This blog is part of our Rails 5.2 series.
Rails has inbuilt feature to preview the emails using Action Mailer previews.
A preview mailer can be setup as shown here.
1class NotificationMailer < ApplicationMailer 2def notify(email: email, body: body) 3user = User.find_by(email: email) 4mail(to: user.email, body: body) 5end 6end 7 8class NotificationMailerPreview < ActionMailer::Preview 9def notify 10NotificationMailer.notify(email: User.first.email, body: "Hi there!") 11end 12end
This will work as expected. But our email template is displayed differently based on user's role. To test this, we need to update the notify method and then check the updated preview.
What if we could just pass the email in the preview URL.
In Rails 5.2, we can pass the params directly in the URL and params will be available to the preview mailers.
Our code can be changed as follows to use the params.
1class NotificationMailerPreview < ActionMailer::Preview 2def notify 3email = params[:email] || User.first.email 4NotificationMailer.notify(email: email, body: "Hi there!") 5end 6end
This allows us to test our mailers with dynamic input as per requirements.