Lesson 8: Changing how Elgg does X

This lesson covers using a plugin hook. It also explains how to add administrative settings.

Problem

Groups can have blogs, but only the person who writes the blog post can edit it. You prefer that group blogs work like the pages tool that allow for collaborative editing. Or maybe you would like to create customized notification messages that are sent to your users through e-mail. You also might want to include custom information when people search your site. The common theme here is that Elgg is doing one thing and you would like it to do it differently.

Solution

Use plugin hooks, which are very similar to events. When something occurs, a plugin hook is triggered and the functions that are registered for that plugin hook are called. The primary difference between events and plugin hooks is that plugin hook functions can return a changed result to the core. Take the 'validate, input' plugin hook as an illustrative example. When a user submits a new blog post...