postmailer/hub.js

HTTP POST -> SMTP proxy, as Express middleware

var EventPlus = require('eventplus');
var UriTemplate = require('uri-templates');

function nameFromUrl(url) {
	return (url + "").replace(/.*?\:\/\//, '');
}

function Transform(obj, options) {
	var receiveTemplates = [].concat(obj.receive || obj.url || []).map(function (spec) {
		if (typeof spec === 'string') return UriTemplate(spec);
		return spec;
	});
	var sendTemplates = [].concat(obj.send || obj.url || []).map(function (spec) {
		if (typeof spec === 'string') return UriTemplate(spec);
		return spec;
	});
	var canonicalTemplates = [].concat(obj.canonical || obj.url || obj.receive || []).map(function (spec) {
		if (typeof spec === 'string') return UriTemplate(spec);
		return spec;
	});
	var allTemplates = receiveTemplates.concat(sendTemplates).concat(canonicalTemplates);
	var name = obj.name;
	var defaultParams = options.defaultParams || {};

	function firstMatch(matchTemplates, replacementTemplates, urls) {
		urls = [].concat(urls);
		for (var i = 0; i < matchTemplates.length; i++) {
			for (var j = 0; j < urls.length; j++) {
				// TODO: normalise to mailto: addresses
				var url = urls[j];
				var params = matchTemplates[i].fromUri(url);
				if (params) {
					var urls = [];
					replacementTemplates.forEach(function (template) {
						var url = template.fill(params);
						if (options.strict) {
							// Check round-trip consistency of params
							var roundTripParams = template.fromUri(url);
							for (var key in roundTripParams) {
								if (roundTripParams[key] != (params[key] || defaultParams[key])) {
									return;
								}
							}
							for (var key in params) {
								if (params[key] != (roundTripParams[key] || defaultParams[key])) {
									return;
								}
							}
						}
						urls.push(url);
					});
					var match = {
						matchedUrl: url,
						urls: urls,
						params: params
					};
					if (typeof name === 'function') {
						match.name = name(params, match);
					} else {
						match.name = name || nameFromUrl(match.urls[0]);
					}
					return match;
				}
			}
		}
		return null;
	}

	this.match = function (urls) {
		return firstMatch(receiveTemplates, sendTemplates, urls);
	};
	this.canonical = function (url) {
		var match = firstMatch(allTemplates, canonicalTemplates, url);
		return match ? match.urls : [];
	}
}
Transform.prototype = {};

function Hub(options) {
	if (!(this instanceof Hub)) return new Hub(options);
	EventPlus.call(this);

	var transforms = [].concat(options.mapping || []).map(function (transformSpec) {
		return new Transform(transformSpec, options);
	});
	this.match = function (urls) {
		for (var i = 0; i < transforms.length; i++) {
			var match = transforms[i].match(urls);
			if (match) return match;
		}
		return null;
	};
	this.canonical = function (url) {
		var result = [];
		for (var i = 0; i < transforms.length; i++) {
			result = result.concat(transforms[i].canonical(urls));
		}
		// Last option is original URL
		result.push(url);
		return result;
	};

	// Mail and chat events must be handled
	this.on('mail', function (mail) {
		var error = new Error('Unhandled mail message for ' + mail.target.name);
		error.mail = mail;
		error.urls = mail.target.urls;
		this.emit('error', error);
	});
	this.on('chat', function (chat) {
		var error = new Error('Unhandled chat message for ' + chat.target.name);
		error.chat = chat;
		error.urls = chat.target.urls;
		this.emit('error', error);
	});
}
Hub.prototype = Object.create(EventPlus.prototype);

module.exports = Hub;