如何自定义 WCF 错误行为

Question

我正在创建一个 WCF 服务来提供 REST-ful Web HTTP 服务。这就是我想要的：

http://myservice/correct/url

这应该以 JSON/XML 格式返回结果

http://myservice/incorrect/url

这应该返回自定义的错误消息，而不是标准的“未找到端点”。错误。

我了解了 IErrorHandler 接口，并扩展了 WebHttpBehavior 类。但不起作用。

Answer 1

最简单的方法是定义操作以处理“未找到”情况 - 通过使用 '*' 的 UriTemplate（如果没有其他模板与传入请求匹配，它将匹配）。下面的代码展示了它的一个例子。

public class Post_0424d917_89cd_43c8_be70_5d4c6934b48c
{
    [ServiceContract]
    public interface ITest
    {
        [WebGet(UriTemplate = "/Echo?text={text}")]
        string EchoGet(string text);
        [WebInvoke(UriTemplate = "/Echo")]
        string EchoPost(string text);
        [WebGet(UriTemplate = "*")]
        Stream ErrorForGet();
        [WebInvoke(UriTemplate = "*")]
        Stream ErrorForPost();
    }
    public class Service : ITest
    {
        public string EchoGet(string text) { return text; }
        public string EchoPost(string text) { return text; }
        public Stream ErrorForPost() { return this.ErrorForGet(); }
        public Stream ErrorForGet()
        {
            WebOperationContext.Current.OutgoingResponse.StatusCode = HttpStatusCode.NotFound;
            WebOperationContext.Current.OutgoingResponse.ContentType = "text/html";
            string result = @"<html>
  <head>
    <title>Resource not found</title>
  </head>
  <body>
    <h1>This resource cannot be found</h1>
  </body>
</html>";
            return new MemoryStream(Encoding.UTF8.GetBytes(result));
        }
    }
    static void SendRequest(string uri, string method, string contentType, string body)
    {
        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(uri);
        req.Method = method;
        if (!String.IsNullOrEmpty(contentType))
        {
            req.ContentType = contentType;
        }

        if (body != null)
        {
            byte[] bodyBytes = Encoding.UTF8.GetBytes(body);
            req.GetRequestStream().Write(bodyBytes, 0, bodyBytes.Length);
            req.GetRequestStream().Close();
        }

        HttpWebResponse resp;
        try
        {
            resp = (HttpWebResponse)req.GetResponse();
        }
        catch (WebException e)
        {
            resp = (HttpWebResponse)e.Response;
        }

        Console.WriteLine("HTTP/{0} {1} {2}", resp.ProtocolVersion, (int)resp.StatusCode, resp.StatusDescription);
        foreach (string headerName in resp.Headers.AllKeys)
        {
            Console.WriteLine("{0}: {1}", headerName, resp.Headers[headerName]);
        }

        Console.WriteLine();
        Console.WriteLine(new StreamReader(resp.GetResponseStream()).ReadToEnd());

        Console.WriteLine();
        Console.WriteLine("  *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*  ");
        Console.WriteLine();
    }
    public static void Test()
    {
        string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
        ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
        host.AddServiceEndpoint(typeof(ITest), new WebHttpBinding(), "").Behaviors.Add(new WebHttpBehavior());
        host.Open();
        Console.WriteLine("Host opened");

        SendRequest(baseAddress + "/Echo?text=hello", "GET", null, null);
        SendRequest(baseAddress + "/Echo", "POST", "application/json", "\"world\"");

        SendRequest(baseAddress + "/NotFound", "GET", null, null);
        SendRequest(baseAddress + "/NotFound", "POST", "text/xml", "<body/>");

        Console.Write("Press ENTER to close the host");
        Console.ReadLine();
        host.Close();
    }
}