DataFlex

Socket Convert Existing TCP Connection to SSL/TLS

Demonstrates the Chilkat Socket ConvertToSsl method. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSock
    Boolean iUseTls
    Integer iPort
    Integer iMaxWaitMs
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatSocket)) To hoSock
    If (Not(IsComObjectCreated(hoSock))) Begin
        Send CreateComObject of hoSock
    End

    // --------------------------------------------------------------------
    // This example uses the public TCP/TLS echo service at https://tcpbin.com/
    // --------------------------------------------------------------------

    // The echo server at tcpbin.com expects to receive TCP connections on port 4242, and TLS connections on port 4243.
    // We could simply connect to port 4243 using TLS like this.
    // However, further below, this example shows how to initially make a TCP connection, and then convert the connection to TLS.
    Move True To iUseTls
    Move 4243 To iPort
    Move 5000 To iMaxWaitMs
    Get ComConnect Of hoSock "tcpbin.com" iPort iUseTls iMaxWaitMs To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSock To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // OK, we have a TLS connection.
    // Note: The server chooses the TLS protocol version. 
    // We can see the version of the TLS connection that was established:
    Get ComTlsVersion Of hoSock To sTemp1
    Showln "TLS version: " sTemp1

    Get ComClose Of hoSock iMaxWaitMs To iSuccess

    // ---------------------------------------------------------------------
    // Now we'll do the same, except first we connect to port 4243 using TCP,
    // and then convert the connection to TLS.
    // 
    // This may seem pointless, and it is for the case w/ this server.  However, there could be situations
    // where you're interacting with a server of some kind where there is a need to convert to/from TLS.
    // (This is common internal to many protocols, such as SMTP, IMAP, FTP, etc., and it is often called "explicit" SSL/TLS)

    // Connect again, except this time useTls is False, so we only have a simple TCP connection after this call.
    Move False To iUseTls
    Get ComConnect Of hoSock "tcpbin.com" iPort iUseTls iMaxWaitMs To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSock To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Convert the existing TCP connection to TLS.
    // (The method name uses "SSL" because long ago, at the time of initial development, TLS 1.0 did not yet exist.)
    Get ComConvertToSsl Of hoSock To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSock To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // OK, we now have a TLS connection.
    // Again, we can see the TLS version:
    Get ComTlsVersion Of hoSock To sTemp1
    Showln "TLS version: " sTemp1

    Get ComClose Of hoSock iMaxWaitMs To iSuccess


End_Procedure