Codex flagged: the previous version cleared the AbortController
timeout in a finally{} block right after \`await fetch()\`, but
fetch() resolves as soon as the response headers arrive — the
body read happened later in the \`reader.read()\` loop with no
timeout protection. An upstream that drip-feeds bytes (or stops
mid-stream) would leave the dev server hanging on
reader.read() forever.
Single AbortController + timeout now covers the entire request
lifecycle (DNS + TLS + headers + body). The clearTimeout moves to
the outer finally{} so it fires regardless of return path
(success, 4xx, 5xx, abort) but never AHEAD of the body read.
Side benefit: AbortError thrown by the controller's timeout (or
by the size-cap controller.abort()) now lands in the catch clause
with a distinguishable error.name === 'AbortError'. Translate it
to a 504 Gateway Timeout when the timeout was the cause, so the
caller can distinguish a slow-upstream from a generic
fetch failure (502).
Codex flagged: the previous version did
\`Buffer.from(await upstream.arrayBuffer())\` which buffers the
entire upstream body into memory with no upper bound. Wikimedia
Commons originals can be 100 MB+, and a malicious request could
point at any arbitrarily-large file on an allow-listed host (an
upstream big enough to OOM the dev server is reachable behind
plenty of legitimate-looking URLs).
Hard 16 MiB cap on every proxied response:
- Read upstream's declared Content-Length first; reject (413) if
it already advertises more than the cap, before reading a single
byte.
- Stream the body via \`getReader()\`, accumulate in chunks, and
bail (cancel reader, abort fetch, return 413) the moment total
bytes cross the cap. Subsequent chunks are never buffered.
- Move the timeout from \`AbortSignal.timeout(15000)\` to a manual
AbortController so the same controller can also abort on
size-limit hit.
16 MiB sits well above any reasonable thumbnail and even high-res
4K JPEGs (~5–8 MiB), but well below the territory that risks
heap pressure from a single fetch.
Image #40 logs showed three "Failed to load image" errors for
api.openverse.org/...thumb/ URLs even though the search-pipeline
successfully fetched URLs from openverse via the dev server (the
HTTPS_PROXY fix from 3a6f8480 routes server-side fetches through the
local proxy). The browser-side image loader doesn't go through the
same dispatcher: \`new Image(); img.src = url\` does a direct
browser fetch that ignores HTTP_PROXY env vars, so on a machine that
requires the proxy to reach openverse.org the canvas paints the
placeholder visual even though the search-pipeline already found a
valid image URL.
New endpoint \`/api/ai/image-proxy?url=<encoded-url>\`:
- Proxies image bytes through the dev server.
- Reuses \`configureProxyDispatcher\` so the upstream fetch routes
through HTTPS_PROXY (same path as image-search).
- Allow-lists known image hosts (openverse, wikimedia, flickr's
static CDN) to prevent the dev server being used as an open
proxy. Unknown hosts get 403.
- Forwards Content-Type and Cache-Control from upstream.
- Sets Access-Control-Allow-Origin: * so canvas readback works.
\`mapOpenverseResult\` and \`mapWikimediaPages\` now return thumbUrl
wrapped via \`viaImageProxy(externalUrl)\`. The browser fetches
\`/api/ai/image-proxy?url=...\` (same-origin, no proxy needed),
the server fetches the upstream (with proxy), bytes flow back,
the canvas paints the photo. Test expectations updated to assert
the proxy wrapper.
Net effect: with HTTPS_PROXY set, image search end-to-end (search
results found AND images actually load in canvas) works on
proxy-required dev machines. With no proxy env var set
(production / CI), the cascade is still well-behaved — proxy
dispatcher is a no-op, server fetch is direct, no proxy wrapping
is necessary but it doesn't hurt either (the endpoint just adds
a hop).
