Topic
Step-by-step guides for getting things done in WordPress.
WordPress Tutorials
Raising this number is widely recommended as a database cleanup measure, and it is not one. Autosaves reuse a single row per author, so the thing people are trying to trim is revisions, which this constant does not touch.
WordPress Tutorials
Setting this constant to direct makes the prompt disappear, which is why it spreads as a fix. The prompt was a symptom of file ownership, and silencing it without fixing ownership moves the failure somewhere less obvious.
WordPress Tutorials
One line removes the built-in code editor from the dashboard. It does not stop an administrator installing a plugin that edits the same files, which is why it is a hardening step rather than a lock.
WordPress Tutorials
The filter is the supported way to rewrite mail before it is sent, and it has one blind spot: a plugin that redefines the mail function entirely never fires it. That is exactly what many delivery plugins do.
WordPress Tutorials
The front end filter takes an array and the admin one takes a string. Swapping the two is the single most common reason a class appears on one side of the site and breaks the other.
WordPress Tutorials
The hook fires on autosaves, on revisions, on bulk edits and on every post type. Left unguarded it runs several times for a single click, and code that updates the post from inside it runs forever.
WordPress Tutorials
Adding a type to this array is half the job. WordPress checks the real contents of the file separately, and a file whose innards do not match its extension is rejected even after the type is allowed.
WordPress Tutorials
This is the last filter before a template is loaded, and it is one of the few where returning nothing produces a blank white page rather than a default. Whatever the callback returns is loaded, including an empty string.
WordPress Tutorials
Appending a block of text here is four lines and a recursion bug waiting to happen. The filter runs on archives, in widgets and in the REST response, so content added without a guard ends up in places nobody was shown a preview of.
WordPress Tutorials
The hook name says scripts and it handles both. It also covers the front end only, which is why a stylesheet loaded here is missing from the block editor and from the login screen.
WordPress Tutorials
The hook fires for every query on the request, including the ones building the admin menu and the media library. A callback without guards does not customise the blog — it rewrites the whole site.
WooCommerce
The filter changes a glyph and nothing else. The store still trades in the currency configured in settings, so a symbol swapped without a matching currency change makes the store lie about what it charges.