[sr-dev] [kamailio/kamailio] Error when sending NOTIFYs in the presence of disconnected websocket watchers (Issue #4118)

### Description if multiple sip websocket clients are subscribed to some UA and one of the watchers suddenly disappears (e.g. the web page is reloaded), then no NOTIFY is ever sent after issuing a `pres_refresh_watchers()`. The following error is logged: ``` WARNING: <core> [core/msg_translator.c:3007]: via_builder(): TCP/TLS connection (id: 0) for WebSocket could not be found ERROR: tm [t_msgbuilder.c:1423]: assemble_via(): via building failed ERROR: tm [t_msgbuilder.c:1614]: build_uac_req(): error while assembling Via ERROR: tm [uac.c:552]: t_uac_prepare(): Error while building message ERROR: presence [notify.c:1734]: send_notify_request(): in function tm t_request_within() ERROR: presence [notify.c:1829]: notify(): sending Notify not successful ERROR: presence [notify.c:1585]: query_db_notify(): Could not send notify for [event]=dialog ERROR: presence [presence.c:739]: pres_refresh_watchers(): sending Notify requests ``` ### Troubleshooting when the client disconnects, the old watcher is not removed from the active_watchers table, instead it coexists with the new one, but the stale connection causes the error above when sending the notify, and then all of the following watchers (even the valid ones) are skipped too. Looking at the logs, the valid watchers are not notified because the while loop [here](https://github.com/kamailio/kamailio/blob/b96bc11a54f11ec688429c057bf… is skipped because of the `goto done` line in case of errors, which happens because it fails to build the via header for the message relevant to the stale websocket connection. By breaking out of the while loop, the remaining subs in the `subs_array` are skipped. #### Reproduction Just subscribe to a sip client using a websocket-based phone, then abruptly disconnect it (e.g. by reloading the web page) and then issue a `pres_refresh_watchers()` to make it generate a notify. #### Debugging Data #### Log Messages #### SIP Traffic ### Possible Solutions I tried to use the "websocket:closed" route to purge stale connections, but to my knowledge there are no APIs to clean invalid watchers. A possible solution could be to automatically remove the watchers on disconnection and maybe skip the invalid ones without exiting from the refresh loop ### Additional Information kamailio 5.8.2 * **Operating System**: Rocky Linux 9 -- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/4118 You are receiving this because you are subscribed to this thread. Message ID: &lt;kamailio/kamailio/issues/4118(a)github.com&gt;