Initial scaffold: push-to-deploy + auth-proxy + public-switch template

2026-06-22 11:33:43 +02:00
commit e031064dcf
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+/**
+ * Server-side API proxy for the backend. ⭐ THE SYSTEMIC AUTH FIX ⭐
+ *
+ * Do NOT replace this with a static `rewrites()` proxy in next.config.mjs. A
+ * static rewrite forwards requests as-is and CANNOT inject an Authorization
+ * header — that was the root cause of the "no token reaches the backend" bug
+ * (every browser fetch hit the backend unauthenticated → 401/500). This cost
+ * ~9 days on CannaManage; the template ships the fix so it never recurs.
+ *
+ * This Route Handler runs on the server, reads the NextAuth session via
+ * `auth()` (so the JWT never leaves the server), and forwards the request to
+ * `${BACKEND_URL}/api/v1/<path>` with `Authorization: Bearer <accessToken>`.
+ *
+ * Method- and content-agnostic: query string preserved; raw request body
+ * streamed unparsed (JSON + multipart uploads + binary all work); upstream
+ * response body streamed back verbatim (byte-exact downloads).
+ *
+ * Adjust the upstream path prefix (`/api/v1/`) if your backend differs.
+ */
+import { NextResponse } from "next/server"
+
+import type { NextRequest } from "next/server"
+
+import { auth } from "@/lib/auth"
+
+// Always run dynamically — this proxy depends on per-request auth + body.
+export const dynamic = "force-dynamic"
+
+const BACKEND_URL = process.env.BACKEND_URL || "http://localhost:8080"
+
+// Hop-by-hop and host-specific headers that must not be forwarded upstream.
+const STRIPPED_REQUEST_HEADERS = new Set([
+  "host",
+  "connection",
+  "content-length",
+  "transfer-encoding",
+  "accept-encoding",
+])
+
+// Headers that must not be copied from the upstream response back to the client.
+const STRIPPED_RESPONSE_HEADERS = new Set([
+  "connection",
+  "transfer-encoding",
+  "content-encoding",
+  "content-length",
+])
+
+async function proxy(req: NextRequest, path: string[]): Promise<NextResponse> {
+  const session = await auth()
+  const accessToken = session?.accessToken
+
+  // Build the upstream URL: /api/backend/<path> → BACKEND_URL/api/v1/<path>
+  const search = req.nextUrl.search // includes leading "?" or ""
+  const upstreamUrl = `${BACKEND_URL}/api/v1/${path.join("/")}${search}`
+
+  // Clone the incoming headers, stripping hop-by-hop/host ones, then inject auth.
+  const headers = new Headers()
+  req.headers.forEach((value, key) => {
+    if (!STRIPPED_REQUEST_HEADERS.has(key.toLowerCase())) {
+      headers.set(key, value)
+    }
+  })
+  if (accessToken) {
+    headers.set("Authorization", `Bearer ${accessToken}`)
+  }
+
+  const method = req.method.toUpperCase()
+  const hasBody = method !== "GET" && method !== "HEAD"
+
+  try {
+    const upstream = await fetch(upstreamUrl, {
+      method,
+      headers,
+      // Stream the raw body through unparsed (works for JSON + multipart + binary).
+      body: hasBody ? req.body : undefined,
+      // Required by undici/Node when sending a streaming request body.
+      ...(hasBody ? { duplex: "half" } : {}),
+      redirect: "manual",
+      cache: "no-store",
+    } as RequestInit)
+
+    // Copy upstream response headers, dropping ones that break a re-emitted body.
+    const responseHeaders = new Headers()
+    upstream.headers.forEach((value, key) => {
+      if (!STRIPPED_RESPONSE_HEADERS.has(key.toLowerCase())) {
+        responseHeaders.set(key, value)
+      }
+    })
+
+    // Stream the body straight back — byte-exact for downloads.
+    return new NextResponse(upstream.body, {
+      status: upstream.status,
+      statusText: upstream.statusText,
+      headers: responseHeaders,
+    })
+  } catch {
+    return NextResponse.json(
+      { code: "BACKEND_UNREACHABLE", message: "Unable to reach the API." },
+      { status: 502 }
+    )
+  }
+}
+
+// Next.js 15: the second arg's `params` is a Promise.
+type Ctx = { params: Promise<{ path: string[] }> }
+
+export async function GET(req: NextRequest, ctx: Ctx) {
+  return proxy(req, (await ctx.params).path)
+}
+export async function POST(req: NextRequest, ctx: Ctx) {
+  return proxy(req, (await ctx.params).path)
+}
+export async function PUT(req: NextRequest, ctx: Ctx) {
+  return proxy(req, (await ctx.params).path)
+}
+export async function PATCH(req: NextRequest, ctx: Ctx) {
+  return proxy(req, (await ctx.params).path)
+}
+export async function DELETE(req: NextRequest, ctx: Ctx) {
+  return proxy(req, (await ctx.params).path)
+}