How to Include Assets/Resources in a Swift Package Manager Library

How to include assets / resources in a Swift Package Manager library?

Using Swift 5.3 it's finally possible to add localized resources /p>

The Package initializer now has a defaultLocalization parameter which can be used for localization resources.

public init(
    name: String,
    defaultLocalization: LocalizationTag = nil, // New defaultLocalization parameter.
    pkgConfig: String? = nil,
    providers: [SystemPackageProvider]? = nil,
    products: [Product] = [],
    dependencies: [Dependency] = [],
    targets: [Target] = [],
    swiftLanguageVersions: [Int]? = nil,
    cLanguageStandard: CLanguageStandard? = nil,
    cxxLanguageStandard: CXXLanguageStandard? = nil
)

Let's say you have an Icon.png which you want to be localised for English and German speaking people.

The images should be included in Resources/en.lproj/Icon.png & Resources/de.lproj/Icon.png.

After you can reference them in your package like that:

let package = Package(
    name: "BestPackage",
    defaultLocalization: "en",
    targets: [
        .target(name: "BestTarget", resources: [
            .process("Resources/Icon.png"),
        ])
    ]
)

Please note LocalizationTag is a wrapper of IETF Language Tag.

Credits and input from following proposals overview, please check it for more details.

Use resources in unit tests with Swift Package Manager

Swift 5.3

See Apple Documentation: "Bundling Resources with a Swift Package"

Swift 5.3 includes Package Manager Resources SE-0271 evolution proposal with "Status: Implemented (Swift 5.3)".

Resources aren't always intended for use by clients of the package; one use of resources might include test fixtures that are only needed by unit tests. Such resources would not be incorporated into clients of the package along with the library code, but would only be used while running the package's tests.

• Add a new resources parameter in target and testTarget APIs to allow declaring resource files explicitly.

SwiftPM uses file system conventions for determining the set of source files that belongs to each target in a package: specifically, a target's source files are those that are located underneath the designated "target directory" for the target. By default this is a directory that has the same name as the target and is located in "Sources" (for a regular target) or "Tests" (for a test target), but this location can be customized in the package manifest.

// Get path to DefaultSettings.plist file.
let path = Bundle.module.path(forResource: "DefaultSettings", ofType: "plist")

// Load an image that can be in an asset archive in a bundle.
let image = UIImage(named: "MyIcon", in: Bundle.module, compatibleWith: UITraitCollection(userInterfaceStyle: .dark))

// Find a vertex function in a compiled Metal shader library.
let shader = try mtlDevice.makeDefaultLibrary(bundle: Bundle.module).makeFunction(name: "vertexShader")

// Load a texture.
let texture = MTKTextureLoader(device: mtlDevice).newTexture(name: "Grass", scaleFactor: 1.0, bundle: Bundle.module, options: options)

Example

// swift-tools-version:5.3
import PackageDescription

  targets: [
    .target(
      name: "Example",
      dependencies: [],
      resources: [
        // Apply platform-specific rules.
        // For example, images might be optimized per specific platform rule.
        // If path is a directory, the rule is applied recursively.
        // By default, a file will be copied if no rule applies.
        // Process file in Sources/Example/Resources/*
        .process("Resources"),
      ]),
    .testTarget(
      name: "ExampleTests",
      dependencies: [Example],
      resources: [
        // Copy Tests/ExampleTests/Resources directories as-is. 
        // Use to retain directory structure.
        // Will be at top level in bundle.
        .copy("Resources"),
      ]),

Reported Issues & Possible Workarounds

• Swift 5.3 SPM Resources in tests uses wrong bundle path?
• Swift Package Manager - Resources in test targets

Xcode

Bundle.module is generated by SwiftPM (see Build/BuildPlan.swift SwiftTargetBuildDescription generateResourceAccessor()) and thus not present in Foundation.Bundle when built by Xcode.

A comparable approach in Xcode would be to manually add a Resources reference folder to the Xcode project, add an Xcode build phase copy to put the Resource into some *.bundle directory, and add a some custom #ifdef XCODE_BUILD compiler directive for the Xcode build to work with the resources.

#if XCODE_BUILD
extension Foundation.Bundle {
    
    /// Returns resource bundle as a `Bundle`.
    /// Requires Xcode copy phase to locate files into `ExecutableName.bundle`;
    /// or `ExecutableNameTests.bundle` for test resources
    static var module: Bundle = {
        var thisModuleName = "CLIQuickstartLib"
        var url = Bundle.main.bundleURL
        
        for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
            url = bundle.bundleURL.deletingLastPathComponent()
            thisModuleName = thisModuleName.appending("Tests")
        }
        
        url = url.appendingPathComponent("\(thisModuleName).bundle")
        
        guard let bundle = Bundle(url: url) else {
            fatalError("Foundation.Bundle.module could not load resource bundle: \(url.path)")
        }
        
        return bundle
    }()
    
    /// Directory containing resource bundle
    static var moduleDir: URL = {
        var url = Bundle.main.bundleURL
        for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
            // remove 'ExecutableNameTests.xctest' path component
            url = bundle.bundleURL.deletingLastPathComponent()
        }
        return url
    }()
    
}
#endif

Load fonts from a Swift Package

✅ It is supported now

From Swift 5.3, you can add any resources to the target, including images, assets, fonts, zip, etc. Using the directory name will include all subfiles of the directory:

    .target(
        name: "ABUIKit",
        dependencies: [],
        resources: [.process("Resources") // <- this will add Resource directory to the target
        ]
    ),

Note that you should put the Resources folder under sources/packageName to make it recognizable.

⚠️ Also, Don't forget to register them!

You need to register fonts to make it work. So you can use frameworks like FontBlaster.

_{NOTE: You can always write your own code, but I prefer to use an existing framework and contribute my extra needs to them}

So you call this somewhere early in the module's code (like some init method):

FontBlaster.blast(bundle: .module)

Then you can use the font inside or even outside of the module!

---

There is no need to name the font manually!

It will register all included fonts automatically. You can double-check the loaded fonts right after calling the blast method:

FontBlaster.loadedFonts.forEach { print("quot;, $0) }

---

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