VB.NET

WebSocket Connect

See more WebSocket Examples

Demonstrates how to establish a WebSocket connection. Once the connection is established, messages may be sent back-and-forth. Messages are sent in frames, where the last frame in the message is indicated by a "final" bit. A frame constitutes the entire message if the first frame sent has the "final" bit sent. (In most cases, you'll probably be sending single-frame messages.) VB.NET

Dim success As Boolean = False

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

' --------------------------------------------------
' A WebSocket connection begins life as an HTTP GET request containing a few special header fields,
' such as "Upgrade: websocket".   

' Your application will use the Chilkat Rest class to send the initial HTTP GET.  This allows you
' to use the full capability of the Chilkat Rest class to customize the GET for any particular situation.
' For example:
' 
'   - If custom HTTP request header fields must be added.
'   - If authentication is required, such as OAuth2, OAuth1, Basic HTTP Auth, etc.
'   - If HTTPS, SSH Tunneling, Proxies (HTTP or SOCKS), or other advanced connection or TLS features are required.
' 

Dim rest As New Chilkat.Rest
success = rest.Connect("someserver.com",80,False,False)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


Dim ws As New Chilkat.WebSocket

' Tell the WebSocket to use this connection.
success = ws.UseConnection(rest)
If (success <> True) Then
    Debug.WriteLine(ws.LastErrorText)
    Exit Sub
End If


' Add the standard WebSocket open handshake headers that will be needed.
' (This adds the required HTTP request headers to the rest object.)
ws.AddClientHeaders()

' Add any additional headers that might be desired.
' Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
rest.AddHeader("Sec-WebSocket-Protocol","x-something")
rest.AddHeader("Origin","http://someserver.com")

' Do the open handshake.
Dim responseBody As String = rest.FullRequestNoBody("GET","/something")
If (rest.LastMethodSuccess <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' If successful, the HTTP response status code should be 101,
' and the response body will be empty. (If it failed, we'll have a look
' at the response body..)
Dim statusCode As Integer = rest.ResponseStatusCode
Debug.WriteLine("Response status code: " & statusCode)

If (statusCode <> 101) Then
    Debug.WriteLine(responseBody)
    Debug.WriteLine("-- Failed because of unexpected response status code.")
    Exit Sub
End If


' We have the expected 101 response, so let's now validate the 
' contents of the response, such as the value sent by the server in the
' Sec-WebSocket-Accept header. 
success = ws.ValidateServerHandshake()
If (success <> True) Then
    Debug.WriteLine(ws.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("WebSocket connection successful.")

' The application may now begin sending and receiving frames on the WebSocket connection.
' (At this point, we're done with the rest object...)