This is the module exactly as released in Apache httpd 2.4.20. The list of changes to the last version here, 1.2.8, is:
- incrementing keepalives on each request started so that logging %k gives
increasing numbers per master http2 connection. New documented variables
in env, usable in custom log formats: H2_PUSH, H2_PUSHED, H2_PUSHED_ON,
H2_STREAM_ID and H2_STREAM_TAG. - more efficient passing of response bodies with less contention
and file bucket forwarding. - fix for missing score board updates on request count, fix for memory leak
on slave connection reuse. - disabling PUSH when client sends GOAWAY. Slave connections are reused for
several requests, improved performance and better memory use. - fixes problem with wrong lifetime of file buckets on main connection.
- fixes incorrect denial of requests without :authority header.
- give control to async mpm for keepalive timeouts only when no streams are
open and even if only after 1 sec delay. Under load, event mpm discards
connections otherwise too quickly. - fixed possible read after free when streams were cancelled early by the
client. - fixed possible deadlock during connection shutdown. Thanks to @frankstolle
for reporting and getting the necessary data. - fixed apr_uint64_t formatting in a log statement to user proper APR def,
thanks to @Sp1l. - number of worker threads allowed to a connection is adjusting
dynamically. Starting with 4, the number is doubled when streams can be
served without block on http/2 connection flow. The number is halfed, when
the server has to wait on client flow control grants.
This can happen with a maximum frequency of 5 times per second.
When a connection occupies too many workers, repeatable requests
(GET/HEAD/OPTIONS) are cancelled and placed back in the queue. Should that
not suffice and a stream is busy longer than the server timeout, the
connection will be aborted with error code ENHANCE_YOUR_CALM.
This does not limit the number of streams a client may open, rather the
number of server threads a connection might use. - allowing link header to specify multiple "rel" values, space-separated
inside a quoted string. Prohibiting push when Link parameter "nopush" is
present. - reworked connection state handling. Idle connections accept a GOAWAY from
the client without further reply. Otherwise the module makes a best effort
to send one last GOAWAY to the client. - the values from standard directives Timeout and KeepAliveTimeout properly
are applied to http/2 connections. - idle connections are returned to async mpms. new hook "pre_close_connection"
used to send GOAWAY frame when not already done. Setting event mpm server
config "by hand" for the main connection to the correct negotiated server. - keep-alive blocking reads are done with 1 second timeouts to check for MPM
stopping. Will announce early GOAWAY and finish processing open streams,
then close. - bytes read/written on slave connections are reported via the optional
mod_logio functions. Fixes PR 58871. - connections how keep a "push diary" where hashes of already pushed resources
are kept. See directive H2PushDiarySize for managing this. Push diaries can
be initialized by clients via the "Cache-Digest" request header.
This carries a base64url encoded. compressed Golomb set as described
in https://datatracker.ietf.org/doc/draft-kazuho-h2-cache-digest/
Introduced a status handler for HTTP/2 connections, giving various counters
and statistics about the current connection, plus its cache digest value
in a JSON record. Not a replacement for more HTTP/2 in the server status.
Configured as
<Location "/http2-status">
SetHandler http2-status
- Fixed flushing of last GOAWAY frame. Previously, that frame did not always
reach the client, causing some to fail the next request.
Fixed calculation of last stream id accepted as described in rfc7540.
Reading in KEEPALIVE state now correctly shown in scoreboard.
Fixed possible race in connection shutdown after review by Ylavic.
Fixed segfault on connection shutdown, callback ran into a semi dismantled session. - Added support for experimental accept-push-policy draft
(https://tools.ietf.org/html/draft-ruellan-http-accept-push-policy-00). Clients
may now influence server pushes by sending accept-push-policy headers. - new r->subprocess_env variables HTTP2 and H2PUSH, set to "on"
when available for request. - mod_status/scoreboard: showing connection protocol in new column, new
ap_update_child_status methods for updating server/description. mod_ssl
sets vhost negotiated by servername directly.