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Cloud Native Notifications Library

Airhorn is built to enable a more robust notification system. We focused on making it cloud native by default (using cloud services).

Table of Contents

• Features
• Library API and Examples
• Supported Cloud Service Providers
• How to Contribute
• Licensing

Features

• GitOps Based Templating System - email, SMS, mobile push, and webhooks all in one place!
• Email Notifications - easily send email across multiple providers and even load balance or active/passive fail over.
• SMS Notifications - SMS that is easy to use via a robust template system.
• Mobile Push Notifications - Push to IOS and Android devices.
• Webhook Notifications - Built right into the system as a native feature with retry support.
• 100% Code Coverage / Tested with Integration Tests
• Built using ecto for handling multiple templates
• This package is native ESM and no longer provides a CommonJS export. If your project uses CommonJS, you'll have to convert to ESM or use the dynamic import() function. Please don't open issues for questions regarding CommonJS / ESM. To learn more about using ESM please read this from sindresorhus: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99

Library API

send()

The send() function, located in airhorn.ts, is used to send notifications. It accepts the following parameters:

• to (string): The address to send the message to. Based on the message provider, this address can be either a phone number, an email address, or a web address.
• from (string): The address of the sender of the message.
• templateName (string): The name of the template to use for the message.
• providerType (ProviderType): The type of message to be sent. ProviderType is an enum with the values SMTP, SMS, WEBHOOK, and MOBILE_PUSH.
• data (any): The information to pass to the message. This parameter is typically a data object or a string. The data can include the raw message to be sent, or it can be used to populate a message template.
• languageCode (string): The language code of the message template to be sent.

sendSMTP()

The sendSMTP() function, located in airhorn.ts, is used to send SMTP notifications. It accepts the following parameters:

• to (string): The address to send the message to. Based on the message provider, this address can be either a phone number, an email address, or a web address.
• from (string): The address of the sender of the message.
• templateName (string): The name of the template to use for the message.
• data (any): The information to pass to the message. This parameter is typically a data object or a string. The data can include the raw message to be sent, or it can be used to populate a message template.
• languageCode (string): The language code of the message template to be sent.

sendSMS()

The sendSMS() function, located in airhorn.ts, is used to send SMS notifications. It accepts the following parameters:

• to (string): The address to send the message to. Based on the message provider, this address can be either a phone number, an email address, or a web address.
• from (string): The address of the sender of the message.
• templateName (string): The name of the template to use for the message.
• data (any): The information to pass to the message. This parameter is typically a data object or a string. The data can include the raw message to be sent, or it can be used to populate a message template.
• languageCode (string): The language code of the message template to be sent.

sendWebhook()

The sendWebhook() function, located in airhorn.ts, is used to send Webhook notifications. It accepts the following parameters:

• to (string): The address to send the message to. Based on the message provider, this address can be either a phone number, an email address, or a web address.
• from (string): The address of the sender of the message.
• templateName (string): The name of the template to use for the message.
• data (any): The information to pass to the message. This parameter is typically a data object or a string. The data can include the raw message to be sent, or it can be used to populate a message template.
• languageCode (string): The language code of the message template to be sent.

sendMobilePush()

The sendMobilePush() function, located in airhorn.ts, is used to send Mobile Push notifications. It accepts the following parameters:

• to (string): The address to send the message to. Based on the message provider, this address can be either a phone number, an email address, or a web address.
• from (string): The address of the sender of the message.
• templateName (string): The name of the template to use for the message.
• data (any): The information to pass to the message. This parameter is typically a data object or a string. The data can include the raw message to be sent, or it can be used to populate a message template.
• languageCode (string): The language code of the message template to be sent.

config

The Config class, enables you to configure the settings of Airhorn. It accepts the following parameters:

• TEMPLATE_PATH (string): The path where the notification system checks for templates. By default, this is set to './templates'
• DEFAULT_TEMPLATE_LANGUAGE (string): The default language code the notification system uses for localization, if a language code is not provided. By default, this is set to 'en' for English localization.
• ENVIRONMENT (string): The environment that the notification system uses to deploy messages. By default, this is set to 'development'
• TWILIO_SMS_ACCOUNT_SID (string): The ID of your Twilio SMS account. By default, this value is a null string.
• TWILIO_SMS_AUTH_TOKEN (string): The authentication token for your Twilio SMS account. By default, this value is a null string.
• TWILIO_SENDGRID_API_KEY (string): The API key for your Twilio SendGrid account. By default, this value is a null string.
• AWS_SES_REGION (string): For AWS, the endpoint region where an email is sent. By default, this value is a null string.
• AWS_SMS_REGION (string): For AWS, The endpoint region where an SMS is sent. By default, this value is a null string.
• AWS_SNS_REGION (string): For AWS, the endpoint region where a push notification is sent. By default, this value is a null string.
• FIREBASE_CERT (string): The certificate for sending push notifications through Google Firebase. By default, this value is a null string.

These settings can be overridden by passing them in when you create a new instance of Airnorn:

const airhorn = new Airhorn({
    TEMPLATE_PATH: './templates',
    DEFAULT_TEMPLATE_LANGUAGE: 'en',
    ENVIRONMENT: 'development',
    TWILIO_SMS_ACCOUNT_SID: '',
    TWILIO_SMS_AUTH_TOKEN: '',
    TWILIO_SENDGRID_API_KEY: '',
    AWS_SES_REGION: '',
    AWS_SMS_REGION: '',
    AWS_SNS_REGION: '',
    FIREBASE_CERT: ''
    });
});

You can also pass these settings via your process.env at the start of your application.

Templates

This library supports the use of templates to easily send formatted messages to different providers. Sample templates can be found in test/templates within the subdirectories cool-multi-lingual, generic-template-foo, and multiple-types-bar.

By default, Config will look for templates at ./templates. However, this path can be manually adjusted if needed.

Language Localization

With templates, users can easily send messages in different languages. A sample architecture for language localized templates can be found in the cool-multi-lingual directory within test/templates. This directory contains folders for English and Spanish language codes, 'en' and 'es' respectively. Each of these directories contains SMS, SMTP, and Webhook templates in the appropriate language. To send notifications in a specific language, users can simply provide the appropriate languageCode parameter to the send() function.

Template Overrides

When looking at the sample templates, we can see that some of them support word substitution. For example, the generic SMTP template looks like this:

---
subject: Generic Hello
---
<p>Hello {{ firstName }} {{ lastName }}</p>
<p>Your email is {{ email }} and this is a generic template</p>

To substitute the appropriate text for firstName, lastName, and email, users can provide the appropriate data to the send() function. This data is then passed to the template and rendered automatically.

Examples for using this library

This library can be used to easily send a variety of notifications. In this section, we'll cover how to implement some simple use cases.

Sending a simple email

Using the send function, we can email '[email protected]' from '[email protected]' using the generic template 'generic-template-foo'. We'll also use the provider type ProviderType.SMTP to indicate that we're sending an email:

import { Airhorn, ProviderType } from 'airhorn';
const airhorn = new Airhorn();
await airhorn.send('[email protected]', '[email protected]', 'generic-template-foo', ProviderType.SMTP);

Sending a simple webhook

Here, we'll send a simple webhook to the URL 'https://httpbin.org/post':

const airhorn = new Airhorn();
airhorn.send('https://httpbin.org/post', 'foo', 'bar', ProviderType.WEBHOOK);

Using multiple providers

In this example, we'll send a message using multiple email providers:

1. Add in the AWS SES configuration
2. Add in the Sendgrid configuration
3. Send the message and it will randomly balance between the two providers.

const airhorn = new Airhorn({
        AWS_SES_REGION = 'us-east-1',
        TWILIO_SENDGRID_API_KEY = 'SENDGRID_API_KEY'
	});

await airhorn.send('[email protected]', '[email protected]', 'generic-template-foo', ProviderType.SMTP);

Supported Cloud Service Providers

This library supports sending notifications via email, SMS, and Mobile Push for the following providers:

• Email: AWS SES and Twilio Sendgrid
• SMS: AWS SMS and Twilio
• Mobile Push: AWS SNS and Google Firebase

In this section, we'll describe how to use each of these notification services.

Email providers

This library supports sending emails via AWS SES and Twilio Sendgrid.

AWS SES

After configuring your system to use AWS SES, you can easily use airhorn to send emails. In this example, we'll email '[email protected]' from '[email protected]' using the email template 'generic-template-foo'. We'll list the provider type as ProviderType.SMTP to indicate that we're sending an email:

const airhorn = new Airhorn({
        AWS_SES_REGION = 'us-east-1',
	});
await airhorn.send('[email protected]', '[email protected]', 'generic-template-foo', ProviderType.SMTP);

Twilio Sendgrid

To send emails via Twilio Sendgrid, first update the TWILIO_SENDGRID_API_KEY value in config.ts. Then, we can use the same syntax as above to send an email through Twilio Sendgrid:

const airhorn = new Airhorn({
        TWILIO_SENDGRID_API_KEY = 'SENDGRID_API_KEY'
	});
await airhorn.send('[email protected]', '[email protected]', 'generic-template-foo', ProviderType.SMTP);

SMS providers

This library supports sending SMS using AWS SMS and Twilio.

AWS SMS

Once your system is configured to use AWS SMS, you can send SMS notifications through AWS SMS. In this example, we'll send the notification to the phone number '5555555555' from the number '5552223333' with the raw text data 'Test message text'. Then, we'll list the provider type as ProviderType.SMS.

const airhorn = new Airhorn({
        AWS_SMS_REGION = 'us-east-1',
    });
await airhorn.send('5555555555', '5552223333', 'Test message text', ProviderType.SMS);

Twilio SMS

To send SMS notifications via Twilio SMS, first update the TWILIO_SMS_ACCOUNT_SID and the TWILIO_SMS_AUTH_TOKEN values via the options as shown below. Then, we can send an SMS notification using the same syntax as above:

const airhorn = new Airhorn({
        TWILIO_SMS_ACCOUNT_SID = 'TWILIO_SMS_ACCOUNT_SID',
        TWILIO_SMS_AUTH_TOKEN = 'TWILIO_SMS_AUTH_TOKEN'
    });
await airhorn.send('5555555555', '5552223333', 'Test message text', ProviderType.SMS);

Mobile push providers

This library supports sending Mobile Push notifications using AWS SNS and Google Firebase.

AWS SNS

To use AWS SNS you will need to create a new SNS application in the AWS console and integrate the AWS SNS SDK into your application.

1. Obtain the credentials and device token for the mobile platforms that you want to support.
2. Use the credentials to create a platform application object (PlatformApplicationArn) using Amazon SNS. For more information, see Creating a platform endpoint.
3. Use the returned credentials to request a device token for your mobile app and device from the mobile platforms. The token you receive represents your mobile app and device.
4. Use the device token and the PlatformApplicationArn to create a platform endpoint object (EndpointArn) using Amazon SNS. For more information, see Creating a platform endpoint.

Then, you can send the push message to the device endpoint using airhorn:

const airhorn = new Airhorn({
        AWS_SNS_REGION = 'us-east-1',
    });
await airhorn.send('endpointArn', '', 'generic-template-foo', ProviderType.MOBILE_PUSH);

Firebase for Mobile Push

To use Firebase in your application, you will need to create a new project in the Firebase console and integrate the Firebase SDK according to the Firebase documentation.

In your Firebase Project Settings, go to the Service accounts tab to generate your private key as a json file and put the content of the file as FIREBASE_CERT environment variable.

Then, you can send the push message to the device endpoint using airhorn:

const airhorn = new Airhorn({
        FIREBASE_CERT = 'FIREBASE_CERT'
    });
await airhorn.send('endpointArn', '', 'generic-template-foo', ProviderType.MOBILE_PUSH);

How to Contribute

Now that you've set up your workspace, you're ready to contribute changes to the airhorn repository you can refer to the CONTRIBUTING guide. If you have any questions please feel free to ask by creating an issue and label it question.

Licensing

This project is licensed under MIT and copyright by Jared Wray 2021-future.