Saved rules

A rule is a find-and-replace you keep. It has a name, a handle, a scope, and all the matching options from the Replace screen. Saved rules are Pro.

They are worth having for three quite different reasons.

Rules you run by hand

The plainest use. You run the same replacement every few months, or you want a colleague to run it without retyping a regular expression that took you twenty minutes to get right.

Save it once, then run it from Scrub → Rules, or from the console:

php craft scrub/run/rule fix-legacy-links

The rule carries its own scope, so it stops where it stopped last time.

Real-time rules

A real-time rule rewrites rendered output rather than stored content. Nothing in the database changes. Turning the rule off is the undo.

That sounds like a lesser version of the real thing, and it's the opposite. It's for the replacements you can't safely commit to. A brand is mid-rename and legal hasn't signed off. A supplier's name is wrong in four thousand places and you'd like the site to be right today while you work out whether the underlying content should change. A phone number changed and you do not want to touch nine years of blog posts to fix it.

It's HTML-aware. The replacement runs over text, not over markup, so a rule that changes widget to gadget doesn't touch class="widget-grid", <a href="/widgets"> or an alt attribute you didn't mean to rewrite. Turn off HTML aware on the rule if you genuinely want to rewrite attributes too.

It's cheap when it's off. The hook attaches to the page template only, and only when Pro is active, real-time is enabled, and at least one real-time rule exists. On a site with none, a front-end request never touches Scrub at all. The list of active rules is cached, so the question "are there any?" is not a database query per request.

It applies to the page template, not to every partial. A partial rendered inside a page would otherwise be rewritten once on its own and again as part of the page around it.

On-save rules

An on-save rule runs when an element is saved. New content gets the replacement without anybody remembering to go and apply it.

This is the one for a rule that will never be finished: an old product name that keeps coming back because it's still in somebody's copy-paste buffer, a supplier's address that three people type from memory, a unit that should always be written kg and is sometimes written Kg.

On-save rules write to the database, so they are recorded and undoable like any other run.

Scheduled rules

A rule can carry a cadence of daily, weekly or monthly. Due rules run from:

php craft scrub/run/due

Put that on a cron and the rule keeps the site tidy on its own. due runs only what is actually due, so calling it hourly is harmless.

Precedence and order

Rules have a sort order and run in it. A rule that is disabled does not run, in any mode. The Pro gate is checked at run time, not at save time, so a site that drops back to Lite keeps its rules and stops applying them, rather than losing them.