Santosh Sahoo toshsan

#System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

##Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Option 1: Command-line download extension as zip and extract

extension_id=jifpbeccnghkjeaalbbjmodiffmgedin   # change this ID
curl -L -o "$extension_id.zip" "https://clients2.google.com/service/update2/crx?response=redirect&os=mac&arch=x86-64&nacl_arch=x86-64&prod=chromecrx&prodchannel=stable&prodversion=44.0.2403.130&x=id%3D$extension_id%26uc" 
unzip -d "$extension_id-source" "$extension_id.zip"

Thx to crxviewer for the magic download URL.

	/* bling.js */

	window.$ = document.querySelectorAll.bind(document);

	Node.prototype.on = window.on = function (name, fn) {
	this.addEventListener(name, fn);
	}

	NodeList.prototype.__proto__ = Array.prototype;

	<head>
	...
	<meta name="viewport" content="width=device-width">
	...
	</head>

	# tested on Debian
	# require [email protected] with --enable-libfreetype for drawtext extension

	# ffmpeg streaming to ffserver feed
	# file -> ffmpeg (playback) -> ffmpeg (add timestamp) -> ffmpeg (add timestamp) -> ffserver (FFM delivery)

	ffmpeg -i your-file.mp4 -tune zerolatency -filter:v "setpts=1.0*PTS" -f nut pipe:1 \
	\| ffmpeg -re -i pipe:0 -vf "drawtext=expansion=normal:fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf:reload=1:textfile=test.txt: x=50: y=50: fontcolor=white" -tune zerolatency -f nut pipe:1 \
	\| ffmpeg -y -i pipe:0 -tune zerolatency http://ffserver-ip:7000/feed1.ffm

	#!/usr/bin/env python
	#
	# Copyright (c) 2004, 2005 Google Inc.
	# All rights reserved.
	#
	# Redistribution and use in source and binary forms, with or without
	# modification, are permitted provided that the following conditions
	# are met:
	#
	# * Redistributions of source code must retain the above copyright

	from redis import Redis
	import simplejson

	class Resque(object):
	"""Dirt simple Resque client in Python. Can be used to create jobs."""
	redis_server = 'localhost:6379'

	def __init__(self):
	host, port = self.redis_server.split(':')
	self.redis = Redis(host=host, port=int(port))

	from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
	from urlparse import parse_qs
	from cgi import parse_header, parse_multipart
	from SocketServer import ForkingMixIn


	class ForkingHTTPServer(ForkingMixIn, HTTPServer):

	def finish_request(self, request, client_address):
	request.settimeout(30)

	#!/usr/bin/env python
	"""
	Very simple HTTP server in python.

	Usage::
	./dummy-web-server.py [<port>]

	Send a GET request::
	curl http://localhost

	A
	a
	aa
	aal
	aalii
	aam
	Aani
	aardvark
	aardwolf
	Aaron