mod_auth_openidc discovery response is broken with matching ProxyPass enabled

Issue

• If a ProxyPass matches a request, it cannot receive a discovery response from mod_auth_openidc as we expect. mod_auth_openidc works if the ProxyPass is disabled. From debug logs, mod_auth_openidc defers the discovery response to be given during the handler hook:

[Thu May 18 11:46:05.017987 2023] [auth_openidc:debug] [pid 121870:tid 140413968389888] src/mod_auth_openidc.c(2277): [client 127.0.0.1:44966] oidc_authenticate_user: enter
[Thu May 18 11:46:05.017989 2023] [auth_openidc:debug] [pid 121870:tid 140413968389888] src/mod_auth_openidc.c(2288): [client 127.0.0.1:44966] oidc_authenticate_user: defer discovery to the content handler
[Thu May 18 11:46:05.017993 2023] [auth_openidc:debug] [pid 121870:tid 140413968389888] src/mod_auth_openidc.c(4045): [client 127.0.0.1:44966] oidc_authz_checker: enter: require_args="accessAllowed:true"
[Thu May 18 11:46:05.017996 2023] [authz_core:debug] [pid 121870:tid 140413968389888] mod_authz_core.c(820): [client 127.0.0.1:44966] AH01626: authorization result of Require claim accessAllowed:true: granted
[Thu May 18 11:46:05.017999 2023] [authz_core:debug] [pid 121870:tid 140413968389888] mod_authz_core.c(820): [client 127.0.0.1:44966] AH01626: authorization result of <RequireAny>: granted

• But mod_proxy handles the request first in the hook handler phase so mod_auth_openidc does not process it:

[Thu May 18 11:46:05.018020 2023] [proxy:debug] [pid 121870:tid 140413968389888] mod_proxy.c(1265): [client 127.0.0.1:44966] AH01143: Running scheme http handler (attempt 0)
[Thu May 18 11:46:05.018024 2023] [proxy_ajp:debug] [pid 121870:tid 140413968389888] mod_proxy_ajp.c(764): [client 127.0.0.1:44966] AH00894: declining URL http://localhost/helloworld/
[Thu May 18 11:46:05.018027 2023] [proxy_fcgi:debug] [pid 121870:tid 140413968389888] mod_proxy_fcgi.c(1021): [client 127.0.0.1:44966] AH01076: url: http://localhost/helloworld/ proxyname: (null) proxyport: 0
[Thu May 18 11:46:05.018030 2023] [proxy_fcgi:debug] [pid 121870:tid 140413968389888] mod_proxy_fcgi.c(1024): [client 127.0.0.1:44966] AH01077: declining URL http://localhost/helloworld/
[Thu May 18 11:46:05.018041 2023] [proxy:debug] [pid 121870:tid 140413968389888] proxy_util.c(2353): AH00942: HTTP: has acquired connection for (localhost)
[Thu May 18 11:46:05.018045 2023] [proxy:debug] [pid 121870:tid 140413968389888] proxy_util.c(2408): [client 127.0.0.1:44966] AH00944: connecting http://localhost/helloworld/ to localhost:80
[Thu May 18 11:46:05.018204 2023] [proxy:debug] [pid 121870:tid 140413968389888] proxy_util.c(2634): [client 127.0.0.1:44966] AH00947: connected /helloworld/ to localhost:80
[Thu May 18 11:46:05.018283 2023] [proxy:debug] [pid 121870:tid 140413968389888] proxy_util.c(3095): (13)Permission denied: AH00957: HTTP: attempt to connect to 127.0.0.1:80 (localhost) failed
[Thu May 18 11:46:05.018326 2023] [proxy:error] [pid 121870:tid 140413968389888] (13)Permission denied: AH00957: HTTP: attempt to connect to 127.0.0.1:80 (localhost) failed
[Thu May 18 11:46:05.018333 2023] [proxy_http:error] [pid 121870:tid 140413968389888] [client 127.0.0.1:44966] AH01114: HTTP: failed to make connection to backend: localhost