javier
b6f9633420
This PR contains the work done to refactor the _Localization_ package and tidy the project a little bit. To provider further details about the work: * The `Negotiate` function was moved to the _Localization_ package. * The `WebsiteRequestContext` context no longer resolves a default language at creation; it starts empty and relies on the `LocalizationMiddleware` middleware to fill it in. * Fixed the local dependency path to Packages/Localization for the **Website** package as it only resolved inside the Xcode workspace before, breaking swift build, the Makefile, and the Docker build). * Updated the `README` file to document language negotiation, the GET /health route, and the full middleware chain; doc comments across the moved/renamed types were brought back in sync with the code. Reviewed-on: rock-n-code/loud-amsterdam#11 Co-authored-by: Javier Cicchelli <javier@rock-n-code.com> Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>
102 lines
3.2 KiB
Swift
102 lines
3.2 KiB
Swift
import Foundation
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/// Negotiates the best supported language for a request from its `Accept-Language` header.
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///
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/// Bound to a bundle's catalog languages via ``LanguageList``, an instance is invoked like a
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/// function — through ``callAsFunction(acceptLanguage:)`` — to resolve a header value to a
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/// supported language identifier, falling back to the default language.
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public struct Negotiate: Sendable {
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// MARK: Properties
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/// The supported languages and default language, derived from the bundle's String Catalog.
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private let list: LanguageList
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// MARK: Initializers
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/// Creates a language negotiator backed by the given bundle's String Catalog.
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/// - Parameter bundle: the bundle whose String Catalog defines the supported languages.
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public init(
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bundle: Bundle
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) {
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self.list = .init(bundle: bundle)
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}
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// MARK: Methods
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/// Picks the best supported language for the given `Accept-Language` header value.
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///
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/// Invoked by calling the instance directly, for example `negotiate(acceptLanguage: header)`.
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/// The header is split into its language tags (dropping any `q` weights), then matched against
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/// the supported languages with `Bundle.preferredLocalizations(from:forPreferences:)`. When the
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/// header is absent or matches nothing, the default language is returned.
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/// - Parameter acceptLanguage: the raw `Accept-Language` header value, if any.
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/// - Returns: the identifier of the supported language to serve.
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public func callAsFunction(
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acceptLanguage language: String?
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) -> String {
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guard let language else {
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return list.default
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}
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let tags = tags(from: language)
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guard !tags.isEmpty else {
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return list.default
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}
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let preferred = Bundle.preferredLocalizations(
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from: list.all,
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forPreferences: tags
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)
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return preferred.first
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?? list.default
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}
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}
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// MARK: - Helpers
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private extension Negotiate {
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// MARK: Methods
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/// Extracts the ordered language tags from an `Accept-Language` header value.
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///
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/// Each comma-separated entry is reduced to its language tag by dropping the `;q=` weight, and
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/// blank entries are removed. The original order is kept, which mirrors descending preference
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/// closely enough for `preferredLocalizations(from:forPreferences:)` to resolve correctly.
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/// - Parameter acceptLanguage: the raw `Accept-Language` header value.
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/// - Returns: the ordered, weight-stripped language tags.
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func tags(
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from acceptLanguage: String
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) -> [String] {
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acceptLanguage
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.split(separator: .Separator.comma)
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.map { entry in
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entry
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.split(separator: .Separator.semicolon)
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.first
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.map(String.init)?
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.trimmingCharacters(in: .whitespaces)
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?? .empty
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}
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.filter { !$0.isEmpty }
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}
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}
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// MARK: - Constants
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private extension Character {
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enum Separator {
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static let comma: Character = ","
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static let semicolon: Character = ";"
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}
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}
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private extension String {
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static let empty: String = ""
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}
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