Articles and podcasts about Swift development, by John Sundell.

Genius Scan SDK

Presented by the Genius Scan SDK

This article has been archived, as it was published several years ago, so some of its information might now be outdated. For more recent articles, please visit the main article feed.

Defining static URLs using string literals

Published on 17 Jul 2017
Basics article available: Strings

Tired of using URL(string: "url")! for static URLs? Make URL conform to ExpressibleByStringLiteral and you can now simply use "url" instead.

extension URL: ExpressibleByStringLiteral {
    // By using 'StaticString' we disable string interpolation, for safety
    public init(stringLiteral value: StaticString) {
        self = URL(string: "\(value)").require(hint: "Invalid URL string literal: \(value)")
    }
}

// We can now define URLs using static string literals 🎉
let url: URL = "https://www.swiftbysundell.com"
let task = URLSession.shared.dataTask(with: "https://www.swiftbysundell.com")

// In Swift 3 or earlier, you also have to implement 2 additional initializers
extension URL {
    public init(extendedGraphemeClusterLiteral value: StaticString) {
        self.init(stringLiteral: value)
    }

    public init(unicodeScalarLiteral value: StaticString) {
        self.init(stringLiteral: value)
    }
}

To find the extension that adds the require() method on Optional that I use above, check out Require.

Genius Scan SDK

Swift by Sundell is brought to you by the Genius Scan SDK — Add a powerful document scanner to any mobile app, and turn scans into high-quality PDFs with one line of code. Try it today.