameof(GetUser), new { id = user.Id }, new UserDto(user));
}
}
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
public class TokenService
{
private readonly IConfiguration _config;
public TokenService(IConfiguration config) => _config = config;
public string GenerateToken(User user)
{
var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Key"]!));
var credentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
var claims = new[]
{
new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
new Claim(ClaimTypes.Email, user.Email),
new Claim(ClaimTypes.Name, user.Name)
};
var token = new JwtSecurityToken(
issuer: _config["Jwt:Issuer"],
audience: _config["Jwt:Audience"],
claims: claims,
expires: DateTime.UtcNow.AddHours(1),
signingCredentials: credentials
);
return new JwtSecurityTokenHandler().WriteToken(token);
}
}
public class EmailSenderService : BackgroundService
{
private readonly ILogger<EmailSenderService> _logger;
private readonly IServiceProvider _services;
public EmailSenderService(ILogger<EmailSenderService> logger, IServiceProvider services)
{
_logger = logger;
_services = services;
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
while (!stoppingToken.IsCancellationRequested)
{
using var scope = _services.CreateScope();
var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
var pendingEmails = await db.PendingEmails
.Where(e => !e.Sent)
.Take(10)
.ToListAsync(stoppingToken);
foreach (var email in pendingEmails)
{
await SendEmailAsync(email);
email.Sent = true;
}
await db.SaveChangesAsync(stoppingToken);
await Task.Delay(TimeSpan.FromMinutes(1), stoppingToken);
}
}
private async Task SendEmailAsync(PendingEmail email)
{
// Send email logic
_logger.LogInformation("Sending email to {Email}", email.To);
}
}