Twilio Functions blacklist example

gistfile1.txt

const got = require('got');
const crypto = require('crypto');

const blacklist = [
  'cnn is isis',
	'side of beef',    
];

const blacklist_replies = [
  "Message: GOTO is not allowed in a stored procedure handler",
  ...
];

exports.handler = function(context, event, callback) {
    const signature = getSignature(context.AUTH_TOKEN, context.URL, event);

    if (blacklist.some(v => { return event.Body.toLowerCase().indexOf(v) >= 0; })) {
        console.log('filtering: ' + event.Body);
        let twiml = new Twilio.twiml.MessagingResponse();
        const idx = Math.floor(Math.random() * blacklist_replies.length);
        twiml.message(blacklist_replies[idx]);

        slackUrl = 'https://hooks.slack.com/services/' + context.SLACK_SERVICE;
        slackMessage = "Filtered: " + event.Body + "\n";
        slackMessage = slackMessage + "SmsSid: " + event.SmsSid + "\n";
        slackMessage = slackMessage + "From: " + event.From;
        slackPayload = JSON.stringify({ text: slackMessage });

        got.post(slackUrl, {
            body: slackPayload
        })
        .then(response => callback(null, twiml))
        .catch(error => {
            console.err('error from slack: ' + error.response.body);
            return callback(null, twiml);
        });
    } else {
        got.post(context.URL, {
            body: event,
            headers: {
                'X-Twilio-Signature': signature
            }
        }).then(response => {
            callback(null, response.body);
        }).catch(error => callback(error, null));
    }
};

function getSignature(authToken, url, params) {
    Object.keys(params).sort().forEach((key) => {
        url = url + key + params[key];
    });

    return crypto.createHmac('sha1', authToken).update(Buffer.from(url, 'utf-8')).digest('Base64');
}