Project Problem:

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The notification service can be described as a messenger service responsible for handling email and SMS transactions. It enables an organisation's members (Staff and Customers) to get notified of events occurring on their accounts.

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Proposed Solution

My proposed solution is that notification topics are defined and potential recipients ( MFI members (Staff or Customers) ) are subscribed to the topic when their account is created. Hence, in the occurrence of an event which matches the topic, a topic mapper will provide all staff members who need to be notified of the event. NB: Topic definition and topic mappings are persisted into the database.

So, when an actual event occurs, the system knows the subscribers to notify and now the notification has to be generated. An event listener will listen for Spring Event Emitters generated. Then the notification service will start by creating a  notification object for the event, the notification then converted into an Email or SMS. To personalise the message, a subscriber prefines their language and communication preference during account creation. This is used to localize and separate notifications into SMS and Emails.

The localised messages are now formatted using a template associated to a topic.

The prepared messages will be passed to the Email services such as google’s SMTP server or Twilio SMS to be transmitted. I propose that the system allows multiple configurations to accommodate cases where the application supports multiple organisations who use different services.

Data (Notification, Notification mapping, Templates, Topics, Topics mappings, Subscribers) generated will be persisted into the Microservice’s database.

Subsystems Breakdown

EventListener

An event listener will listen for Spring EventEmitters generated. For instance for a new client creation the NotificationEventListener will capture the event emittered and generate the notification content

• NotificationEventListener

• Has a JmsListener to listen to emitted event

• Initiates the NotificationEventService

• NotificationService

• Has an SMSService Object

• Has an EmailService Object

• Creates a NotificationMapper

• Creates a recipient and their notification

• Gets recipients details

• Localize the message using subscriber preference

• Sends the email or SMS

Domain

This package will define the class for the entities in the problem domain.

• Notification

• States the Recipient

• states the action

• states the content

• NotificationMapper

• Takes topic mapping and map notifications to subscribers

• NotificationMapperRepository

• Accumulate NotificationMappings

Configuration

This will be used to configure the behaviour of the system.

• NotificationConfiguration

• Has SMSConfiguration

• Has EmailConfiguration

• SMSConfiguration

• Define sender’s Number

• Defines and sets sms service authentication credentials

• EmailConfiguration

• Defines and sets mail service host

• Defines and sets mail service ports

• Defines and sets authentication credentials

SMSService

Use the Twilio SMS service and google SMTP Server

• SMSDomainService

• AuthenticateClient

• AuthenticationClientRecordsRepository

EmailService

• EmailDomainService

• AuthenticateClient

• AuthenticationClientRecordsRepository

This component will use the template component to form the message format. The template will abstract the various message formats. I believe using Apache Velocity to prepare default themes and allow the user to generate custom templates woube be a good consideration. Also, given that Fineract CN and Velocity [ http://velocity.apache.org/  ] share the same license it will be easier to use them

Template

• SMS templates

• Email Templates

API & DAO

The DAO  will be used to access resources in the Database and also persist data from the notification Microservice into its down database

• TopicDAO

• Get and set predefined topics

• SubscriberDAO

• Get and persist subscriber communication preference

• Get and persist language preference

• NotificationDAO

• Get and persist content

• Get and persist notification id

• Get and persist action

• Get and persist action ID

• Get and persist office id

• Get and persist topic mappings

• TopicMapperDAO

• Get and persist topic id

• Get and persist topic mappings

Navigation:

Description

The notification service can be described as a messenger service responsible for handling email, push notifications and SMS transactions. It enables members (Staff and Customers) of a tenant to get notified of events occurring on their accounts.

It uses JMS Listeners to subscribe to event topics registered the system's message broker (ActiveMQ).

Once the message has been received, it determines the template, the gateway and the builds the content of the message.

Please consider contributing! 

1. Repository
2. Drive Containing Relevant documents

Service Roadmap/Feature

1. Implement basic SMS and Email integration
   1. Interface with Twilio
   2. Gmail integration
2. Incorporate notification microservice into demo-server to enable testing.
3. Basic Message Templating
4. Rest API
   1. Documentation

5. Add support for FINCN Mobile

   1. Implement FCM push notification with a multi-tenanted approach
      1. Resources: Official FCM Documentation, FCM implementation in Java, 
6. Replicate SMS/Email/Push Notifications functionalities for Portfolio/Office/Group/Employee Event Listener
7. OTP through Push Notifications, SMS and Email
8. Message Localisation
9. Disable SMS and Email for specific users by using a custom field in customer
10. Tenant Reputation Management
    1. Notification subscription and unsubscribe feature via SMS and email
11. Message Templating
    1. Bulk SMS/Email/Push Notification
       1. Customized Bulk SMS
       2. Generic SMS
    2. Customized Messaging
       1. Templating
12. Assess the feasibility of third-party integration with other messaging services
    1. Amazon SES Multitenant Solution
13. Final test plan

Objectives for ongoing Iteration

Objectives for 3rd Iteration

Other Resource

Building a notification service in a multi-tenanted service-oriented architecture can be very complex. Here are a few resources to help assess some of the complexities involved.

1. Building scalable multitenant email sending programs

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