maximize Cloudflare edge caching

frontend/app/api/cities/detail-batch/route.ts

@@ -1,6 +1,9 @@
 import { NextRequest, NextResponse } from "next/server";
 import { proxyBackendJsonGet } from "@/lib/api-proxy";
-import { buildCityDetailProxyCachePolicy } from "@/lib/proxy-cache-policy";
+import {
+  buildCityDetailProxyCachePolicy,
+  NO_STORE_CACHE_CONTROL,
+} from "@/lib/proxy-cache-policy";
 import {
   createProxyTimer,
   finishProxyTimedResponse,
@@ -79,7 +82,7 @@ export async function GET(req: NextRequest) {
 
   const forceRefresh = req.nextUrl.searchParams.get("force_refresh") ?? "false";
   const requestedCities = parseRequestedCities(req);
-  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh, 15);
+  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh);
   const searchParams = new URLSearchParams({
     cities: req.nextUrl.searchParams.get("cities") || "",
     force_refresh: forceRefresh,
@@ -100,7 +103,7 @@ export async function GET(req: NextRequest) {
         data &&
         typeof data === "object" &&
         (data as { partial?: unknown }).partial === true
-          ? "no-store, max-age=0"
+          ? NO_STORE_CACHE_CONTROL
           : cachePolicy.responseCacheControl,
       fetchCache: "no-store",
       publicMessage: "Failed to fetch city detail batch",
@@ -108,7 +111,10 @@ export async function GET(req: NextRequest) {
       signal: controller.signal,
       timeoutResponse: () =>
         NextResponse.json(buildCityDetailBatchTimeoutPayload(requestedCities), {
-          headers: { "Cache-Control": "no-store, max-age=0" },
+          headers: {
+            "Cache-Control": NO_STORE_CACHE_CONTROL,
+            "Cloudflare-CDN-Cache-Control": NO_STORE_CACHE_CONTROL,
+          },
           status: 200,
         }),
       timeoutPublicMessage: "City detail batch request timed out",

frontend/app/api/cities/route.ts

@@ -1,12 +1,15 @@
 import { NextRequest } from "next/server";
 import { proxyBackendJsonGet } from "@/lib/api-proxy";
 import { buildCachedJsonResponse } from "@/lib/http-cache";
+import {
+  buildCityListCacheControl,
+  buildStaticCityListFallbackCacheControl,
+} from "@/lib/proxy-cache-policy";
 import { STATIC_CITY_LIST } from "@/lib/static-cities";
 
 const API_BASE = process.env.POLYWEATHER_API_BASE_URL;
-const CITIES_CACHE_CONTROL = "public, max-age=0, s-maxage=60, stale-while-revalidate=300";
-const STATIC_CITIES_CACHE_CONTROL =
-  "public, max-age=0, s-maxage=300, stale-while-revalidate=3600";
+const CITIES_CACHE_CONTROL = buildCityListCacheControl();
+const STATIC_CITIES_CACHE_CONTROL = buildStaticCityListFallbackCacheControl();
 const CITIES_BACKEND_TIMEOUT_MS = Number(
   process.env.POLYWEATHER_CITIES_BACKEND_TIMEOUT_MS || 1000,
 );

frontend/app/api/city/[name]/detail/route.ts

@@ -49,7 +49,7 @@ export async function GET(
 
   const { name } = await timer.measure("route_params", () => context.params);
   const forceRefresh = req.nextUrl.searchParams.get("force_refresh") ?? "false";
-  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh, 15);
+  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh);
   const depth = req.nextUrl.searchParams.get("depth");
   const marketSlug = req.nextUrl.searchParams.get("market_slug");
   const targetDate = req.nextUrl.searchParams.get("target_date");
@@ -82,7 +82,7 @@ export async function GET(
         headers: auth.headers,
         ...(cachePolicy.fetchMode === "no-store"
           ? { cache: "no-store" as const }
-          : { next: { revalidate: cachePolicy.revalidateSeconds ?? 15 } }),
+          : { next: { revalidate: cachePolicy.revalidateSeconds ?? 60 } }),
       }),
     );
     const backendServerTiming = res.headers.get("server-timing") || "";

frontend/app/api/city/[name]/route.ts

@@ -139,7 +139,7 @@ export async function GET(
   const { name } = await context.params;
   const forceRefresh = req.nextUrl.searchParams.get("force_refresh") ?? "false";
   const depth = req.nextUrl.searchParams.get("depth") ?? "panel";
-  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh, 15);
+  const cachePolicy = buildCityDetailProxyCachePolicy(forceRefresh);
   const url = `${API_BASE}/api/city/${encodeURIComponent(name)}?force_refresh=${forceRefresh}&depth=${encodeURIComponent(depth)}`;
 
   try {
@@ -150,7 +150,7 @@ export async function GET(
       headers: auth.headers,
       ...(cachePolicy.fetchMode === "no-store"
         ? { cache: "no-store" as const }
-        : { next: { revalidate: cachePolicy.revalidateSeconds ?? 15 } }),
+        : { next: { revalidate: cachePolicy.revalidateSeconds ?? 60 } }),
     });
     if (!res.ok) {
       const raw = await res.text();
@@ -159,7 +159,7 @@ export async function GET(
         headers: auth.headers,
         ...(cachePolicy.fetchMode === "no-store"
           ? { cache: "no-store" as const }
-          : { next: { revalidate: 10 } }),
+          : { next: { revalidate: cachePolicy.revalidateSeconds ?? 60 } }),
       });
       if (summaryRes.ok) {
         const summaryData = await summaryRes.json();
@@ -168,7 +168,7 @@ export async function GET(
           buildFallbackCityDetail(name, depth, summaryData),
           cachePolicy.fetchMode === "no-store"
             ? cachePolicy.responseCacheControl
-            : "public, max-age=0, s-maxage=10, stale-while-revalidate=30",
+            : cachePolicy.responseCacheControl,
         );
         response.headers.set("X-PolyWeather-Fallback", "summary");
         return applyAuthResponseCookies(response, auth.response);