So i have written code to allow me to download files from an FTP server using the system.io.stream function in vb.net. Now I need to be able to find the length of the stream, when i has finished.
I have worked with streamreader in the past but this stream doesn't work in the same way so i'm not sure how to proceed.
Try
Dim request As System.Net.FtpWebRequest
request = DirectCast(System.Net.WebRequest.Create("ftp://ftp.server.com/Folder/" & FileName & ".pdf"), System.Net.FtpWebRequest)
request.Credentials = New System.Net.NetworkCredential("Username", "Password")
request.Method = System.Net.WebRequestMethods.Ftp.DownloadFile
Dim stream As System.IO.Stream = request.GetResponse.GetResponseStream
'Dim OutPutFilepath As String = "DownloadTest" & "\" & IO.Path.GetFileName("ftp://ftp.Server.com/Folder/")
output = System.IO.File.Create("C:\Users\ASUS\Documents\TestFile2.pdf")
output.Close()
stream.Close()
Console.WriteLine("Downloaded")
Console.ReadLine()
Catch ex As Exception
MsgBox(ex.Message)
End Try
Also, I have tried using the stream.length feature however, i got an exception saying something along the lines of "this stream does not support seek functions".
Thanks in advance
Related
I'm making a web request that completes successfully most of the time (target$ is a URL). But occasionally my code throws a valid exception, 404 not found, if the URL target$ doesn't exist, and execution stops. The code:
Sub scrape(target$)
Dim request As WebRequest = WebRequest.Create(target$)
Dim response As WebResponse = request.GetResponse()
Dim dataStream As Stream = response.GetResponseStream()
' Open the stream using a StreamReader for easy access.
Dim reader As New StreamReader(dataStream)
' Read the content.
Dim responseFromServer As String = reader.ReadToEnd()
txtResponse.Text = ""
txtResponse.Text = responseFromServer
' Clean up the streams and the response.
reader.Close()
response.Close()
end sub
The exception, if thrown, happens in the second line, "Dim response...". So I tried adding a "try-catch" as shown.
Sub scrape(target$)
Dim request As WebRequest = WebRequest.Create(target$)
Dim response As WebResponse = request.GetResponse()
Try
Dim dataStream As Stream = response.GetResponseStream()
Catch
exflag = True
End Try
' Open the stream using a StreamReader for easy access.
Dim reader As New StreamReader(dataStream)
' Read the content.
Dim responseFromServer As String = reader.ReadToEnd()
txtResponse.Text = ""
txtResponse.Text = responseFromServer
' Clean up the streams and the response.
reader.Close()
response.Close()
end sub
But now when I try to compile the code, VisualStudio tells me that "datastream is not declared" and the compile fails.
What am I doing wrong and how do I catch the exception when it's thrown?
Thanks...
A while ago I wrote a programme in VB.NET to use the Betfair Exchange API. It has worked perfectly for months, but overnight on Tuesday it stopped working. I can still log in, but from Wednesday I have been unable to get anything else from the server.
Betfair are investigating, but according to them nobody else seems to be experiencing the same problem - although I'm not sure how many will be using VB.NET.
Below is the function I have been using to obtain data from the API. Like I said it was working on Tuesday night but not from Wednesday morning. Is there anything here which is "not perfect" or "could be better", or perhaps there is some alternative code I could try? Or is there something which might have happened on my pc which has caused the problem?
The programme falls over at the line "dataStream = request.GetRequestStream() ". The error is "Received an unexpected EOF or 0 bytes from the transport stream."
I would be grateful for any advice that anyone could offer. Thank you!
Public Function CreateRequest(ByVal postData As String, Optional ByVal accountsApi As Boolean = False)
Dim Url As String = "https://api.betfair.com/exchange/betting/json-rpc/v1"
If accountsApi Then Url = "https://api.betfair.com/exchange/account/json-rpc/v1"
Dim request As WebRequest = Nothing
Dim dataStream As Stream = Nothing
Dim response As WebResponse = Nothing
Dim strResponseStatus As String = ""
Dim reader As StreamReader = Nothing
Dim responseFromServer As String = ""
Try
request = WebRequest.Create(New Uri(Url))
request.Method = "POST"
request.ContentType = "application/json-rpc"
request.Headers.Add(HttpRequestHeader.AcceptCharset, "ISO-8859-1,utf-8")
request.Headers.Add("X-Application", appKey)
request.Headers.Add("X-Authentication", sessToken)
Dim byteArray As Byte() = Encoding.UTF8.GetBytes(postData) ' Data to post such as ListEvents, ListMarketCatalogue etc
request.ContentLength = byteArray.Length ' Set the ContentLength property of the WebRequest.
dataStream = request.GetRequestStream() ' Get the request stream.
dataStream.Write(byteArray, 0, byteArray.Length) ' Write the data to the request stream.
dataStream.Close() ' Close the Stream object.
response = request.GetResponse() ' Get the response.
strResponseStatus = CType(response, HttpWebResponse).StatusDescription ' Display the status below if required
dataStream = response.GetResponseStream() ' Get the stream containing content returned by the server.
reader = New StreamReader(dataStream) ' Open the stream using a StreamReader for easy access.
responseFromServer = reader.ReadToEnd() ' Read the content.
reader.Close() : dataStream.Close() : response.Close()
Catch ex As Exception
MsgBox("CreateRequest Error" & vbCrLf & ex.Message, MsgBoxStyle.Critical, " Error")
End Try
Return responseFromServer
End Function
I would check that the provider hasn't recently deprecated use of TLS 1.0 (as they should have done before now, in fact).
If so, your code needs to enforce use of TLS 1.1+:
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;
This only has to be set once, usually in the (static) type initializer or similar.
And I 100% agree with Andrew Mortimer that you should use Using blocks wherever possible. I'd also suggest moving all of your string values into variables or constants to clean things up and keep them maintainable. Eg:
Const ContentType As String = "application/json-rpc"
...
request.ContentType = ContentType
UPDATE
I just found this announcement on their site:
https://forum.developer.betfair.com/forum/developer-program/announcements/33563-tls-1-0-no-longer-supported-from-1st-december-all-betfair-api-endpoints
If you are allowed to use external dependencies within this project I would recommend using RestSharp nuget package it works really well for creating API requests and getting there response without having to use httpclient which gets messy.
Link: https://restsharp.dev/
When using the following code, if I specify a wrong username/password combination I get a 407 error.
If I use a correct one, I get the page requested.
If I try again with a wrong username/password I get a normal response.
For some reason, WebRequest caches the proxy's username/password (CredentialCache) combination for the requested URL. If I change the URL pointing to a different domain, I get a proper 407.
How can I stop WebRequest from using last successful credential?
Dim request As WebRequest = WebRequest.Create("http://contoso.com")
request.Proxy = New WebProxy("http://myproxy:8080")
Dim username = InputBox("Username")
Dim password = InputBox("Password")
request.Proxy.Credentials = New NetworkCredential(username, password)
Try
Using response = request.GetResponse()
' Display the status.
txt_response.Text = CType(response, HttpWebResponse).StatusDescription & "Response is from cache?: " & response.IsFromCache
' Get the stream containing content returned by the server.
Dim dataStream As Stream = response.GetResponseStream()
' Open the stream using a StreamReader for easy access.
Dim reader As New StreamReader(dataStream)
' Read the content.
Dim responseFromServer As String = reader.ReadToEnd()
' Display the content.
txt_Result.Text = responseFromServer
' Clean up the streams and the response.
reader.Close()
response.Close()
End Using
Catch ex As WebException
txt_response.Text = ex.Status & ": " & ex.Message
End Try
I have searched but couldn't get any real solution to creating a file on my website by uploading the file from the local system using VB.net
This is my code so far
Dim rdr As New FileStream(ReSaveFile, FileMode.Open)
Dim req As HttpWebRequest = DirectCast(WebRequest.Create("http://www.timemedian.com/display.txt"), HttpWebRequest)
req.Method = "POST"
' you might use "POST"
req.ContentLength = rdr.Length
req.AllowWriteStreamBuffering = True
Dim reqStream As Stream = req.GetRequestStream()
Dim inData As Byte() = New Byte(rdr.Length - 1) {}
' Get data from upload file to inData
Dim bytesRead As Integer = rdr.Read(inData, 0, rdr.Length)
' put data into request stream
reqStream.Write(inData, 0, rdr.Length)
rdr.Close()
req.GetResponse()
' after uploading close stream
reqStream.Close()
but I cant possible see the error. Please help
I uploaded the file using ftp protocol like this
Try
Dim mReq1 As System.Net.FtpWebRequest = DirectCast(System.Net.WebRequest.Create("ftp://ftp.websitename.com//" & SetID & ".pvx"), System.Net.FtpWebRequest)
mReq1.Credentials = New System.Net.NetworkCredential("username", "password")
mReq1.Method = System.Net.WebRequestMethods.Ftp.UploadFile
Dim MFile1() As Byte = System.IO.File.ReadAllBytes(ReSaveFile)
Dim mStream1 As System.IO.Stream = mReq1.GetRequestStream()
mStream1.Write(MFile1, 0, MFile1.Length)
mStream1.Close()
mStream1.Dispose()
Catch ex As Exception
MsgBox("Your file was not fully posted to the remote server. PVX Mail may not function properly")
Exit Sub
End Try
I am attempting to perform a FTP Put function to an AS/400 IBM Mainframe with VB.NET. I am able to upload a file however, I need to be able to capture each output response from the mainframe for logging purposes. In short capture what prints out on the cmd screen if I were to perform the FTP manually. Any suggestions would be greatly appreciated.
Depending on the library you are using, you should be able to get some kind of response object or string from the FTP server for each command you submit. You can then parse these responses and dump them into a file/destination/source of your choosing.
EDIT: Since you're using the FTPWebRequest/Response library, you'll want to have your FTPWebRequest object dump its results into the FTPWebResponse object and then read the entire stream with code something like this:
Dim request As FtpWebRequest = DirectCast(WebRequest.Create(serverUri), FtpWebRequest)
request.Method = WebRequestMethods.Ftp.ListDirectory
Dim response As FtpWebResponse = DirectCast(request.GetResponse(), FtpWebResponse)
Dim responseStream As Stream = Nothing
Dim readStream As StreamReader = Nothing
Try
responseStream = response.GetResponseStream()
readStream = New StreamReader(responseStream, System.Text.Encoding.UTF8)
If readStream IsNot Nothing Then
Console.WriteLine(readStream.ReadToEnd())
End If
Console.WriteLine("List status: " & response.StatusDescription)
Finally
If readStream IsNot Nothing Then
readStream.Close()
End If
If response IsNot Nothing Then
response.Close()
End If
End Try
Return True
End Function
You should be able to tailor this code to your own in order to retrieve the response details you need.