Validate webhook notifications

When you create an integration, you provide outboundNotificationWebhookSignatureSecretToken.

To validate outbound open messages use the outboundNotificationWebhookSignatureSecretToken from the X-Hub-Signature-256 header. This header automatically accompanies all webhook requests sent to outboundNotificationWebhookUrl.

const crypto = require('crypto');

// integration - the integration object
// normalizedMessage - the NormalizedMessage payload
// request - webhook request object

const normalizedMessage = request.data;
const signature = request.headers['X-Hub-Signature-256'];
const secretToken = integration.outboundNotificationWebhookSignatureSecretToken;
const messageHash = crypto.createHmac('sha256', secretToken)
    .update(JSON.stringify(normalizedMessage))
    .digest('base64');

if (`sha256=${messageHash}` !== signature) {
    throw new Error("Webhook Validation Failed! Throw this away.");
} else {
    processMessages(normalizedMessage);
}

The Genesys Cloud Messaging platform retries a webhook request up to 5 times if the request times out (10 seconds) or responds with a retryable HTTP status code (429, 5xx).

A full retry sequence with timeouts would take 85 seconds and looks like this:

1. Initial request (10-second timeout)
2. 5-second delay
3. 1st retry (10-second timeout)
4. 5-second delay
5. 2nd retry (10-second timeout)
6. 5-second delay
7. 3rd retry (10-second timeout)
8. 5-second delay
9. 4th retry (10-second timeout)
10. 5-second delay
11. 5th retry (10-second timeout)