Trevor Turk trevorturk

Optimizing Rails Static Assets on Heroku Cedar

Serving Rails static assets is hard, especially on Heroku Cedar where Heroku forces Rails to serve static assets itself (which isn't particularly performant nor worth your dyno-dollar)---this is different than Heroku Bamboo which used Varnish and is no more. To make the best of the situation, I highly recomend:

Using the Heroku-Deflater gem which will selectively gzips assets (it gzips text-based files; and excludes images or binary files, which can actually be bigger when gzipped)
Configure your production environment to set cache-control headers and get out of denial about how static assets are being served on Heroku Cedar
Use AWS Cloudfront (or a CDN of your choosing) to serve the assets. Cloudfront is great because you can use the same Distribution

Cached Properties

Complicated, time expensive computed properties can be cached using the following pattern.

var a = Cached(0) {
    (a: Int) -> Int in
    print("did calculate")
    return a + 100
}

Spurred by recent events (https://news.ycombinator.com/item?id=8244700), this is a quick set of jotted-down thoughts about the state of "Semantic" Versioning, and why we should be fighting the good fight against it.

For a long time in the history of software, version numbers indicated the relative progress and change in a given piece of software. A major release (1.x.x) was major, a minor release (x.1.x) was minor, and a patch release was just a small patch. You could evaluate a given piece of software by name + version, and get a feeling for how far away version 2.0.1 was from version 2.8.0.

But Semantic Versioning (henceforth, SemVer), as specified at http://semver.org/, changes this to prioritize a mechanistic understanding of a codebase over a human one. Any "breaking" change to the software must be accompanied with a new major version number. It's alright for robots, but bad for us.

SemVer tries to compress a huge amount of information — the nature of the change, the percentage of users that wil

class String
  def to_proc
    Proc.new { |n| self.split(".").inject(n) { |n, method| n.send(method) } }
  end
end

&gt;&gt; Person.first(2).map(&amp;"name.downcase.reverse.capitalize")

	# Cleans up branches like:
	# if Shopify.rails_next?
	# # Rails 5 login
	# else
	# # Rails 4 login
	# end
	module RuboCop
	module Cop
	module ShopifyRails
	class RailsNextUnless < Cop

	# Channel
	class CommentsChannel < ApplicationCable::Channel
	def self.broadcast_comment(comment)
	broadcast_to comment.message, comment: CommentsController.render(
	partial: 'comments/comment', locals: { comment: comment }
	)
	end

	def follow(data)
	stop_all_streams

	func migrateUserDefaultsToAppGroups() {

	// User Defaults - Old
	let userDefaults = NSUserDefaults.standardUserDefaults()

	// App Groups Default - New
	let groupDefaults = NSUserDefaults(suiteName: "group.myGroup")

	// Key to track if we migrated
	let didMigrateToAppGroups = "DidMigrateToAppGroups"

	# Based on: http://donpottinger.net/blog/2014/11/17/bye-bye-heroku-hello-dokku.html

	# Add to gemfile:
	ruby '2.1.2'
	gem 'pg'
	gem 'puma'
	gem 'rails_12factor'
	gem 'searchkick'
	gem 'typhoeus'

	func timeAgoSinceDate(date:NSDate, numericDates:Bool) -> String {
	let calendar = NSCalendar.currentCalendar()
	let unitFlags = NSCalendarUnit.CalendarUnitMinute \| NSCalendarUnit.CalendarUnitHour \| NSCalendarUnit.CalendarUnitDay \| NSCalendarUnit.CalendarUnitWeekOfYear \| NSCalendarUnit.CalendarUnitMonth \| NSCalendarUnit.CalendarUnitYear \| NSCalendarUnit.CalendarUnitSecond
	let now = NSDate()
	let earliest = now.earlierDate(date)
	let latest = (earliest == now) ? date : now
	let components:NSDateComponents = calendar.components(unitFlags, fromDate: earliest, toDate: latest, options: nil)

	if (components.year >= 2) {
	return "\(components.year) years ago"

	requirement: your db name must have the same name as your app. (it does not have _development on the name)

	save this script in a common folder outside your project.