feat: export reproducible retrieval history snapshots

frontend/src/services/exports.ts

@@ -0,0 +1,19 @@
+import { apiDownload } from './session'
+import type { RetrievalRunResult } from '../api'
+import type { RagContext } from './rag'
+
+export type ExportSelection = { run_ids: string[]; include_contexts?: boolean }
+export type ExportManifest = {
+  record_type: 'manifest'; schema_version: 'nalati-retrieval-export-v1'; export_id: string; exported_at: string;
+  selection: Required<ExportSelection>; counts: { retrieval_runs: number; rag_contexts: number }; records_sha256: string;
+  snapshot_semantics: 'stored_history_not_current_corpus';
+  generation_measurements: { status: 'not_called'; usage: null; cost: null; currency: null }
+}
+export type ExportRecord = ExportManifest
+  | { record_type: 'retrieval_run'; id: string; ranking_unit: 'knowledge_item' | 'chunk'; payload: RetrievalRunResult }
+  | { record_type: 'rag_context'; id: string; payload: RagContext }
+
+// Returns bytes/metadata; callers explicitly choose whether and where to save the file.
+export const exportRetrievalHistory = (payload: ExportSelection) => apiDownload(
+  '/api/retrieval/exports', { method: 'POST', body: JSON.stringify(payload) }, true,
+)

frontend/src/services/session.ts

@@ -6,10 +6,10 @@ export class ApiError extends Error {
 
 export function clearSessionToken() { csrfToken = null }
 
-export async function apiRequest<T>(path: string, init: RequestInit = {}, protect = false): Promise<T> {
+async function request(path: string, init: RequestInit, protect: boolean, accept: string): Promise<Response> {
   if (protect && !csrfToken) await apiRequest('/api/auth/me')
   const headers = new Headers(init.headers)
-  headers.set('Accept', 'application/json')
+  headers.set('Accept', accept)
   if (init.body) headers.set('Content-Type', 'application/json')
   if (protect && csrfToken) headers.set('X-CSRF-Token', csrfToken)
   const response = await fetch(path, { ...init, credentials: 'include', headers })
@@ -19,6 +19,11 @@ export async function apiRequest<T>(path: string, init: RequestInit = {}, protec
     const detail = body && typeof body === 'object' && 'detail' in body ? body.detail : null
     throw new ApiError(response.status, typeof detail === 'string' ? detail : `请求失败（${response.status}），请检查登录状态或填写内容。`)
   }
+  return response
+}
+
+export async function apiRequest<T>(path: string, init: RequestInit = {}, protect = false): Promise<T> {
+  const response = await request(path, init, protect, 'application/json')
   if (response.status === 204) return undefined as T
   const data = await response.json()
   if (path === '/api/auth/login' || path === '/api/auth/me') {
@@ -26,3 +31,12 @@ export async function apiRequest<T>(path: string, init: RequestInit = {}, protec
   }
   return data as T
 }
+
+export type ApiDownload = { blob: Blob; filename: string; recordsSha256: string | null }
+
+export async function apiDownload(path: string, init: RequestInit = {}, protect = false): Promise<ApiDownload> {
+  const response = await request(path, init, protect, 'application/x-ndjson')
+  const disposition = response.headers.get('Content-Disposition') ?? ''
+  const filename = /^attachment; filename="([A-Za-z0-9._-]+)"$/.exec(disposition)?.[1] ?? 'download.jsonl'
+  return { blob: await response.blob(), filename, recordsSha256: response.headers.get('X-Records-SHA256') }
+}