Konstantinos Stratis kstratis

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion

Creating an API-Only Application with Ruby on Rails

01 - Create a new API-only Rails app

rails new ror-app-name --api

02 - Basic Scaffold

01 - Model

This step is for creating a very basic level of model for us to work in. If you know already, or wish to apply your own custom models with relationships you can skip this step.

psql: FATAL: Peer authentication failed for user “postgres” (or any user)

The connection failed because by default psql connects over UNIX sockets using peer authentication, that requires the current UNIX user to have the same user name as psql. So you will have to create the UNIX user postgres and then login as postgres or use sudo -u postgres psql database-name for accessing the database (and psql should not ask for a password).

If you cannot or do not want to create the UNIX user, like if you just want to connect to your database for ad hoc queries, forcing a socket connection using psql --host=localhost --dbname=database-name --username=postgres (as pointed out by @meyerson answer) will solve your immediate problem.

But if you intend to force password authentication over Unix sockets instead of the peer method, try changing the following pg_hba.conf* line:

from

	ACTIVE_CLASS = 'is-active'.freeze

	def active_for(options)
	name_of_controller = options.fetch(:controller) { nil }
	name_of_action = options.fetch(:action) { nil }
	request_path = options.fetch(:path) { nil }

	return ACTIVE_CLASS if request_path && request_path == request.path

	if name_of_controller == controller_name

	from concurrent.futures import ThreadPoolExecutor
	from threading import BoundedSemaphore


	class BoundedExecutor:
	"""BoundedExecutor behaves as a ThreadPoolExecutor which will block on
	calls to submit() once the limit given as "bound" work items are queued for
	execution.

	:param bound: Integer - the maximum number of items in the work queue

	# spec/support/webpack.rb

	module WebpackTestBuild
	TS_FILE = Rails.root.join("tmp", "webpack-spec-timestamp")
	class << self
	attr_accessor :already_built
	end

	def self.run_webpack
	puts "running webpack-test"

	var p = () => console.log(f);
	{
	p(); // undefined
	console.log(f); // function f(){}

	f = 1;

	p(); // undefined
	console.log(f); // 1