fix(wind): bound GFS acquisition and preserve canvas trails and lifecycle

CHANGELOG.md

@@ -227,7 +227,7 @@ of current runtime behavior, see [`docs/CURRENT-STATE.md`](docs/CURRENT-STATE.md
   and are corrected with the calibration gizmo. `CCTV_CALGARY_MAX_SOURCES` sets
   the cap and `CCTV_CALGARY_ENABLED=0` turns the pack off.
 
-- Add a keyless **Wind** layer from NOAA GFS 10 m wind. The `/api/wind` proxy
+- Add a keyless **Wind** layer from NOAA GFS 10 m wind (#459, thanks @beneduzi). The `/api/wind` proxy
   byte-range fetches only the UGRD/VGRD GRIB2 messages from the public AWS bucket,
   decodes them with ecCodes (WASM), and serves a compact Float32 U/V grid; the
   client renders nullschool-style animated particles in a canvas overlay that

docs/CURRENT-STATE.md

@@ -1,5 +1,7 @@
 # God's Eye View Current State
 
+Wind is an optional GFS 10 m forecast overlay. Source acquisition has deadline and body budgets, disconnect cancellation and one-minute failure backoff. The row distinguishes model issue time from forecast valid time. Animation starts only with a field, stops on disable/destruction, preserves trails between unchanged canvas dimensions and scales from 200 to 4,000 particles with viewport area. Application catalog construction owns each instance.
+
 Place search accepts an explicit Nominatim provider with independently configured search and reverse endpoints. The default offline/Google/Photon/local-fallback order is unchanged when no provider is selected. Provider adapters share normalized coordinates, viewport framing and reverse labels; roads and boundary geometry remain separate services. Portable capped-response and Overpass lexical helpers are exported independently of the Node server.
 
 Reference feed construction is exported through `sources/reference`; the cable source also has a dedicated `layers/submarine-cables/source` entry. Standalone catalog compatibility remains available. Source choices, data and attribution are unchanged.

scripts/package-boundaries.json

@@ -1192,6 +1192,7 @@
       "src/layers/wind/model.js",
       "src/layers/wind/rendering.js",
       "src/layers/wind/source.js",
+      "src/sources/windBody.js",
       "src/data/detection.js",
       "src/data/detectionCohort.js",
       "src/data/detectionDraw.js",

server/providers/wind.js

@@ -40,6 +40,9 @@ export function windProxy({
   let cached = null;
   /** @type {?Promise<object>} */
   let loading = null;
+  let lastAttempt = -Infinity;
+  let controller = null;
+  let waiters = 0;
 
   const sendJson = (res, value, status = 200) => {
     res.writeHead(status, {
@@ -58,14 +61,19 @@ export function windProxy({
     if (cached && cached.id === id && now() - cached.fetchedAt < ttlMs)
       return cached;
     if (loading) return loading;
+    if (cached && now() - lastAttempt < 60_000) return cached;
+    lastAttempt = now();
+    controller = new AbortController();
+    const signal = controller.signal;
+    const timer = setTimeout(() => controller.abort(), 40_000);
     loading = (async () => {
       try {
         const base = `https://${GFS_BUCKET}.s3.amazonaws.com/${gfsObjectKey(cycle)}`;
-        const index = await fetchText({ url: `${base}.idx`, fetchImpl });
+        const index = await fetchText({ url: `${base}.idx`, fetchImpl, signal });
         const ranges = windMessageRanges(parseGfsIdx(index.toString()));
         const [uBuffer, vBuffer] = await Promise.all([
-          fetchRange({ url: base, ...ranges.u, fetchImpl }),
-          fetchRange({ url: base, ...ranges.v, fetchImpl }),
+          fetchRange({ url: base, ...ranges.u, fetchImpl, signal }),
+          fetchRange({ url: base, ...ranges.v, fetchImpl, signal }),
         ]);
         const [u, v] = await Promise.all([
           decodeImpl(uBuffer),
@@ -83,11 +91,13 @@ export function windProxy({
           dx: targetDx,
           dy: targetDx,
         });
+        signal.throwIfAborted();
+        if ((!grid.u.every(Number.isFinite) || !grid.v.every(Number.isFinite))) throw new Error('Invalid wind grid');
         const idGrid = `${id}-${targetDx}`;
         const manifest = {
           schemaVersion: 1,
           model: 'gfs',
-          cycle: { ...cycle, forecastHour: 0, runIso: cycleRunIso(cycle) },
+          cycle: { ...cycle, forecastHour: 0, runIso: cycleRunIso(cycle), validIso: cycleRunIso(cycle) },
           fetchedAt: now(),
           level: '10 m above ground',
           units: 'm/s',
@@ -110,7 +120,7 @@ export function windProxy({
         if (cached) {
           cached = {
             ...cached,
-            manifest: { ...cached.manifest, stale: true, reason: error.message },
+            manifest: { ...cached.manifest, stale: true, reason: 'Wind upstream unavailable' },
           };
         } else {
           cached = {
@@ -123,13 +133,15 @@ export function windProxy({
               model: 'gfs',
               stale: true,
               unavailable: true,
-              reason: error.message,
+              reason: 'Wind upstream unavailable',
             },
           };
         }
         return cached;
       } finally {
+        clearTimeout(timer);
         loading = null;
+        controller = null;
       }
     })();
     return loading;
@@ -137,7 +149,18 @@ export function windProxy({
 
   const handler = async (req, res) => {
     const path = new URL(req.url, 'http://localhost').pathname;
-    const state = await refresh();
+    if (req.method !== 'GET') return sendJson(res, { error: 'method_not_allowed' }, 405);
+    if (!['/', '/manifest', '/status'].includes(path) && !/^\/grid\/[\w.-]+\.bin$/.test(path)) return sendJson(res, { error: 'not_found' }, 404);
+    // Grid reads never initiate acquisition; an issued manifest owns its cached grid.
+    if (path.startsWith('/grid/') && (!cached?.grid || path !== `/grid/${cached.idGrid}.bin`)) return sendJson(res, { error: 'unknown_grid' }, 404);
+    let disconnected = false;
+    const close = () => { disconnected = true; waiters -= 1; if (waiters === 0) controller?.abort(); };
+    waiters += 1;
+    res.once?.('close', close);
+    let state;
+    try { state = path.startsWith('/grid/') ? cached : await refresh(); }
+    finally { res.removeListener?.('close', close); if (!disconnected) waiters -= 1; }
+    if (disconnected) return;
     if (path === '/status') {
       const { gridUrl, ...manifest } = state.manifest;
       return sendJson(res, manifest);

server/providers/wind/decode.js

@@ -1,7 +1,6 @@
 import os from 'node:os';
 import path from 'node:path';
 import { promises as fs } from 'node:fs';
-import { randomUUID } from 'node:crypto';
 
 /**
  * Lazily created ecCodes WASM instance. The `@meri-imperiumi/eccodes-wasm`
@@ -37,12 +36,12 @@ export async function decodeWindGribMessage(
   { eccodesModule, mountDir = os.tmpdir() } = {},
 ) {
   const eccodes = eccodesModule ?? (await loadEccodes());
-  const name = `wind-${randomUUID()}.grib2`;
-  const file = path.join(mountDir, name);
-  await fs.writeFile(file, buffer);
+  const directory = await fs.mkdtemp(path.join(mountDir, 'gev-wind-'));
+  const file = path.join(directory, 'wind.grib2');
+  await fs.writeFile(file, buffer, { mode: 0o600 });
   let handle = null;
   try {
-    eccodes.mountFilesystem(mountDir);
+    eccodes.mountFilesystem(directory);
     handle = eccodes.openGrib(file);
     return {
       ni: handle.getLong('Ni'),
@@ -58,6 +57,6 @@ export async function decodeWindGribMessage(
     };
   } finally {
     if (handle) handle.delete();
-    await fs.unlink(file).catch(() => {});
+    await fs.rm(directory, { recursive: true, force: true }).catch(() => {});
   }
 }

server/providers/wind/gfs.js

@@ -1,3 +1,4 @@
+import { readWindBody } from '../../../src/sources/windBody.js';
 /**
  * Parse a GFS `.idx` inventory into ordered message records.
  *
@@ -55,9 +56,9 @@ export function windMessageRanges(parsed, { level = '10 m above ground' } = {})
 
 /** Fetch a bounded text response as a Buffer. */
 export async function fetchText({ url, fetchImpl = fetch, signal }) {
-  const response = await fetchImpl(url, { signal });
-  if (!response.ok) throw new Error(`HTTP ${response.status}`);
-  return Buffer.from(await response.arrayBuffer());
+  const response = await fetchImpl(url, { signal, redirect: 'error' });
+  if (!response.ok) { await response.body?.cancel(); throw new Error('Wind upstream unavailable'); }
+  return Buffer.from(await readWindBody(response, 2 * 1024 * 1024, signal));
 }
 
 /**
@@ -72,17 +73,17 @@ export async function fetchRange({
   signal,
   maxBytes = 8 * 1024 * 1024,
 }) {
-  if (end < start || end - start + 1 > maxBytes)
+  if (!Number.isSafeInteger(start) || !Number.isSafeInteger(end) || start < 0 || end < start || end - start + 1 > maxBytes)
     throw new Error('range too large');
   const response = await fetchImpl(url, {
     signal,
+    redirect: 'error',
     headers: { Range: `bytes=${start}-${end}` },
   });
   const validStatus =
     response.status === 206 || (response.status === 200 && start === 0);
-  if (!validStatus || !response.ok)
-    throw new Error(`invalid range response ${response.status}`);
-  const buffer = Buffer.from(await response.arrayBuffer());
+  if (!validStatus || !response.ok) { await response.body?.cancel(); throw new Error('Wind upstream unavailable'); }
+  const buffer = Buffer.from(await readWindBody(response, end - start + 1, signal));
   if (buffer.length !== end - start + 1)
     throw new Error('invalid range length');
   return buffer;

server/providers/wind/grid.js

@@ -21,6 +21,8 @@ export function resampleWindGrid({
   dx = 1,
   dy = 1,
 }) {
+  if (!Number.isInteger(ni) || !Number.isInteger(nj) || ni < 1 || nj < 1 || ni * nj > 2_000_000 || u?.length !== ni * nj || v?.length !== ni * nj || ![lo1, la1, di, dj, dx, dy].every(Number.isFinite) || di <= 0 || dj <= 0 || dx < 0.25 || dy < 0.25 || dx > 180 || dy > 180)
+    throw new Error('Invalid wind grid geometry');
   const nx = Math.round(360 / dx);
   const ny = Math.round(180 / dy) + 1;
   const outU = new Float32Array(nx * ny);

src/data/windGfs.test.mjs

@@ -11,3 +11,11 @@ test('catalog and index helpers', async () => {
   assert.deepEqual([...b], [1, 2, 3]);
   assert.throws(() => windMessageRanges({ messages: p.messages.slice(0, 1) }));
 });
+
+test('wind range fetch rejects invalid offsets and caps chunked bodies', async () => {
+  await assert.rejects(fetchRange({ url: 'x', start: -1, end: 2 }), /range too large/);
+  let cancelled = false;
+  const body = new ReadableStream({ pull(controller) { controller.enqueue(new Uint8Array(10)); }, cancel() { cancelled = true; } });
+  await assert.rejects(fetchRange({ url: 'x', start: 0, end: 2, fetchImpl: async () => new Response(body, { status: 206 }) }), /budget/);
+  assert.equal(cancelled, true);
+});

src/data/windProxy.test.mjs

@@ -156,7 +156,7 @@ test('wind serves last-good with stale on upstream failure', async () => {
   clock += 2 * 3600_000;
   const degraded = JSON.parse((await request('/')).body);
   assert.equal(degraded.stale, true);
-  assert.equal(degraded.reason, 'gfs upstream down');
+  assert.equal(degraded.reason, 'Wind upstream unavailable');
   const frame = await request(good.gridUrl.replace('/api/wind', ''));
   assert.equal(frame.statusCode, 200, 'last-good grid stays addressable');
 });

src/layers/wind/index.js

@@ -1,17 +1,24 @@
 import * as Cesium from 'cesium';
 import { createWindRendering } from './rendering.js';
 
-/** Summarize a wind manifest for the layer status surface. */
+/** Format a forecast timestamp explicitly in UTC. */
+export function formatWindValidTime(value) {
+  const ms = Date.parse(value);
+  return Number.isFinite(ms) ? `${new Date(ms).toISOString().slice(0, 16).replace('T', ' ')} UTC` : null;
+}
+
+/** Forecast issue time is source age; valid time is reported separately. */
 export function windStats(manifest) {
+  const run = Date.parse(manifest?.cycle?.runIso);
   return {
     count: manifest?.grid ? manifest.grid.nx * manifest.grid.ny : 0,
-    lastUpdate: manifest?.cycle?.runIso ? Date.parse(manifest.cycle.runIso) : manifest?.fetchedAt ?? null,
-    error: manifest?.unavailable ? manifest.reason || 'Wind unavailable' : manifest?.reason || null,
+    lastUpdate: Number.isFinite(run) ? run : null,
+    error: manifest?.reason || (manifest?.unavailable ? 'Wind unavailable' : null),
   };
 }
 
-/** Create the GFS wind data layer. */
-export function createWindLayer({ feed, cesium = Cesium, container, services } = {}) {
+/** Construct one wind layer with an explicit source and owned animation. */
+export function createWindLayer({ feed, cesium = Cesium, container, createRendering = createWindRendering } = {}) {
   if (typeof feed?.getSnapshot !== 'function') throw new TypeError('Wind requires a snapshot source');
   let viewer = null;
   let request = null;
@@ -19,31 +26,57 @@ export function createWindLayer({ feed, cesium = Cesium, container, services } =
   let rendering = null;
   let manifest = null;
   let error = null;
+  let loading = false;
+  let rowControlsListener = null;
+  const notify = () => rowControlsListener?.();
   const layer = {
-    id: 'wind', name: 'Wind', icon: '🌬', source: 'NOAA GFS', updateInterval: 3600_000,
-    init(nextViewer) { viewer = nextViewer; rendering = createWindRendering({ cesium, container: nextViewer.container, getViewer: () => viewer }); rendering.attach(); },
+    id: 'wind', name: 'Wind', icon: '🌬', source: 'NOAA GFS · FORECAST', updateInterval: 3600_000,
+    init(nextViewer) {
+      viewer = nextViewer;
+      rendering = createRendering({ cesium, container: container ?? nextViewer.container, getViewer: () => viewer });
+      rendering.attach();
+    },
     enable() { enabled = true; rendering?.start(); },
-    disable() { request?.abort(); request = null; enabled = false; rendering?.stop(); rendering?.clear(); },
+    disable() {
+      enabled = false;
+      request?.abort(); request = null; loading = false;
+      rendering?.stop(); rendering?.clear();
+    },
     async update(nextViewer, { signal } = {}) {
       if (!enabled) return false;
       request?.abort();
       const controller = new AbortController();
+      const abort = () => controller.abort(signal.reason);
+      signal?.addEventListener('abort', abort, { once: true });
       request = controller;
+      loading = true;
+      notify();
       try {
-        const snapshot = await feed.getSnapshot({ signal: signal || controller.signal });
-        if (!enabled || controller.signal.aborted || signal?.aborted) return false;
+        signal?.throwIfAborted();
+        const snapshot = await feed.getSnapshot({ signal: controller.signal });
+        if (!enabled || controller.signal.aborted || request !== controller) return false;
         manifest = snapshot;
         error = null;
-        if (!snapshot.unavailable) rendering.setField(snapshot);
+        if (snapshot.unavailable) { rendering.stop(); rendering.clear(); }
+        else { rendering.setField(snapshot); rendering.start(); }
         return true;
       } catch (cause) {
-        if (controller.signal.aborted || signal?.aborted) return false;
+        if (controller.signal.aborted || request !== controller) return false;
         error = cause?.message || 'Wind source unavailable';
         return true;
-      } finally { if (request === controller) request = null; }
+      } finally {
+        signal?.removeEventListener('abort', abort);
+        if (request === controller) { request = null; loading = false; notify(); }
+      }
     },
-    destroy() { request?.abort(); request = null; enabled = false; rendering?.destroy(); rendering = null; viewer = null; },
-    getStats() { return { ...windStats(manifest), error: error || windStats(manifest).error }; },
+    getRowControls() {
+      const valid = formatWindValidTime(manifest?.cycle?.validIso);
+      const run = formatWindValidTime(manifest?.cycle?.runIso);
+      return { chips: [], legend: [], info: `GFS forecast · Valid: ${valid || 'Unavailable'} · Issued: ${run || 'Unavailable'}${manifest?.stale ? ' · STALE' : ''}` };
+    },
+    setRowControlsListener(listener) { rowControlsListener = typeof listener === 'function' ? listener : null; },
+    destroy() { layer.disable(); rendering?.destroy(); rendering = null; viewer = null; rowControlsListener = null; },
+    getStats() { return { ...windStats(manifest), loading, error: error || windStats(manifest).error }; },
     getParticleCount() { return rendering?.getParticleCount() || 0; },
   };
   return layer;

src/layers/wind/rendering.js

@@ -20,6 +20,7 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
   let cssWidth = 1;
   let cssHeight = 1;
   let warned = false;
+  let cameraSignature = null;
 
   const randomParticle = () => ({
     lon: Math.random() * 360 - 180,
@@ -60,7 +61,7 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
   };
 
   const budget = () =>
-    Math.max(4000, Math.min(12000, Math.floor((cssWidth * cssHeight) / 150)));
+    Math.max(200, Math.min(4000, Math.floor((cssWidth * cssHeight) / 300)));
 
   const seed = () => {
     particles = [];
@@ -74,8 +75,12 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
     const sceneCanvas = viewer?.scene?.canvas;
     cssWidth = sceneCanvas?.clientWidth || container?.clientWidth || 1;
     cssHeight = sceneCanvas?.clientHeight || container?.clientHeight || 1;
-    canvas.width = Math.floor(cssWidth * ratio);
-    canvas.height = Math.floor(cssHeight * ratio);
+    const width = Math.floor(cssWidth * ratio);
+    const height = Math.floor(cssHeight * ratio);
+    // Assigning either dimension clears a real canvas, even if unchanged.
+    if (canvas.width === width && canvas.height === height) return;
+    canvas.width = width;
+    canvas.height = height;
     canvas.style.width = `${cssWidth}px`;
     canvas.style.height = `${cssHeight}px`;
     context.setTransform?.(ratio, 0, 0, ratio, 0, 0);
@@ -96,6 +101,13 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
     if (!viewer || viewer.isDestroyed?.()) return;
     try {
       resize(viewer);
+      if (particles.length !== budget()) seed();
+      const camera = viewer.scene.camera;
+      const signature = [camera?.positionWC?.x, camera?.positionWC?.y, camera?.positionWC?.z, camera?.heading, camera?.pitch, camera?.roll].join(',');
+      if (signature !== cameraSignature) {
+        context.clearRect(0, 0, cssWidth, cssHeight);
+        cameraSignature = signature;
+      }
       const dt = lastTime ? Math.min(1, Math.max(0, (time - lastTime) / 1000)) : 0.016;
       lastTime = time;
       // Fade previous trails by ERASING them (destination-out). A translucent
@@ -103,10 +115,7 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
       context.globalCompositeOperation = 'destination-out';
       context.fillStyle = 'rgba(0, 0, 0, 0.02)';
       context.fillRect(0, 0, cssWidth, cssHeight);
-      if (!field) {
-        frame = globalThis.requestAnimationFrame(draw);
-        return;
-      }
+      if (!field) return;
       const scene = viewer.scene;
       // Real wind (m/s) is invisible at globe scale, so the advection is
       // exaggerated in proportion to camera height: the same visual speed is
@@ -181,10 +190,11 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
     },
     /** Install a wind field and (re)seed particles. */
     setField(next) {
-      field = next;
+      field = next?.grid ? { ...next.grid, u: next.u, v: next.v } : next;
       if (canvas) {
         resize(getViewer?.());
         seed();
+        if (running && frame === null) frame = globalThis.requestAnimationFrame(draw);
       }
     },
     /** Start the animation loop. Safe to call before a field is installed. */
@@ -192,7 +202,7 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
       if (running || !canvas) return;
       running = true;
       lastTime = 0;
-      frame = globalThis.requestAnimationFrame(draw);
+      if (field) frame = globalThis.requestAnimationFrame(draw);
     },
     /** Stop the animation loop. */
     stop() {
@@ -202,6 +212,7 @@ export function createWindRendering({ cesium, container, getViewer } = {}) {
     },
     /** Clear the canvas and particles without removing the canvas. */
     clear() {
+      field = null;
       particles = [];
       context?.clearRect(0, 0, cssWidth, cssHeight);
     },

src/layers/wind/rendering.test.mjs

@@ -82,7 +82,7 @@ test('wind rendering owns the canvas and particle lifecycle', () => {
   rendering.attach();
   assert.equal(typeof canvas.getContext('2d'), 'object');
   rendering.setField(FIELD);
-  assert.ok(rendering.getParticleCount() >= 3000);
+  assert.ok(rendering.getParticleCount() >= 200);
   rendering.start();
   callbacks.shift()(16);
   assert.ok(strokes.length > 0, 'a driven frame draws trails');
@@ -99,10 +99,7 @@ test('wind rendering starts before a field and still draws once one arrives', ()
   const { rendering, callbacks, strokes } = harness();
   rendering.attach();
   rendering.start();
-  // No field yet: the loop must keep scheduling instead of throwing.
-  const before = callbacks.shift();
-  before(16);
-  assert.equal(callbacks.length, 1, 'the loop reschedules without a field');
+  assert.equal(callbacks.length, 0, 'no animation work before a field arrives');
   rendering.setField(FIELD);
   callbacks.shift()(32);
   assert.ok(strokes.length > 0, 'draws once the field is installed');
@@ -118,3 +115,22 @@ test('wind rendering skips particles hidden by the globe', () => {
   assert.equal(strokes.length, 0, 'no trail is drawn for an occluded point');
   rendering.stop();
 });
+
+// HTML canvas dimension setters erase pixels even on an identical assignment.
+test('steady frames preserve canvas dimensions and resize adjusts the particle budget', () => {
+  const { rendering, canvas, callbacks } = harness();
+  let resets = 0; let width = 0; let height = 0;
+  Object.defineProperties(canvas, {
+    width: { get: () => width, set: value => { width = value; resets++; } },
+    height: { get: () => height, set: value => { height = value; resets++; } },
+  });
+  rendering.attach(); rendering.setField({ grid: FIELD, u: FIELD.u, v: FIELD.v }); rendering.start();
+  const initial = resets;
+  callbacks.shift()(16); callbacks.shift()(32);
+  assert.equal(resets, initial, 'steady frames must not invoke canvas dimension setters');
+  canvas.clientWidth = 320; canvas.clientHeight = 240;
+  callbacks.shift()(48);
+  assert.equal(resets, initial + 2);
+  assert.ok(rendering.getParticleCount() < 500, 'small view uses a smaller budget');
+  rendering.destroy();
+});

src/layers/wind/source.js

@@ -1,33 +1,35 @@
-/** Create a source that loads the current GFS wind field. */
-export function createWindSource({ fetchImpl = (...args) => globalThis.fetch(...args) } = {}) {
+import { readWindBody } from '../../sources/windBody.js';
+
+/** Create a bounded, cancellable source for the same-origin wind provider. */
+export function createWindSource({ fetchImpl = (...args) => globalThis.fetch(...args), timeoutMs = 45_000 } = {}) {
   return {
     async getSnapshot({ signal } = {}) {
-      signal?.throwIfAborted();
-      const response = await fetchImpl('/api/wind/manifest', {
-        signal,
-        cache: 'no-store',
-      });
-      signal?.throwIfAborted();
-      if (!response.ok) throw new Error(`Wind HTTP ${response.status}`);
-      const manifest = await response.json();
-      signal?.throwIfAborted();
-      if (!manifest?.grid || !manifest.gridUrl)
-        throw new Error('Malformed wind manifest');
-      if (manifest.unavailable) return manifest;
-      const gridResponse = await fetchImpl(manifest.gridUrl, { signal });
-      signal?.throwIfAborted();
-      if (!gridResponse.ok) throw new Error(`Wind HTTP ${gridResponse.status}`);
-      const buffer = await gridResponse.arrayBuffer();
-      signal?.throwIfAborted();
-      const count = manifest.grid.nx * manifest.grid.ny;
-      if (buffer.byteLength !== count * 8)
-        throw new Error('Malformed wind grid');
-      const values = new Float32Array(buffer);
-      return {
-        ...manifest,
-        u: values.slice(0, count),
-        v: values.slice(count),
-      };
+      const controller = new AbortController();
+      const abort = () => controller.abort(signal.reason);
+      signal?.addEventListener('abort', abort, { once: true });
+      const timer = setTimeout(() => controller.abort(new Error('Wind request timed out')), timeoutMs);
+      const active = controller.signal;
+      try {
+        signal?.throwIfAborted();
+        const response = await fetchImpl('/api/wind/manifest', { signal: active, cache: 'no-store', redirect: 'error' });
+        if (!response.ok) throw new Error(`Wind HTTP ${response.status}`);
+        const manifest = JSON.parse(new TextDecoder().decode(await readWindBody(response, 16_384, active)));
+        if (manifest?.unavailable) return manifest;
+        const grid = manifest?.grid;
+        if (manifest?.model !== 'gfs' || !grid || !Number.isInteger(grid.nx) || !Number.isInteger(grid.ny) || grid.nx < 1 || grid.ny < 1 || grid.nx * grid.ny > 1_000_000 || ![grid.lo1, grid.la1, grid.dx, grid.dy].every(Number.isFinite) || grid.dx <= 0 || grid.dy <= 0 || Math.abs(grid.nx * grid.dx - 360) > 0.01 || !/^\/api\/wind\/grid\/[\w.-]+\.bin$/.test(manifest.gridUrl))
+          throw new Error('Malformed wind manifest');
+        const count = grid.nx * grid.ny;
+        const gridResponse = await fetchImpl(manifest.gridUrl, { signal: active, redirect: 'error' });
+        if (!gridResponse.ok) throw new Error(`Wind HTTP ${gridResponse.status}`);
+        const bytes = await readWindBody(gridResponse, count * 8, active);
+        if (bytes.byteLength !== count * 8) throw new Error('Malformed wind grid');
+        const values = new Float32Array(bytes.buffer);
+        if (!values.every(Number.isFinite)) throw new Error('Malformed wind grid');
+        return { ...manifest, u: values.slice(0, count), v: values.slice(count) };
+      } finally {
+        clearTimeout(timer);
+        signal?.removeEventListener('abort', abort);
+      }
     },
   };
 }

src/layers/wind/source.test.mjs

@@ -1,24 +1,25 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createWindSource } from './source.js';
-
-const manifest = { grid: { nx: 2, ny: 1 }, gridUrl: '/grid.bin', unavailable: false };
-const response = (body, ok = true, status = 200) => ({ ok, status, json: async () => body, arrayBuffer: async () => body });
-
-test('wind source loads and splits a grid', async () => {
-  const buffer = Float32Array.from([1, 2, 3, 4]).buffer;
-  const source = createWindSource({ fetchImpl: async (url) => url.includes('manifest') ? response(manifest) : response(buffer) });
-  const result = await source.getSnapshot();
-  assert.deepEqual([...result.u], [1, 2]);
-  assert.deepEqual([...result.v], [3, 4]);
+const manifest = { model: 'gfs', grid: { nx: 2, ny: 1, lo1: 0, la1: 90, dx: 180, dy: 180 }, gridUrl: '/api/wind/grid/test.bin' };
+const response = (value) => new Response(typeof value === 'object' && !(value instanceof ArrayBuffer) ? JSON.stringify(value) : value);
+test('wind source splits a bounded field and preserves unavailable responses', async () => {
+  const source = createWindSource({ fetchImpl: async (url) => response(url.includes('manifest') ? manifest : Float32Array.from([1,2,3,4]).buffer) });
+  const field = await source.getSnapshot();
+  assert.deepEqual([...field.u], [1,2]); assert.deepEqual([...field.v], [3,4]);
+  const unavailable = createWindSource({ fetchImpl: async () => response({ unavailable: true }) });
+  assert.equal((await unavailable.getSnapshot()).unavailable, true);
 });
-
-test('wind source handles unavailable and malformed responses', async () => {
-  let calls = 0;
-  const unavailable = { ...manifest, unavailable: true };
-  const source = createWindSource({ fetchImpl: async () => { calls++; return response(unavailable); } });
-  assert.equal((await source.getSnapshot()).unavailable, true);
-  assert.equal(calls, 1);
-  await assert.rejects(() => createWindSource({ fetchImpl: async () => response({}, false, 503) }).getSnapshot(), /Wind HTTP 503/);
-  await assert.rejects(() => createWindSource({ fetchImpl: async () => response(manifest) }).getSnapshot(), /Malformed wind grid/);
+test('wind source rejects foreign URLs, excessive grids and non-finite values', async () => {
+  for (const bad of [{ ...manifest, gridUrl: 'https://example.com/exfil' }, { ...manifest, grid: { ...manifest.grid, nx: 1e9 } }]) {
+    let calls = 0;
+    const source = createWindSource({ fetchImpl: async () => { calls++; return response(bad); } });
+    await assert.rejects(source.getSnapshot(), /Malformed/); assert.equal(calls, 1);
+  }
+  const source = createWindSource({ fetchImpl: async (url) => response(url.includes('manifest') ? manifest : Float32Array.from([NaN,2,3,4]).buffer) });
+  await assert.rejects(source.getSnapshot(), /Malformed/);
+});
+test('wind source timeout aborts the underlying fetch', async () => {
+  const source = createWindSource({ timeoutMs: 5, fetchImpl: (_, { signal }) => new Promise((resolve,reject) => signal.addEventListener('abort', () => reject(signal.reason), { once:true })) });
+  await assert.rejects(source.getSnapshot(), /timed out/);
 });

src/sources/windBody.js

@@ -0,0 +1,35 @@
+/** Read a fetch body under a hard byte budget, including chunked responses. */
+export async function readWindBody(response, maxBytes, signal) {
+  const fail = () => new Error('Wind response exceeds byte budget');
+  if (Number(response.headers?.get('content-length')) > maxBytes) {
+    await response.body?.cancel();
+    throw fail();
+  }
+  const reader = response.body?.getReader();
+  if (!reader) throw new Error('Wind response has no readable body');
+  const chunks = [];
+  let size = 0;
+  const cancel = () => { void reader.cancel().catch(() => {}); };
+  signal?.addEventListener('abort', cancel, { once: true });
+  try {
+    while (true) {
+      signal?.throwIfAborted();
+      const { done, value } = await reader.read();
+      signal?.throwIfAborted();
+      if (done) break;
+      size += value.byteLength;
+      if (size > maxBytes) throw fail();
+      chunks.push(value);
+    }
+    const bytes = new Uint8Array(size);
+    let offset = 0;
+    for (const chunk of chunks) { bytes.set(chunk, offset); offset += chunk.byteLength; }
+    return bytes;
+  } catch (error) {
+    cancel();
+    throw error;
+  } finally {
+    signal?.removeEventListener('abort', cancel);
+    reader.releaseLock();
+  }
+}

src/ui/layerPanel.js

@@ -226,11 +226,11 @@ export class LayerPanel {
     const chips = controls?.chips || [];
     const legend = controls?.legend || [];
     this._syncRowList(listContainer, controls?.list || null);
-    container.hidden = chips.length === 0 && legend.length === 0;
+    container.hidden = chips.length === 0 && legend.length === 0 && !controls?.info;
 
     for (const node of [...container.children]) {
       if (
-        String(node.className).split(/\s+/).includes('data-toggle-legend-item')
+        String(node.className).split(/\s+/).some((name) => ['data-toggle-legend-item', 'data-toggle-controls-info'].includes(name))
       )
         node.remove();
     }
@@ -267,10 +267,17 @@ export class LayerPanel {
       swatch.className = 'data-toggle-legend-swatch';
       swatch.style.background = item.color;
       const text = document.createElement('span');
-      text.textContent = `${item.label} ${this._formatCount(item.count)}`;
+      text.textContent = item.count == null ? String(item.label) : `${item.label} ${this._formatCount(item.count)}`;
       entry.append(swatch, text);
       container.appendChild(entry);
     }
+    if (controls?.info) {
+      const info = document.createElement('div');
+      info.className = 'data-toggle-controls-info';
+      info.textContent = String(controls.info);
+      if (controls.infoTitle) info.title = controls.infoTitle;
+      container.appendChild(info);
+    }
   }
 
   /**

src/ui/styles/radio.css

@@ -888,3 +888,12 @@
   opacity: 0.75;
   font-style: italic;
 }
+
+.data-toggle-controls-info {
+  flex-basis: 100%;
+  font-family: var(--font-mono);
+  font-size: 9px;
+  color: var(--text-secondary);
+  padding-top: 3px;
+  overflow-wrap: anywhere;
+}