esquinas’s gists

esquinas / test_n_plus_ones_spec.rb

Last active January 25, 2024 15:40

Tests N+1 queries in Rails using RSpec

	# frozen_string_literal: true

	RSpec.describe TestNPlusOnes do
	describe "<something>" do
	subject(:generate) { puts("<Do something with the DB>") }
	# Technique seen in ActiveRecord's #assert_queries_count to use with Minitest:
	# https://github.com/rails/rails/blob/0496a5f994f134695bf7bdc02dacdf24925bc67c/activerecord/lib/active_record/testing/query_assertions.rb#L99
	it "avoids N+1 queries" do
	number_of_queries = 0
	counter = ->(*, payload) {

esquinas / sql_fiddling.sql

Last active September 2, 2022 15:35

How to play with SQL with no actual table (POSTGRES flavor)

	-- WINDOW EXAMPLE:
	SELECT id
	, col1
	, col2
	, bool_col
	, datecuen
	, (CASE WHEN bool_col IS NOT NULL
	THEN SUM(col1) OVER win1
	+ SUM(col2) OVER win1
	ELSE 0

esquinas / cantor_functions.rb

Created September 29, 2021 12:14

Ruby implementation of the Cantor pairing function to uniquely encode two natural numbers into a single natural number while being order sensitive.

	# LINK: https://en.wikipedia.org/wiki/Pairing_function#Cantor_pairing_function
	# LINK: https://www.cantorsparadise.com/cantor-pairing-function-e213a8a89c2b

	def inv_cantor(z)
	w = ((Math.sqrt(8.0*z.to_f + 1.0) - 1.0) / 2.0).floor
	t = (w**2 + w) / 2
	y = (z - t)
	x = (w - y)
	[x, y]
	end

esquinas / json_create_additions_example.rb

Last active May 7, 2021 09:38

Example for Ruby JSON.parse option create_additions?

	require 'json'

	class Person
	attr_accessor :name, :age

	def initialize(name, age)
	@name = name
	@age = age
	end

esquinas / mongo_id_from_date.rb

Last active December 24, 2020 10:59

Convert a timestamp to MongoDB ObjectId to get fast (indexed) create_at queries for free.

	# USAGE:
	# ------
	# mongo_id_from_date Date.parse('2020-12-24') # => "5fe3da000000000000000000"
	# mongo_id_from_date(Time.now) # => "5fe471d90000000000000000"

	def mongo_id_from_date(date)
	min_date = Time.at 0
	max_date = Time.at 0xffffffff
	raise "Error: date must be between #{min_date.to_date} and #{max_date.to_date}" if date < min_date \|\| date > max_date

esquinas / gist:3291de1c711fa6816daedddf3402e9bd

Created December 9, 2020 14:34

Script to check ruby syntax of all Ruby files in project directory.

	#!/usr/bin/env bash
	echo 'STATIC-CHECKING RUBY SYNTAX OF ALL RB & RAKE FILES IN PROJECT'
	echo
	find . \| grep ".*\.rb$" \| xargs -L 1 ruby -c
	find . \| grep ".*\.rake$" \| xargs -L 1 ruby -c

esquinas / number_to_base64.rb

Last active August 25, 2020 15:37

Convert integers (or hex ids) into url-safe base64 strings saving space compared to hexadecimal (like Mongo) IE: "b380d04df5a7ea1d22cc4a54" could be passed as "s4DQTfWn6h0izEpU" in an url param saving 8 characters.

	# frozen_string_literal: true

	require 'base64'

	def number_to_base64(number, base: nil)
	valid_base = ->(b) {
	b.is_a?(Integer) && b > 1
	}
	hex2int = ->(hex_chars) {
	hex_chars.to_i(16)

esquinas / hybrid-example.rb

Created July 20, 2020 12:23

Best-of-both-worlds example (DI + hard-coded constants) from this article: https://www.rubypigeon.com/posts/dependency_injection_containers_vs_hardcoded_constants/

	# Usage:
	# - To load default dependencies: `register_user = RegisterUser.build`
	# - To inject own dependencies (for testing or reuse):
	# ```rb
	# register_admin = RegisterUser.new(validator: AdminValidator.new, repo: AdminRepository.new)
	# ```
	class RegisterUser
	attr_reader :validator, :repo

	def self.build

esquinas / hash_to_struct.rb

Last active July 23, 2020 13:18

Monkeypatch to mock this feature https://bugs.ruby-lang.org/issues/16986 but using a Hash#to_struct method.

	# Usage:
	# my_struct = { alpha: 1, beta: 2, 'charlie' => 3 }.to_struct
	# my_struct.alpha # => 1
	# my_struct.beta # => 2
	# my_struct.charlie # => 3
	# Remember, to compare structs: `my_struct.to_h == other_struct.to_h`
	#
	# Usage to get deep structs:
	# my_deep_struct = {
	# email: '[email protected]',

esquinas / el_quijote_utf8.txt

Last active April 17, 2020 18:08 — forked from jsdario/el_quijote.txt

El Quijote en texto plano, UTF-8 y CRLF (final de línea de Windows)

This file has been truncated, but you can view the full file.

	DON QUIJOTE DE LA MANCHA
	Miguel de Cervantes Saavedra

	PRIMERA PARTE
	CAPÍTULO 1: Que trata de la condición y ejercicio del famoso hidalgo D. Quijote de la Mancha

Enrique Esquinas esquinas