From 191e2b8a8323051352db6edd0a5cb541a371b0ff Mon Sep 17 00:00:00 2001
From: Mark <mark@zorin1>
Date: Sun, 15 Mar 2026 18:00:55 -0400
Subject: [PATCH] fix: add stall detection to resumable downloader

Axios stream timeout only covers initial connection, not the body.
Once streaming starts, a stalled server would hang indefinitely.

- Added stallTimeout param (default 60s) to DoResumableDownloadParams
- Reset a timer on every received chunk; abort if no data arrives within the window
- Treat stall errors as retriable network errors in doResumableDownloadWithRetry
  so partial downloads can resume from where they left off
---
 admin/app/utils/downloads.ts | 27 ++++++++++++++++++++++++++-
 admin/types/downloads.ts     |  2 ++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/admin/app/utils/downloads.ts b/admin/app/utils/downloads.ts
index 7c36378..6bc96a8 100644
--- a/admin/app/utils/downloads.ts
+++ b/admin/app/utils/downloads.ts
@@ -18,6 +18,7 @@ export async function doResumableDownload({
   url,
   filepath,
   timeout = 30000,
+  stallTimeout = 60000,
   signal,
   onProgress,
   onComplete,
@@ -88,11 +89,30 @@ export async function doResumableDownload({
     let lastProgressTime = Date.now()
     let lastDownloadedBytes = startByte
 
+    // Stall detection: abort if no data received within stallTimeout ms
+    let lastReceivedBytes = startByte
+    let stallTimer = setTimeout(() => {
+      cleanup(new Error(`Download stalled: no data received for ${stallTimeout}ms from ${url}`))
+    }, stallTimeout)
+
+    const resetStallTimer = () => {
+      clearTimeout(stallTimer)
+      stallTimer = setTimeout(() => {
+        cleanup(new Error(`Download stalled: no data received for ${stallTimeout}ms from ${url}`))
+      }, stallTimeout)
+    }
+
     // Progress tracking stream to monitor data flow
     const progressStream = new Transform({
       transform(chunk: Buffer, _: any, callback: Function) {
         downloadedBytes += chunk.length
 
+        // Reset stall timer on every chunk received
+        if (downloadedBytes > lastReceivedBytes) {
+          lastReceivedBytes = downloadedBytes
+          resetStallTimer()
+        }
+
         // Update progress tracking
         const now = Date.now()
         if (onProgress && now - lastProgressTime >= 500) {
@@ -118,6 +138,7 @@ export async function doResumableDownload({
 
     // Handle errors and cleanup
     const cleanup = (error?: Error) => {
+      clearTimeout(stallTimer)
       progressStream.destroy()
       response.data.destroy()
       writeStream.destroy()
@@ -136,6 +157,7 @@ export async function doResumableDownload({
     })
 
     writeStream.on('finish', async () => {
+      clearTimeout(stallTimer)
       if (onProgress) {
         onProgress({
           downloadedBytes,
@@ -191,7 +213,10 @@ export async function doResumableDownloadWithRetry({
 
       const isAborted = error.name === 'AbortError' || error.code === 'ABORT_ERR'
       const isNetworkError =
-        error.code === 'ECONNRESET' || error.code === 'ENOTFOUND' || error.code === 'ETIMEDOUT'
+        error.code === 'ECONNRESET' ||
+        error.code === 'ENOTFOUND' ||
+        error.code === 'ETIMEDOUT' ||
+        (error.message as string)?.includes('stalled')
 
       onAttemptError?.(error, attempt)
       if (isAborted) {
diff --git a/admin/types/downloads.ts b/admin/types/downloads.ts
index 11734f6..9652186 100644
--- a/admin/types/downloads.ts
+++ b/admin/types/downloads.ts
@@ -7,6 +7,8 @@ export type DoResumableDownloadParams = {
   onProgress?: (progress: DoResumableDownloadProgress) => void
   onComplete?: (url: string, path: string) => void | Promise<void>
   forceNew?: boolean
+  /** How long (ms) to wait without receiving data before aborting. Defaults to 60000 (60s). */
+  stallTimeout?: number
 }
 
 export type DoResumableDownloadWithRetryParams = DoResumableDownloadParams & {