perf(producer): download a remote video once per render (#6637)

packages/producer/src/services/htmlCompiler.remoteDownloadOnce.test.ts

@@ -0,0 +1,39 @@
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, expect, it, vi } from "vitest";
+import { compileForRender } from "./htmlCompiler.js";
+
+const downloads = vi.hoisted(() => [] as { url: string; destDir: string }[]);
+vi.mock("../utils/urlDownloader.js", async (importOriginal) => ({
+  ...(await importOriginal<typeof import("../utils/urlDownloader.js")>()),
+  downloadToTemp: async (url: string, destDir: string) => {
+    downloads.push({ url, destDir });
+    throw new Error("offline test");
+  },
+  fetchPublicHttpsText: async () => {
+    throw new Error("offline test");
+  },
+}));
+
+const dirs: string[] = [];
+afterEach(() => {
+  downloads.length = 0;
+  for (const dir of dirs.splice(0)) rmSync(dir, { recursive: true, force: true });
+});
+
+// The download cache is keyed by url and folder: one folder is what makes the second request a cache hit.
+it("asks for a remote video in one folder for both its duration probe and its localisation", async () => {
+  const dir = mkdtempSync(join(tmpdir(), "hf-remote-once-"));
+  dirs.push(dir);
+  const url = "https://media.example.com/clip.mp4";
+  const htmlPath = join(dir, "index.html");
+  writeFileSync(
+    htmlPath,
+    `<!doctype html><html><body><main data-composition-id="root" data-start="0" data-width="16" data-height="16"><video id="v" muted src="${url}" data-start="0" data-track-index="0"></video></main></body></html>`,
+  );
+  await compileForRender(dir, htmlPath, join(dir, "out"), { allowSystemFontCapture: false });
+  const forClip = downloads.filter((call) => call.url === url);
+  expect(forClip.length).toBeGreaterThanOrEqual(2);
+  expect(new Set(forClip.map((call) => call.destDir)).size).toBe(1);
+});

packages/producer/src/services/htmlCompiler.ts

@@ -504,9 +504,10 @@ async function resolveMediaDuration(
   let filePath = src;
 
   if (isHttpUrl(src)) {
-    if (!existsSync(downloadDir)) mkdirSync(downloadDir, { recursive: true });
+    const remoteDir = join(downloadDir, REMOTE_MEDIA_SUBDIR);
+    if (!existsSync(remoteDir)) mkdirSync(remoteDir, { recursive: true });
     try {
-      filePath = await downloadToTemp(src, downloadDir, undefined, undefined, undefined, {
+      filePath = await downloadToTemp(src, remoteDir, undefined, undefined, undefined, {
         onTelemetry: logRemoteDownloadTelemetry,
       });
     } catch {