feat(mcp): подготовить сервер и доступ к приёмке

lib/proxy-backend-request.ts

@@ -0,0 +1,52 @@
+import type { NextRequest } from "next/server"
+import { backendInternalUrl } from "@/lib/backend-internal-url"
+
+type ProxyBackendRequestOptions = {
+  method?: string
+  forwardRequestBody?: boolean
+}
+
+export async function proxyBackendRequest(
+  request: NextRequest,
+  backendPath: string,
+  options: ProxyBackendRequestOptions = {},
+): Promise<Response> {
+  const method = options.method ?? request.method
+  const headers = new Headers()
+  for (const [key, value] of request.headers.entries()) {
+    const lower = key.toLowerCase()
+    if (lower === "host" || lower === "connection") continue
+    headers.set(key, value)
+  }
+
+  const fetchInit: RequestInit & { duplex?: "half" } = {
+    method,
+    headers,
+    cache: "no-store",
+  }
+
+  const forwardRequestBody = options.forwardRequestBody ?? !["GET", "HEAD"].includes(method)
+  if (forwardRequestBody && request.body) {
+    fetchInit.body = request.body
+    fetchInit.duplex = "half"
+  }
+
+  try {
+    const upstream = await fetch(`${backendInternalUrl()}${backendPath}`, fetchInit)
+    const responseHeaders = new Headers()
+    const contentType = upstream.headers.get("Content-Type")
+    const contentDisposition = upstream.headers.get("Content-Disposition")
+    if (contentType) responseHeaders.set("Content-Type", contentType)
+    if (contentDisposition) responseHeaders.set("Content-Disposition", contentDisposition)
+    const databaseOutcome = upstream.headers.get("X-System-Database-Outcome")
+    if (databaseOutcome) responseHeaders.set("X-System-Database-Outcome", databaseOutcome)
+
+    return new Response(upstream.body, {
+      status: upstream.status,
+      headers: responseHeaders,
+    })
+  } catch (error) {
+    const message = error instanceof Error ? error.message : "Не удалось связаться с бекендом"
+    return Response.json({ error: message }, { status: 502 })
+  }
+}