Question

我正在使用ASP.NET Core 2.2 ApiController，并且具有以下内容：

[ApiController]
public class PostController : Controller {
  [HttpGet("posts")]
  public async Task<IActionResult> Get() {
    return BadRequest();
  }
}

在这种情况下，我得到以下响应：

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "Bad Request",
  "status": 400,
  "traceId": "0HLMFSL0C7SKB:00000001"
}

但是如果我返回如下数据：

[ApiController]
public class PostController : Controller {
  [HttpGet("posts")]
  public async Task<IActionResult> Get() {
    List<String> errors = new List<String> { "Code is invalid" };
    return BadRequest(new { errors = errors });
  }
}

我得到以下信息：

{
  "errors": ["Code is invalid"]
}

为什么没有内容返回时ApiController会添加类型，标题，状态和traceId？

我希望响应始终像这样：

{
  "errors": ["Code is invalid"],
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "Bad Request",
  "status": 400,
  "traceId": "0HLMFSL0C7SKB:00000001"
}

Answer 1

默认ControllerBase.BadRequest()响应内容是因为您已将[ApiController]属性应用于控制器。在线记录如下：

https://docs.microsoft.com/en-us/aspnet/core/web-api/?view=aspnetcore-2.2#problem-details-for-error-status-codes

当兼容版本为2.2或更高版本时，MVC会将错误结果（状态码为400或更高的结果）转换为ProblemDetails的结果。 ProblemDetails类型基于RFC 7807规范，用于在HTTP响应中提供机器可读的错误详细信息。

这包括type，title,状态and traceId`值：https://docs.microsoft.com/en-us/aspnet/core/web-api/?view=aspnetcore-2.2#problem-details-for-error-status-codes

如果您未应用[ApiController]，则ControllerBase.BadRequest()将返回带有HTTP 400状态码的空响应。

接受ControllerBase.BadRequest或value响应对象的model的所有重载都将被序列化并返回，而不是使用ApiController默认响应。

Answer 2

对于ProblemDetails，取决于ObjectResult是否继承自IClientErrorActionResult。

您可以按照以下步骤进行解决：

MyBadRequestObjectResult

public class MyBadRequestObjectResult : BadRequestObjectResult, IClientErrorActionResult
{
    public MyBadRequestObjectResult() : base((object)null)
    {
    }

    public MyBadRequestObjectResult(object error) : base(error)
    {
    }
}

自定义ProblemDetailsErrorFactory

public class ProblemDetailsErrorFactory: IClientErrorFactory
{
    private static readonly string TraceIdentifierKey = "traceId";
    private static readonly string ErrorsKey = "errors";
    private readonly ApiBehaviorOptions _options;

    public ProblemDetailsErrorFactory(IOptions<ApiBehaviorOptions> options)
    {
        _options = options?.Value ?? throw new ArgumentNullException(nameof(options));
    }

    public IActionResult GetClientError(ActionContext actionContext, IClientErrorActionResult clientError)
    {
        var problemDetails = new ProblemDetails
        {
            Status = clientError.StatusCode,
            Type = "about:blank",
        };

        if (clientError.StatusCode is int statusCode &&
            _options.ClientErrorMapping.TryGetValue(statusCode, out var errorData))
        {
            problemDetails.Title = errorData.Title;
            problemDetails.Type = errorData.Link;
            SetErrors(actionContext, problemDetails);
            SetTraceId(actionContext, problemDetails);
        }

        return new ObjectResult(problemDetails)
        {
            StatusCode = problemDetails.Status,
            ContentTypes =
            {
                "application/problem+json",
                "application/problem+xml",
            },
        };
    }
    internal static void SetErrors(ActionContext actionContext, ProblemDetails problemDetails)
    {
        if (actionContext is ResultExecutingContext resultExecutingContext)
        {
            if (resultExecutingContext.Result is BadRequestObjectResult result)
            {
                problemDetails.Extensions[ErrorsKey] = result.Value;
            }
        }
        //var errors = actionContext.HttpContext.
    }
    internal static void SetTraceId(ActionContext actionContext, ProblemDetails problemDetails)
    {
        var traceId = Activity.Current?.Id ?? actionContext.HttpContext.TraceIdentifier;
        problemDetails.Extensions[TraceIdentifierKey] = traceId;
    }

}

注册ProblemDetailsErrorFactory

public void ConfigureServices(IServiceCollection services)
{
    services.TryAddSingleton<IClientErrorFactory, ProblemDetailsErrorFactory>();

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

控制器操作

[ApiController]
public class PostController : Controller
{
    [HttpGet("posts")]
    public IActionResult Get()
    {
        return new MyBadRequestObjectResult();
    }
    [HttpGet("posts1")]
    public IActionResult Get1()
    {
        List<String> errors = new List<String> { "Code is invalid" };
        return new MyBadRequestObjectResult(errors);
    }
}

Answer 3

尝试使用JsonConvert序列化您的错误请求。

返回BadRequest（JsonConvert.Serialize（新列表{“代码无效”}））;

Answer 4

您无需返回BadRequest()结果，而只需返回ValidationProblem()结果。这将为您提供ProblemDetails对象响应，并填充当前的ModelState错误。

ApiController并不总是在BadRequest中返回数据

4 个答案: