STREAM::expression and "thread safety"

HTTP/2 allows multiplexed requests.

 

The individual HTTP/2 requests in the TCP connection will be separated into Streams (based on Stream ID) at the HTTP_REQUEST and responses combined back into the connection at HTTP_RESPONSE.

 

Between those two events, each Stream is an individual Stream context, and items such as TCL variables and STREAM::expression only exist in that Stream context. You cannot access the Connection context from within the Stream context, so if you need to store a Connection variable for access from within the Stream context, it needs to be stored globally (i.e using table).

 

So from HTTP_REQUEST to HTTP_RESPONSE, STREAM:: is limited in scope to the Stream, and will not interfere with other request/responses.