Two bugs introduced by the Next.js proxy Route Handler:
1. ERR_CONTENT_DECODING_FAILED — Node.js fetch() automatically
decompresses gzip/br responses from the backend, but the proxy was
still forwarding Content-Encoding and Content-Length headers to the
browser. The browser would then try to decompress already-decompressed
data and fail. Fixed by stripping Content-Encoding and Content-Length
from upstream response headers.
2. BACKEND_URL shell env leak into Docker Compose — docker-compose.yml
used ${BACKEND_URL:-http://backend:8000}, which was being overridden
by BACKEND_URL=http://localhost:8000 set in .mise.local.toml for local
dev. Inside the frontend container, localhost:8000 does not exist,
causing all proxied requests to return 502. Fixed by hardcoding
http://backend:8000 in docker-compose.yml so the shell environment
cannot override it.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Former-commit-id: 036c62d2c0
Previously, NEXT_PUBLIC_API_URL was a build-time Next.js variable, making
it impossible to configure the backend URL in docker-compose `environment`
without rebuilding the image.
This change introduces a proper server-side proxy:
- next.config.ts: adds a rewrite rule that forwards all /api/* requests
to BACKEND_URL (read at server startup, not baked at build time).
Defaults to http://localhost:8000 so local dev works without config.
- api.ts: API_BASE is now an empty string — all fetch calls use relative
/api/... paths, which the Next.js server proxies to the backend.
- docker-compose.yml: replaces NEXT_PUBLIC_API_URL build arg with a
runtime BACKEND_URL env var defaulting to http://backend:8000, using
Docker's internal networking. Port 8000 no longer needs to be exposed.
- README: updates Docker setup docs, standalone compose example, and
environment variable reference to reflect BACKEND_URL.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Former-commit-id: a3b18e23c1
David Parry