The notify.php script allows a site administrator to configure PmWiki to send email messages whenever pages are changed on the wiki site. Notifications can be configured so that multiple page changes over a short period of time are combined into a single email message (to avoid flooding mailboxes).
This feature is useful for sites and pages that have infrequent updates, as it eliminates the need to frequently check RecentChanges pages just to see if anything has changed.
In order for notifications to work, the notify.php script must be enabled in the site's local customization. Usually this is as simple as placing the following in local/config.php:
Once enabled, the notification system gets its configuration from the Site.NotifyList page. The Site.NotifyList page contains entries of the form:
This says that information about page changes should be periodically emailed to firstname.lastname@example.org. The Site.NotifyList page can contain multiple "notify=" lines to cause notifications to be sent to multiple addresses; the "notify=" lines can be concealed by placing them inside of an
A number of options exist for limiting the pages that result in a notification. The
# send notifications about the Main group to email@example.com firstname.lastname@example.org group=Main # notify email@example.com of any changes to the home page firstname.lastname@example.org name=Main.HomePage # notify email@example.com of changes to pages except in Main firstname.lastname@example.org group=-Main
For maintaining arbitrary lists of pages, i.e., "watchlists", it's generally easier to build a trail of pages to be watched. The following entry in Site.NotifyList will send email@example.com an email containing changes to any of the pages listed in the Profiles.Alice trail:
# notify Alice of changes to pages listed in Profiles.Alice firstname.lastname@example.org trail=Profiles.Alice
Note that once this entry has been added to Site.NotifyList, Alice can easily change her watchlist by editing the Profiles.Alice page, and doesn't need to edit the Site.NotifyList page. In particular, this means that an administrator can restrict editing of Site.NotifyList, yet allow individuals to maintain custom watchlists in other pages.
Limitations of this feature:
This is probably a good place to point out that edit access to Site.NotifyList should be controlled, otherwise malicious persons can use the notification capability to flood others' electronic mailboxes. By default, Site.Notify is blocked against edits except by the admin (as is the case for most pages in the Site group). It may also be useful to place a read password on the Site.NotifyList page, to restrict the availability of email addresses from spam harvesters.
Controlling notification frequency
To prevent flooding of recipients' mailboxes, the notify script uses a "squelch" value as the minimum amount of time that must elapse between messages sent to any given email address. The default squelch setting is 10800 (three hours), which means that once a recipient address is sent a notification message, it will not receive another for at least three hours. Any edits that occur during the squelch interval are queued for the next notification message.
The site administrator can change the default squelch interval via the
# enable notifications
In addition, individual addresses can specify a custom squelch parameter in the Site.NotifyList page:
# Alice receives at most one email per day email@example.com squelch=86400 # Bob can get notifications hourly firstname.lastname@example.org trail=Profiles.Bob squelch=3600 # Charles uses the site default squelch email@example.com
Because a page will often receive several edits in rapid succession (e.g., a long post followed by several minor edits), a site administrator can also set a
# enable notifications
Note that the squelch and delay values are minimums; notifications are sent on the first execution of PmWiki after the delay period has expired. For inactive sites, this could be much longer than the specified delay periods. This isn't really considered an issue since timely notifications are less important on relatively inactive sites. (Active sites will generally receive timely notifications.)
Note for Windows installations
Sites running PHP under Windows may not have PHP's mail function configured correctly. Such sites may need to add a line like
to config.php, where smtp.server.com is the name of your host's preferred outgoing mail server.
# send notifications to firstname.lastname@example.org