(PureBasic) WebSocket Connect

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.)

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkRest.pb"
IncludeFile "CkWebSocket.pb"

Procedure ChilkatExample()

    ;  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.
    ; 

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkRest::ckConnect(rest,"someserver.com",80,0,0)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ws.i = CkWebSocket::ckCreate()
    If ws.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Tell the WebSocket to use this connection.
    success = CkWebSocket::ckUseConnection(ws,rest)
    If success <> 1
        Debug CkWebSocket::ckLastErrorText(ws)
        CkRest::ckDispose(rest)
        CkWebSocket::ckDispose(ws)
        ProcedureReturn
    EndIf

    ;  Add the standard WebSocket open handshake headers that will be needed.
    ;  (This adds the required HTTP request headers to the rest object.)
    CkWebSocket::ckAddClientHeaders(ws)

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

    ;  Do the open handshake.
    responseBody.s = CkRest::ckFullRequestNoBody(rest,"GET","/something")
    If CkRest::ckLastMethodSuccess(rest) <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkWebSocket::ckDispose(ws)
        ProcedureReturn
    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..)
    statusCode.i = CkRest::ckResponseStatusCode(rest)
    Debug "Response status code: " + Str(statusCode)

    If statusCode <> 101
        Debug responseBody
        Debug "-- Failed because of unexpected response status code."
        CkRest::ckDispose(rest)
        CkWebSocket::ckDispose(ws)
        ProcedureReturn
    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.
    success = CkWebSocket::ckValidateServerHandshake(ws)
    If success <> 1
        Debug CkWebSocket::ckLastErrorText(ws)
        CkRest::ckDispose(rest)
        CkWebSocket::ckDispose(ws)
        ProcedureReturn
    EndIf

    Debug "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...)


    CkRest::ckDispose(rest)
    CkWebSocket::ckDispose(ws)


    ProcedureReturn
EndProcedure