编辑 1/26/14：微软刚刚在最新的 WebAPI 2.1 更新中添加了“全局错误处理”。
好的，我想我明白了。它有几个部分。
首先：为您的错误创建一个控制器。我根据 HTTP 错误代码命名了我的操作。
public class ErrorController : ApiController {
[AllowAnonymous]
[ActionName("Get")]
public HttpResponseMessage Get() {
return Request.CreateErrorInfoResponse(HttpStatusCode.InternalServerError, title: "Unknown Error");
}
[AllowAnonymous]
[ActionName("404")]
[HttpGet]
public HttpResponseMessage Status404() {
return Request.CreateErrorInfoResponse(HttpStatusCode.NotFound, description: "No resource matches the URL specified.");
}
[AllowAnonymous]
[ActionName("400")]
[HttpGet]
public HttpResponseMessage Status400() {
return Request.CreateErrorInfoResponse(HttpStatusCode.BadRequest);
}
[AllowAnonymous]
[ActionName("500")]
[HttpGet]
public HttpResponseMessage Status500() {
return Request.CreateErrorInfoResponse(HttpStatusCode.InternalServerError);
}
}
接下来，我创建了一个GenericExceptionFilterAttribute检查是否填充了 HttpActionExecutedContext.Exception 以及响应是否仍然为空。如果这两种情况都为真，那么它会生成一个响应。
public class GenericExceptionFilterAttribute : ExceptionFilterAttribute {
public GenericExceptionFilterAttribute()
: base() {
DefaultHandler = (context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.InternalServerError, "Internal Server Error", "An unepected error occoured on the server.", exception: ex);
}
readonly Dictionary<Type, Func<HttpActionExecutedContext, Exception, HttpResponseMessage>> exceptionHandlers = new Dictionary<Type, Func<HttpActionExecutedContext, Exception, HttpResponseMessage>>();
public Func<HttpActionExecutedContext, Exception, HttpResponseMessage> DefaultHandler { get; set; }
public void AddExceptionHandler<T>(Func<HttpActionExecutedContext, Exception, HttpResponseMessage> handler) where T : Exception {
exceptionHandlers.Add(typeof(T), handler);
}
public override void OnException(HttpActionExecutedContext context) {
if (context.Exception == null) return;
try {
var exType = context.Exception.GetType();
if (exceptionHandlers.ContainsKey(exType))
context.Response = exceptionHandlers[exType](context, context.Exception);
if(context.Response == null && DefaultHandler != null)
context.Response = DefaultHandler(context, context.Exception);
}
catch (Exception ex) {
context.Response = context.Request.CreateErrorInfoResponse(HttpStatusCode.InternalServerError, description: "Error while building the exception response.", exception: ex);
}
}
}
在我的例子中，我使用了一个通用处理程序，我可以注册对每种主要异常类型的支持，并将这些异常类型中的每一种映射到特定的 HTTP 响应代码。现在在你的全局注册你的异常类型和处理程序这个过滤器global.asax.cs：
// These filters override the default ASP.NET exception handling to create REST-Friendly error responses.
var exceptionFormatter = new GenericExceptionFilterAttribute();
exceptionFormatter.AddExceptionHandler<NotImplementedException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.InternalServerError, "Not Implemented", "This method has not yet been implemented. Please try your request again at a later date.", exception: ex));
exceptionFormatter.AddExceptionHandler<ArgumentException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.BadRequest, exception: ex));
exceptionFormatter.AddExceptionHandler<ArgumentNullException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.BadRequest, exception: ex));
exceptionFormatter.AddExceptionHandler<ArgumentOutOfRangeException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.BadRequest, exception: ex));
exceptionFormatter.AddExceptionHandler<FormatException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.BadRequest, exception: ex));
exceptionFormatter.AddExceptionHandler<NotSupportedException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.BadRequest, "Not Supported", exception: ex));
exceptionFormatter.AddExceptionHandler<InvalidOperationException>((context, ex) => context.Request.CreateErrorInfoResponse(System.Net.HttpStatusCode.BadRequest, "Invalid Operation", exception: ex));
GlobalConfiguration.Filters.Add(exceptionFormatter)
接下来，创建一个包罗万象的路由，将所有未知请求发送到新的错误处理程序：
config.Routes.MapHttpRoute(
name: "DefaultCatchall",
routeTemplate: "{*url}",
defaults: new {
controller = "Error",
action = "404"
}
);
并且，总结一下，让 IIS 通过 ASP.NET 处理所有请求，方法是将其添加到您的web.config：
<configuration>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true" />
</system.webServer>
</configuration>
或者，您还可以使用 的customErrors部分web.config将所有错误重定向到新的错误处理程序。
