Nearly a year ago I broke down user_load() and user_save() in Drupal 5. I had to put together workflows for a number of jobs, specifically integrating the creation, instantiation and updating of users with an external system. Fast forward nearly twelve months, and we have to do it all over again for D6, for different work. So here's a PDF of user_load() and user_save() in Drupal 5 and 6.
The flowcharts have been especially useful in coding in the most Drupalish way possible. Drupal core (and well-behaved modules) is built with a hook-based architecture. That means that before and/or after important events, Drupal calls all the functions which follow a particular naming convention: any module which, in effect, implements a hook. That means your code can tag along with Drupal’s powerful core, making hook essential to developing modules efficiently.
What's changed between Drupals 5 and 6? Not much, to be honest:
- Loading now tries to grab an object, rather than checking if an ID has been returned by the database first
- Updating clears the sessions for newly-blocked users, effectively kicking them out; it also sends notification emails through
- Creating doesn't grab a new ID for the user, pre-creation, owing to D6's better database abstractions
For your convenience and mine, all six workflows are now in the same PDF. That makes it easier to compare 5 and 6 side by side, but it also makes clear some of the very minor errors I made in the original Drupal 5 diagrams. Well, best let them stand, for transparency's sake. And besides: if a man's errors are his portals of discovery, you'd be lucky to fit the chipmunk of serendipity through these.