asp.net - 处理来自 HttpWebRequest.GetResponse 的错误

Question

我在尝试让 SMS API 与 .NET 一起工作( ZeepMobile ，如果你感兴趣的话)时经历了一段荒谬的时光...我已经使用 .NET 几年了，但尽管如此关于社交网络和 API 的内容，我需要稍微了解一下 HttpWebRequest。我是新手，但并不是全新的；我能够毫不费力地将我的网站连接到 Twitter(即，我能够修改某人的代码来为我工作)。

无论如何，他们的 API 的工作方式是发送 SMS 消息，您向他们发送 POST，然后他们回复您。我可以很好地发送它，但每次我这样做时，我都会收到黄色死亡错误页(YEPOD)，而不是回显一些有助于找出错误的内容，大意是“远程服务器返回了一个错误”。错误:(400) 错误请求。”这发生在我的线路上:

'...creation of httpwebrequest here...'
Dim myWebResponse As WebResponse
myWebResponse = request.GetResponse() '<--- error line

有没有什么方法可以简单地从服务器接收错误，而不是让网络服务器抛出异常并给我 YEPOD？

或者更好的是，任何人都可以发布他们的 Zeep 代码的工作示例吗？ :)

谢谢!

编辑:这是我的整个代码块:

Public Shared Function SendTextMessage(ByVal username As String, _
ByVal txt As String) As String
    Dim content As String = "user_id=" + _
username + "&body=" + Current.Server.UrlEncode(txt)

    Dim httpDate As String = DateTime.Now.ToString("r")
    Dim canonicalString As String = API_KEY & httpDate & content

    Dim encoding As New System.Text.UTF8Encoding
    Dim hmacSha As New HMACSHA1(encoding.GetBytes(SECRET_ACCESS_KEY))

    Dim hash() As Byte = hmacSha.ComputeHash(encoding.GetBytes(canonicalString))
    Dim b64 As String = Convert.ToBase64String(hash)

    'connect with zeep'
    Dim request As HttpWebRequest = CType(WebRequest.Create(_
"https://api.zeepmobile.com/messaging/2008-07-14/send_message"), HttpWebRequest)
    request.Method = "POST"
    request.ServicePoint.Expect100Continue = False

    ' set the authorization levels'
    request.Headers.Add("Authorization", "Zeep " & API_KEY & ":" & b64)
    request.ContentType = "application/x-www-form-urlencoded"
    request.ContentLength = content.Length

    ' set up and write to stream'
    Dim reqStream As New StreamWriter(request.GetRequestStream())
    reqStream.Write(content)
    reqStream.Close()
    Dim msg As String = ""
    msg = reqStream.ToString

    Dim myWebResponse As WebResponse
    Dim myResponseStream As Stream
    Dim myStreamReader As StreamReader

    myWebResponse = request.GetResponse()

    myResponseStream = myWebResponse.GetResponseStream()
    myStreamReader = New StreamReader(myResponseStream)
    msg = myStreamReader.ReadToEnd()
    myStreamReader.Close()
    myResponseStream.Close()

    ' Close the WebResponse'
    myWebResponse.Close()
    Return msg
End Function

Answer 1

试试这个:

Dim req As HttpWebRequest = DirectCast(WebRequest.Create(url), HttpWebRequest)
'' set up request
Try
    Using response = req.GetResponse()
        '' success in here
    End Using
Catch ex As WebException
    Console.WriteLine(ex.Status)
    If ex.Response IsNot Nothing Then
        '' can use ex.Response.Status, .StatusDescription
        If ex.Response.ContentLength <> 0 Then
            Using stream = ex.Response.GetResponseStream()
                Using reader = New StreamReader(stream)
                    Console.WriteLine(reader.ReadToEnd())
                End Using
            End Using
        End If
    End If
End Try

<小时/>

C#版本

HttpWebRequest req = (HttpWebRequest) WebRequest.Create(url);
// set up request
try {
    using (var response = req.GetResponse()) {
        // success in here
        }
}
catch (WebException ex) {
    Console.WriteLine(ex.Status);
    if (ex.Response != null) {
        // can use ex.Response.Status, .StatusDescription
        if (ex.Response.ContentLength != 0) {
            using (var stream = ex.Response.GetResponseStream()) {
                using (var reader = new StreamReader(stream)) {
                    Console.WriteLine(reader.ReadToEnd());
                }
            }
        }
    }    
}

<小时/>

这是您的代码，稍作修改:

Try
    'connect with zeep'
    Dim request As HttpWebRequest = CType(WebRequest.Create( _
"https://api.zeepmobile.com/messaging/2008-07-14/send_message"), HttpWebRequest)
    request.Method = "POST"
    request.ServicePoint.Expect100Continue = False

    ' set the authorization levels'
    request.Headers.Add("Authorization", "Zeep " & API_KEY & ":" & b64)
    request.ContentType = "application/x-www-form-urlencoded"
    request.ContentLength = content.Length

    ' set up and write to stream'
    Using requestStream As Stream = request.GetRequestStream()
        Using requestWriter As New StreamWriter(requestStream)
            requestWriter.Write(content)
        End Using
    End Using

    Using myWebResponse As WebResponse = request.GetResponse()
        Using myResponseStream As Stream = myWebResponse.GetResponseStream()
            Using myStreamReader As StreamReader = New StreamReader(myResponseStream)
                Return myStreamReader.ReadToEnd()
            End Using
        End Using
    End Using
Catch ex As WebException
    Console.WriteLine(ex.Status)
    If ex.Response IsNot Nothing Then
        '' can use ex.Response.Status, .StatusDescription
        If ex.Response.ContentLength <> 0 Then
            Using stream = ex.Response.GetResponseStream()
                Using reader = New StreamReader(stream)
                    Console.WriteLine(reader.ReadToEnd())
                End Using
            End Using
        End If
    End If
End Try

<小时/>

转储 header :

Dim headers As WebHeaderCollection = request.Headers
' Displays the headers. Works with HttpWebResponse.Headers as well
Debug.WriteLine(headers.ToString())

' And so does this
For Each hdr As String In headers
    Dim headerMessage As String = String.Format("{0}: {1}", hdr, headers(hdr))
    Debug.WriteLine(headerMessage)
Next