Matomo HooksViewer Plugin

Never install this plugin on a production instance. It is a development tool: it exposes internal hook arguments and writes a log file on every request.

HooksViewer subscribes to every event Matomo dispatches and shows you, for each request, which hooks fire, in what order, and with what arguments. It is the fastest way to find the right event to listen to when you build a Matomo plugin.

Three tools work side by side:

1. Inline panel in the Matomo UI, for super users. Every HTML response gets a collapsible HooksViewer panel listing the hooks fired while it was built: at the top of full pages, and inside each widget or AJAX HTML fragment. Search the list by hook name, or inside the arguments, and open a hook to see a pretty-printed, multi-line dump of its arguments.
2. Hook catalog under Administration → Diagnostic → Hooks Viewer. Every known hook with its description and parameters (taken from the docblock in the source code), the file and line where it is posted, the plugins listening to it, and a ready-to-paste registerEvents() snippet. Search it, filter it by category, or show only the hooks that have listeners.
3. Log file at tmp/logs/hooksviewer.log. Every hook from every request, including API calls, tracker hits and console commands, is appended with a timestamp, a request id and the arguments. Watch it with tail -f tmp/logs/hooksviewer.log.

The panel is written once the response is complete, and only when that response really is HTML. JSON controllers, API calls, graph data, exports, images and tracker hits stay byte-exact, and pages keep their doctype, so the dashboard, widgets and third-party clients keep working while you explore.

The list of subscribed events is discovered automatically by scanning core/ and plugins/ for Piwik::postEvent('…') call sites the first time the plugin runs, and whenever the source tree changes. The result is cached in tmp/cache/hooksviewer-catalog.php.

You do not have to update the plugin when Matomo or a third-party plugin introduces new events: they show up the next time the cache is rebuilt.

1. Open the Marketplace in your Matomo admin (as a super user).
2. Search for HooksViewer.
3. Install, then activate.

1. Activate the plugin while you are exploring or debugging.
2. Browse the page or trigger the workflow you care about.
3. Expand the HooksViewer panel and search it, or tail -f the log.
4. Click Open in the hook catalog on any hook to read its documentation and see who listens to it.
5. Deactivate the plugin when you are done.

• Matomo 6.x
• PHP 8.1 or newer
• MySQL 8.0+ or MariaDB 10.6+

For Matomo 5, use HooksViewer 2.x.

Built by Openmost. Issues and pull requests welcome at https://github.com/openmost/HooksViewer.

GPL v3 or later.