Nsryjdtyk

This is a unix timestamp based data, which needs to be scrapped.
Files in server can be 1542688763.png or 1542688763.jpg
so my system decrement a given unix timestamp, one by one and check if the file exists.
A web developer made the same thing and his is vry fast. He said me, that due to improper usage of IO bound and CPU bound process, and improper requst and await code, my program is slower. Can anyone help?

Imports System.Net.Http

Imports System.Net

Imports System.IO

Imports System.Threading







Public Class Form1

    Dim VarHoldingUnix As Double

    Dim KotafOund As Integer

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        VarHoldingUnix = ToUnix(Date.Now)

        TextBox1.Text = VarHoldingUnix

    End Sub



    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

        Dim DRON As Date

        DRON = FromUnix(VarHoldingUnix, 0)

        MsgBox(DRON)

        MsgBox(DateAndTime.Day(DRON))

    End Sub



    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click

        Dim ABCD As Task





        While Not KotafOund = TextBox3.Text

            ToolStripLabel1.Text = FromUnix(VarHoldingUnix, 0)

            Application.DoEvents()

            ABCD = MakeRequests(300)

        End While



        MsgBox("END")

        End



    End Sub



    Async Function MakeRequests(noS2find As Integer) As Task



        Dim tasks As List(Of Task(Of Boolean)) = New List(Of Task(Of Boolean))

        Dim tasks2 As List(Of Task(Of Boolean)) = New List(Of Task(Of Boolean))

        Dim itemsF As Integer = noS2find



        Dim DRON As Date

        Dim DronDate As String



        Dim MyYear, MyMonth As String



        DRON = FromUnix(VarHoldingUnix, 0)







        For i = 1 To itemsF

            i = i + 1

            DRON = FromUnix(VarHoldingUnix, 0)

            'DronDate = (DateAndTime.Day(DRON))





            Dim MYURLJPG As String = "https://www.secru.com/img/" & VarHoldingUnix & ".png"

            tasks.Add(CheckPageExists1(MYURLJPG))

            'await Task.Run(() => CheckPageExists1(MYURLJPG));

            Dim MYURLPNG As String = "https://www.secru.com/img/" & VarHoldingUnix & ".jpg"

            tasks2.Add(CheckPageExists2(MYURLPNG))

            'await Task.Run(() => CheckPageExists2(MYURLPNG))



            VarHoldingUnix = VarHoldingUnix - 1

        Next



        While tasks.Select(Function(x) x.Result).Count < tasks.Count

            Thread.Sleep(100)

        End While



        While tasks2.Select(Function(x) x.Result).Count < tasks2.Count

            Thread.Sleep(100)

        End While







    End Function



    Private Async Function CheckPageExists1(ByVal url As String) As Task(Of Boolean)





        Dim request As Net.HttpWebRequest = Net.WebRequest.Create(url)

        request.Method = "HEAD"

        'Dim response As Net.HttpWebResponse

        request.Timeout = 5



        Dim Result As Boolean



        Try

            Using response As HttpWebResponse = Await request.GetResponseAsync.ConfigureAwait(False)

                Using responseReader As New IO.StreamReader(response.GetResponseStream)



                    Dim actualResponse As String = Await responseReader.ReadToEndAsync

                    Result = True

                    KotafOund = KotafOund + 1

                    Process.Start(url)

                End Using

            End Using

        Catch ex As Exception

            'IMAGE DOES NOT EXITS

            Result = False

        End Try



        Return Result



    End Function

    Private Async Function CheckPageExists2(ByVal url As String) As Task(Of Boolean)







        Dim request As Net.HttpWebRequest = Net.WebRequest.Create(url)

        'Dim response As Net.HttpWebResponse

        request.Method = "HEAD"

        request.Timeout = 5



        Dim Result As Boolean



        Try

            Using response As HttpWebResponse = Await request.GetResponseAsync.ConfigureAwait(False)

                Using responseReader As New IO.StreamReader(response.GetResponseStream)



                    Dim actualResponse As String = Await responseReader.ReadToEndAsync

                    Result = True

                    KotafOund = KotafOund + 1

                    Process.Start(url)

                End Using

            End Using

        Catch ex As Exception

            'IMAGE DOES NOT EXITS

            Result = False

        End Try



        Return Result



    End Function



    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click

        VarHoldingUnix = TextBox1.Text



        MsgBox("Confirmed New UNIX-VARIABLE " & VarHoldingUnix)

    End Sub

End Class

I think inside Async Function MakeRequests I have to use this code

While tasks.Select(Function(x) x.Result).Count < tasks.Count

   Await Task.Delay(100)

End While

instead of

While tasks.Select(Function(x) x.Result).Count < tasks.Count

   Thread.Sleep(100)

End While

but i am not getting a perfect balance of the no of milliseconds i set within wait (100) now, and

ABCD = MakeRequests(300)

can be 200 or may be 2000.

I dont know....you guys are better knowledgeable

Have you tried this?

Private Async Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click



    While Not KotafOund = TextBox3.Text

        ToolStripLabel1.Text = FromUnix(VarHoldingUnix, 0)

        Await MakeRequests(300)

    End While



    MsgBox("END")

    End



End Sub