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GenServer Cheatsheet by Benjamin Tan Wei Hao

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When does terminate/2 get called in a gen_server?

This is what the [official documentation][1] says about the terminate/2 callback for a gen_server:

This function is called by a gen_server when it is about to terminate. It should be the opposite of Module:init/1 and do any necessary cleaning up. When it returns, the gen_server terminates with Reason. The return value is ignored.

Reason is a term denoting the stop reason and State is the internal state of the gen_server.

Reason depends on why the gen_server is terminating. If it is because another callback function has returned a stop tuple {stop,..}, Reason will have the value specified in that tuple. If it is due to a failure, Reason is the error reason.

2015-01-29 Unofficial Relay FAQ

Compilation of questions and answers about Relay from React.js Conf.

Disclaimer: I work on Relay at Facebook. Relay is a complex system on which we're iterating aggressively. I'll do my best here to provide accurate, useful answers, but the details are subject to change. I may also be wrong. Feedback and additional questions are welcome.

What is Relay?

Relay is a new framework from Facebook that provides data-fetching functionality for React applications. It was announced at React.js Conf (January 2015).

OAUTH2

The Problem

I’m a web app that wants to allow other web apps access to my users’ information, but I want to ensure that the user says it’s ok.

The Solution

I can’t trust the other web apps, so I must interact with my users directly. I’ll let them know that the other app is trying to get their info, and ask whether they want to grant that permission. Oauth defines a way to initiate that permission verification from the other app’s site so that the user experience is smooth. If the user grants permission, I issue an AuthToken to the other app which it can use to make requests for that user's info.

Note on encryption

Oauth2 has nothing to do with encryption -- it relies upon SSL to keep things (like the client app’s shared_secret) secure.

	function convertMS( milliseconds ) {
	var day, hour, minute, seconds;
	seconds = Math.floor(milliseconds / 1000);
	minute = Math.floor(seconds / 60);
	seconds = seconds % 60;
	hour = Math.floor(minute / 60);
	minute = minute % 60;
	day = Math.floor(hour / 24);
	hour = hour % 24;
	return {

	git commit --amend --author "Jonny Appleseed <jonny.appleseed@gmail.com>" --no-edit && \
	git rebase --continue
	...
	git push origin master --force

	# Steps to build and install tmux from source.
	# Takes < 25 seconds on EC2 env [even on a low-end config instance].

	VERSION=2.7
	sudo yum -y remove tmux
	sudo yum -y install wget tar libevent-devel ncurses-devel
	wget https://github.com/tmux/tmux/releases/download/${VERSION}/tmux-${VERSION}.tar.gz
	tar xzf tmux-${VERSION}.tar.gz
	rm -f tmux-${VERSION}.tar.gz
	cd tmux-${VERSION}

	<!DOCTYPE html>
	<html>
	<head>
	<title>My Iframe</title>
	</head>
	<body>

	<button>Botão</button>

	<script type="text/javascript">

	/*
	In the node.js intro tutorial (http://nodejs.org/), they show a basic tcp
	server, but for some reason omit a client connecting to it. I added an
	example at the bottom.

	Save the following server in example.js:
	*/

	var net = require('net');