Posted by Oli Filth on 06/14/23 11:31

Maarten said the following on 08/11/2005 14:45:
> Hi there Angelos,
>
> You could create a javascript function that sends a signal to the
> server when the editing page unloads. onUnload is a standard javascript
> event supported by every browser (that has javascript support switched
> on).

Unfortunately, this isn't failsafe by any stretch of the imagination;
e.g. Javascript disabled, browser crashes, computer crashes, internet
connection lost. I also believe that onUnload is fired if the user
refreshes the page in their browser.

Even if these events only occur once in a day, your database is
immediately unsynchronised, and will probably require manual
intervention to sort it out.


> Alternatively, if your server supports cron jobs, you could create a
> program that runs in the background and checks the flag's status every
> 30 minutes or so. If the status hasn't changed for, say more than 30
> minutes, you may assume the user has left the page and the flag should
> be reset. This acts as a sort of timeout function.

IMO, a cron job is unnecessary. If you store the "check-out" time of
each article in the DB, then you can perform time-out checks can be
performed every time a user requests a PHP page.

e.g. perform the following query at the top of every script:

UPDATE articles
SET isCheckedOut = 0
WHERE (checkOutTime + X) < NOW()

In practice, you can probably find ways to avoid doing this amount of
processing in every script, but you get the general idea...


--
Oli

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