refactor(media): share response size limiter

src/media/read-response-with-limit.ts

@@ -0,0 +1,52 @@
+export async function readResponseWithLimit(
+  res: Response,
+  maxBytes: number,
+  opts?: {
+    onOverflow?: (params: { size: number; maxBytes: number; res: Response }) => Error;
+  },
+): Promise<Buffer> {
+  const onOverflow =
+    opts?.onOverflow ??
+    ((params: { size: number; maxBytes: number }) =>
+      new Error(`Content too large: ${params.size} bytes (limit: ${params.maxBytes} bytes)`));
+
+  const body = res.body;
+  if (!body || typeof body.getReader !== "function") {
+    const fallback = Buffer.from(await res.arrayBuffer());
+    if (fallback.length > maxBytes) {
+      throw onOverflow({ size: fallback.length, maxBytes, res });
+    }
+    return fallback;
+  }
+
+  const reader = body.getReader();
+  const chunks: Uint8Array[] = [];
+  let total = 0;
+  try {
+    while (true) {
+      const { done, value } = await reader.read();
+      if (done) {
+        break;
+      }
+      if (value?.length) {
+        total += value.length;
+        if (total > maxBytes) {
+          try {
+            await reader.cancel();
+          } catch {}
+          throw onOverflow({ size: total, maxBytes, res });
+        }
+        chunks.push(value);
+      }
+    }
+  } finally {
+    try {
+      reader.releaseLock();
+    } catch {}
+  }
+
+  return Buffer.concat(
+    chunks.map((chunk) => Buffer.from(chunk)),
+    total,
+  );
+}