app/sitemap.ts

@@ -0,0 +1,62 @@
+import type { MetadataRoute } from "next";
+import { routing } from "@/i18n/routing";
+import { getAllPosts } from "@/lib/posts";
+import { siteConfig } from "@/lib/site-config";
+
+/**
+ * 动态生成 sitemap.xml。
+ *
+ * 覆盖：首页、关于页，以及全部已发布文章（草稿不会出现在这里）。
+ * 每个条目都带上 hreflang alternate，帮助搜索引擎理解多语言对应关系。
+ *
+ * 内容来自数据库，因此 sitemap 也在请求时生成并缓存，
+ * 而不是在构建期固化——否则构建之后新增的文章不会出现在 sitemap 中。
+ *
+ * 注意：Next.js 要求 sitemap 返回绝对 URL。
+ */
+export const revalidate = 60;
+
+export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
+	const posts = await getAllPosts();
+
+	/** 为一条路径生成所有语言的 alternates */
+	const buildAlternates = (path: string) => ({
+		languages: Object.fromEntries(
+			routing.locales.map((locale) => [
+				locale,
+				`${siteConfig.url}/${locale}${path}`,
+			]),
+		),
+	});
+
+	const staticEntries: MetadataRoute.Sitemap = routing.locales.flatMap(
+		(locale) => [
+			{
+				url: `${siteConfig.url}/${locale}`,
+				lastModified: new Date(),
+				changeFrequency: "daily" as const,
+				priority: 1,
+				alternates: buildAlternates(""),
+			},
+			{
+				url: `${siteConfig.url}/${locale}/about`,
+				lastModified: new Date(),
+				changeFrequency: "monthly" as const,
+				priority: 0.6,
+				alternates: buildAlternates("/about"),
+			},
+		],
+	);
+
+	const postEntries: MetadataRoute.Sitemap = routing.locales.flatMap((locale) =>
+		posts.map((post) => ({
+			url: `${siteConfig.url}/${locale}/posts/${post.slug}`,
+			lastModified: new Date(`${post.date}T00:00:00Z`),
+			changeFrequency: "weekly" as const,
+			priority: 0.8,
+			alternates: buildAlternates(`/posts/${post.slug}`),
+		})),
+	);
+
+	return [...staticEntries, ...postEntries];
+}