rjwkerkhof - 2024-04-09

Dear all,

I am developing a Web Socket Client in Codesys 3.5 using the Web Socket Client SL library to retrieve data from a third party. Connecting and reading works fine however after 40 seconds the connection gets interrupted by the server due to keepalive ping timeout.

After discussion with third party it seems that the Web Socket Client SL library replys to the Ping request of the Web Socket server BUT does not add the "Application data" = 4 bytes in the body of the Pingframe to the Pongframe.

Therefor the server does not recognize the Pongframe send by the Web Socket Client SL library and automatically disconnects.

Is this a known issue with the libary or am I doing something wrong? Is there a workaround to add the 4 bytes manually to the Pongframe before replying it to the server?

Thanks in advance,