wip(docs): i18n (#12681)

packages/web/src/middleware.ts

@@ -0,0 +1,77 @@
+import { defineMiddleware } from "astro:middleware"
+import { matchLocale } from "./i18n/locales"
+
+function docsAlias(pathname: string) {
+  const hit = /^\/docs\/([^/]+)(\/.*)?$/.exec(pathname)
+  if (!hit) return null
+
+  const value = hit[1] ?? ""
+  const tail = hit[2] ?? ""
+  const locale = matchLocale(value)
+  if (!locale) return null
+  if (locale === "root") return `/docs${tail}`
+  if (value === locale) return null
+
+  return `/docs/${locale}${tail}`
+}
+
+function localeFromCookie(header: string | null) {
+  if (!header) return null
+  const raw = header
+    .split(";")
+    .map((x) => x.trim())
+    .find((x) => x.startsWith("oc_locale="))
+    ?.slice("oc_locale=".length)
+  if (!raw) return null
+  return matchLocale(raw)
+}
+
+function localeFromAcceptLanguage(header: string | null) {
+  if (!header) return "root"
+
+  const items = header
+    .split(",")
+    .map((raw) => raw.trim())
+    .filter(Boolean)
+    .map((raw) => {
+      const parts = raw.split(";").map((x) => x.trim())
+      const lang = parts[0] ?? ""
+      const q = parts
+        .slice(1)
+        .find((x) => x.startsWith("q="))
+        ?.slice(2)
+      return {
+        lang,
+        q: q ? Number.parseFloat(q) : 1,
+      }
+    })
+    .sort((a, b) => b.q - a.q)
+
+  const locale = items
+    .map((item) => item.lang)
+    .filter((lang) => lang && lang !== "*")
+    .map((lang) => matchLocale(lang))
+    .find((lang) => lang)
+
+  return locale ?? "root"
+}
+
+export const onRequest = defineMiddleware((ctx, next) => {
+  const alias = docsAlias(ctx.url.pathname)
+  if (alias) {
+    const url = new URL(ctx.request.url)
+    url.pathname = alias
+    return ctx.redirect(url.toString(), 302)
+  }
+
+  if (ctx.url.pathname !== "/docs" && ctx.url.pathname !== "/docs/") return next()
+
+  const locale =
+    localeFromCookie(ctx.request.headers.get("cookie")) ??
+    localeFromAcceptLanguage(ctx.request.headers.get("accept-language"))
+  if (!locale || locale === "root") return next()
+
+  const url = new URL(ctx.request.url)
+  url.pathname = `/docs/${locale}/`
+  return ctx.redirect(url.toString(), 302)
+})