How can I read the response from a web request when the Status is not 200?
I am having difficulty getting the response text from a HTTP web request in vb.net when I get a web exception.
This is the code I am doing it with.
Try
myWebResponse = CType(request.GetResponse(), HttpWebResponse)
myStreamReader = New StreamReader(myWebResponse.GetResponseStream())
ResponseText = myStreamReader.ReadToEnd
If myWebResponse.StatusCode = HttpStatusCode.Accepted Or myWebResponse.StatusCode = 200 Then
SendResult = True 'Sent
SendStatus = 1 'message sent successfully
Try
Integer.TryParse(myWebResponse.Headers("Number-Of-MT-PDU"), num_MT_PDU)
Catch ex As Exception
End Try
Else
SendStatus = 2 'message processed but not sent successfully
End If
Catch e As WebException
If (e.Status = WebExceptionStatus.ProtocolError) Then
Dim response As WebResponse = e.Response
Using (response)
Dim httpResponse As HttpWebResponse = CType(response, HttpWebResponse)
statusCode = httpResponse.StatusCode
Try
myStreamReader = New StreamReader(response.GetResponseStream())
Using (myStreamReader)
ResponseText = myStreamReader.ReadToEnd & "Status Description = " & HttpWebResponse.StatusDescription
End Using
Catch ex As Exception
Logger.LogError(Me, ex)
End Try
End Using
Annoyingly, the API I am contacting uses a 404 as a valid response. If I put the request in a browser some message text will be displayed. I want to be able to use that text in my program. I can not simply use the error code to determine actions as I don't think I can differentiate between a valid 404 response and an actual error.
In the code this line
myWebResponse = CType(request.GetResponse(), HttpWebResponse)
throws an exception.
In the exception I can get the 404 code and the description but not the response stream. It is always null.
If I get a 200 response I get the text in the Response stream no problem.
In the web exception response object (in Visual Studios debugger) I have checked the headers and the object values and can't find the response text anywhere. If I stick the request URL in a browser I get response text back even though it is a 404.
The raw response in fiddler:
HTTP/1.1 404 Not Found Connection: close Content-Type: text/plain; charset=UTF-8 Content-Length: 35 "The response Message"
Any ideas on how I can get "The response Message" in my program? I have to use .Net on the server.
Thanks for any help anybody can give.
This LINQPad query works fine, dumping the HTML provided by my web server's "Not Found" error web page:
Dim rq = System.Net.WebRequest.Create(New Uri("http://localhost/test"))
Try
Dim rs = rq.GetResponse
rs.Dump
Catch Ex As System.Net.WebException
Dim rs = Ex.Response
Call (New StreamReader(rs.GetResponseStream)).ReadToEnd.Dump
End Try
FYI Your code works for me, except the presumed typo re HttpWebResponse.StatusDescription (and commenting out "unrelated stuff"), again as a LINQPad query (in .NET 4.0):
Dim request = WebRequest.Create("http://localhost/test")
Dim myStreamReader As StreamReader
Dim SendStatus As Integer = -1
Dim statusCode As HttpStatusCode
Dim ResponseText As String
Try
Dim myWebResponse = CType(request.GetResponse(), HttpWebResponse)
myStreamReader = New StreamReader(myWebResponse.GetResponseStream())
ResponseText = myStreamReader.ReadToEnd
If myWebResponse.StatusCode = HttpStatusCode.Accepted Or myWebResponse.StatusCode = 200 Then
'SendResult = True 'Sent
SendStatus = 1 'message sent successfully
'Try
' Integer.TryParse(myWebResponse.Headers("Number-Of-MT-PDU"), num_MT_PDU)
'Catch ex As Exception
'End Try
Else
SendStatus = 2 'message processed but not sent successfully
End If
Catch e As WebException
If (e.Status = WebExceptionStatus.ProtocolError) Then
Dim response As WebResponse = e.Response
Using (response)
Dim httpResponse As HttpWebResponse = CType(response, HttpWebResponse)
statusCode = httpResponse.StatusCode
Try
myStreamReader = New StreamReader(response.GetResponseStream())
Using (myStreamReader)
ResponseText = myStreamReader.ReadToEnd & "Status Description = " & httpResponse.StatusDescription ' HttpWebResponse.StatusDescription
End Using
Catch ex As Exception
'Logger.LogError(Me, ex)
ex.Dump("Exception")
End Try
End Using
End If
End Try
ResponseText.Dump("ResponseText")
I have also confirmed the above code (with the inferred As clauses added and converting the .Dump calls to Console.WriteLine ) works in .NET 2.0 with VB8.
Note that the key is that even though the act of GetResponseStream() throws a .NET WebException, the HttpWebResponse is actually passed to the WebException object, so when in the Catch, you do a new GetResponseStream() on the WebException.Response object.
Below, very similar code for when in the Catch of the initial GetResponseStream()
Try
OriginalResponseStream = GetResponseStream(OriginalHTTPWebResponse)
Catch wex as WebException
Dim response As WebResponse = wex.Response
Dim statusCode As HttpStatusCode
Dim ResponseText As String
Dim httpResponse As HttpWebResponse = CType(response, HttpWebResponse)
statusCode = httpResponse.StatusCode
Try
Dim myStreamReader As New StreamReader(response.GetResponseStream())
Using (myStreamReader)
ResponseText = myStreamReader.ReadToEnd
Process(ResponseText) '<===as in whatever you need to do with the response
End Using
Catch ex As Exception
HandleIt(ex.Message) '<===as in whatever you want to do if Exception during the above
End Try
End Try