Custom Template'd Email in AEM

AEM provides OOTB email templates to send emails for workflow notification, completion, etc.
But those templates are plain text and cannot provide rich UI and limited to few dynamic properties.
Example - OOTB workflow notification email template contains plain text and other variables like an event, workitem, user, host properties, etc.

More info about Email Templates for Workflow Notification at https://helpx.adobe.com/experience-manager/6-3/sites/administering/using/notification.html#ConfiguringtheWorkflowEmailNotificationService

Custom Email
Custom Email Service/Servlet/Process Step:

You can create a utility/Servlet/workflow Process, whichever trigger the email and use com.day.cq.mailer.MessageGatewayService to send template based email.

Add Below dependencies in POM. or check dependencies using dependency finder at http://localhost:4504/system/console/depfinder

Pom dependencies
Create a utility class, In this class inject MessageGatewayService service using Reference annotation and Create a map with all the dynamic properties.

e.g.
@Reference
private MessageGatewayService messageGatewayService;

final Map<String, String> parameters = new HashMap<String, String>();
parameters.put("title", "Demo Email");

Create org.apache.commons.mail.HtmlEmail class object with template and map parameters.

HtmlEmail email = mailTemplate.getEmail(StrLookup.mapLookup(parameters), HtmlEmail.class);

Find the below Servlet Example for complete code -
https://github.com/arunpatidar02/aem63app-repo/blob/master/java/email/HTMLEmailServlet.java

Custom Email template.txt 

You can create a custom HTML5 template like an HTML page and save it as .txt in CRX repository wherever you want.
All the variable values can be replaced with properties set in the code e.g. ${title}

Example template available at
https://github.com/arunpatidar02/aem63app-repo/blob/master/java/email/html5-template.txt

OSGi Config to Send an email: 

For AEM to be able to send emails, the Day CQ Mail Service needs to be properly configured. Please check at
https://helpx.adobe.com/experience-manager/6-3/sites/administering/using/notification.html#configmail

Sample configuration for sending email using Gmail SMTP server

That’s it. Find the sample email trigger by https://github.com/arunpatidar02/aem63app-repo/blob/master/java/email/HTMLEmailServlet.java servlet.

Find the complete code used in this blog at Github.