EA WP AWS SNS - Client REST Endpoint

A WordPress plugin providing a REST API endpoint to receive messages from Amazon Web Services Simple Notification Service for other plugins to consume.

Purpose

We send emails from WordPress via AWS SES (using WP SES plugin). A sister plugin of this, EA WP AWS SES Bounce Handler uses this plugin to receive the notifications before processing them itself.

We are using AWS Transcribe to transcribe videos on AnabolicTV.com and when it completes, AWS SNS communicates to our WordPress instance that the job is finished so we can retrieve the output.

How To Use

The plugin adds a REST endpoint at <https://your-website.com>/wp-json/ea/v1/aws-sns/ which should be used when you create an AWS SNS subscription.

Once a SubscriptionConfirmation request is received, a notice will be displayed in the WordPress admin UI allowing the user to confirm or dismiss.

When a subscription has been confirmed, messages from SNS of type Notification will be parsed and fire the ea_aws_sns_notification action.

In your plugin, handle using:

add_filter( 'ea_aws_sns_notification', 'my_notification_handler', 10, 5 );

/*
 * @param array   $handled					List of plugins that have handled this notification.
 * @param string  $notification_topic_arn	$body->TopicArn
 * @param array   $headers                	HTTP headers received
 * @param object  $body                  	HTTP body received
 * @param object  $message                	$body->Message JSON decoded
 */
function my_notification_handler( $handled, $notification_topic_arn, $headers, $body, $message ) {

	$my_topic_arn = ...

	if( $my_topic_arn != $notification_topic_arn ) {
		return $handled;
	}
	
	// Handle
	
	...
	
	// Confirm the notification has been handled.
	$handled[] = array( 'my-plugin-name', __FUNCTION__ );	
	
	return $handled;
}

See: sample notification headers and body.

Notes

Unsubscribing

This plugin does not keep a record of active subscriptions.

Deactivating/uninstalling does not unsubscribe from SNS notifications, but AWS SNS Delivery Policies says:

Amazon SNS considers HTTP status codes 400 to 499 to indicate permanent delivery failure.

Notifications do contain a property "UnsubscribeURL" but which needs to be signed by an IAM account with appropriate permissions, thus this plugin cannot handle it.

Plugins using this plugin may have the appropriate IAM credentials, so could store the UnsubscribeURL and use the credentials to cleanly unsubscribe during deactivation and uninstall.

This Plugin as a Requirement

add_action( 'admin_notices', 'admin_notice_requirements' );

function admin_notice_requirements() {

	$my_plugin_name = "MY PLUGIN";

	// Don't irritate users with plugin install suggestions while they're already installing plugins.
	if( isset( $_GET['action'] ) && $_GET['action'] == 'install-plugin' ) {
		return;
	}

	if( ! is_plugin_active( 'ea-wp-aws-sns-client-rest-endpoint/ea-wp-aws-sns-client-rest-endpoint.php' ) ) {

		echo '<div class="notice notice-warning is-dismissible"><p><b><i>'. $my_plugin_name .'</i></b> requires <a href="https://github.com/EnhancedAthlete/ea-wp-aws-sns-client-rest-endpoint"><i>EA WP AWS SNS - Client REST Endpoint</i></a> installed and active to function correctly.</p></div>';
	}
}

Logging

To handle logs, write functions for ea_log_notice, ea_log_info, ea_log_debug, ea_log_error:

add_action( 'ea_log_info', 'my_info_log_handler', 10, 4 );

function my_info_log_handler( $plugin_name, $plugin_version, $message, $context = array() ) {
	error_log( $message );
}

We have an internal logging setup that boils down to this, but isn't yet worth publishing.

WordPress Plugin Directory

The WordPress Plugin Directory does not accept "framework plugins or library plugins". If submitting a plugin to the directory with this code, please be considerate and namespace the SNS code so others can use it in their plugins too without class name conflicts.

Test

Run composer install to install WP Mock and PHP Unit dependencies.

Run phpunit tests --bootstrap ./tests/bootstrap.php to test.

TODO

• Localise time from UTC ("subscription confirmation request received on...")
• Delete subscription requests over 3 days old: SNS API Reference says "Confirmation tokens are valid for three days."
• Add REST API 'description' for OPTION requests
• i18n
• Non AJAX confirm/dismiss
• An action could be add to allow plugins automatically confirm subscriptions
• Logging is haphazard so far, could do with systematic approach
• CI: GitHub release archives

Acknowledgements

Built by Brian Henry using WordPress Plugin Boilerplate and WP Mock for: