arch1t3cht

What you NEED to Know Before Touching a Video File

Hanging out in subtitling and video re-editing communities, I see my fair share of novice video editors and video encoders, and see plenty of them make the classic beginner mistakes when it comes to working with videos. A man can only read "Use Handbrake to convert your mkv to an mp4 :)" so many times before losing it, so I am writing this article to channel the resulting psychic damage into something productive.

If you are new to working with videos (or, let's face it, even if you aren't), please read through this guide to avoid making mistakes that can cost you lots of computing power, storage space, or video quality.

kylefox

class AddRecordUuidToActiveStorageAttachments < ActiveRecord::Migration[5.2]
  def change
    # After applying this migration, you'll need to manually go through your
    # attachments and populate the new `record_uuid` column.
    # If you're unable to do this, you'll probably have to delete all your attachments.
    # You've pretty much got useless garbage data if that's the case :(
    add_column :active_storage_attachments, :record_uuid, :uuid
  end
end

stefaneng

echo '[{"key": 1}, {"key": 2}, {"key": 1}]' | jq 'group_by (.key)[] | {key: .[0].key, length: length}'

joepie91

Your blockchain must have all of the following properties:

• It's a merkle tree, or a construct with equivalent properties.
• There is no single point of trust or authority; nodes are operated by different parties.
• Multiple 'forks' of the blockchain may exist - that is, nodes may disagree on what the full sequence of blocks looks like.
• In the case of such a fork, there must exist a deterministic consensus algorithm of some sort to decide what the "real" blockchain looks like (ie. which fork is "correct").
• The consensus algorithm must be executable with only the information contained in the blockchain (or its forks), and no external input (eg. no decisionmaking from a centralized 'trust node').

If your blockchain is missing any of the above properties, it is not a blockchain, it is just a ledger.

joshdover

Idiomatic React Testing Patterns

Testing React components seems simple at first. Then you need to test something that isn't a pure interaction and things seem to break down. These 4 patterns should help you write readable, flexible tests for the type of component you are testing.

Setup

I recommend doing all setup in the most functional way possible. If you can avoid it, don't set variables in a beforeEach. This will help ensure tests are isolated and make things a bit easier to reason about. I use a pattern that gives great defaults for each test example but allows every example to override props when needed:

paragonie-scott

Hello software developers,

Please check your code to ensure you're not making one of the following mistakes related to cryptography.

I. General Mistakes

• Writing your own home-grown cryptography primitives (For example: Mifare Classic)
  • Exception: For the sake of learning, but don't deploy it in production.
• Using a fast hash function (e.g. MD5, SHA256) for storing passwords. Use bcrypt instead.
• Not using a cryptographically secure random number generator

obstschale

Octave CheatSheet

GNU Octave is a high-level interpreted language, primarily intended for numerical computations.
(via GNU Octave)

Hint: I also mad an octave docset for Dash: https://github.com/obstschale/octave-docset

Basics

toolmantim

# A simple Makefile alternative to using Grunt for your static asset compilation
#
## Usage
#
#   $ npm install
#
# And then you can run various commands:
#
#   $ make            # compile files that need compiling
#   $ make clean all  # remove target files and recompile from scratch

focusaurus

const express = require("express");
const router = express.Router();

router.get('/', function (req, res) {
  res.send("This is the '/' route in ep_app");
});

module.exports = router;

teropa

Tutorials

• The best tutorials are in the introductory books. See below.
• Getting Started with Clojure - A detailed tutorial on getting a modern (as of Jan 2013) Clojure workflow going.
  • Emacs Live is a nice development environment based on Emacs.
• Understanding The Clojure Development Ecosystem
• Clojure Docs Site is a community-driven doc site with good tutorials, and reference material going somewhat deeper than individual API docs.
• Functional Programming for the Rest of Us is a classic introduction to functional thinking
• [A comprehensive article on namespaces and different ways of requiring them](http://blog.8thlight.com/colin-jones/2010/12/05/clojure-libs-and-namespaces-require-use-import-and-ns.