How does Rails know when to delete a record from the `sessions` table?

Question

How does Rails know when to delete a record from the sessions table?

For example, if a user visits the website, a session record is created, but when the user closes the browser window, the server doesn't get any notification, so how does Rails delete records from sessions table?

Dzmitry · Answer 1 · 2011-12-01T12:18:51.473

7

There are simplier ways:

ActiveRecord::SessionStore::Session.delete_all(["updated_at < ?", 12.hours.ago])

You can call it after some Action in Controller and this piece of code kill all dead sessions.

Of course it is disputable technique, but the simplest.

Full story

edited Dec 01 '11 at 12:18

answered Nov 30 '11 at 12:53

Dzmitry

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I'd really want to do something like that asynchronously, like from a cronjob. – Dogweather Apr 24 '12 at 02:39
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This worked well, run through rails runner along with whenever gem to make it as a cron job. – Rystraum Sep 25 '12 at 07:25
We had a similar problem and wanted to get away from running this via cron, so we're experimenting with MySQL Events: http://dev.mysql.com/doc/refman/5.5/en/create-event.html. Hopefully that helps others running into the same thing. – Chip Castle Mar 04 '13 at 18:08
Here is the updated "Full Story" link regard using a datastore as a disputable technique. http://www.isnorcreative.com/blog/deleting-old-ruby-on-rails-active-record-sessions-using-whenever-and-capistrano We use database storage for sessions when working with multiple web servers. It is a good solution as long as you keep stale sessions purged, otherwise, it bloats horribly. – scarver2 Jul 20 '13 at 13:11

score 3 · Accepted Answer · edited May 23 '17 at 12:29

You have to provide your own implementation of session expiration, to my understanding.

This API page gives you a pretty decent answer to how that works. You create your database table with the extra attributes created_on and updated_at (and you get timestamps for free) and then you just create a job to expire them whenever you want by looking at the updated_at attribute.

This post has details of how to run a job.

How does Rails know when to delete a record from the `sessions` table?

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