Adam Dilek adamdilek

Rails 7 new features. Before and After

Add ComparisonValidator
PostgreSQL generated columns
PostgreSQL custom enum types
Add tracking of belongs_to association
association_previously_changed? method
Add invert_where method
Add associated method
Add missing method
Active Record Encryption

OpenCV Bindings for Torch

The OpenCV library implements tons of useful image processing and computer vision algorithms, as well as the high-level GUI API. Written in C++, it has bindings in Python, Java, MATLAB/Octave, C#, Perl and Ruby. We present the Lua bindings that are based on Torch, made by VisionLabs with support from Facebook and Google Deepmind.

By combining OpenCV with scientific computation abilities of Torch, one gets an even more powerful framework capable of handling computer vision routines (e.g. face detection), interfacing video streams (including cameras), easier data visualization, GUI interaction and many more. In addition, most of the computationally intensive algorithms are available on GPU via Cutorch. All these features may be essentially useful for those dealing with deep learning applied to images.

Usage Examples

How to install nginx (>= 1.9.5) with http2 support on Ubuntu 14.04 LTS (Trusty)

IMPORTANT: Backup your nginx site configs (usually under /etc/nginx/sites-available)!

Remove old nginx

Remove old nginx incl. nginx-common:

apt-get autoremove --purge nginx nginx-common

Integrate Gem/Engine and main Rails app

Overview

Paths
Routes
Add functionality to controller
Improving (Extending or overriding) Engine functionality
Helpers
Assets

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Screencasting Framework

The following document is a written account of the Code School screencasting framework. It should be used as a reference of the accompanying screencast on the topic.

Why you should care about screencasting?

You're probably aren't going to take the time to read this document if you're not interested, but there are a lot of nice side effects caused by learning how to create quality screencasts.

Communicating more effectively - At Envy Labs we produce screencasts for our clients all the time. Whether it's demoing a new feature or for a presentation for an invester, they're often much more effective and pleasent than a phone call or screen sharing.

	#!/bin/sh

	# Based on gist.github.com/gboudreau/install-ffmpeg-amazon-linux.sh
	# and https://trac.ffmpeg.org/wiki/CompilationGuide/Centos
	if [ "`/usr/bin/whoami`" != "root" ]; then
	echo "You need to execute this script as root."
	exit 1
	fi

	cat > /etc/yum.repos.d/centos.repo<<EOF

	# Backup
	docker exec CONTAINER /usr/bin/mysqldump -u root --password=root DATABASE > backup.sql

	# Restore
	cat backup.sql \| docker exec -i CONTAINER /usr/bin/mysql -u root --password=root DATABASE

	Because I couldn't find these with a quick Google search on 28 April 2015:

	Usage:
	rails new APP_PATH [options]

	Options:
	-r, [--ruby=PATH] # Path to the Ruby binary of your choice
	# Default: /home/brian/.rvm/rubies/ruby-2.2.0/bin/ruby
	-m, [--template=TEMPLATE] # Path to some application template (can be a filesystem path or URL)
	[--skip-gemfile], [--no-skip-gemfile] # Don't create a Gemfile

	// Run this from the commandline:
	// phantomjs runner.js \| ffmpeg -y -c:v png -f image2pipe -r 24 -t 10 -i - -c:v libx264 -pix_fmt yuv420p -movflags +faststart output.mp4

	var page = require('webpage').create(),
	address = 'http://s.codepen.io/phanan/fullembedgrid/YPLewm?type=embed&safe=true&_t=1424767252279',
	duration = 3, // duration of the video, in seconds
	framerate = 24, // number of frames per second. 24 is a good value.
	counter = 0,
	width = 500,
	height = 500;