Simon Rascovsky MD, M.Sc simonmd

Arel Cheatsheet on Steroids

A (more) complete cheatsheet for Arel, including NamedFunction functions, raw SQL and window functions.

Tables

posts = Arel::Table.new(:posts)
posts = Post.arel_table # ActiveRecord

Table alias

NDJSON is a convenient format for storing or streaming structured data that may be processed one record at a time.

Each line is a valid JSON value
Line separator is ‘\n’

1. Convert JSON to NDJSON?

cat test.json | jq -c '.[]' > testNDJSON.json

Run list-buckets command (OSX/Linux/UNIX) to list all S3 buckets available in your AWS account:

aws s3api list-buckets
  --query 'Buckets[*].Name'

The command output should return the name of each S3 bucket available in your AWS account:

Adaptive Streaming has become the neccessity for streaming video and audio. Unfortantely, as of this post, there isn't a whole lot of tutorials that accumulate all of the steps to get this working. Hopefully this post achieves that. This post focuses on using Amazon Web Services (AWS) to transcode for HLS and DASH and be the Content Delivery Network (CDN) that delivers the stream to your web page. We'll be using Video.js for the HTML5 player as well as javascript support libaries to make Video.js work with HLS and DASH.

So Here's what you need:

Set up three S3 buckets

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.

Effective Engineer - Notes

By Edmond Lau
Highly Recommended 👍
http://www.theeffectiveengineer.com/

	// See tth.im/s3json for a full explanation of this code

	const AWS = require('aws-sdk');
	const S3 = new AWS.S3();

	exports.handler = async (_, context) => {
	try {
	const query = 'SELECT * FROM s3object[].results[] r;';

	// test query is against data from https://swapi.co/api/planets/?page=2

	#!/usr/bin/env ruby
	#
	# Prerequisites:
	# gem install bundler
	# bundle install

	dependencies = `bundle show \| grep '*' \| awk '{print $2, $3}' \| sed -e 's/(//' -e 's/)//'`.split("\n")

	dependencies.each do \|dependency\|
	(gem_name, version) = dependency.split

	/**
	* @author knee-cola / https://github.com/knee-cola
	* Original file URL: https://gist.github.com/knee-cola/37875bc4359609b96c9f329cd2a68fa1
	*/

	// This is a simple progressive image loader for Three.js
	// It enables the smaller image files to be loaded first,
	// before the big texture image is fully loaded.
	//
	// The images are loaded in the order they are passed

	brew tap homebrew/versions
	brew install v8-315

	gem install libv8 -v '3.16.14.13' -- --with-system-v8
	gem install therubyracer -- --with-v8-dir=/usr/local/opt/v8-315

	bundle install

	# Install QEMU OSX port with ARM support
	sudo port install qemu +target_arm
	export QEMU=$(which qemu-system-arm)

	# Dowload kernel and export location
	curl -OL \
	https://github.com/dhruvvyas90/qemu-rpi-kernel/blob/master/kernel-qemu-4.1.7-jessie
	export RPI_KERNEL=./kernel-qemu-4.1.7-jessie

	# Download filesystem and export location