feat: vue-seo-layer, the Nuxt half of the SummerCMS SEO plugin

server/plugins/seo-client-address.ts

@@ -0,0 +1,17 @@
+// Keeps the visitor's address available to route-cached SSR renders.
+//
+// An app rule such as `'/**': { swr }` renders cached pages from a copy of
+// the request without headers. The SEO API throttles per client address,
+// so forwarding only the Nuxt peer would put every cache miss in one bucket.
+// The event context is shared with that copy, so the incoming
+// x-forwarded-for plus the peer address is recorded here, before the cached
+// handler runs, and resolveSeo and the 404 report forward it.
+
+export default defineNitroPlugin((nitroApp) => {
+  nitroApp.hooks.hook('request', (event) => {
+    const forwarded = [getRequestHeader(event, 'x-forwarded-for'), event.node.req.socket?.remoteAddress]
+      .filter((v): v is string => typeof v === 'string' && v !== '')
+      .join(', ')
+    event.context.seoForwardedFor = forwarded
+  })
+})

server/plugins/seo-notfound.ts

@@ -0,0 +1,53 @@
+// Reports every page answered 404 to the SEO plugin's 404 log
+// (POST /notfound with the bearer token). A page that throws a 404 (an
+// unknown route, a missing record) goes through Nitro's error path, which
+// skips afterResponse, so both the `error` hook and `afterResponse` report,
+// once per request. Only page views count: GET requests that accept
+// text/html, never Nuxt's own paths (/_nuxt, /__nuxt_error, …) or the API
+// routes, and nothing without the token configured. A failed report is
+// logged once and never touches the response.
+
+import type { H3Event } from 'h3'
+import { seoResolvableUrl } from '../../app/utils/seo.ts'
+
+let warned = false
+
+function report(event: H3Event) {
+  if (event.context.seoNotFoundReported) return
+  if (event.method !== 'GET') return
+  if (!(getRequestHeader(event, 'accept') ?? '').includes('text/html')) return
+  const config = useRuntimeConfig(event)
+  if ((config.public.seo as { enabled?: boolean } | undefined)?.enabled === false) return
+  const seo = config.seo as { apiBase: string; notfoundToken?: string; timeoutMs?: number }
+  const token = seo.notfoundToken?.trim()
+  if (!token) return
+  const url = seoResolvableUrl(event.path)
+  if (!url) return
+  event.context.seoNotFoundReported = true
+
+  const referer = getRequestHeader(event, 'referer') ?? ''
+  const forwarded = event.context.seoForwardedFor as string | undefined
+  const sent = $fetch('/notfound', {
+    baseURL: seo.apiBase,
+    method: 'POST',
+    body: { url: url.slice(0, 2048), referer: referer.slice(0, 1024) },
+    headers: { authorization: `Bearer ${token}`, ...(forwarded ? { 'x-forwarded-for': forwarded } : {}) },
+    timeout: Number(seo.timeoutMs) || 1500,
+  }).catch((err: unknown) => {
+    if (!warned) {
+      warned = true
+      console.warn('[vue-seo-layer] 404 report failed:', (err as Error)?.message ?? err)
+    }
+  })
+  event.waitUntil?.(sent)
+}
+
+export default defineNitroPlugin((nitroApp) => {
+  nitroApp.hooks.hook('error', (error, { event }) => {
+    const status = (error as { statusCode?: number } | null)?.statusCode
+    if (event && status === 404) report(event)
+  })
+  nitroApp.hooks.hook('afterResponse', (event) => {
+    if (event.node.res.statusCode === 404) report(event)
+  })
+})