Introduction

After importing a large amount of resources, or any action generating a large amount of emails, we would like the emails to be grouped by operator and template into one single email resuming the action performed.

When the number of emails ina digest is below or equal 10, all the emails are rendered within the email digest.

When the number of emails under a digest is above 10 emails, only a summary email is sent.

This document describes the approach taken.

How to add a digest template

Typically, the digest templates are added in the plugins, e.g. in EmailDigestPlugin for the default email digests, using the DigestTemplateRegistry:

DigestTemplateRegistry::getInstance()
    ->addTemplate(new ResourceChangesDigestTemplate(5))
    ->addTemplate(new ResourceShareDigestTemplate(1))
    ...

The priority of the digest template may be passed in the constructor. Default is 10, the highest priority is 1.

Technical specifications

This section describes the various components involved in the sending of email digest.

DigestTemplateRegistry

This class gathers all the digest templates. Typically, it is used in the EmailDigestPlugin::bootstrap(); to register which digest templates are available. Note that templates are added in when performing an action at the command line only.

AbstractDigestTemplate

A digest template defines the email templates that will be covered by a digest, the priority of a digest, the template used by this digest when the number of emails is above 10.

Default priority is 10, and a number below enhances the priority. So priority 1 is higher than priority 2.

You may follow the abstract methods of this abstract template to build a new digest template.

DigestsCollection

When sending or previewing a batch of emails (per default 100, see PASSBOLT_PLUGINS_EMAIL_DIGEST_BATCH_SIZE_LIMIT), the emails are attributed to a digest, if they are candidates to a digest, or will be rendered as single emails. The DigestsCollection iterates through all the emails to be sent and creates digests resp. assigns to these digests the emails candidate.

Digest

A digest contains the emails for:

• a single operator
• a single recipient
• a single digest template

The marshalEmails method renders the emails within the digest, returning an EmailDigest.

EmailDigest

This class is the conversion of a Digest into an object that can be sent as an email. It is the email realization of a digest, with all the information needed to create an email to be sent.

Summary

The developer registers AbstractDigestTemplates. When emails are sent, these are grouped in Digests of the same recipient and operator by the DigestsCollection, or left as single emails if they do not find a matching digest template.

When sending the emails, each Digest is previewed resp. sent thanks to the EmailDigest class.