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school_compare/nextjs-app/app/api/[...path]/route.ts
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/**
* Runtime proxy for /api/* → the FastAPI backend.
*
* This replaces the old next.config.js `rewrites()` proxy, whose destination
* was baked into the build (routes-manifest.json) from FASTAPI_URL at build
* time. Because one frontend image is promoted staging→prod, a baked hostname
* forced every environment to name the backend identically; a mismatch (e.g.
* a `backend_stg` service) produced `getaddrinfo ENOTFOUND backend`.
*
* A route handler reads process.env.FASTAPI_URL on each request, so the same
* image adapts to whatever the backend is called in each environment.
*/
import { type NextRequest, NextResponse } from 'next/server';
export const dynamic = 'force-dynamic';
export const runtime = 'nodejs';
// FASTAPI_URL already includes the `/api` suffix (e.g. http://backend:80/api).
function backendBase(): string {
return process.env.FASTAPI_URL || process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8000/api';
}
// Hop-by-hop / length headers must not be copied across a proxy — undici has
// already decoded the body, so a stale content-encoding/length corrupts it.
const STRIPPED_RESPONSE_HEADERS = ['content-encoding', 'content-length', 'transfer-encoding', 'connection'];
const METHODS_WITH_BODY = new Set(['POST', 'PUT', 'PATCH', 'DELETE']);
async function handler(req: NextRequest, ctx: { params: Promise<{ path: string[] }> }) {
const { path } = await ctx.params;
const target = `${backendBase()}/${path.join('/')}${req.nextUrl.search}`;
const headers = new Headers(req.headers);
headers.delete('host');
headers.delete('connection');
const init: RequestInit & { duplex?: 'half' } = {
method: req.method,
headers,
redirect: 'manual',
cache: 'no-store',
};
if (METHODS_WITH_BODY.has(req.method)) {
init.body = req.body;
init.duplex = 'half';
}
let upstream: Response;
try {
upstream = await fetch(target, init);
} catch (err) {
// e.g. DNS failure or connection refused — surface a clean 502 instead of
// an opaque proxy crash so callers can degrade gracefully.
return NextResponse.json({ detail: 'Upstream request failed' }, { status: 502 });
}
const responseHeaders = new Headers(upstream.headers);
for (const h of STRIPPED_RESPONSE_HEADERS) responseHeaders.delete(h);
return new NextResponse(upstream.body, {
status: upstream.status,
statusText: upstream.statusText,
headers: responseHeaders,
});
}
export {
handler as GET,
handler as HEAD,
handler as POST,
handler as PUT,
handler as PATCH,
handler as DELETE,
handler as OPTIONS,
};