PureBasic

WebSocket Connect through HTTP Proxy

See more WebSocket Examples

This example shows how to establish a WebSocket connection through an HTTP proxy server. PureBasic

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

Procedure ChilkatExample()

    success.i = 0

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

    ; --------------------------------------------------
    ; This example borrows the code from the REST using HTTP Proxy example.
    ; We first use the Chilkat Socket object to establish a connection to the WebSocket server through an HTTP proxy.
    ; Next, the Rest object uses the Socket object for its connection.
    ; Finally, the WebSocket object uses the Rest object for its connection.  
    ; 

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

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

    ; Set the HTTP proxy domain or IP address, and port.
    CkSocket::setCkHttpProxyHostname(socket, "192.168.1.79")
    CkSocket::setCkHttpProxyPort(socket, 808)

    ; Provide authentication to the HTTP proxy, if needed.
    CkSocket::setCkHttpProxyUsername(socket, "HTTP_PROXY_LOGIN")
    CkSocket::setCkHttpProxyPassword(socket, "HTTP_PROXY_PASSWORD")
    CkSocket::setCkHttpProxyAuthMethod(socket, "Basic")

    ; Indicate that HTTP requests (i.e. the WebSocket opening handshake) will be sent over the socket.
    ; This is important for how the HTTP proxy connection is established.
    CkSocket::setCkHttpProxyForHttp(socket, 1)

    ; Connect to the websocket server through the HTTP proxy.
    bTls.i = 0
    port.i = 80
    maxWaitMs.i = 5000
    success = CkSocket::ckConnect(socket,"some-websocket-server.com",port,bTls,maxWaitMs)
    If success <> 1
        Debug "Connect Failure Error Code: " + Str(CkSocket::ckConnectFailReason(socket))
        Debug CkSocket::ckLastErrorText(socket)
        CkRest::ckDispose(rest)
        CkSocket::ckDispose(socket)
        ProcedureReturn
    EndIf

    ; Tell the Rest object to use the connected socket.
    success = CkRest::ckUseConnection(rest,socket,1)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkSocket::ckDispose(socket)
        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)
        CkSocket::ckDispose(socket)
        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-some-websocket-subprotocol")
    CkRest::ckAddHeader(rest,"Origin","http://some-websocket-server.com")

    ; Do the open handshake.
    responseBody.s = CkRest::ckFullRequestNoBody(rest,"GET","/something")
    If CkRest::ckLastMethodSuccess(rest) <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkSocket::ckDispose(socket)
        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)
        CkSocket::ckDispose(socket)
        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)
        CkSocket::ckDispose(socket)
        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 and socket objects...)

    Debug "Success."


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


    ProcedureReturn
EndProcedure