効率的なC# API設計とドキュメント生成の方法

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
}

public class User
{
    public int Id { get; set; }

    [Required]
    public string Name { get; set; }

    [EmailAddress]
    public string Email { get; set; }
}

public class UserValidator
{
    public bool Validate(User user)
    {
        if (string.IsNullOrWhiteSpace(user.Name))
        {
            return false;
        }
        if (!new EmailAddressAttribute().IsValid(user.Email))
        {
            return false;
        }
        return true;
    }
}

try
{
    // 処理コード
}
catch (Exception ex)
{
    // エラーレスポンスを生成
    var errorResponse = new { Message = ex.Message };
    return StatusCode(500, errorResponse);
}

{
    "status": "success",
    "data": {
        "id": 1,
        "name": "John Doe",
        "email": "john.doe@example.com"
    }
}

{
    "status": "error",
    "message": "Resource not found"
}

public class ErrorHandlingMiddleware
{
    private readonly RequestDelegate _next;

    public ErrorHandlingMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task Invoke(HttpContext context)
    {
        try
        {
            await _next(context);
        }
        catch (Exception ex)
        {
            await HandleExceptionAsync(context, ex);
        }
    }

    private static Task HandleExceptionAsync(HttpContext context, Exception exception)
    {
        var response = new { Message = "An unexpected error occurred." };
        context.Response.ContentType = "application/json";
        context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
        return context.Response.WriteAsync(JsonConvert.SerializeObject(response));
    }
}

// JWTトークンの生成
var securityKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("YourSecretKey"));
var credentials = new SigningCredentials(securityKey, SecurityAlgorithms.HmacSha256);

var token = new JwtSecurityToken(
    issuer: "yourdomain.com",
    audience: "yourdomain.com",
    expires: DateTime.Now.AddMinutes(30),
    signingCredentials: credentials
);

var tokenHandler = new JwtSecurityTokenHandler();
var jwtToken = tokenHandler.WriteToken(token);

// ポリシーの定義
services.AddAuthorization(options =>
{
    options.AddPolicy("AdminOnly", policy => policy.RequireClaim("Admin"));
});

// コントローラーでの使用
[Authorize(Policy = "AdminOnly")]
public IActionResult GetAdminData()
{
    return Ok("This is admin data.");
}

// Roleの設定
[Authorize(Roles = "Admin")]
public IActionResult AdminEndpoint()
{
    return Ok("This is an admin endpoint.");
}

// ユーザーにRoleを割り当てる
var user = new ClaimsPrincipal(new ClaimsIdentity(new Claim[]
{
    new Claim(ClaimTypes.Name, "user1"),
    new Claim(ClaimTypes.Role, "Admin")
}, "mock"));

GET /v1/users
GET /v2/users

GET /users?version=1
GET /users?version=2

GET /users
Header: api-version: 1

// Startup.csでの設定
public void ConfigureServices(IServiceCollection services)
{
    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API", Version = "v1" });
    });
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // Swaggerミドルウェアの追加
    app.UseSwagger();
    app.UseSwaggerUI(c =>
    {
        c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
    });
}

// NSwagの設定例
services.AddOpenApiDocument(configure =>
{
    configure.Title = "My API";
});

/// <summary>
/// ユーザーを取得する
/// </summary>
/// <returns>ユーザーリスト</returns>
[HttpGet]
public IEnumerable<User> GetUsers()
{
    // メソッドの実装
}

app.UseSwaggerUI(c =>
{
    c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
    c.RoutePrefix = string.Empty; // ルートURLでホスティングする場合
});

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseSwaggerUI(c =>
    {
        c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
        c.InjectStylesheet("/swagger-ui/custom.css"); // カスタムCSSの適用
    });
}

/// <summary>
/// 新しいユーザーを作成する
/// </summary>
/// <param name="user">ユーザー情報</param>
/// <returns>作成されたユーザー</returns>
[HttpPost]
public ActionResult<User> CreateUser([FromBody] User user)
{
    // メソッドの実装
}

services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API", Version = "v1" });
    c.DocInclusionPredicate((docName, apiDesc) =>
    {
        // 特定のエンドポイントを除外するロジック
        return !apiDesc.RelativePath.Contains("hidden");
    });
});

// カスタムテンプレートの設定
services.AddOpenApiDocument(configure =>
{
    configure.Title = "My API";
    configure.Description = "This is a customized API documentation.";
    configure.GenerateExamples = true;
});

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

[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    private static List<User> Users = new List<User>
    {
        new User { Id = 1, Name = "John Doe", Email = "john.doe@example.com" },
        new User { Id = 2, Name = "Jane Smith", Email = "jane.smith@example.com" }
    };

    [HttpGet]
    public ActionResult<IEnumerable<User>> GetUsers()
    {
        return Ok(Users);
    }

    [HttpGet("{id}")]
    public ActionResult<User> GetUser(int id)
    {
        var user = Users.Find(u => u.Id == id);
        if (user == null)
        {
            return NotFound();
        }
        return Ok(user);
    }

    [HttpPost]
    public ActionResult<User> CreateUser([FromBody] User user)
    {
        user.Id = Users.Count + 1;
        Users.Add(user);
        return CreatedAtAction(nameof(GetUser), new { id = user.Id }, user);
    }

    [HttpPut("{id}")]
    public ActionResult UpdateUser(int id, [FromBody] User updatedUser)
    {
        var user = Users.Find(u => u.Id == id);
        if (user == null)
        {
            return NotFound();
        }
        user.Name = updatedUser.Name;
        user.Email = updatedUser.Email;
        return NoContent();
    }

    [HttpDelete("{id}")]
    public ActionResult DeleteUser(int id)
    {
        var user = Users.Find(u => u.Id == id);
        if (user == null)
        {
            return NotFound();
        }
        Users.Remove(user);
        return NoContent();
    }
}

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
}

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
using Newtonsoft.Json;

public class ApiClient
{
    private readonly HttpClient _httpClient;

    public ApiClient(string baseAddress)
    {
        _httpClient = new HttpClient { BaseAddress = new Uri(baseAddress) };
        _httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    }

    public async Task<User> GetUserAsync(int id)
    {
        HttpResponseMessage response = await _httpClient.GetAsync($"api/users/{id}");
        response.EnsureSuccessStatusCode();
        string responseBody = await response.Content.ReadAsStringAsync();
        return JsonConvert.DeserializeObject<User>(responseBody);
    }
}

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
}