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

60 lines
2.0 KiB
Swift

import Foundation
import HTTPTypes
import Hummingbird
import Localization
/// Resolves the visitor's preferred language and records it on the request context.
///
/// Placed ahead of the localized responders in the middleware chain, it reads the request's `Accept-Language` header, negotiates the best supported
/// match (falling back to the default language), and stores it on the context's ``LocalizedRequestContext/language``.
///
/// The request is otherwise passed through untouched — the URL and routing are not affected — so each page is served at its existing path and varies its
/// content by header.
public struct LocalizationMiddleware<Context: LocalizedRequestContext> {
// MARK: Properties
/// Negotiates the request's language from its `Accept-Language` header.
private let negotiate: Negotiate
// MARK: Initializers
/// Creates a localization middleware that negotiates against the given bundle's String Catalog languages.
/// - Parameter bundle: the bundle whose String Catalog names the supported languages.
public init(
bundle: Bundle
) {
self.negotiate = .init(bundle: bundle)
}
}
// MARK: - RouterMiddleware
extension LocalizationMiddleware: RouterMiddleware {
// MARK: Functions
/// Negotiates the request's language and records it on the context before passing it down.
/// - Parameters:
/// - request: the incoming request.
/// - context: the context the request is resolved against.
/// - next: the next responder in the middleware chain.
/// - Returns: the downstream response.
/// - Throws: any error thrown downstream.
public func handle(
_ request: Request,
context: Context,
next: (Request, Context) async throws -> Response
) async throws -> Response {
var context = context
context.language = negotiate(
acceptLanguage: request.headers[.acceptLanguage]
)
return try await next(request, context)
}
}