Imports System.IO   'used to work with streams
Imports System.Net  'used for client side HTTP communication
Imports System.Text.RegularExpressions 'used to find matches 
Imports System.Drawing.Imaging  'used to read and write image files
Public Class websitemonitor
    Dim startmonitor As Integer  'will be 1 when monitor starts
    Dim radarpic(250) As Image 'holds the radar images
    Dim picshow As Integer  'will be 1 when display selected
    Dim picnum As Integer  'number of the radar picture
    Dim picnumd As Integer 'pic number used in display routines
    Dim imageadd As String  'address of radar image
    Dim imaget As String 'temp as string + dosent work on array
    Dim req As WebRequest   ' used to get the stream back from the server
    Dim rsp As WebResponse   'response
    Dim ms As MemoryStream   ' used to move the image into the PictureBox
    Dim filepath As String  ' filepath of my document on user computer
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        startmonitor = 1
        webcallnow()
    End Sub
    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        Webcallnow()
    End Sub
    Private Sub webcallnow()
        If startmonitor = 1 Then  'get site and image
            'enter the required radar site
            Dim Url As String = TextBox1.Text
            Dim Page As String 'this will hold the full web page
            Try      'wrap in try catch blocks to ensure timely release
                'create the request for the web page
                Dim PageRequest As HttpWebRequest = CType(WebRequest.Create(Url), HttpWebRequest)
                'get the respose this could take time
                Dim PageResponse As WebResponse = PageRequest.GetResponse()
                'read the response into a stream 'r'
                Dim r As New StreamReader(PageResponse.GetResponseStream())
                'put into standard string page
                Page = r.ReadToEnd() 'start to finish
                'close stream
                r.Close()
            Catch err As Exception  'write error message to textbox
                TextBox3.Text = "internet not working  " & err.ToString()
                Return
            End Try
            'use text.regularexpression regex to find match for title
            Dim TitlePattern As String = "<title>(?<match>.*?)</title>"
            Dim TitleRegex As New Regex(TitlePattern, RegexOptions.IgnoreCase Or RegexOptions.Singleline)
            Dim TitleMatch As Match = TitleRegex.Match(Page)
            If TitleMatch.Success Then
                TextBox2.Text = "Found site: " & TitleMatch.Groups("match").Value
            End If
            'use text.regularexpression regex to find match for radar picture
            Dim TitlePatternp As String = "/radar/IDR(?<match>.*?)border=0"
            'to change image subsitute your<img src ...............>
            Dim TitleRegexp As New Regex(TitlePatternp, RegexOptions.IgnoreCase Or RegexOptions.Singleline)
            Dim TitleMatchp As Match = TitleRegexp.Match(Page)
            If TitleMatchp.Success Then
                TextBox4.Text = "Found image: " & "/radar/IDR" & TitleMatchp.Groups("match").Value & "        Total images found=" & picnum
                imageadd = TitleMatchp.Groups("match").Value
                imageadd = "http://mirror.bom.gov.au/radar/IDR" & imageadd
            End If
            If picnum = 0 Or imaget <> imageadd Then  ' First time through get first image
                imaget = imageadd 'only get new image when we have new image on site
                imagereceive(imageadd, picnum)
                picnum = picnum + 1
            End If
        End If
    End Sub
    Private Sub imagereceive(ByVal imageadd, ByVal picnum)
        ' This method requests and receives an image from a website. The file 
        ' is streamed back to this method, which copies the contents into a 
        ' MemoryStream, then associates the MemoryStream with a PictureBox on 
        ' the form. The contents are streamed using the ResponseStream of the 
        ' WebResponse class. The stream access is wrapped in Try/Catch blocks 
        ' to ensure timely release of the resources.
        Dim picnumsave As String 'file string
        Try
            ' This creates the WebRequest for the image at BOM
            req = WebRequest.Create(imageadd)
            ' Use a GET since we' re not sending any data
            req.Method = "GET"
            ' ObjRef to get the server's response.
            Try
                ' This causes the round-trip to retrieve the image.
                rsp = req.GetResponse()
                ' Create a MemoryStream to hold the image
                ms = New MemoryStream()
                ' Copy the streamed image into the MemoryStream
                CopyData(rsp.GetResponseStream(), ms)
                ' Load the image into the Picture array
                radarpic(picnum) = Image.FromStream(ms)
                displayimage.Image = radarpic(picnum)
                'get file path for new image
                Dim picnums As String = picnum
                picnumsave = "radar" + picnums + ".gif"  'must specify gif
                filepath = System.IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, "radarimage")
                filepath = System.IO.Path.Combine(filepath, picnumsave)
                ' get new file path for next image
                displayimage.Image.Save(filepath, ImageFormat.Gif)
                'displayimage.Image.Save("C:\Documents and Settings\carl\My Documents\My Pictures\radar.gif", ImageFormat.Gif)
                'this instruction saves image to computer file system
                TextBox3.Text = "image received corectly. The image received is displayed below"
            Catch exp As Exception
                ' Will catch any error that we're not explicitly trapping.
                MessageBox.Show(exp.Message, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Stop)
            Finally
                ' Guarantee the streams will be closed
                If Not ms Is Nothing Then ms.Close()
                If Not rsp Is Nothing Then rsp.GetResponseStream.Close()
            End Try
        Catch exp As Exception
            ' Will catch any error that we're not explicitly trapping.
            MessageBox.Show(exp.Message, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Stop)
        End Try
    End Sub
    Private Sub CopyData(ByVal FromStream As Stream, ByVal ToStream As Stream)
        ' This routine copies content from one stream to another, regardless
        ' of the media represented by the stream.
        ' This will track the # bytes read from the FromStream
        Dim intBytesRead As Integer
        ' The maximum size of each read
        Const intSize As Integer = 4096
        Dim bytes(intSize) As Byte
        ' Read the first bit of content, then write and read all the content
        ' From the FromStream to the ToStream.
        intBytesRead = FromStream.Read(bytes, 0, intSize)
        While intBytesRead > 0
            ToStream.Write(bytes, 0, intBytesRead)
            intBytesRead = FromStream.Read(bytes, 0, intSize)
        End While
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        picshow = 1 'display the images
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        If picshow = 1 And picnum > 0 Then
            'display selected and have 1 or more pics 
            displayimage.Image = radarpic(picnumd)
            Label3.Text = picnumd + 1
            picnumd = picnumd + 1
            If picnumd = picnum Then
                picnumd = 0 'last displayed so start again
            End If
        End If
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        picshow = 0  'pause the image display
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        If picnumd > 0 Then 'cant go back to minus
            picnumd = picnumd - 1  'get previous image
        End If
        displayimage.Image = radarpic(picnumd)  'display
        Label3.Text = picnumd + 1
    End Sub

    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        If picnumd < picnum - 1 Then 'cant go pass the last
            picnumd = picnumd + 1 'get next image
        End If
        displayimage.Image = radarpic(picnumd)  'display
        Label3.Text = picnumd + 1
    End Sub

    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
        startmonitor = 0 'end monitor of site
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        filepath = System.IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, "radarimage")
        My.Computer.FileSystem.CreateDirectory(filepath)
        'creates a folder radarimages in my documents on user computer
    End Sub

    Private Sub RadioButton1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton1.CheckedChanged
        Timer1.Interval = 250
    End Sub

    Private Sub RadioButton2_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton2.CheckedChanged
        Timer1.Interval = 500
    End Sub

    Private Sub RadioButton3_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton3.CheckedChanged
        Timer1.Interval = 1500
    End Sub
End Class