mailchimp/lib/mailchimp/MailChimpWebhook.js

A node.js wrapper for the MailChimp API.

var http = require('http'),
    util = require('util'),
    url = require('url'),
    qs = require('qs'),
    EventEmitter = require('events').EventEmitter;

/**
 * A server that listens for POST requests from MailChimp which are issued on
 * special events as specified on their Webhook page. Please refer to that page
 * on how to set everything up.
 *
 * @see http://www.mailchimp.com/api/webhooks/
 *
 * If the server receives a valid request from MailChimp the received data is
 * wrapped in a nice object and an event is emitted which you can listen for
 * in your application and then take further action.
 *
 * Available options are:
 *  - port   Port the server is going to listen on. Defaults to 8100.
 *  - secret Secret key as suggested on the Webhook page which is then simply
 *           added as a pathname to the Webhook URL in your MailChimp account
 *           and checked for here. Nothing too fancy but a small enhancement to
 *           security. Leave empty (default setting) if you don't want to use a
 *           secret key. Example: If you set the secret to 'ChimpSecret' you
 *           would enter the Webhook URL http://www.yourdomain.com/ChimpSecret
 *           in the MailChimp Webhook settings.
 *  - secure Takes credentials generated by the crypto module and enables HTTPS
 *           support for the server when present.
 *
 * @param options Configuration options
 * @return Instance of {@link MailChimpWebhook}
 */
function MailChimpWebhook (options) {

	var self = this;

	if (!options)
		options = {};

	EventEmitter.call(this);

	this.httpPort = options.port || 8100;
	this.secret = options.secret || '';
	this.secure = options.secure || false;

	this.allowedTypes = [
	                     'subscribe',
	                     'unsubscribe',
	                     'profile',
	                     'upemail',
	                     'cleaned',
                         'campaign'
	                    ];

	var server = http.createServer(function (request, response) {

		var requestBody = '';
		var requestUrl = url.parse(request.url);

		if (self.secret !== '' && requestUrl.pathname !== '/'+self.secret) {
			self.emit('error', 'Received a request with an invalid secret key.');
			response.writeHead(500, { 'Content-Type' : 'text/plain' });
			response.end();
			return;
		}

		// Say "hi" to the webhook validator, the only request not sent via POST
		if (request.headers['user-agent'] === 'MailChimp.com WebHook Validator') {
			response.writeHead(200, { 'Content-Type' : 'text/plain' });
			response.end();
			return;
		}

		if (request.method != 'POST') {
			self.emit('error', 'Received something other than a POST request.');
			response.writeHead(500, { 'Content-Type' : 'text/plain' });
			response.end();
			return;
		}

        request.on('data', function (chunk) {
        	requestBody += chunk;
        });

        request.on('end', function () {

        	var payload = qs.parse(requestBody);
    		var meta = { type : payload.type, fired_at : payload.fired_at };
    		var data = payload.data;

    		if (meta.type && ~self.allowedTypes.indexOf(meta.type)) {
    			self.emit(payload.type, data, meta);
    			response.writeHead(200, { 'Content-Type' : 'text/plain' });
    			response.end();
    		} else {
    			self.emit('error', 'Received a request with an unknown type of payload.');
    			response.writeHead(500, { 'Content-Type' : 'text/plain' });
    			response.end();
    		}

        });

	});

	if (this.secure)
		server.setSecure(this.secure);

	server.listen(this.httpPort);

}

util.inherits(MailChimpWebhook, EventEmitter);
module.exports = MailChimpWebhook;