DataFlex

WebSocket Connect through HTTP Proxy

See more WebSocket Examples

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vRest
    Handle hoRest
    Variant vSocket
    Handle hoSocket
    Boolean iBTls
    Integer iPort
    Integer iMaxWaitMs
    Handle hoWs
    String sResponseBody
    Integer iStatusCode
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

    Move False To iSuccess

    // 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.  
    // 

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End
    Get Create (RefClass(cComChilkatSocket)) To hoSocket
    If (Not(IsComObjectCreated(hoSocket))) Begin
        Send CreateComObject of hoSocket
    End

    // Set the HTTP proxy domain or IP address, and port.
    Set ComHttpProxyHostname Of hoSocket To "192.168.1.79"
    Set ComHttpProxyPort Of hoSocket To 808

    // Provide authentication to the HTTP proxy, if needed.
    Set ComHttpProxyUsername Of hoSocket To "HTTP_PROXY_LOGIN"
    Set ComHttpProxyPassword Of hoSocket To "HTTP_PROXY_PASSWORD"
    Set ComHttpProxyAuthMethod Of hoSocket To "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.
    Set ComHttpProxyForHttp Of hoSocket To True

    // Connect to the websocket server through the HTTP proxy.
    Move False To iBTls
    Move 80 To iPort
    Move 5000 To iMaxWaitMs
    Get ComConnect Of hoSocket "some-websocket-server.com" iPort iBTls iMaxWaitMs To iSuccess
    If (iSuccess <> True) Begin
        Get ComConnectFailReason Of hoSocket To iTemp1
        Showln "Connect Failure Error Code: " iTemp1
        Get ComLastErrorText Of hoSocket To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Tell the Rest object to use the connected socket.
    Get pvComObject of hoSocket to vSocket
    Get ComUseConnection Of hoRest vSocket True To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatWebSocket)) To hoWs
    If (Not(IsComObjectCreated(hoWs))) Begin
        Send CreateComObject of hoWs
    End

    // Tell the WebSocket to use this connection.
    Get pvComObject of hoRest to vRest
    Get ComUseConnection Of hoWs vRest To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Add the standard WebSocket open handshake headers that will be needed.
    // (This adds the required HTTP request headers to the rest object.)
    Get ComAddClientHeaders Of hoWs To iSuccess

    // Add any additional headers that might be desired.
    // Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
    Get ComAddHeader Of hoRest "Sec-WebSocket-Protocol" "x-some-websocket-subprotocol" To iSuccess
    Get ComAddHeader Of hoRest "Origin" "http://some-websocket-server.com" To iSuccess

    // Do the open handshake.
    Get ComFullRequestNoBody Of hoRest "GET" "/something" To sResponseBody
    Get ComLastMethodSuccess Of hoRest To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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..)
    Get ComResponseStatusCode Of hoRest To iStatusCode
    Showln "Response status code: " iStatusCode

    If (iStatusCode <> 101) Begin
        Showln sResponseBody
        Showln "-- Failed because of unexpected response status code."
        Procedure_Return
    End

    // 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. 
    Get ComValidateServerHandshake Of hoWs To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "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...)

    Showln "Success."


End_Procedure