Summary

In this chapter, we discussed many things. We saw how logging works in Drupal 8, how the mail API can be used programmatically (and extended), and how the token system can be employed to make our text more dynamic.

While going through this chapter, we also enriched our Hello World module. So, apart from understanding the theory about logging, we created our own logging channel service and logger plugin. For the latter, we decided to send out emails when log messages were of the type error. In doing this, we took a look at the mail API and how we can use it programmatically. We saw that, by default, PHP's native mail() function is used to send out emails, but we can create our own plugin very easily to use whatever external service we want--yet another great example of extensibility via plugins.

Lastly, we looked at tokens in Drupal 8. We saw what components make up the API, how we can programmatically use existing tokens (replace them with the help of contextual data), and how we can define our own tokens for others to use. These are the main tenets of extensibility (and sharing)--using something someone else has exposed to you, and exposing something for someone else to use.

In the next chapter, we will look at another great topic--theming. Even though you may think that this falls within the purview of a frontend developer, module developers play an important role. Yes, much of the styling, client-side scripting, and visual architecture can be, and is, done by what we call themers. However, module developers need to understand and use theming tools to ensure that their data is rendered in the proper way. So, in the next chapter, we will focus on that.