Chapter 3: Logging and Mailing

In the previous chapter, we learned about some of the more common things most Drupal module developers will have to know, starting with the basics, that is, creating a Drupal module.

In this chapter, we will take things further and cover some other important tasks a developer will have to perform:

• We will take a look at how logging works in Drupal 9. In doing so, we will cover some examples by expanding on our Hello World module.
• We will look at the Mail API in Drupal, namely, how we can send emails with the default setup (PHP mail). However, more than that, I will show you how to create your own email system to integrate with your (perhaps external) mail service; remember plugins? This will be yet another good example of using a plugin to extend existing capabilities.
• At the end of the chapter, we will also look at the Drupal token system. We'll do so in the context of us replacing certain tokens with contextual data so that the emails we send out are a bit more dynamic.

By the end of this chapter, you should be able to add logging to your Drupal module and feel comfortable sending emails programmatically. Additionally, you'll understand how tokens work, and as a bonus, see how you can define your own tokens.