HTTP Redirect Handling

Examine HTTP redirects.

Download Chilkat HTTP ActiveX

Dim http As New ChilkatHttp

Dim success As Long

'  Any string unlocks the component for the 1st 30-days.
success = http.UnlockComponent("Anything for 30-day trial")
If (success <> 1) Then
    MsgBox http.LastErrorText
    Exit Sub
End If

Dim url As String
Dim html As String
Dim status As Long

url = "http://www.planyourweddingonline.co.za/"

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

'  Explicitly set FollowRedirects so that redirects are automatically taken:
http.FollowRedirects = 1

'  Send the HTTP GET and return the content in a string.
html = http.QuickGetStr(url)
If (html = vbNullString ) Then
    MsgBox http.LastErrorText
End If

'  On success, LastErrorText will provide information about
'  what happened during the call.
Text1.Text = Text1.Text & "--------------- LastErrorText ------------------" & vbCrLf
Text1.Refresh
Text1.Text = Text1.Text & http.LastErrorText & vbCrLf
Text1.Refresh
Text1.Text = Text1.Text & "------------------------------------------------" & vbCrLf
Text1.Refresh

'  In this case, we see something like this:
'  ChilkatLog:
'    QuickGetHtml:
'      DllDate: Jul 27 2007
'      url: http://www.planyourweddingonline.co.za/
'      httpServer: www.planyourweddingonline.co.za
'      port: 80
'      StatusCode: 302
'      StatusText: Found
'      Reading chunked response
'      redirectUrl: main/main/home/index.php
'      url: http://www.planyourweddingonline.co.za/main/main/home/index.php
'      StatusCode: 302
'      StatusText: Found
'      Reading chunked response
'      redirectUrl: /main/main/home/index.php?SMC=1
'      url: http://www.planyourweddingonline.co.za/main/main/home/index.php?SMC=1
'      StatusCode: 200
'      StatusText: OK
'      CompressedSize: 7434
'      UncompressedSize: 40999

'  Was the GET redirected?
If (http.WasRedirected = 1) Then
    Text1.Text = Text1.Text & "Chilkat HTTP followed the redirect." & vbCrLf
    Text1.Refresh

    '  Display the final redirect URL:
    Text1.Text = Text1.Text & "Final URL:" & vbCrLf
    Text1.Refresh
    Text1.Text = Text1.Text & http.FinalRedirectUrl & vbCrLf
    Text1.Refresh

    '  Note the HTML returned is from the final redirect URL.

Else
    Text1.Text = Text1.Text & "Not redirected." & vbCrLf
    Text1.Refresh
End If

status = http.LastStatus
If (status = 200) Then
    Text1.Text = Text1.Text & "status = 200, OK!" & vbCrLf
    Text1.Refresh
Else
    Text1.Text = Text1.Text & "HTTP Response status = " _
         & status & vbCrLf
    Text1.Refresh

    '  Display the complete response header.
    Text1.Text = Text1.Text & http.LastResponseHeader & vbCrLf
    Text1.Refresh
End If

'  Now try it without following redirects:
Text1.Text = Text1.Text & "-------- Now trying without following redirects...." & vbCrLf
Text1.Refresh
http.FollowRedirects = 0

'  Send the HTTP GET and return the content in a string.
html = http.QuickGetStr(url)
If (html = vbNullString ) Then
    '  the HTML string can NULL if a 302 redirect response is received.
    Text1.Text = Text1.Text & "HTML string returned NULL..." & vbCrLf
    Text1.Refresh
End If

'  On success, LastErrorText will provide information about
'  what happened during the call.
Text1.Text = Text1.Text & "--------------- LastErrorText ------------------" & vbCrLf
Text1.Refresh
Text1.Text = Text1.Text & http.LastErrorText & vbCrLf
Text1.Refresh
Text1.Text = Text1.Text & "------------------------------------------------" & vbCrLf
Text1.Refresh

'  In this case, we see something like this:
'  ChilkatLog:
'    QuickGetHtml:
'      DllDate: Jul 27 2007
'      url: http://www.planyourweddingonline.co.za/
'      StatusCode: 302
'      StatusText: Found
'      Reading chunked response
'      redirectUrl: main/main/home/index.php

'  Was this a redirect?  Even if FollowRedirects is false,
'  WasRedirected will be true (non-zero) if the response
'  indicated a redirect.
If (http.WasRedirected = 1) Then
    Text1.Text = Text1.Text & "This was a redirect response" & vbCrLf
    Text1.Refresh

    '  When redirects are not followed, FinalRedirectUrl
    '  contains the redirect URL that would've been taken...
    '  Display the redirect URL, which was not taken...
    Text1.Text = Text1.Text & "Redirect URL:" & vbCrLf
    Text1.Refresh
    Text1.Text = Text1.Text & http.FinalRedirectUrl & vbCrLf
    Text1.Refresh

Else
    Text1.Text = Text1.Text & "Not redirected." & vbCrLf
    Text1.Refresh
End If

status = http.LastStatus
If (status = 200) Then
    Text1.Text = Text1.Text & "status = 200, OK!" & vbCrLf
    Text1.Refresh
Else
    Text1.Text = Text1.Text & "HTTP Response status = " _
         & status & vbCrLf
    Text1.Refresh

    '  Display the complete response header.
    Text1.Text = Text1.Text & http.LastResponseHeader & vbCrLf
    Text1.Refresh
End If