Media Scanner is a tool that attempts to scan your site for linked assets. This tool is primarily intended as a reference for what assets are in use. It does a best guess effort to find all linked assets and provides a media browser to review them.
Media Scanner is limited in that it can not detect the original URL of a masked asset, like those using pThumb or similar to generate a scaled image. It also can not parse through subsections of dynamically generated pages, like those built with getPage.
With that in mind, it can be very helpful with identifying possible unused assets.
Install via package management. To generate the initial link stats, go to the Media Scanner manager page found under the "Media" drop down and click on the "Scan Media" button. This will take a while, depending on the size of your site. If this fails, you may need to manually run the included scanning script via CLI or cron.
If the automatic scanning fails, you can run the included scanning script manually. This is useful if you have a large site, or if you want to run the scanning script via cron.
To run the scanning script, you need to SSH into your server and run the following command:
php /path/to/your/modx/core/components/mediascanner/cron/generate.2x.php
Or for MODX 3.x Versions:
php /path/to/your/modx/core/components/mediascanner/cron/generate.3x.php
Once completed, this will output the number of resources indexed. You can then go to the Media Scanner manager page and verify it is showing the newly discovered links.
In general, the automatic scanning should work fine. It renders a page on save, and scans it for links. However, the links can change if you make adjustments to a template or chunk in your site that would affect the frontend links. If this happens, you can run the scanning script manually to update the links, or go to the manager page and click "Regenerate Links".
Due to the way automatic scanning works, it may slow down the save event on
your site depending on how your site is set up. If you want to disable automatic
scanning, you can do so by setting the mediascanner.allow_regenerate_onsave
system setting to No. It is recommended you then run the scanning script
manually via cron.
If you are just having issues with scanning a specific page, Media Scanner will
first attempt to automatically resolve it by skipping the resource. If that fails
you can manually add the Resource ID to the mediascanner.skip_skan system
setting. This is a comma-separated list of resources to skip when scanning for
new assets.
In the event you have a large site that consistently fails to generate links with the provided button. You can disable it in system settings. This will prevent the button from showing up in the manager page. It is recommended you then run the scanning script manually via cron.
To disable the button, set the system setting
mediascanner.allow_regenerate_button to No.