客户端没有收到来自 ApiController 的自定义 HttpResponseException答案

【问题标题】：Client doesn't receive custom HttpResponseException from ApiController客户端没有收到来自 ApiController 的自定义 HttpResponseException
【发布时间】：2015-07-16 08:05:43
【问题描述】：

我为我的 Web API 控制器操作创建了一个异常过滤器，但它似乎没有做任何事情（即使它确实被调用了）。

属性

public class ExceptionHandlerAttribute : ExceptionFilterAttribute
{
    public override void OnException(HttpActionExecutedContext context)
    {
        context.Response = new HttpResponseMessage(HttpStatusCode.BadRequest);
        context.Response.Content = new StringContent("My content");
        context.Response.ReasonPhrase = "My reason";
    }
}

我也试过了：

public override void OnException(HttpActionExecutedContext context)
{
    throw new HttpResponseException(
        new HttpResponseMessage(HttpStatusCode.BadRequest)
        {
            Content = new StringContent("The content"),
            ReasonPhrase = "The reason"
        });
}

控制器

[ExceptionHandler]
public class MyController : ApiController
{
    [Route("MyRoute"), HttpGet]
    public MyModel Index() {
        // code causing exception
    }
}

WebApiConfig

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Filters.Add(new ExceptionHandlerAttribute());
    }
}

但是，当发生异常时，客户端会收到以下信息：

【问题讨论】：

它被调用了吗？
是的，它正在被调用。

标签： c# .net asp.net-mvc asp.net-web-api

【解决方案1】：

您需要在异常过滤器的响应中抛出 HttpResponseException：

public override void OnException(HttpActionExecutedContext context)
{
    throw new HttpResponseException(
        new HttpResponseMessage(HttpStatusCode.BadRequest)
        {
            Content = new StringContent("The content"),
            ReasonPhrase = "The reason"
        });
}

这里有更多关于how to handle exceptions in Web API的详细信息。

【讨论】：

【解决方案2】：

您的 API 端代码没问题。但得到响应应该是这样的（使用 WebException 捕获）：

string getResponse(WebRequest request, out exceptionOccured)
{
    exceptionOccured = false;
    try
    {
        HttpWebResponse resp = (HttpWebResponse)request.GetResponse();
        var stream = resp.GetResponseStream();
        using (var reader = new StreamReader(stream))
        {
            return reader.ReadToEnd();
        }
    }
    catch (WebException ex)
    {
        exceptionOccured = true;
        using (var stream = ex.Response.GetResponseStream())
        {
            using (var reader = new StreamReader(stream))
            {
                return reader.ReadToEnd();
            }
        }
    }
    catch (Exception ex)
    {
        exceptionOccured = true;
        // Something more serious happened
        // like for example you don't have network access
        // we cannot talk about a server exception here as
        // the server probably was never reached
        return ex.Message;
    }
}

【讨论】：