Visual FoxPro

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.) Visual FoxPro

LOCAL lnSuccess
LOCAL loRest
LOCAL loWs
LOCAL lcResponseBody
LOCAL lnStatusCode

lnSuccess = 0

*  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.
*  

loRest = CreateObject('Chilkat.Rest')
lnSuccess = loRest.Connect("someserver.com",80,0,0)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

loWs = CreateObject('Chilkat.WebSocket')

*  Tell the WebSocket to use this connection.
lnSuccess = loWs.UseConnection(loRest)
IF (lnSuccess <> 1) THEN
    ? loWs.LastErrorText
    RELEASE loRest
    RELEASE loWs
    CANCEL
ENDIF

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

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

*  Do the open handshake.
lcResponseBody = loRest.FullRequestNoBody("GET","/something")
IF (loRest.LastMethodSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loWs
    CANCEL
ENDIF

*  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..)
lnStatusCode = loRest.ResponseStatusCode
? "Response status code: " + STR(lnStatusCode)

IF (lnStatusCode <> 101) THEN
    ? lcResponseBody
    ? "-- Failed because of unexpected response status code."
    RELEASE loRest
    RELEASE loWs
    CANCEL
ENDIF

*  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. 
lnSuccess = loWs.ValidateServerHandshake()
IF (lnSuccess <> 1) THEN
    ? loWs.LastErrorText
    RELEASE loRest
    RELEASE loWs
    CANCEL
ENDIF

? "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...)

RELEASE loRest
RELEASE loWs