Question

在我的WebAPI项目中，我使用ClusterableStop添加JWT身份验证。在我的OAuthProvider的Owin.Security.OAuth内，我使用以下行设置错误：

GrantResourceOwnerCredentials

将其作为以下内容返回给客户：

context.SetError("invalid_grant", "Account locked.");

在用户进行身份验证后，他尝试对我的某个控制器执行“正常”请求时，当模型无效时，他会得到以下响应（使用FluentValidation）：

{
  "error": "invalid_grant",
  "error_description": "Account locked."
}

这两个请求都返回{ "message": "The request is invalid.", "modelState": { "client.Email": [ "Email is not valid." ], "client.Password": [ "Password is required." ] } }，但有时您必须查找400 Bad Request字段，有时候查找error_description

I was able to create自定义响应消息，但这仅适用于我返回的结果。

我的问题是：是否可以在message和其他地方返回的回复中将message替换为error？

我读过ModelValidatorProviders但我不知道这是不是一个好的起点。 FluentValidation应该不是问题，因为它只是向ExceptionFilterAttribute添加错误。

修改
接下来我要修复的是WebApi中返回数据的命名约定不一致 - 当从ModelState返回错误时我们有OAuthProvider，但是当error_details返回BadRequest时（来自ModelState）我们ApiController。如您所见，首先使用modelState和第二snake_case。

Answer 1

更新的答案（使用中间件）

由于Web API原始委托处理程序的想法意味着它不像OAuth中间件那样在管道中足够早，因此需要创建自定义中间件......

public static class ErrorMessageFormatter {

    public static IAppBuilder UseCommonErrorResponse(this IAppBuilder app) {
        app.Use<JsonErrorFormatter>();
        return app;
    }

    public class JsonErrorFormatter : OwinMiddleware {
        public JsonErrorFormatter(OwinMiddleware next)
            : base(next) {
        }

        public override async Task Invoke(IOwinContext context) {
            var owinRequest = context.Request;
            var owinResponse = context.Response;
            //buffer the response stream for later
            var owinResponseStream = owinResponse.Body;
            //buffer the response stream in order to intercept downstream writes
            using (var responseBuffer = new MemoryStream()) {
                //assign the buffer to the resonse body
                owinResponse.Body = responseBuffer;

                await Next.Invoke(context);

                //reset body
                owinResponse.Body = owinResponseStream;

                if (responseBuffer.CanSeek && responseBuffer.Length > 0 && responseBuffer.Position > 0) {
                    //reset buffer to read its content
                    responseBuffer.Seek(0, SeekOrigin.Begin);
                }

                if (!IsSuccessStatusCode(owinResponse.StatusCode) && responseBuffer.Length > 0) {
                    //NOTE: perform your own content negotiation if desired but for this, using JSON
                    var body = await CreateCommonApiResponse(owinResponse, responseBuffer);

                    var content = JsonConvert.SerializeObject(body);

                    var mediaType = MediaTypeHeaderValue.Parse(owinResponse.ContentType);
                    using (var customResponseBody = new StringContent(content, Encoding.UTF8, mediaType.MediaType)) {
                        var customResponseStream = await customResponseBody.ReadAsStreamAsync();
                        await customResponseStream.CopyToAsync(owinResponseStream, (int)customResponseStream.Length, owinRequest.CallCancelled);
                        owinResponse.ContentLength = customResponseStream.Length;
                    }
                } else {
                    //copy buffer to response stream this will push it down to client
                    await responseBuffer.CopyToAsync(owinResponseStream, (int)responseBuffer.Length, owinRequest.CallCancelled);
                    owinResponse.ContentLength = responseBuffer.Length;
                }
            }
        }

        async Task<object> CreateCommonApiResponse(IOwinResponse response, Stream stream) {

            var json = await new StreamReader(stream).ReadToEndAsync();

            var statusCode = ((HttpStatusCode)response.StatusCode).ToString();
            var responseReason = response.ReasonPhrase ?? statusCode;

            //Is this a HttpError
            var httpError = JsonConvert.DeserializeObject<HttpError>(json);
            if (httpError != null) {
                return new {
                    error = httpError.Message ?? responseReason,
                    error_description = (object)httpError.MessageDetail
                    ?? (object)httpError.ModelState
                    ?? (object)httpError.ExceptionMessage
                };
            }

            //Is this an OAuth Error
            var oAuthError = Newtonsoft.Json.Linq.JObject.Parse(json);
            if (oAuthError["error"] != null && oAuthError["error_description"] != null) {
                dynamic obj = oAuthError;
                return new {
                    error = (string)obj.error,
                    error_description = (object)obj.error_description
                };
            }

            //Is this some other unknown error (Just wrap in common model)
            var error = JsonConvert.DeserializeObject(json);
            return new {
                error = responseReason,
                error_description = error
            };
        }

        bool IsSuccessStatusCode(int statusCode) {
            return statusCode >= 200 && statusCode <= 299;
        }
    }
}

...并在添加身份验证中间件和web api处理程序之前在管道中注册。

public class Startup {
    public void Configuration(IAppBuilder app) {

        app.UseResponseEncrypterMiddleware();

        app.UseRequestLogger();

        //...(after logging middle ware)
        app.UseCommonErrorResponse();

        //... (before auth middle ware)

        //...code removed for brevity
    }
}

这个例子只是一个基本的开始。它应该足够简单，能够扩展这个起点。

虽然在这个示例中，常见模型看起来像是从OAuthProvider返回的内容，但是可以使用任何常见的对象模型。

通过一些内存单元测试对其进行测试，并通过TDD能够使其正常工作。

[TestClass]
public class UnifiedErrorMessageTests {
    [TestMethod]
    public async Task _OWIN_Response_Should_Pass_When_Ok() {
        //Arrange
        var message = "\"Hello World\"";
        var expectedResponse = "\"I am working\"";

        using (var server = TestServer.Create<WebApiTestStartup>()) {
            var client = server.HttpClient;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            var content = new StringContent(message, Encoding.UTF8, "application/json");

            //Act
            var response = await client.PostAsync("/api/Foo", content);

            //Assert
            Assert.IsTrue(response.IsSuccessStatusCode);

            var result = await response.Content.ReadAsStringAsync();

            Assert.AreEqual(expectedResponse, result);
        }
    }

    [TestMethod]
    public async Task _OWIN_Response_Should_Be_Unified_When_BadRequest() {
        //Arrange
        var expectedResponse = "invalid_grant";

        using (var server = TestServer.Create<WebApiTestStartup>()) {
            var client = server.HttpClient;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            var content = new StringContent(expectedResponse, Encoding.UTF8, "application/json");

            //Act
            var response = await client.PostAsync("/api/Foo", content);

            //Assert
            Assert.IsFalse(response.IsSuccessStatusCode);

            var result = await response.Content.ReadAsAsync<dynamic>();

            Assert.AreEqual(expectedResponse, (string)result.error_description);
        }
    }

    [TestMethod]
    public async Task _OWIN_Response_Should_Be_Unified_When_MethodNotAllowed() {
        //Arrange
        var expectedResponse = "Method Not Allowed";

        using (var server = TestServer.Create<WebApiTestStartup>()) {
            var client = server.HttpClient;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            //Act
            var response = await client.GetAsync("/api/Foo");

            //Assert
            Assert.IsFalse(response.IsSuccessStatusCode);

            var result = await response.Content.ReadAsAsync<dynamic>();

            Assert.AreEqual(expectedResponse, (string)result.error);
        }
    }

    [TestMethod]
    public async Task _OWIN_Response_Should_Be_Unified_When_NotFound() {
        //Arrange
        var expectedResponse = "Not Found";

        using (var server = TestServer.Create<WebApiTestStartup>()) {
            var client = server.HttpClient;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            //Act
            var response = await client.GetAsync("/api/Bar");

            //Assert
            Assert.IsFalse(response.IsSuccessStatusCode);

            var result = await response.Content.ReadAsAsync<dynamic>();

            Assert.AreEqual(expectedResponse, (string)result.error);
        }
    }

    public class WebApiTestStartup {
        public void Configuration(IAppBuilder app) {

            app.UseCommonErrorMessageMiddleware();

            var config = new HttpConfiguration();
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );

            app.UseWebApi(config);
        }
    }

    public class FooController : ApiController {
        public FooController() {

        }
        [HttpPost]
        public IHttpActionResult Bar([FromBody]string input) {
            if (input == "Hello World")
                return Ok("I am working");

            return BadRequest("invalid_grant");
        }
    }
}

原始答案（使用DelegatingHandler）

考虑使用DelegatingHandler

引自在线发现的文章。

委托处理程序对于横切关注点非常有用。他们陷入了非常早期和非常晚期的阶段请求 - 响应管道使它们成为操作的理想选择在将其发回客户端之前做出回应。

此示例是针对HttpError响应

的统一错误消息的简化尝试

public class HttpErrorHandler : DelegatingHandler {

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) {
        var response = await base.SendAsync(request, cancellationToken);

        return NormalizeResponse(request, response);
    }

    private HttpResponseMessage NormalizeResponse(HttpRequestMessage request, HttpResponseMessage response) {
        object content;
        if (!response.IsSuccessStatusCode && response.TryGetContentValue(out content)) {

            var error = content as HttpError;
            if (error != null) {

                var unifiedModel = new {
                    error = error.Message,
                    error_description = (object)error.MessageDetail ?? error.ModelState
                };

                var newResponse = request.CreateResponse(response.StatusCode, unifiedModel);

                foreach (var header in response.Headers) {
                    newResponse.Headers.Add(header.Key, header.Value);
                }

                return newResponse;
            }

        }
        return response;
    }
}

虽然这个示例非常基础，但扩展它以满足您的自定义需求是微不足道的。

现在只需将处理程序添加到管道

即可

public static class WebApiConfig {
    public static void Register(HttpConfiguration config) {

        config.MessageHandlers.Add(new HttpErrorHandler());

        // Other code not shown...
    }
}

消息处理程序的调用顺序与它们出现的顺序相同    MessageHandlers 集合。因为它们是嵌套的，所以响应消息以另一个方向传播。也就是说，最后一个处理程序是   第一个收到回复消息。

来源：HTTP Message Handlers in ASP.NET Web API

Answer 2

是否可以在响应中替换带有错误的消息由ModelValidatorProviders返回

我们可能会使用重载SetError来执行此操作，将错误替换为消息。

BaseValidatingContext<TOptions>.SetError Method (String)

将此上下文标记为未由应用程序验证，并分配各种错误信息属性。 HasError变为true，并且IsValidated因调用而变为false。

string msg = "{\"message\": \"Account locked.\"}";
context.SetError(msg); 
Response.StatusCode = 400;
context.Response.Write(msg);

WebAPi - 统一来自ApiController和OAuthAuthorizationServerProvider的错误消息格式

2 个答案: