用 Cloudflare Worker 给 Hexo 博客加上真实的访问统计（零本地依赖）

/**
 * Cloudflare Analytics Worker
 * Cron 拉 zone 级 PV/UV → 聚合 → 写 KV；前端同源 GET 读 KV
 */
const GRAPHQL_ENDPOINT = 'https://api.cloudflare.com/client/v4/graphql';
const KV_KEY = 'stats';

function ymd(d) { return d.toISOString().slice(0, 10); }

async function fetchDailyGroups(token, zoneTag, sinceDate, untilDate) {
  const query = `
    query ($zoneTag: String!, $since: String!, $until: String!) {
      viewer {
        zones(filter: { zoneTag: $zoneTag }) {
          httpRequests1dGroups(
            limit: 366
            filter: { date_geq: $since, date_leq: $until }
            orderBy: [date_ASC]
          ) {
            dimensions { date }
            sum { pageViews requests }
            uniq { uniques }
          }
        }
      }
    }`;

  const res = await fetch(GRAPHQL_ENDPOINT, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      Authorization: `Bearer ${token}`,
    },
    body: JSON.stringify({ query, variables: { zoneTag, since: sinceDate, until: untilDate } }),
  });

  const json = await res.json();
  if (json.errors && json.errors.length) throw new Error('GraphQL: ' + JSON.stringify(json.errors));
  const zones = json?.data?.viewer?.zones;
  if (!zones || !zones.length) throw new Error('空 zones，检查 ZONE_TAG 与 token 权限');
  return zones[0].httpRequests1dGroups || [];
}

function aggregate(groups) {
  const now = new Date();
  const todayKey = ymd(now);
  const yesterday = new Date(now);
  yesterday.setUTCDate(yesterday.getUTCDate() - 1);
  const yesterdayKey = ymd(yesterday);
  const monthAgo = new Date(now); monthAgo.setUTCDate(monthAgo.getUTCDate() - 30);
  const yearAgo = new Date(now);  yearAgo.setUTCDate(yearAgo.getUTCDate() - 365);

  const out = { today_pv: 0, today_uv: 0, yesterday_pv: 0, yesterday_uv: 0, last_month_pv: 0, last_year_pv: 0 };
  for (const g of groups) {
    const date = g.dimensions.date;
    const pv = g.sum?.pageViews || 0;
    const uv = g.uniq?.uniques || 0;
    const d = new Date(date + 'T00:00:00Z');
    if (date === todayKey)    { out.today_pv = pv; out.today_uv = uv; }
    if (date === yesterdayKey){ out.yesterday_pv = pv; out.yesterday_uv = uv; }
    if (d >= monthAgo) out.last_month_pv += pv;
    if (d >= yearAgo)  out.last_year_pv  += pv;
  }
  return out;
}

async function refresh(env) {
  const groups = await fetchDailyGroups(env.CF_API_TOKEN, env.ZONE_TAG, ymd(new Date(Date.now() - 364 * 864e5)), ymd(new Date()));
  const stats = aggregate(groups);
  stats.updated_at = new Date().toISOString();
  await env.STATS.put(KV_KEY, JSON.stringify(stats));
  return stats;
}

export default {
  async scheduled(event, env, ctx) {
    ctx.waitUntil(refresh(env).catch((e) => console.error('refresh failed:', e.message)));
  },
  async fetch(request, env) {
    const url = new URL(request.url);
    if (url.searchParams.get('refresh') === '1') {
      const key = url.searchParams.get('key');
      if (!env.REFRESH_KEY || key !== env.REFRESH_KEY) return new Response('unauthorized', { status: 401 });
      const stats = await refresh(env);
      return new Response(JSON.stringify({ ok: true, ...stats }), { headers: { 'Content-Type': 'application/json' } });
    }
    const cached = await env.STATS.get(KV_KEY);
    if (!cached) {
      try { return new Response(JSON.stringify(await refresh(env)), { headers: { 'Content-Type': 'application/json' } }); }
      catch (e) { return new Response(JSON.stringify({ error: e.message }), { status: 200 }); }
    }
    return new Response(cached, { headers: { 'Content-Type': 'application/json', 'Access-Control-Allow-Origin': '*' } });
  },
};