The WebhookClient library in Oracle Digital Assistant's Node.js SDK simplifies the setting up of sending and receiving messages in Webhook channels. If you aren't using the SDK, here's what you need to know about creating inbound messages.

The call for sending messages to your digital assistant (or skill) must have:

1. An X-Hub-Signature header containing the SHA256 value of the payload. The call includes functions that create this hash using Secret Key as the key.

   const body = Buffer.from(JSON.stringify(messageToBot), 'utf8');
       const headers = {};
       headers['Content-Type'] = 'application/json; charset=utf-8';
       headers['X-Hub-Signature'] = buildSignatureHeader(body, channelSecretKey);
   
   ...
   
   function buildSignatureHeader(buf, channelSecretKey) {
       return 'sha256=' + buildSignature(buf, channelSecretKey);
   }
   
   function buildSignature(buf, channelSecretKey) {
       const hmac = crypto.createHmac('sha256', Buffer.from(channelSecretKey, 'utf8'));
       hmac.update(buf);
       return hmac.digest('hex');
   }

   BOT_WEBHOOK_URL and BOT_WEBHOOK_SECRET are environment variables that you set on the Node server. Using these environment variables enables you to avoid hard-coding sensitive information directly in the webhook

2. A JSON object with userId, profile, and messagePayload properties:

   {
    "userId": "33c0bcBc8e-378c-4496-bc2a-b2b9647de2317",
    "profile": {
       "firstName": "Bob",
       "lastName": "Franklin",
       "age": 45
      },
    "messagePayload": {....}
   }

   Property	Description	Type	Required?
   userId	A unique identifier for the user. This ID is specific to the caller.	String	Yes
   profile	Properties that represent the user, like firstName and LastName.	JSON object	No
   messagePayload	The messagePayload can be text, postback, attachment, and location.	JSON object	Yes

   Note
   
   If your skill or digital assistant needs to detect the user language, be sure that profile.locale and profile.languageTag are set to null in the Webhook messages.

The WebhookClient library in Oracle Digital Assistant's Node.js SDK simplifies the setting up of sending and receiving messages in Webhook channels. If you aren't using the SDK, here's what you need to know about creating outbound messages.

You need to publish the calls in the JSON format that Digital Assistant expects, along with the authorization header.