A PushCacheFilter contains the logic to associate secondary resources
to primary resources.
PushCacheFilter calls a Jetty-specific API on the request dispatcher:
Dispatcher.push(ServletRequest). This is a technology preview of the
push functionality slated for Servlet 4.0.
The push() invocation arrives to the transport and it is converted to
HTTP/2 specific PUSH_PROMISE, along with the mechanism to simulate
the request for the secondary resource.
It's now sent after a call to onPreface(), which has been moved to
the common interface Session.Listener (from ServerSession.Listener),
so that client applications can customize the SETTINGS to send to the
server.
Flow control window updates are now processed by the flusher, so that
it is the only component that handles window updates.
In the process of this refactoring, HTTP2Flusher was refactored out
of HTTP2Session.
There is a difference between the value set via configuration, that
always refer to remote streams (streams initiated by remote peers),
and the value received via SETTINGS frame, that always refer to local
streams (streams initiated locally).
This refactor strives to remove duplication between the Metadata class and the HttpURI class.
Both classes have been made mutable (as they partially were anyway so best not to pretend).
HttpURI now holds the decomposed strings rather than a single string with indexes. This allows it to be rebuilt after changing just parts of the URI. It is now a lot more similar to the
JVM URI class and we could consider replacing it (after checking peformance).
Next step is to refactor the Request class to prevent it duplicating these fields.
Greg Wilkins
Simone Bordet