Question

我有一个asp.net mvc路由，它接受一个url并做一个简单的get并从请求中返回状态代码。

<AcceptVerbs(HttpVerbs.Post)> _
Public Function ValidateUrlStatusCode(ByVal url As String) As ActionResult
   Dim code As Integer = 0

   Try
      Dim request As HttpWebRequest = CType(WebRequest.Create(url), HttpWebRequest)
      request.Method = "GET"
      request.AllowAutoRedirect = True
      Using response As HttpWebResponse = request.GetResponse
         response.Close()
         code = response.StatusCode
      End Using
   Catch ex As Exception
      code = HttpStatusCode.InternalServerError
   End Try
   Return Content(code, "text/plain")
End Function

现在，如果我使用firefox（使用Firebug）并转到网址http://www.facebook.com/blah.html，我会收到预期的404返回。但是，如果我使用我的应用程序通过ajax调用调用mvc路由，我得到200.如果我将请求对象的AllowAutoRedirect设置为false，我得到302.我从来没有得到404.我再次通过Firebug验证这一点。谁能指出我做错了什么？

谢谢！

Answer 1

如果您使用FaceBook，请确保设置用户代理，否则该网站会将您重定向到标准HTML页面，向您解释（因此200状态代码）：

request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0) Gecko/20100101 Firefox/4.0";

当从HttpWebRequest返回状态代码不同于200时，将抛出异常，更具体地说是WebException。因此，您需要捕获此WebException并在包含Response的HttpWebResponse属性中找到404 StatusCode。

此外，我可能会使用WebClient来简化代码：

Public Function ValidateUrlStatusCode(url As String) As ActionResult
    Dim code = 0
    Try
        Using client = New WebClient()
            client.Headers(HttpRequestHeader.UserAgent) = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0) Gecko/20100101 Firefox/4.0"
            Dim response = client.DownloadString(url)
        End Using
    Catch ex As WebException
        Dim httpResponse = TryCast(ex.Response, HttpWebResponse)
        If httpResponse IsNot Nothing Then
            code = CInt(httpResponse.StatusCode)
        End If
    End Try

    Return Content(code.ToString(), "text/plain")
End Function

在客户端：

<script type="text/javascript">
    $.ajax({
        url: '@Url.Action("ValidateUrlStatusCode")',
        type: 'POST',
        data: { url: 'http://www.facebook.com/blah.html' },
        success: function (result) {
            alert(result);
        }
    });
</script>

从Mvc路由返回错误的http状态代码

1 个答案: