https://community.cloudera.com/t5/Support-Questions/NiFi-websocket-subprotocols-support/m-p/413061#M253825 <P>&nbsp;</P><P>Hello,</P><P>For a project, I need to configure a WebSocket connection using NiFi. I also need to define a custom sub-protocol in the “Sec-WebSocket-Protocol” header.</P><P>I have seen that some custom headers can be defined in the parent FF with the “header.Something” attribute. In fact, all headers are defined except for the sub-protocol. How can I achieve this without having to develop my own processor?</P><P>My GenerateFlowFile has the following attributes: `header.Sec-WebSocket-Protocol = Test` and another `header.Test = Test2`.</P><P>The request retrieved by Wireshark only uses header.Test. Is it normal ?<BR />Thanks.</P><P>(related to&nbsp;<A href="https://community.cloudera.com/t5/Support-Questions/Nifi-websocket-subprotocols/m-p/311764#M224816" target="_blank">https://community.cloudera.com/t5/Support-Questions/Nifi-websocket-subprotocols/m-p/311764#M224816</A>&nbsp;and <A href="https://community.cloudera.com/t5/Support-Questions/NiFi-WebSocket-Headers/m-p/361488" target="_blank">https://community.cloudera.com/t5/Support-Questions/NiFi-WebSocket-Headers/m-p/361488</A>)</P> Tue, 09 Dec 2025 10:11:49 GMT Tituya 2025-12-09T10:11:49Z https://community.cloudera.com/t5/Support-Questions/NiFi-websocket-subprotocols-support/m-p/413061#M253825 <P>&nbsp;</P><P>Hello,</P><P>For a project, I need to configure a WebSocket connection using NiFi. I also need to define a custom sub-protocol in the “Sec-WebSocket-Protocol” header.</P><P>I have seen that some custom headers can be defined in the parent FF with the “header.Something” attribute. In fact, all headers are defined except for the sub-protocol. How can I achieve this without having to develop my own processor?</P><P>My GenerateFlowFile has the following attributes: `header.Sec-WebSocket-Protocol = Test` and another `header.Test = Test2`.</P><P>The request retrieved by Wireshark only uses header.Test. Is it normal ?<BR />Thanks.</P><P>(related to&nbsp;<A href="https://community.cloudera.com/t5/Support-Questions/Nifi-websocket-subprotocols/m-p/311764#M224816" target="_blank">https://community.cloudera.com/t5/Support-Questions/Nifi-websocket-subprotocols/m-p/311764#M224816</A>&nbsp;and <A href="https://community.cloudera.com/t5/Support-Questions/NiFi-WebSocket-Headers/m-p/361488" target="_blank">https://community.cloudera.com/t5/Support-Questions/NiFi-WebSocket-Headers/m-p/361488</A>)</P> Tue, 09 Dec 2025 10:11:49 GMT https://community.cloudera.com/t5/Support-Questions/NiFi-websocket-subprotocols-support/m-p/413061#M253825 Tituya 2025-12-09T10:11:49Z https://community.cloudera.com/t5/Support-Questions/NiFi-websocket-subprotocols-support/m-p/413079#M253839 <P><a href="https://community.cloudera.com/t5/user/viewprofilepage/user-id/138152">@Tituya</a>&nbsp;Welcome to the Cloudera Community!<BR /><BR />To help you get the best possible solution, I have tagged our NiFi experts&nbsp;<a href="https://community.cloudera.com/t5/user/viewprofilepage/user-id/35454">@MattWho</a>&nbsp;<a href="https://community.cloudera.com/t5/user/viewprofilepage/user-id/38301">@mburgess</a>&nbsp;&nbsp;who may be able to assist you further.<BR /><BR />Please keep us updated on your post, and we hope you find a satisfactory solution to your query.</P> Wed, 10 Dec 2025 18:14:25 GMT https://community.cloudera.com/t5/Support-Questions/NiFi-websocket-subprotocols-support/m-p/413079#M253839 DianaTorres 2025-12-10T18:14:25Z