update things in node when files change

ioUtils.js

var request = require('request');
var fs = require('fs');

// file watches seem fuxed so I have some hacky workarounds in here

/**
 * @param url (string) url to get like: "http://www.google.com"
 * @param path (string) path to file like: "/tmp/test/myfile.js"
 * @param callback(err, stuff)
 */
exports.urlToFile = function(url, path, callback) {
	request(url, function(err, response, body) {
		if (!err && response.statusCode === 200) {
			fs.writeFile(path, body, callback);
		} else {
			callback(err || "status code: " + response.statusCode, url);
		}
	});
};


var watching = {};

/**
 * @param filePath
 * @param callback
 * @return fsWatcher with watch.close() method
 * the fs.watch is buggy so this sorta fixes it
 * can be called multiple times without quing up multiple watcher
 * watchers can all be removed with unwatchAll
 */
exports.watch = function(filePath, callback) {

	var watch = watching[filePath];

	if (watch) {
		exports.unwatch(filePath);
	}

	function changeHandler(err, data) {
		console.log("ioUtils REWATCH ----- " + data + " ------ " + filePath);
		fs.exists(filePath, function (exists) {
			if (exists) {
				watching[filePath].close();
				setTimeout(function() {
					fs.exists(filePath, function (exists) {
						if (exists) {
							watching[filePath] = fs.watch(filePath, changeHandler);
						}
					});
				}, 300);
			}
		});
		callback(err, data);
	}

	console.log("ioUtils.watch", filePath);

	return watching[filePath] = fs.watch(filePath, changeHandler);
};

exports.unwatch = function(filePath, cb) {

	console.log("ioUtils.unwatch", filePath);

	var watch = watching[filePath];

	if (watch) {
		watch.close();
		delete watching[filePath];
	}

	fs.unwatchFile(filePath); // this is probably unnecessary but wtf its a no-op if there is no watch
};

exports.unwatchAll = function() {
	$each(watching, function(watch, filePath) {
		exports.unwatch(filePath);
	});
};

viewsController.js

var     fs = 			require('fs'),
	io = 			require("../utils/ioUtils.js"),
	viewPath = 		process.cwd() + "/views/",
	viewExtension = 	"js",
	validExtensionRe = 	new RegExp("^.+\\."+viewExtension+"$"),
	viewsList = 		[];


// testing

// aboutPage examplesPage splashPage supportPage;
// todo traverse folder to get this list
var views = ("headInclude headerInclude indexPage footerInclude bottomInclude "+
			 "loginPage signupPage accountPage docsPage").split(" ");

var updateView = function(filePath) {
	fs.exists(filePath, function(exists) {
		if (exists) {
			delete require.cache[filePath];
			require(filePath);
		}
	});
};

var updateViews = function(viewPath, cb) {
	fs.readdir(viewPath, function(err, files) {
		console.log("fs.readdir cb", arguments);

		var newViewsList = $filter(files, function(val) {
			return val.match(validExtensionRe);
		});

		var added = $filter(newViewsList, function(val) {
			return viewsList.indexOf(val) === -1;
		});
		var deleted = $filter(viewsList, function(val) {
			return newViewsList.indexOf(val) === -1;
		});

		viewsList = newViewsList;

		console.log("updateViews callback", arguments);
		console.log("full list", newViewsList, "added", added, "deleted", deleted);

		// update the watches for all files in this folder
		// todo: support nested folders
		$parallel({
			unwatchDeleted: function(outerPush) {
				$parallel(deleted, function(filePush, fileName) {
					io.unwatch(viewPath + fileName);
					filePush(null, viewPath + fileName);
				}, outerPush);
			},
			watchAdded: function(outerPush) {
				$parallel(added, function(filePush, fileName) {
					io.watch(viewPath + fileName, function(err, data) {
						console.log("update view");
						updateView(viewPath + fileName);
					});
					updateView(viewPath + fileName);
					filePush(null, viewPath + fileName);
				}, outerPush);
			}
		}, cb);
	});
};


io.watch(viewPath, function() {
	console.log("watch dir");
	updateViews(viewPath, function() {
		console.log("updateViews callback", arguments);
	});
});

updateViews(viewPath, function() {
	console.log("updateViews callback", arguments);
});