Puneet Lakhina puneetlakhina

Bits'bout Play2 Architecture

Play2 Simple HTTP API

Essential blueprint of Play2 architecture is pretty simple and it should be easy to explain in a fairly short blog post. The framework can be understood progressively at different levels; each time having better exposure to some aspects of its design.

The core of Play2 is really small, surrounded by a fair amount of useful APIs, services and structure to make Web Programming tasks easier.

Basically, Play2 is an API that abstractly have the folllowing type

Install Homebrew

http://mxcl.github.com/homebrew/

/usr/bin/ruby -e "$(curl -fsSL https://raw.github.com/gist/323731)"
brew help
cd ~
mate .bashrc

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	import os, fnmatch

	def locate(pattern, root=os.curdir):
	'''Locate all files matching supplied filename pattern in and below
	supplied root directory.'''
	for path, dirs, files in os.walk(os.path.abspath(root)):
	for filename in fnmatch.filter(files, pattern):
	yield os.path.join(path, filename)

	if __name__ == '__main__':

	http://s3.amazonaws.com/stanford_videos/cs229/videos/01.1-Introduction-Welcome.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/01.b-Introduction-WhatIsMachineLearning.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/01.3-Introduction-SupervisedLearning.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/01.d-Introduction-UnsupervisedLearning.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/02.1-LinearRegressionWithOneVariable-ModelRepresentation.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/02.2-LinearRegressionWithOneVariable-CostFunction.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/02.3-LinearRegressionWithOneVariable-CostFunctionIntuitionI.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/02.4-LinearRegressionWithOneVariable-CostFunctionIntuitionII.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/02.5-LinearRegressionWithOneVariable-GradientDescent.mp4
	http://s3.amazonaws.com/stanford_videos/cs229/videos/02.6-LinearRegressionWithOneVariabl