multi-threaded code to check proxies - vb.net

Question

I'm suffering with this VB.Net 2017 code which is supposed to check if Proxies working or not. Sometimes it reach to an end successfully, and sometimes the program never reach and end or take lots of time to do so, although I have specified the timeout for every webrequest to be 11000... Also, the list of working proxies always has duplicates! I don't know how that happens, althoug the original (raw) list is unique!
Could you please help? This is supposed to wait till the 99 threads finished then another 99 (or the remaining threads) kick-started.
P.S. MYWEBSITE.com works for me only and it displays the IP address of the visitor, i.e. to double check if the proxy has worked fine
Imports System.Net
Imports System.IO
Imports System
Imports System.Text.RegularExpressions
Imports System.Threading
Public Class frmMain
Dim FinalWorkingProxies As New List(Of String)()
Private Sub btnBrowse_Click(sender As Object, e As EventArgs) Handles btnBrowse.Click
Control.CheckForIllegalCrossThreadCalls = False
PB.Maximum = txtRawIP.Lines.Count
PB.Value = 0
StartCheckingIP(0)
End Sub
Function StartCheckingIP(ByVal num As Integer)
For I As Integer = num To txtRawIP.Lines.Count - 1
Dim StrIPOnly As String = txtRawIP.Lines(I)
StrIPOnly = Trim(StrIPOnly.TrimStart("0"c)) 'remove any leading zeros
Try
Dim clsThreads As New System.Threading.Thread(AddressOf CheckIP)
clsThreads.Start(StrIPOnly)
Catch ex As Exception
MsgBox(I)
End Try
If (I > 0 And (I Mod 99 = 0)) Then Exit For
Next
Return True
End Function
Private Function CheckIP(ByVal Prox As String) As Boolean
'txtHTML.Text += vbCrLf & Prox
'txtHTML.Refresh()
Dim txtWebResult As String = ""
Dim OriginalFullProx As String = Trim(Prox)
Dim proxyObject As WebProxy = New WebProxy("http://" & OriginalFullProx & "/")
proxyObject.BypassProxyOnLocal = True
Prox = Prox.Substring(0, Prox.IndexOf(":"))
Dim sURL As String
sURL = "http://MYWEBSITE.com/testip.php"
Dim wrGETURL As WebRequest
wrGETURL = WebRequest.Create(sURL)
wrGETURL.Proxy = proxyObject
wrGETURL.Timeout = 6000
txtWebResult = "Dosn't work"
Try
Dim objStream As Stream
objStream = wrGETURL.GetResponse.GetResponseStream
Dim objReader As New StreamReader(objStream)
Dim sLine As String = ""
sLine = objReader.ReadLine
If Not sLine Is Nothing Then
txtWebResult = sLine
End If
txtWebResult = Regex.Replace(txtWebResult, “^\s+$[\r\n]*”, “”, RegexOptions.Multiline)
If (Trim(Prox) = Trim(txtWebResult)) Then
FinalWorkingProxies.Add(OriginalFullProx)
End If
Catch ex As Exception
txtWebResult = "Dosn't work"
End Try
If (PB.Value < PB.Maximum) Then PB.Value += 1
PB.Refresh()
If (PB.Value = PB.Maximum) Then
txtFilteredIP.Clear()
Randomize()
Dim RRR As Integer = CInt(Math.Ceiling(Rnd() * 1000)) + 1
Thread.Sleep(RRR)
If (txtFilteredIP.Text <> "") Then Return False
Dim str As String
For Each str In FinalWorkingProxies
txtFilteredIP.Text += str & vbCrLf
Next
ElseIf ((PB.Value - 1) > 0 And ((PB.Value - 1) Mod 99 = 0)) Then
StartCheckingIP(PB.Value)
End If
Return True
End Function
Private Sub txtRawIP_TextChanged(sender As Object, e As EventArgs) Handles txtRawIP.TextChanged
lblRawIPTotal.Text = "Total: " & txtRawIP.Lines.Count
End Sub
Private Sub txtFilteredIP_TextChanged(sender As Object, e As EventArgs) Handles txtFilteredIP.TextChanged
lblFilteredIPTotal.Text = "Total: " & txtFilteredIP.Lines.Count
End Sub
End Class
Here is the modified code, but it stills takes long of time to finalize long list of proxies, although I sat max concurrent connection to 2000 and timeout to 8sec. Please help. Thanks.
Public Class frmMain
Dim FinalWorkingProxies As New List(Of String)()
Private Sub btnBrowse_Click(sender As Object, e As EventArgs) Handles btnBrowse.Click
'Control.CheckForIllegalCrossThreadCalls = False
ServicePointManager.Expect100Continue = False
ServicePointManager.DefaultConnectionLimit = 2000
'ServicePointManager.Expect100Continue = True
FinalWorkingProxies.Clear()
PB.Maximum = txtRawIP.Lines.Count
PB.Value = 0
StartCheckingIP(0)
End Sub
Function StartCheckingIP(ByVal num As Integer)
For I As Integer = num To txtRawIP.Lines.Count - 1
Dim StrIPOnly As String = txtRawIP.Lines(I)
StrIPOnly = Trim(StrIPOnly.TrimStart("0"c)) 'remove any leading zeros
Try
Dim clsThreads As New System.Threading.Thread(AddressOf CheckIP)
clsThreads.Start(StrIPOnly)
Catch ex As Exception
MsgBox(I)
End Try
If (I > 0 And (I Mod 333 = 0)) Then Exit For
Next
Return True
End Function
Private Function CheckIP(ByVal Prox As String) As Boolean
'txtHTML.Text += vbCrLf & Prox
'txtHTML.Refresh()
Dim txtWebResult As String = ""
Dim OriginalFullProx As String = Trim(Prox)
Dim proxyObject As WebProxy = New WebProxy("http://" & OriginalFullProx & "/")
proxyObject.BypassProxyOnLocal = True
Prox = Prox.Substring(0, Prox.IndexOf(":"))
Dim sURL As String
sURL = "http://MYWEBSITE.com/testip.php"
Dim wrGETURL As WebRequest
wrGETURL = WebRequest.Create(sURL)
wrGETURL.Proxy = proxyObject
wrGETURL.Timeout = 8000
txtWebResult = "Dosn't work"
Try
Dim objStream As Stream
objStream = wrGETURL.GetResponse.GetResponseStream
Dim objReader As New StreamReader(objStream)
Dim sLine As String = ""
sLine = objReader.ReadLine
If Not sLine Is Nothing Then
txtWebResult = sLine
End If
txtWebResult = Regex.Replace(txtWebResult, “^\s+$[\r\n]*”, “”, RegexOptions.Multiline)
If (Trim(Prox) = Trim(txtWebResult)) Then
'Now know exact country
sURL = "http://ip-api.com/xml/" & Prox
wrGETURL = WebRequest.Create(sURL)
wrGETURL.Proxy = proxyObject
wrGETURL.Timeout = 8000
objStream = wrGETURL.GetResponse.GetResponseStream
Dim objReader2 As New StreamReader(objStream)
Dim FullCODEOFAPI As String = objReader2.ReadToEnd()
Dim XMLR As XmlReader
XMLR = XmlReader.Create(New StringReader(FullCODEOFAPI))
XMLR.ReadToFollowing("country")
XMLR.Read()
OriginalFullProx += "-" + XMLR.Value
FinalWorkingProxies.Add(OriginalFullProx)
End If
Catch ex As Exception
txtWebResult = "Dosn't work"
End Try
If (PB.Value < PB.Maximum) Then UpdatePB(1)
If (PB.Value = PB.Maximum) Then
UpdateFilteredList(1)
ElseIf ((PB.Value - 1) > 0 And ((PB.Value - 1) Mod 333 = 0)) Then
StartCheckingIP(PB.Value)
End If
Return True
End Function
Private Delegate Sub UpdatePBDelegate(ByVal PBVal As Integer)
Private Sub UpdatePB(ByVal PBVal As Integer)
If PB.InvokeRequired Then
PB.Invoke(New UpdatePBDelegate(AddressOf UpdatePB), New Object() {PBVal})
Else
PB.Value += PBVal
PB.Refresh()
End If
End Sub
Private Delegate Sub UpdateFilteredListDelegate()
Private Sub UpdateFilteredList(ByVal TMP As Integer)
If txtFilteredIP.InvokeRequired Then
txtFilteredIP.Invoke(New UpdatePBDelegate(AddressOf UpdateFilteredList), New Object() {TMP})
Else
txtFilteredIP.Clear()
Dim str As String
For Each str In FinalWorkingProxies
txtFilteredIP.Text += str & vbCrLf
Next
End If
End Sub
Private Sub txtRawIP_TextChanged(sender As Object, e As EventArgs) Handles txtRawIP.TextChanged
lblRawIPTotal.Text = "Total: " & txtRawIP.Lines.Count
End Sub
Private Sub txtFilteredIP_TextChanged(sender As Object, e As EventArgs) Handles txtFilteredIP.TextChanged
lblFilteredIPTotal.Text = "Total: " & txtFilteredIP.Lines.Count
End Sub
Private Sub btnLoadList_Click(sender As Object, e As EventArgs) Handles btnLoadList.Click
OFD.ShowDialog()
If (OFD.FileName <> "") Then
txtRawIP.Text = File.ReadAllText(OFD.FileName)
End If
End Sub
End Class