parallel middlewares

parallel.coffee

async = require 'async'

# The `parallel` middleware allows to run several middlewares in parallel.
# It does this by simply using AsyncJS' `applyEach` on the middlewares.
# 
# The middlewares will receive 3 parameters: `request`, `response` and
# `next`, in the same way and order they usually get them. As the
# execution is in parallel, if one of the middlewares will have an error
# the second one will continue to execute. If an error is passed to the
# `next` callback it will be passed correctly forward.
# 
# Example usage:
# 
#   @get '/connect/facebook/callback',
#     controllers.players.authentication.facebook,
#     middlewares.parallel(
#       controllers.players.authentication.update_gender_statistics,
#       middlewares.background_jobs.queue
#     )
# 
# See AsyncJS docs for more info: https://github.com/caolan/async#applyEach
# 
module.exports = parallel = (middlewares...) ->
	return (req, res, next) ->
		async.applyEach middlewares, req, res, (err) ->
			next(error)