Drupal time based triggers

I'm building an event signup system and integrating it with Ubercart. Each event is a product and has a price and a start time. I wish to be able to trigger an action one week before the event starts. The action is supposed to send an email to the users that bought the event and perform a capture on the registrant's cre开发者_运维问答dit card. But where do I define the action and how do I trigger it one week before event start?

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I assume you're talking about Drupal 6, since you're mentioning ubercart. Does the action to send the email you're takling about already exist?

If it does, you can assign it under Site Building | Triggers | Cron. If it doesn't show up in the list of actions, you might need the Triggerunlock module.

If the action doesn't exist, you're going to have to write the PHP code to send the emails and do the calculations. You will need to create your own module and either use hook_cron, or create a custom action.