[PR #513] [MERGED] fix: image optimizer fallback stream reuse #635

New issue

Closed

opened 2026-05-06 13:09:13 +02:00 by BreizhHardware · 0 comments

BreizhHardware commented

2026-05-06 13:09:13 +02:00

Owner

📋 Pull Request Information

Original PR: https://github.com/cloudflare/vinext/pull/513
Author: @JaredStowell
Created: 3/13/2026
Status: ✅ Merged
Merged: 3/13/2026
Merged by: @james-elicx

Base: main ← Head: jstowell/fix-image-optimizer-fallback

📝 Commits (2)

855211d fix image optimizer fallback
906b47a refetch on failure

📊 Changes

4 files changed (+291 additions, -15 deletions)

View changed files

📝 packages/vinext/src/index.ts (+2 -1)
📝 packages/vinext/src/server/image-optimization.ts (+25 -11)
➕ tests/image-optimization-parity.test.ts (+151 -0)
📝 tests/shims.test.ts (+113 -3)

📄 Description

Fix /_vinext/image fallback behavior when image transformation fails after consuming the source stream.

This also fixes a Pages Router dev-mode parity bug where local image redirects did not percent-encode unicode paths in the Location header.

Root cause

The image optimization path on Workers streams the source image into the transform handler. If the transform implementation starts consuming the source stream and then throws, the original response body can no longer be reused safely for fallback.

Fix

tries the transform normally
tries to serve the original source response directly if transform fails
re-fetches the source image only if the fallback path cannot reuse the original body because it was already disturbed/locked

This keeps the normal success path streaming and avoids tee-based buffering, while still recovering correctly from consumed-stream failures.

Changes

replace clone-based fallback in the shared image optimizer with refetch-on-failure fallback
preserve cache/security headers on passthrough responses via a shared helper
fix Pages Router dev image redirects to emit percent-encoded Location headers for unicode paths
add regression tests for:
- transform failure before body consumption
- transform failure after body consumption
- refetch fallback header behavior
- refetch fallback 404 behavior
- refetch fallback unsafe-content behavior
add integration tests for local unicode and space-containing image URLs in both App Router and Pages Router

Testing

pnpm test tests/shims.test.ts -t "handleImageOptimization"
pnpm test tests/image-optimization-parity.test.ts
pnpm run fmt
pnpm run typecheck

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/cloudflare/vinext/pull/513 **Author:** [@JaredStowell](https://github.com/JaredStowell) **Created:** 3/13/2026 **Status:** ✅ Merged **Merged:** 3/13/2026 **Merged by:** [@james-elicx](https://github.com/james-elicx) **Base:** `main` ← **Head:** `jstowell/fix-image-optimizer-fallback` --- ### 📝 Commits (2) - [`855211d`](https://github.com/cloudflare/vinext/commit/855211d229be5077f67383cffa0fd5621dbdc1cb) fix image optimizer fallback - [`906b47a`](https://github.com/cloudflare/vinext/commit/906b47a3a441e0831bf98be3d1ca51b0176b047c) refetch on failure ### 📊 Changes **4 files changed** (+291 additions, -15 deletions) <details> <summary>View changed files</summary> 📝 `packages/vinext/src/index.ts` (+2 -1) 📝 `packages/vinext/src/server/image-optimization.ts` (+25 -11) ➕ `tests/image-optimization-parity.test.ts` (+151 -0) 📝 `tests/shims.test.ts` (+113 -3) </details> ### 📄 Description Fix `/_vinext/image` fallback behavior when image transformation fails after consuming the source stream. This also fixes a Pages Router dev-mode parity bug where local image redirects did not percent-encode unicode paths in the `Location` header. ## Root cause The image optimization path on Workers streams the source image into the transform handler. If the transform implementation starts consuming the source stream and then throws, the original response body can no longer be reused safely for fallback. ## Fix 1. tries the transform normally 2. tries to serve the original source response directly if transform fails 3. re-fetches the source image only if the fallback path cannot reuse the original body because it was already disturbed/locked This keeps the normal success path streaming and avoids tee-based buffering, while still recovering correctly from consumed-stream failures. ## Changes - replace clone-based fallback in the shared image optimizer with refetch-on-failure fallback - preserve cache/security headers on passthrough responses via a shared helper - fix Pages Router dev image redirects to emit percent-encoded `Location` headers for unicode paths - add regression tests for: - transform failure before body consumption - transform failure after body consumption - refetch fallback header behavior - refetch fallback 404 behavior - refetch fallback unsafe-content behavior - add integration tests for local unicode and space-containing image URLs in both App Router and Pages Router ## Testing - `pnpm test tests/shims.test.ts -t "handleImageOptimization"` - `pnpm test tests/image-optimization-parity.test.ts` - `pnpm run fmt` - `pnpm run typecheck` --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>