(Visual Basic) TCP Socket Connect through HTTP Proxy

Demonstrates how to connect through an HTTP proxy server.

Download Chilkat Socket ActiveX

Dim socket As New ChilkatSocket

Dim success As Long
success = socket.UnlockComponent("Anything for 30-day trial")
If (success <> 1) Then
    Text1.Text = Text1.Text & socket.LastErrorText & vbCrLf
    Exit Sub
End If

'  To connect through an HTTP proxy, set the HttpProxyHostname
'  and HttpProxyPort properties to the hostname (or IP address)
'  and port of the HTTP proxy.  Typical port numbers used by
'  HTTP proxy servers are 3128 and 8080.
socket.HttpProxyHostname = "www.my-http-proxy.com"
socket.HttpProxyPort = 3128

'  Important:  Your HTTP proxy server must allow non-HTTP
'  traffic to pass.  Otherwise this does not work.

'  Connect (via the HTTP proxy) to port 5555 of 192.168.1.108.
'  hostname may be a domain name or IP address.
Dim hostname As String
hostname = "192.168.1.108"
Dim ssl As Long
ssl = 0
Dim maxWaitMillisec As Long
maxWaitMillisec = 20000
success = socket.Connect(hostname,5555,ssl,maxWaitMillisec)
If (success <> 1) Then
    Text1.Text = Text1.Text & socket.LastErrorText & vbCrLf
    Exit Sub
End If

'  Set maximum timeouts for reading an writing (in millisec)
socket.MaxReadIdleMs = 10000
socket.MaxSendIdleMs = 10000

'  The ficticious server (in this example) is going to send a "Hello World!"
'  message.  Read it:
Dim receivedMsg As String
receivedMsg = socket.ReceiveString()
If (receivedMsg = vbNullString ) Then
    Text1.Text = Text1.Text & socket.LastErrorText & vbCrLf
    Exit Sub
End If

'  Close the connection with the server
'  Wait a max of 20 seconds (20000 millsec)
socket.Close 20000

MsgBox receivedMsg