init

app/api/radar/route.ts

@@ -0,0 +1,43 @@
+import { NextResponse, type NextRequest } from "next/server";
+import { fetchJson } from "@/lib/weather/http";
+import { errorResponse, forbidCrossSite } from "@/lib/weather/respond";
+import type { RadarFrame } from "@/lib/weather/types";
+
+/**
+ * GET /api/radar → RainViewer frames, oldest first, ready for Leaflet.
+ *
+ * RainViewer publishes an index of frames. Each frame's `path` is a hash, not a
+ * timestamp, so tile URLs must always be built from this index — never guessed.
+ * Docs: https://www.rainviewer.com/api/weather-maps-api.html
+ */
+
+interface RainViewerIndex {
+  host: string;
+  radar: { past: { time: number; path: string }[] };
+}
+
+// Last 7 frames ≈ one hour. Keeps tile requests well under RainViewer's
+// limit of 100 requests per minute per IP.
+const FRAME_COUNT = 7;
+const COLOR_SCHEME = 2; // "Universal Blue", the only scheme still offered
+const OPTIONS = "1_1"; // smoothed, snow shown in its own colors
+
+export async function GET(request: NextRequest) {
+  const blocked = forbidCrossSite(request);
+  if (blocked) return blocked;
+
+  try {
+    const index = await fetchJson<RainViewerIndex>("https://api.rainviewer.com/public/weather-maps.json", "RainViewer", {
+      cacheSeconds: 300, // new frames arrive every 10 minutes
+    });
+
+    const frames: RadarFrame[] = index.radar.past.slice(-FRAME_COUNT).map((frame) => ({
+      time: new Date(frame.time * 1000).toISOString(),
+      url: `${index.host}${frame.path}/256/{z}/{x}/{y}/${COLOR_SCHEME}/${OPTIONS}.png`,
+    }));
+
+    return NextResponse.json(frames);
+  } catch (error) {
+    return errorResponse(error);
+  }
+}