node-procedural-async

Write procedural style code that runs asynchronously. It may look synchronous, but it's not!

Basic Example

var Bernhard = require('procedural-async');
var models = require('./models');

Bernhard.async(function(){
	try {
		// Not needed now, don't block.
		var current_user = models.User.retrieveByName(req.session.username);
		var genre = models.Genre.retrieveByName(req.query.genre);
		// Will wait on results.
		var book_results = models.Book.search({genre: genre.id});
		var favorite_book_ids = current_user.retrieveFavoriteBookIds();
		var response_data = book_results.map(function(book){
			return {
				id: book.id,
				title: book.title,
				author: book.retrieveAuthor().name,
				is_favorite: favorite_book_ids.indexOf(book.id) > -1
			};
		});
	} catch (e) {
		return next(e);
	}
	
	res.json(response_data);
});

Full Example Code

Example Using caolan's (excellent) async

Features

Fully asynchronous, with the option to be synchronous
Execute asynchronous calls immediately, but wait for the results only at the time you need them
Allows for try/catch error handling
instances are subclasses of any class you like
Easy to read and write

How it Works

Under the hood, node-procedural-async uses a combination of Proxies and node-fibers. When you call Bernhard.generate, a proxy class is dynamically generated, instanciated and returned. All calls to the proxy will yield until whatever asynchronous task you started has completed. The asynchronous/synchronous magic comes from fibers, so you must write your procedural-async code inside a function that you pass to Bernhard.async.

Installation

The current version requires node.js v0.11.4 and an experimental untagged version of node-fibers.

Install nvm: curl https://raw.github.com/creationix/nvm/master/install.sh | sh
Install node: nvm install 0.11.4
Install dependencies: npm install procedural-async
Run tests: npm test
Run with harmony: node --harmony your_file.js

Usage

Setting Up Your Asynchronous Code

Bernhard.generate(Class)

Returns an instance that derives from Class. You should return this instance from your asynchronous function immediately.

instance.callback([err, [result]])

Call this on the instance you got from Bernhard.generate when your asynchronous function has completed.

Using Your Asynchronous Code

Bernhard.async(function)

Put all your procedural-async code inside a function that you pass to this method. Inside this function, you can try/catch any errors.

Authors

This library was developed by Ben Kovacevich, David Fenster, and Carlos Gomez at Shutterstock

Acknowledgments

This library would not be possible without Marcel Laverdet's outstanding fibers library.

shutterstock / node-procedural-async Goto Github PK