Get blog data from a separate reusable module with a new waitForIt.

Author: arian

.jshintrc

@@ -2,6 +2,7 @@
   "node": true,
   "browser": true,
   "eqnull": true,
+  "boss": true,
   "predef": [
     "describe",
     "it"

blog/data.js

@@ -0,0 +1,58 @@
+
+var fs = require('fs');
+var path = require('path');
+var async = require('async');
+var waitForIt = require('../lib/waitForIt');
+var pkg = require('../package.json');
+
+var dir = path.join(__dirname, '../', pkg._buildOutput, 'blog/posts');
+
+function loadJSONPosts(callback){
+
+	var JSONPath = dir + '/posts.json';
+
+	try {
+		callback(null, require(JSONPath));
+	} catch (e){
+		callback(new Error(JSONPath + " doesn not exist. \n" +
+			"Did you build the blog with 'node build/blog'?"));
+	}
+
+}
+
+function loadPost(post, callback){
+	fs.readFile(dir + '/' + post.htmlFile, function(err, str){
+		if (err) return callback(err);
+		post.content = str;
+		callback(null, post);
+	});
+}
+
+function loadContent(posts, callback){
+	async.map(posts, loadPost, callback);
+}
+
+function index(posts, callback){
+
+	var total = {
+		posts: posts,
+		urls: {},
+		tags: {}
+	};
+
+	posts.forEach(function(post, i){
+		post.date = new Date(post.date);
+		total.urls[post.permalink] = i;
+		if (post.tags && Array.isArray(post.tags)) post.tags.forEach(function(tag){
+			tag = tag.toLowerCase();
+			(total.tags[tag] || (total.tags[tag] = [])).push(i);
+		});
+	});
+
+	callback(null, total);
+
+}
+
+var load = async.compose(index, loadContent, loadJSONPosts);
+
+module.exports = waitForIt(load);

blog/index.js

@@ -1,45 +1,24 @@
 "use strict";
 
-var fs = require('fs');
-var path = require('path');
-var pkg = require('../package.json');
+var data = require('./data');
 
-var dir = path.join(__dirname, '../', pkg._buildOutput, 'blog/posts');
-
-var posts;
-var JSONPath = dir + '/posts.json';
-
-try {
-	posts = require(JSONPath);
-} catch (e){
-	console.error(JSONPath + " doesn not exist. \n" +
-		"Did you build the blog with 'node build/blog'?");
-	throw e;
-}
-
-var content = posts.map(function(post){
-	return fs.readFileSync(dir + '/' + post.htmlFile);
-});
-
-var postsByURL = {};
-var tags = {};
+var perPage = 2;
 
-posts.forEach(function(post, i){
-	post.date = new Date(post.date);
-	postsByURL[post.permalink] = i;
-	if (post.tags && Array.isArray(post.tags)) post.tags.forEach(function(tag){
-		tag = tag.toLowerCase();
-		(tags[tag] || (tags[tag] = [])).push(i);
+function getData(req, res, next){
+	data.get(function(err, posts){
+		if (err) return next(err);
+		res.locals._posts = posts;
+		next();
 	});
-});
-
-var perPage = 2;
+}
 
 module.exports = function(app){
 
 	var index = function(req, res, next){
 		var page = req.params.page ? parseInt(req.params.page, 10) : 1;
 		var tag = req.params.tag;
+		var posts = res.locals._posts.posts;
+		var tags = res.locals._posts.tags;
 
 		// posts with this tag do not exist
 		if (tag && !tags[tag]) return next();
@@ -68,22 +47,24 @@ module.exports = function(app){
 
 	};
 
-	app.get('/blog', index);
-	app.get('/blog/page/:page', index);
-	app.get('/blog/category/:tag', index);
-	app.get('/blog/category/:tag/page/:page', index);
+	app.get('/blog', getData, index);
+	app.get('/blog/page/:page', getData, index);
+	app.get('/blog/category/:tag', getData, index);
+	app.get('/blog/category/:tag/page/:page', getData, index);
 
-	app.get(/\/blog\/(.+)/, function(req, res, next){
+	app.get(/\/blog\/(.+)/, getData, function(req, res, next){
 		var url = req.params[0];
+		var posts = res.locals._posts.posts;
+		var urls  = res.locals._posts.urls;
 
-		var postIndex = postsByURL[url];
+		var postIndex = urls[url];
 		var post = postIndex != null && posts[postIndex];
 		if (!post) return next();
 
 		res.render('blog/post', {
 			title: "MooTools Blog: " + post.title,
 			post: post,
-			content: content[postIndex],
+			content: post.content,
 			page: 'blog'
 		});
 

lib/waitForIt.js

@@ -0,0 +1,44 @@
+"use strict";
+
+module.exports = function(fn){
+
+	var result, isRunning = false, callbacks = [];
+
+	var done = function(err, res){
+		var cbs = callbacks.slice(), cb;
+		while (cb = cbs.shift()) cb(err, res);
+	};
+
+	return {
+
+		get: function(callback){
+
+			if (result){
+				callback(null, result);
+				return;
+			}
+
+			callbacks.push(callback);
+
+			if (isRunning){
+				return;
+			}
+
+			isRunning = true;
+
+			fn(function(err, res){
+				if (!err) result = res;
+				isRunning = false;
+				done(err, res);
+			});
+
+		},
+
+		reset: function(){
+			result = null;
+			callbacks = [];
+		}
+
+	};
+
+};