Localization support for the Website service (#10)

This PR contains the work done to introduce server-side localization support to the **Website** service so the landing and error pages are served in the visitor's negotiated language, backed by a new reusable Localization package. To provide further details about the work: * Created the _Localization_ package — a bundle-bound `Localize` method and a `LanguageList` type. * Language negotiation — `NegotiateLanguage` method picks the best supported language from the request's _Accept-Language_ header (falling back to the default); the `LocalizationMiddleware` middleware resolves it per request and stores it on a new `LocalizedRequestContext` / `WebsiteRequestContext` context. * Localized responses — `LocalizedHTMLCollectionResponse` pre-renders each page once per language and caches the bytes (with `Content-Language` + `Vary: Accept-Language`), reused by the `RootController` controller and `NotFoundMiddleware` middleware. * The `CachedHTMLResponse` response gained custom-header support. * Localized pages — the `IndexPage` and `ErrorPage` pages now resolve their strings via `Localize` method; * Added `Localizable.xcstrings` catalogs. * Wired the `LocalizationMiddleware` middlewaer into the router. Reviewed-on: rock-n-code/loud-amsterdam#10 Co-authored-by: Javier Cicchelli <javier@rock-n-code.com> Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>
2026-06-29 23:08:36 +00:00
parent 847058d642
commit 6c66ea74cc
24 changed files with 858 additions and 49 deletions
@@ -1,4 +1,5 @@
 import Elementary
+import Foundation
 import Testing

@testable import WebsiteCore
@@ -10,11 +11,14 @@ struct ErrorPageTests {

    @Test
    func `renders its markup`() {
-        let html = ErrorPage().render()
+        let html = ErrorPage(
+            locale: .init(identifier: "en")
+        ).render()

        #expect(html.contains("<!DOCTYPE html>"))
+        #expect(html.contains(#"lang="en""#))
        #expect(html.contains("Page Not Found"))
-        #expect(html.contains("does not exist"))
+        #expect(html.contains("Sorry, but the page you were trying to view does not exist."))
        #expect(html.contains("/css/error.css"))
    }

@@ -1,4 +1,5 @@
 import Elementary
+import Foundation
 import Testing

@testable import WebsiteCore
@@ -10,9 +11,12 @@ struct IndexPageTests {

    @Test
    func `renders its markup`() {
-        let html = IndexPage().render()
+        let html = IndexPage(
+            locale: .init(identifier: "en")
+        ).render()

        #expect(html.contains("<!DOCTYPE html>"))
+        #expect(html.contains(#"lang="en""#))
        #expect(html.contains("/css/style.css"))
        #expect(html.contains("/favicon.ico"))
        #expect(html.contains("/icon.svg"))
@@ -11,9 +11,13 @@ struct RootControllerTests {
    // MARK: Constants
    
    private let app: Application = .init(router: {
-        let router = Router()
-        
-        router.addRoutes(RootController<BasicRequestContext>().routes)
+        let router = Router(context: WebsiteRequestContext.self)
+
+        router.addMiddleware {
+            LocalizationMiddleware()
+        }
+
+        router.addRoutes(RootController<WebsiteRequestContext>().routes)
        
        return router
    }())
@@ -31,6 +35,8 @@ struct RootControllerTests {

                #expect(response.status == .ok)
                #expect(response.headers[.contentType] == "text/html; charset=utf-8")
+                #expect(response.headers[.contentLanguage] == "en")
+                #expect(response.headers[.vary] == "Accept-Language")
                #expect(body.contains("Hello world!"))
            }
        }
@@ -0,0 +1,55 @@
+import HTTPTypes
+import Hummingbird
+import HummingbirdTesting
+import NIOCore
+import Testing
+
+@testable import WebsiteCore
+
+@Suite("LocalizationMiddleware middleware")
+struct LocalizationMiddlewareTests {
+
+    // MARK: Constants
+
+    private let app: Application = .init(router: {
+        let router = Router(context: WebsiteRequestContext.self)
+
+        router.addMiddleware {
+            LocalizationMiddleware()
+        }
+
+        router.get("language") { _, context in
+            context.language
+        }
+
+        return router
+    }())
+
+    // MARK: Functional tests
+
+    @Test
+    func `negotiates a supported language from the header`() async throws {
+        try await app.test(.router) { client in
+            try await client.execute(
+                uri: "/language",
+                method: .get,
+                headers: [.acceptLanguage: "en-US,en;q=0.9"]
+            ) { response in
+                #expect(String(buffer: response.body) == "en")
+            }
+        }
+    }
+
+    @Test
+    func `falls back to the default without a header`() async throws {
+        try await app.test(.router) { client in
+            try await client.execute(
+                uri: "/language",
+                method: .get
+            ) { response in
+                #expect(String(buffer: response.body) == "en")
+            }
+        }
+    }
+
+}
@@ -11,9 +11,10 @@ struct NotFoundMiddlewareTests {
    // MARK: Constants
    
    private let app: Application = .init(router: {
-        let router = Router()
+        let router = Router(context: WebsiteRequestContext.self)
        
        router.addMiddleware {
+            LocalizationMiddleware()
            NotFoundMiddleware()
        }
        
@@ -41,6 +42,8 @@ struct NotFoundMiddlewareTests {

                #expect(response.status == .notFound)
                #expect(response.headers[.contentType] == "text/html; charset=utf-8")
+                #expect(response.headers[.contentLanguage] == "en")
+                #expect(response.headers[.vary] == "Accept-Language")
                #expect(body.contains("Page Not Found"))
            }
        }