![\"\"](\"https:\/\/twproject.com\/support\/wp-content\/uploads\/user-subs.png\")
<\/p>\n<\/p>\n
We have already described Twproject\u2019s event\/subscription capability. Here is describe shortly how this engine works.<\/p>\n
When a user subscribes listening an event, say \u201cToDo created\u201d, it is creating an object called \u201clistener\u201d.<\/p>\n
A listener refers a Twproject object using class and id, has the event it is listening for (called \u201ccommand\u201d), has a validity period, has a user as owner, may be listening for children object too, etc. .<\/p>\n
Usually there are lots of listeners (thousands after some months of real usage).<\/p>\n
When something relevant happens, an \u201cevent\u201d is generated and inserted in the event queue.<\/p>\n
A scheduled job (\u201cEventListenerMatcher\u201d) checks (by default every minute) for each event if there is a subscription listening for. If there is nothing listening, the event is removed.<\/p>\n
If there is a subscription a message is generated by integrating \u201clistener\u201d and \u201cevent\u201d data; the message is inserted in the message queue. Then the event is removed.<\/p>\n
Usually the event queue is empty or contains only a few records.
\nOnce the message is queued it is available for dispatching: \u201cEmailMessageDispatcher\u201d and \u201cStickyMessageDispatcher\u201d are two scheduled jobs that send messages to their respective media channels. Messages for the \u201cnews\u201d or “digest” channel rest in the message list until they are read by the user, then removed. So the message queue should contain elements for \u201cnews\u201d or “digest” channel only.<\/p>\n
Twproject provides list\/search and edit pages for subscriptions, events and messages. Usually you do not need to operate in pages that are intended for monitoring purposes only:<\/p>\n
![\"\"](\"https:\/\/twproject.com\/support\/wp-content\/uploads\/admin-subs.png\")
<\/p>\n","protected":false},"excerpt":{"rendered":"
We have already described Twproject\u2019s event\/subscription capability. Here is describe shortly how this engine works. When a user subscribes listening an event, say \u201cToDo created\u201d, it is creating an object called \u201clistener\u201d. A listener refers a Twproject object using class and id, has the event it is listening for (called \u201ccommand\u201d), has a validity period, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2565,"menu_order":8,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-2675","page","type-page","status-publish","hentry"],"yoast_head":"\n