Chapter 14
Task I: Sending Emails and Processing Payments Efficiently

At this point, we have a website that responds to requests and provides feeds that allow sales of individual titles to be checked periodically. The customer is happier but still not satisfied. The first bit of feedback is that users aren’t getting confirmation emails of their purchases. The second is around payment processing. The customer has arranged for us to integrate with a payment processor that can handle all forms of payment we want to support, but the processor’s API is very slow. The customer wants to know if that will slow down the site.

Sending email is a common need for any web application, and Rails has you covered via Action Mailer,^[70] which you’ll learn in this chapter. Dealing with the slow payment-processing API requires learning about the library Action Mailer is built on, Active Job.^[71] Active Job allows you to run code in a background process so that the user doesn’t have to wait for it to complete. Sending email is slow, which is why Action Mailer uses Active Job to offload the work. This is a common technique you’ll use often when developing web applications. Let’s take it one step at a time and learn how to send email.