message: partial cache update
diff: @@ -7,7 +7,7 @@ async function cache(ctx, next) {
  return await next();
  }
  - const cached = ctx.cache[ctx.path];
  + const cached = ctx.cache[ctx.url];
  if (cached !== undefined && cached.ts && cached.ts + TTL * 1000 > Date.now()) {
  ctx.status = 200;
  ctx.body = cached.body;
  @@ -17,7 +17,7 @@ async function cache(ctx, next) {
  await next();
  ctx.set('Cache-Control', `public, max-age=${TTL}`);
  - ctx.cache[ctx.path] = {
  + ctx.cache[ctx.url] = {
  ts: Date.now(),
  body: ctx.body,
  };
  