Marcin Krzyzanowski krzyzanowskim

Swift Concurrency Manifesto

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

How to setup a practically free CDN using Backblaze B2 and Cloudflare

⚠️ Note 2023-01-21
Some things have changed since I originally wrote this in 2016. I have updated a few minor details, and the advice is still broadly the same, but there are some new Cloudflare features you can (and should) take advantage of. In particular, pay attention to Trevor Stevens' comment here from 22 January 2022, and Matt Stenson's useful caching advice. In addition, Backblaze, with whom Cloudflare are a Bandwidth Alliance partner, have published their own guide detailing how to use Cloudflare's Web Workers to cache content from B2 private buckets. That is worth reading,

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Informative DevForum posts from everyone's favorite DTS member.

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	#!/usr/bin/swift sh
	import Foundation
	import PromiseKit // @mxcl ~> 6.5
	import Swifter // @mattdonnelly == b27a89

	let swifter = Swifter(
	consumerKey: "FILL",
	consumerSecret: "ME",
	oauthToken: "IN",
	oauthTokenSecret: "https://developer.twitter.com/en/docs/basics/apps/overview.html"

	import Foundation

	enum FooType: String, Codable {
	case bar, baz
	}

	protocol Foo: AnyObject, Codable {
	var type: FooType { get }
	}

	import SwiftUI

	struct ContentView: View {
	var body: some View {
	HStack {
	Text("Hello")
	.padding()
	.background(.blue)
	.overlay {
	Color.yellow

	// Run any SwiftUI view as a Mac app.

	import Cocoa
	import SwiftUI

	NSApplication.shared.run {
	VStack {
	Text("Hello, World")
	.padding()
	.background(Capsule().fill(Color.blue))

	// This gist demonstrates how you can implement versioning for a Codable struct to support loading
	// old serialized data after changing the structure. Notable features of this solution:
	//
	// * No need to make new properties optional, or to perform post-processing on the struct after
	// loading in ordeer to populate missing values
	// * No need to change the call site - from the outside this struct behaves just the same
	// as if we had implemented codable directly in the normal way.
	// * Versioning can be applied individually to parents or leaves in a larger tree of
	// structs without affecting the other elements
	// * This approach will work even if the original struct was not designed with versioning in mind