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ccn/Packages/Infrastructure/Sources/Public/Protocols/Asset.swift
T
2026-08-19 23:19:08 +02:00

88 lines
3.2 KiB
Swift

/// An asset shipped with a website: a file stored under the static files root and served by Hummingbird's `FileMiddleware` middleware.
///
/// A conforming asset supplies its file name and the extensions it is available with, each resolving to its own file; the protocol derives the paths from them:
/// the file's path within the static files root and the URL path it is served at, optionally versioned to bust caches. Each file lands in its extension's own
/// folder unless the asset names a ``folder`` of its own.
public protocol Asset: Sendable {
// MARK: Properties
/// The folder within the static files root that holds the asset's files, or `nil` (the default) to use each extension's own folder.
var folder: String? { get }
/// The file extensions the asset is available with.
var fileExtensions: [AssetExtension] { get }
/// The asset's file name, without extension.
var fileName: String { get }
}
// MARK: - Implementations
public extension Asset {
// MARK: Computed
/// The asset's files live in each extension's own folder by default.
var folder: String? { nil }
// MARK: Methods
/// Resolves the asset's path against the given base directory.
///
/// - Parameters:
/// - basePath: the directory the static files are served from.
/// - fileExtension: the extension of the file to resolve.
/// - Returns: the path to the file, relative to the `basePath` path.
func path(
relativeTo basePath: String,
for fileExtension: AssetExtension
) -> String {
let relativePath = relativePath(for: fileExtension)
guard !basePath.isEmpty else {
return relativePath
}
return "\(basePath)/\(relativePath)"
}
/// Resolves the asset's path relative to the static files root (e.g. `"css/shared.css"`).
///
/// This also matches the URL path the file is served at by `FileMiddleware`.
///
/// - Parameter fileExtension: the extension of the file to resolve.
/// - Returns: the path to the file, relative to the static files root.
func relativePath(
for fileExtension: AssetExtension
) -> String {
let file = "\(fileName).\(fileExtension.rawValue)"
return (folder ?? fileExtension.folder)
.map { "\($0)/\(file)" } ?? file
}
/// Resolves the absolute URL path the asset is served at (e.g. `"/css/shared.css"`).
///
/// A version token appends as a `v` query parameter (e.g. `"/css/shared.css?v=abc123"`): `FileMiddleware` ignores the query when
/// resolving the file, while caches key on the full URL, so a deploy that changes the assets busts every cached copy at once.
/// - Parameters:
/// - fileExtension: the extension of the file to resolve.
/// - version: the version token to append, or `nil` to leave the URL unversioned.
/// - Returns: the path to use in `href` and `src` attributes.
func urlPath(
for fileExtension: AssetExtension,
version: String? = nil
) -> String {
let path = "/\(relativePath(for: fileExtension))"
guard let version, !version.isEmpty else {
return path
}
return "\(path)?v=\(version)"
}
}