SecureBlackbox 16: The PreferKeepAlive property is not available anymore. How do I update my code?

Note: This article applies only to SecureBlackbox Legacy. For future development please consider using the latest version.

The PreferKeepAlive property has been removed in favor of KeepAlivePolicy in SBB 13.

To fix your project, you need to open the form with TElHTTPSClient in your IDE, and when you get a message that a property is not found, click Ignore.


KeepAlivePolicy is the enumeration

TSBHTTPKeepAlivePolicy = public (kapStandardDefined, kapPreferKeepAlive, kapRelyOnServer, kapKeepAlivesDisabled);

  • kapStandardDefined - keep-alive preferences are dependent on the chosen and negotiated version of the HTTP protocol (1.0 or 1.1 or later).
  • kapPreferKeepAlive - keep-alive is always requested.
  • kapRelyOnServer - the client doesn't send the Connection header and allows the server to choose the strategy.
  • kapKeepAlivesDisabled - send the "Connection: Close" header and do not use keep-alives.

  • The default value of the property is kapStandardDefined and we recommend keeping it this way.

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