(VB.NET) Manually Follow HTTP Redirects

Demonstrates how to manually follow redirects for an HTTP GET.

Note: This example requires Chilkat v11.0.0 or greater.

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Dim success As Boolean = False

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim http As New Chilkat.Http

' The FollowRedirects property controls whether redirects
' are automatically followed.  The default behavior is to
' automatically follow redirects.

' Explicitly set FollowRedirects so that redirects are NOT automatically taken:
http.FollowRedirects = False

Dim resp As New Chilkat.HttpResponse
success = http.HttpNoBody("GET","http://yandex.ru/",resp)
If (success = False) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


Dim status As Integer = resp.StatusCode
Debug.WriteLine("HTTP Response Status: " & status)

' The FinalRedirectUrl property will contain the redirect URL
' If FollowRedirects was equal to True, then all of the 
' intermediate redirects (if any) would be followed until
' there were no more redirects.  However, because 
' FollowRedirects is not True, FinalRedirectUrl contains
' the next redirect URL.

Dim loopCount As Integer = 0

While (status = 302)

    Debug.WriteLine("Redirect URL: " & http.FinalRedirectUrl)

    Dim nextUrl As String = http.FinalRedirectUrl
    success = http.HttpNoBody("GET",nextUrl,resp)
    If (success = False) Then
        Debug.WriteLine(http.LastErrorText)
        Exit Sub
    End If


    status = resp.StatusCode
    Debug.WriteLine("HTTP Response Status: " & status)

    ' For safety, prevent infinite loops by
    ' keeping a loopCount and only allows following a max 
    ' of 10 redirects:
    loopCount = loopCount + 1
    If (loopCount > 10) Then
        Debug.WriteLine("Too many redirects.")
        Exit Sub
    End If


End While