Dan Blaker danblaker

Ruby and Postgres Regular Expression Syntaxes

Ruby's regular expressions are unusually powerful. Postgres' regular expressions are not as powerful, but they come close; close enough that it's possible to do many pattern-based queries and string transformations entirely in a query.

And sometimes, it's very useful to have a single regular expression that works

Friendly URLs

By default, Rails applications build URLs based on the primary key -- the id column from the database. Imagine we have a Person model and associated controller. We have a person record for Bob Martin that has id number 6. The URL for his show page would be:

/people/6

But, for aesthetic or SEO purposes, we want Bob's name in the URL. The last segment, the 6 here, is called the "slug". Let's look at a few ways to implement better slugs.

	class Worker
	def self.start(num_threads:, queue_size:)
	queue = SizedQueue.new(queue_size)
	worker = new(num_threads: num_threads, queue: queue)
	worker.spawn_threads
	worker
	end

	def initialize(num_threads:, queue:)
	@num_threads = num_threads

	http://stackoverflow.com/questions/22667401/postgres-json-data-type-rails-query
	http://stackoverflow.com/questions/40702813/query-on-postgres-json-array-field-in-rails

	#payload: [{"kind"=>"person"}]
	Segment.where("payload @> ?", [{kind: "person"}].to_json)

	#data: {"interest"=>["music", "movies", "programming"]}
	Segment.where("data @> ?", {"interest": ["music", "movies", "programming"]}.to_json)
	Segment.where("data #>> '{interest, 1}' = 'movies' ")
	Segment.where("jsonb_array_length(data->'interest') > 1")

	#!/bin/bash

	# Source: http://blog.nonuby.com/blog/2012/07/05/copying-env-vars-from-one-heroku-app-to-another/

	set -e

	sourceApp="$1"
	targetApp="$2"

	while read key value; do

	#!/usr/bin/env ruby
	#
	# Ruby script to download a number of files
	# from individual URLs via HTTP/HTTPS/FTP
	# specified in an external file.
	#
	# Author: Tobias Preuss
	# Revision: 2013-04-18 16:26 +0100 UTC
	# License: Creative Commons Attribution-ShareAlike 3.0 Unported

	# bundle exec rake cache:clear
	namespace :cache do
	desc "Clear Rails.cache"
	task :clear do
	Object.const_set "RAILS_CACHE", ActiveSupport::Cache.lookup_store(Rails.configuration.cache_store)
	Rails.cache.clear
	puts "Successfully cleared Rails.cache!"
	end
	end

	git tag -d 12345
	git push origin :refs/tags/12345

	/* That will remove '12345' from the remote repository. */
	/* http://nathanhoad.net/how-to-delete-a-remote-git-tag */