Pathologic is an input filter which can correct paths in links and images in your Drupal content in situations which would otherwise cause them to “break;” for example, if the URL of the site changes, or the content was moved to a different server. Pathologic can also solve the problem of missing images and broken links in your site’s RSS feeds. See more example use cases on the documentation page.
Despite what that lying blue box says below, the Drupal 8 branch of Pathologic is certainly usable and almost feature-complete; the only must-have that's missing is an upgrade path for those updating from a Drupal 7 site. The documentation for how to implement this is scant and I'm not quite savvy enough with Drupal 8 to figure it out on myself yet. If you can help in this regard, please get in touch!
Pathologic is designed to be a simple, set-it-and-forget-it utility. You don't need to enter any special “tags,” path prefixes, or other non-content noise into your content to trigger Pathologic to work; it finds paths it can manage in your content automatically.
As Pathologic is an input filter, installation and configuration is a little more difficult than it is for a standard module — but it's still not that tough, if you follow the full installation and configuration guide here.
Want to know more? Here's some articles about Pathologic by others:
- Module Monday: Pathologic by Jeff Eaton of Lullabot
- How-to screencast by Shane Thomas of Code Karate
- Drupal Pathologic Module Best Solution to Get Rid of Broken Links by Deepu Balan
- Fix broken content links with the Pathologic Module by Caryl J Westerberg of Stanford University
- Avoiding Problems with the Drupal Pathologic Module by Bill Powell of About.com
Trying the new 7.x-3.x branch of Pathologic? Check out the “Upgrading from Pathologic 7.x-2.x” section of the documentation for information on what has changed.