A year ago, we talked about using NSFormatter for formatting data in a human readable format. WWDC2020 brings some updates and changes to the NSFormatter APIs that we need to be aware of. This article will complement the NSFormatter article from last year with best practices and things to look out for.
Improvements for Combinations of Languages and Regions.
NSFormatter always does its best to format the data according to the user’s language and region where relevant. Apple is improving the combinations for this because it’s highly common for people to set their phones in a language that is not commonly used in a given region. This is pretty exciting for me, because I live in Bolivia where people speak Spanish, but I have used my devices in English for as long as I can remember.
Translating our apps in different languages helps us reach wider audiences of different cultures. This reach can increase our app usage considerably and offer more monetization properties.
In this short article we will mention the features Apples gives us to translate our apps to different languages, namely NSLocalizedString and and stringsdict files. You will also understand when you will want to use each, as they have different use cases and an app that takes localization seriously will use both.
While CryptoKit still doesn’t offer many algorithms and functionality, it’s still growing, and this year CryptoKit and do more.
HKDF
Key derivation functions have been available from day one, but it wasn’t possible to derive keys independently. It was only possible to do so if you were using elliptic curve key agreement protocols.
To do this, there is a new HKDF object with static methods. One such method is deriveKey with multiple overloads:
In this article we will talk about actually logging messages, how the framework is “smart enough” to strip out sensitive user info by default, and how we can control what gets stripped.
Logging Messages
The framework supports interpolated strings right out of the box when you are using the new system in Swift.
Working with REST APIs you have no control over can be a little monotonous. This is especially for OAuth 2.0 API that need you to do a little bit of setup, get your API keys with the service provider, and then you need to do the setup on your app’s size: Configure your URL scheme, deal with that URL Scheme, and write code that does something when your app gets called with that URL.
It is no surprise that software tend to write logs to a local file as they execute. As events, errors, or exceptional situations occur, a lot of software takes note of them using a local logging solution. This is done because these practices can allow us to troubleshoot problems for our users, find bugs, and in general understand the behavior of our software in untested or lesser tested scenarios.
When comes to iOS and other Apple platforms, there have always been third party dependencies that allow you to do this. A lot of developers roll their own solution and write events in plain text files. It wasn’t until iOS 8 and macOS 10.10 that Apple provided us with a unified logging system that is easy to use and is very performant - OSLog.
It’s not news that iOS has a heavy a focus on privacy and security. Apple provides us with many tools to make encryption easy, like CryptoKit, a high-level Cryptography framework on iOS. When CryptoKit is not enough, we can leverage older, lower-level APIs to do more cryptographic operations or use cyphers not covered by CryptoKit. We can even make use of the Secure Enclave to leverage hardware-level security to our apps.
This is all cool and dandy but did you know that you don’t need to leverage any of the technologies above to secure data in your app? In this article we will provide a much simpler method to protect user data, without having to know the first thing about Cryptography at all, and without compromising security at all. If you know you need to protect data, you can consider this option before even considering directly dealing with cryptography at all.
Combine allows us to create pipelines for a lot of tasks. Thanks to the fact it can do work concurrently without leveraging callbacks, it is very easy to build things that would otherwise be very complex.
In this short article, we will build a file download queue that downloads images sequentially. You can use this as the base for more complex queues.
The queue will download an array of images sequentially. If you wanted to support concurrent queues, it would probably be wise to instantiate this publisher as many times as necessary.
Apple introduced modern background tasks last year on iOS 13. These new APIs have been out for a little over year (counting the beta period). Many developers have tried to adopt them to moderate success. Many of them have found them to be very unpredictable and that only work a fraction of the time. If you look around the internet (and even on the comments in that article), you will see many developers weren’t able to get them to work as expected.
Xcode 12 introduces the ability for developers to add their own SwiftUI views and modifiers to the Xcode library. This allows people using your code to discover your custom views, makes your codebase easier to learn, and it allows you to visually edit complex views visually rather than with code.
In this short article we will explore how we can add our own views and modifiers to the Xcode library.
