{"id":89783,"date":"2026-08-03T18:16:42","date_gmt":"2026-08-03T10:16:42","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/89783.html"},"modified":"2026-08-03T18:16:42","modified_gmt":"2026-08-03T10:16:42","slug":"fastapi-langchain-%e6%94%bf%e5%8a%a1%e6%94%bf%e7%ad%96-rag-%e5%90%8e%e7%ab%af%e9%a1%b9%e7%9b%ae%e5%ae%9e%e6%88%98%ef%bc%9a%e4%bb%8e%e9%9b%b6%e6%9e%84%e5%bb%ba%e7%94%9f%e4%ba%a7%e7%ba%a7%e6%99%ba","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/89783.html","title":{"rendered":"# FastAPI + LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218\uff1a\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf"},"content":{"rendered":"<h2>FastAPI &#043; LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218&#xff1a;\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf<\/h2>\n<p>\u6458\u8981&#xff1a;\u672c\u6587\u57fa\u4e8e FastAPI \u6846\u67b6\u548c LangChain&#xff0c;\u624b\u628a\u624b\u6559\u4f60\u4ece\u96f6\u6784\u5efa\u4e00\u4e2a\u5b8c\u6574\u7684\u653f\u52a1\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54\u540e\u7aef\u7cfb\u7edf\u3002\u6db5\u76d6\u5e94\u7528\u5de5\u5382\u6a21\u5f0f\u3001Pydantic \u6570\u636e\u6a21\u578b\u3001\u4f9d\u8d56\u6ce8\u5165\u3001\u6587\u4ef6\u4e0a\u4f20\u3001CORS \u914d\u7f6e\u3001\u8def\u7531\u62c6\u5206\u3001LangChain \u96c6\u6210\u3001Embedding \u5411\u91cf\u68c0\u7d22\u3001RAG \u95ee\u7b54 API \u7b49\u5b8c\u6574\u751f\u4ea7\u7ea7\u80fd\u529b\u3002\u6240\u6709\u4ee3\u7801\u53ef\u76f4\u63a5\u590d\u5236\u8fd0\u884c&#xff0c;\u9644\u8e29\u5751\u6e05\u5355\u548c\u4e0a\u7ebf\u68c0\u67e5\u8868\u3002<\/p>\n<hr \/>\n<h3>\u76ee\u5f55<\/h3>\n<ul>\n<li>1. \u9879\u76ee\u6982\u8ff0<\/li>\n<li>2. \u73af\u5883\u51c6\u5907<\/li>\n<li>3. \u5e94\u7528\u5de5\u5382\u4e0e\u914d\u7f6e\u7ba1\u7406<\/li>\n<li>4. \u914d\u7f6e CORS \u4e0e\u5b89\u5168<\/li>\n<li>5. \u8def\u7531\u62c6\u5206\u4e0e API \u6a21\u5757\u5316<\/li>\n<li>6. Pydantic \u6570\u636e\u6a21\u578b<\/li>\n<li>7. \u4f9d\u8d56\u6ce8\u5165<\/li>\n<li>8. \u6587\u4ef6\u4e0a\u4f20\u4e0e\u5904\u7406<\/li>\n<li>9. LangChain \u96c6\u6210&#xff1a;\u6a21\u578b\u4e0e Embedding<\/li>\n<li>10. RAG \u77e5\u8bc6\u5e93\u95ee\u7b54 API<\/li>\n<li>11. \u5065\u5eb7\u68c0\u67e5\u4e0e\u4f18\u96c5\u5173\u95ed<\/li>\n<li>12. \u9879\u76ee\u5b8c\u6574\u7ed3\u6784<\/li>\n<li>13. \u8e29\u5751\u6e05\u5355<\/li>\n<li>14. \u672c\u7ae0\u91cd\u70b9<\/li>\n<li>15. \u5c01\u9762\u56fe\u63d0\u793a\u8bcd<\/li>\n<\/ul>\n<hr \/>\n<h3>1. \u9879\u76ee\u6982\u8ff0<\/h3>\n<p>\u672c\u9879\u76ee\u662f\u4e00\u4e2a\u57fa\u4e8e FastAPI &#043; LangChain \u7684\u653f\u52a1\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54\u540e\u7aef\u7cfb\u7edf&#xff0c;\u5177\u5907\u4ee5\u4e0b\u80fd\u529b&#xff1a;<\/p>\n<ul>\n<li>\u57fa\u4e8e FastAPI \u5e94\u7528\u5de5\u5382\u6a21\u5f0f\u6784\u5efa\u540e\u7aef\u670d\u52a1<\/li>\n<li>\u652f\u6301\u6587\u4ef6\u4e0a\u4f20&#xff08;PDF\/TXT\/MD&#xff09;\u6784\u5efa\u77e5\u8bc6\u5e93\u7d22\u5f15<\/li>\n<li>\u96c6\u6210 DeepSeek \u5927\u8bed\u8a00\u6a21\u578b\u8fdb\u884c\u667a\u80fd\u95ee\u7b54<\/li>\n<li>\u4f7f\u7528 Embedding \u6a21\u578b &#043; Milvus \u5411\u91cf\u6570\u636e\u5e93\u5b9e\u73b0\u8bed\u4e49\u68c0\u7d22<\/li>\n<li>\u63d0\u4f9b\u5b8c\u6574\u7684 RESTful API&#xff08;\u4e0a\u4f20\u6587\u6863\u3001\u95ee\u7b54\u3001\u5065\u5eb7\u68c0\u67e5&#xff09;<\/li>\n<li>\u914d\u7f6e CORS \u652f\u6301\u524d\u540e\u7aef\u8054\u8c03<\/li>\n<li>\u81ea\u52a8 Swagger \u6587\u6863<\/li>\n<\/ul>\n<p>\u6280\u672f\u6808&#xff1a;<\/p>\n<table>\n<tr>\u7ec4\u4ef6\u7248\u672c\u4f5c\u7528<\/tr>\n<tbody>\n<tr>\n<td>FastAPI<\/td>\n<td>0.115&#043;<\/td>\n<td>Web \u6846\u67b6<\/td>\n<\/tr>\n<tr>\n<td>Uvicorn<\/td>\n<td>0.30&#043;<\/td>\n<td>ASGI \u670d\u52a1\u5668<\/td>\n<\/tr>\n<tr>\n<td>Pydantic<\/td>\n<td>2.9&#043;<\/td>\n<td>\u6570\u636e\u6821\u9a8c<\/td>\n<\/tr>\n<tr>\n<td>LangChain<\/td>\n<td>0.3&#043;<\/td>\n<td>LLM \u5e94\u7528\u6846\u67b6<\/td>\n<\/tr>\n<tr>\n<td>DeepSeek<\/td>\n<td>deepseek-chat<\/td>\n<td>\u5927\u8bed\u8a00\u6a21\u578b<\/td>\n<\/tr>\n<tr>\n<td>Milvus<\/td>\n<td>2.3&#043;<\/td>\n<td>\u5411\u91cf\u6570\u636e\u5e93<\/td>\n<\/tr>\n<tr>\n<td>PyPDF<\/td>\n<td>\u6700\u65b0<\/td>\n<td>PDF \u89e3\u6790<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3>2. \u73af\u5883\u51c6\u5907<\/h3>\n<h4>2.1 \u521b\u5efa\u9879\u76ee\u76ee\u5f55<\/h4>\n<p><span class=\"token function\">mkdir<\/span> policy-rag-backend<br \/>\n<span class=\"token builtin class-name\">cd<\/span> policy-rag-backend<\/p>\n<h4>2.2 \u521b\u5efa\u865a\u62df\u73af\u5883<\/h4>\n<p>python <span class=\"token parameter variable\">-m<\/span> venv .venv<\/p>\n<p><span class=\"token comment\"># Windows<\/span><br \/>\n.<span class=\"token punctuation\">\\\\<\/span>.venv<span class=\"token punctuation\">\\\\<\/span>Scripts<span class=\"token punctuation\">\\\\<\/span>activate<\/p>\n<p><span class=\"token comment\"># macOS\/Linux<\/span><br \/>\n<span class=\"token builtin class-name\">source<\/span> .venv\/bin\/activate<\/p>\n<h4>2.3 \u5b89\u88c5\u4f9d\u8d56<\/h4>\n<p>\u521b\u5efa requirements.txt&#xff1a;<\/p>\n<p># Web \u6846\u67b6<br \/>\nfastapi[standard]&gt;&#061;0.115.0<br \/>\nuvicorn[standard]&gt;&#061;0.30.0<br \/>\npython-multipart&gt;&#061;0.0.9<\/p>\n<p># \u914d\u7f6e\u4e0e\u73af\u5883<br \/>\npython-dotenv&gt;&#061;1.0.0<br \/>\npydantic&gt;&#061;2.9.0<br \/>\npydantic-settings&gt;&#061;2.5.0<\/p>\n<p># LangChain<br \/>\nlangchain&gt;&#061;0.3.0<br \/>\nlangchain-openai&gt;&#061;0.2.0<br \/>\nlangchain-community&gt;&#061;0.3.0<br \/>\nlangchain-text-splitters&gt;&#061;0.3.0<\/p>\n<p># \u5411\u91cf\u6570\u636e\u5e93<br \/>\npymilvus&gt;&#061;2.5.0<\/p>\n<p># \u6587\u6863\u89e3\u6790<br \/>\nPyPDF2&gt;&#061;3.0.0<br \/>\npython-docx&gt;&#061;1.1.0<\/p>\n<p>\u5b89\u88c5&#xff1a;<\/p>\n<p>pip <span class=\"token function\">install<\/span> <span class=\"token parameter variable\">-r<\/span> requirements.txt<\/p>\n<h4>2.4 \u521b\u5efa .env \u6587\u4ef6<\/h4>\n<p># DeepSeek \u914d\u7f6e<br \/>\nDEEPSEEK_API_KEY&#061;sk-your-api-key-here<br \/>\nDEEPSEEK_BASE_URL&#061;https:\/\/api.deepseek.com<\/p>\n<p># Milvus \u914d\u7f6e<br \/>\nMILVUS_URI&#061;http:\/\/localhost:19530<br \/>\nMILVUS_COLLECTION_NAME&#061;policy_knowledge<\/p>\n<p># \u4e0a\u4f20\u76ee\u5f55<br \/>\nUPLOAD_DIR&#061;uploads<\/p>\n<p># \u5e94\u7528\u914d\u7f6e<br \/>\nAPP_TITLE&#061;\u653f\u52a1\u653f\u7b56 RAG \u7cfb\u7edf<br \/>\nAPP_DESCRIPTION&#061;\u57fa\u4e8e FastAPI &#043; LangChain \u7684\u667a\u80fd\u653f\u7b56\u95ee\u7b54\u7cfb\u7edf<br \/>\nAPP_VERSION&#061;1.0.0<br \/>\nCORS_ORIGINS&#061;http:\/\/localhost:3000,http:\/\/localhost:5173<\/p>\n<p>\u5b89\u5168\u63d0\u793a&#xff1a;.env \u6587\u4ef6\u5305\u542b API Key&#xff0c;\u5fc5\u987b\u52a0\u5165 .gitignore&#xff0c;\u4e0d\u8981\u63d0\u4ea4\u5230 Git \u4ed3\u5e93\u3002<\/p>\n<hr \/>\n<h3>3. \u5e94\u7528\u5de5\u5382\u4e0e\u914d\u7f6e\u7ba1\u7406<\/h3>\n<h4>3.1 \u4e3a\u4ec0\u4e48\u8981\u7528\u5e94\u7528\u5de5\u5382<\/h4>\n<p>\u5728\u5927\u578b\u9879\u76ee\u4e2d&#xff0c;\u76f4\u63a5\u5199 app &#061; FastAPI() \u4f1a\u9047\u5230\u95ee\u9898&#xff1a;<\/p>\n<ul>\n<li>\u914d\u7f6e\u5206\u6563\u5728\u591a\u4e2a\u6587\u4ef6<\/li>\n<li>\u6d4b\u8bd5\u65f6\u96be\u4ee5\u66ff\u6362\u4f9d\u8d56<\/li>\n<li>\u542f\u52a8\u65f6\u65e0\u6cd5\u6ce8\u5165\u914d\u7f6e<\/li>\n<\/ul>\n<p>\u5e94\u7528\u5de5\u5382\u6a21\u5f0f\u628a\u521b\u5efa\u5e94\u7528\u7684\u903b\u8f91\u5c01\u88c5\u5230\u51fd\u6570\u4e2d&#xff0c;\u652f\u6301&#xff1a;<\/p>\n<ul>\n<li>\u96c6\u4e2d\u7ba1\u7406\u914d\u7f6e<\/li>\n<li>\u6309\u9700\u6ce8\u518c\u8def\u7531<\/li>\n<li>\u7075\u6d3b\u63a7\u5236\u542f\u52a8\u884c\u4e3a<\/li>\n<\/ul>\n<h4>3.2 \u914d\u7f6e\u7ba1\u7406<\/h4>\n<p>\u521b\u5efa backend\/core\/config.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> pydantic_settings <span class=\"token keyword\">import<\/span> BaseSettings<br \/>\n<span class=\"token keyword\">from<\/span> typing <span class=\"token keyword\">import<\/span> List<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Settings<\/span><span class=\"token punctuation\">(<\/span>BaseSettings<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token comment\"># DeepSeek \u914d\u7f6e<\/span><br \/>\n    deepseek_api_key<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;&#034;<\/span><br \/>\n    deepseek_base_url<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;https:\/\/api.deepseek.com&#034;<\/span><\/p>\n<p>    <span class=\"token comment\"># Milvus \u914d\u7f6e<\/span><br \/>\n    milvus_uri<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;http:\/\/localhost:19530&#034;<\/span><br \/>\n    milvus_collection_name<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;policy_knowledge&#034;<\/span><\/p>\n<p>    <span class=\"token comment\"># \u5e94\u7528\u914d\u7f6e<\/span><br \/>\n    app_title<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;\u653f\u52a1\u653f\u7b56 RAG \u7cfb\u7edf&#034;<\/span><br \/>\n    app_description<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;FastAPI &#043; LangChain \u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54\u7cfb\u7edf&#034;<\/span><br \/>\n    app_version<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;1.0.0&#034;<\/span><\/p>\n<p>    <span class=\"token comment\"># CORS \u914d\u7f6e<\/span><br \/>\n    cors_origins<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;http:\/\/localhost:3000&#034;<\/span><\/p>\n<p>    <span class=\"token comment\"># \u4e0a\u4f20\u76ee\u5f55<\/span><br \/>\n    upload_dir<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;uploads&#034;<\/span><\/p>\n<p>    <span class=\"token decorator annotation punctuation\">&#064;property<\/span><br \/>\n    <span class=\"token keyword\">def<\/span> <span class=\"token function\">cors_origin_list<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token operator\">&gt;<\/span> List<span class=\"token punctuation\">[<\/span><span class=\"token builtin\">str<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">[<\/span>origin<span class=\"token punctuation\">.<\/span>strip<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">for<\/span> origin <span class=\"token keyword\">in<\/span> self<span class=\"token punctuation\">.<\/span>cors_origins<span class=\"token punctuation\">.<\/span>split<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;,&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">]<\/span><\/p>\n<p>    <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Config<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        env_file <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;.env&#034;<\/span><br \/>\n        env_file_encoding <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;utf-8&#034;<\/span><\/p>\n<p>settings <span class=\"token operator\">&#061;<\/span> Settings<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u5173\u952e\u70b9&#xff1a;<\/p>\n<ul>\n<li>BaseSettings \u81ea\u52a8\u4ece .env \u8bfb\u53d6\u914d\u7f6e<\/li>\n<li>cors_origin_list \u5c06\u9017\u53f7\u5206\u9694\u7684\u5b57\u7b26\u4e32\u8f6c\u6210\u5217\u8868<\/li>\n<li>\u6240\u6709\u914d\u7f6e\u9879\u90fd\u6709\u9ed8\u8ba4\u503c&#xff0c;\u5f00\u53d1\u65f6\u4e0d\u586b .env \u4e5f\u80fd\u8fd0\u884c<\/li>\n<\/ul>\n<h4>3.3 \u5e94\u7528\u5de5\u5382<\/h4>\n<p>\u521b\u5efa backend\/app\/factory.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> FastAPI<br \/>\n<span class=\"token keyword\">from<\/span> fastapi<span class=\"token punctuation\">.<\/span>middleware<span class=\"token punctuation\">.<\/span>cors <span class=\"token keyword\">import<\/span> CORSMiddleware<br \/>\n<span class=\"token keyword\">from<\/span> pathlib <span class=\"token keyword\">import<\/span> Path<\/p>\n<p><span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<br \/>\n<span class=\"token keyword\">from<\/span> api<span class=\"token punctuation\">.<\/span>routes <span class=\"token keyword\">import<\/span> router<\/p>\n<p><span class=\"token keyword\">def<\/span> <span class=\"token function\">create_app<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token operator\">&gt;<\/span> FastAPI<span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token comment\"># 1. \u521b\u5efa FastAPI \u5e94\u7528<\/span><br \/>\n    app <span class=\"token operator\">&#061;<\/span> FastAPI<span class=\"token punctuation\">(<\/span><br \/>\n        title<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>app_title<span class=\"token punctuation\">,<\/span><br \/>\n        description<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>app_description<span class=\"token punctuation\">,<\/span><br \/>\n        version<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>app_version<span class=\"token punctuation\">,<\/span><br \/>\n        docs_url<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/docs&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        redoc_url<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/redoc&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># 2. \u914d\u7f6e CORS<\/span><br \/>\n    app<span class=\"token punctuation\">.<\/span>add_middleware<span class=\"token punctuation\">(<\/span><br \/>\n        CORSMiddleware<span class=\"token punctuation\">,<\/span><br \/>\n        allow_origins<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>cors_origin_list<span class=\"token punctuation\">,<\/span><br \/>\n        allow_credentials<span class=\"token operator\">&#061;<\/span><span class=\"token boolean\">True<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        allow_methods<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;*&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        allow_headers<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;*&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># 3. \u521b\u5efa\u4e0a\u4f20\u76ee\u5f55<\/span><br \/>\n    upload_path <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span>settings<span class=\"token punctuation\">.<\/span>upload_dir<span class=\"token punctuation\">)<\/span><br \/>\n    upload_path<span class=\"token punctuation\">.<\/span>mkdir<span class=\"token punctuation\">(<\/span>exist_ok<span class=\"token operator\">&#061;<\/span><span class=\"token boolean\">True<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># 4. \u6ce8\u518c\u8def\u7531<\/span><br \/>\n    app<span class=\"token punctuation\">.<\/span>include_router<span class=\"token punctuation\">(<\/span>router<span class=\"token punctuation\">,<\/span> prefix<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/api\/v1&#034;<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># 5. \u6839\u8def\u5f84<\/span><br \/>\n    <span class=\"token decorator annotation punctuation\">&#064;app<span class=\"token punctuation\">.<\/span>get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">root<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token string\">&#034;name&#034;<\/span><span class=\"token punctuation\">:<\/span> settings<span class=\"token punctuation\">.<\/span>app_title<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;version&#034;<\/span><span class=\"token punctuation\">:<\/span> settings<span class=\"token punctuation\">.<\/span>app_version<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;docs&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;\/docs&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;message&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;\u670d\u52a1\u5df2\u542f\u52a8&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> app<\/p>\n<h4>3.4 \u542f\u52a8\u5165\u53e3<\/h4>\n<p>\u521b\u5efa backend\/main.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> app<span class=\"token punctuation\">.<\/span>factory <span class=\"token keyword\">import<\/span> create_app<\/p>\n<p>app <span class=\"token operator\">&#061;<\/span> create_app<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>\u542f\u52a8&#xff1a;<\/p>\n<p><span class=\"token builtin class-name\">cd<\/span> backend<br \/>\npython <span class=\"token parameter variable\">-m<\/span> uvicorn main:app <span class=\"token parameter variable\">&#8211;reload<\/span> <span class=\"token parameter variable\">&#8211;host<\/span> <span class=\"token number\">0.0<\/span>.0.0 <span class=\"token parameter variable\">&#8211;port<\/span> <span class=\"token number\">8000<\/span><\/p>\n<hr \/>\n<h3>4. \u914d\u7f6e CORS \u4e0e\u5b89\u5168<\/h3>\n<h4>4.1 \u4ec0\u4e48\u662f CORS<\/h4>\n<p>**CORS&#xff08;\u8de8\u6e90\u8d44\u6e90\u5171\u4eab&#xff09;**\u89e3\u51b3\u6d4f\u89c8\u5668\u540c\u6e90\u7b56\u7565\u9650\u5236\u3002\u5f53\u524d\u7aef&#xff08;localhost:3000&#xff09;\u8c03\u7528\u540e\u7aef&#xff08;localhost:8000&#xff09;\u65f6&#xff0c;\u6d4f\u89c8\u5668\u4f1a\u963b\u6b62\u8bf7\u6c42&#xff0c;\u9700\u8981\u540e\u7aef\u660e\u786e\u5141\u8bb8\u3002<\/p>\n<h4>4.2 FastAPI \u4e2d\u914d\u7f6e CORS<\/h4>\n<p>\u5728 factory.py \u4e2d\u5df2\u7ecf\u901a\u8fc7 CORSMiddleware \u914d\u7f6e&#xff1a;<\/p>\n<p>app<span class=\"token punctuation\">.<\/span>add_middleware<span class=\"token punctuation\">(<\/span><br \/>\n    CORSMiddleware<span class=\"token punctuation\">,<\/span><br \/>\n    allow_origins<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>cors_origin_list<span class=\"token punctuation\">,<\/span><br \/>\n    allow_credentials<span class=\"token operator\">&#061;<\/span><span class=\"token boolean\">True<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    allow_methods<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;*&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    allow_headers<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;*&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u53c2\u6570\u8bf4\u660e&#xff1a;<\/p>\n<table>\n<tr>\u53c2\u6570\u4f5c\u7528<\/tr>\n<tbody>\n<tr>\n<td>allow_origins<\/td>\n<td>\u5141\u8bb8\u8bbf\u95ee\u7684\u57df\u540d\u5217\u8868<\/td>\n<\/tr>\n<tr>\n<td>allow_credentials<\/td>\n<td>\u662f\u5426\u5141\u8bb8\u643a\u5e26 Cookie\/Token<\/td>\n<\/tr>\n<tr>\n<td>allow_methods<\/td>\n<td>\u5141\u8bb8\u7684 HTTP \u65b9\u6cd5<\/td>\n<\/tr>\n<tr>\n<td>allow_headers<\/td>\n<td>\u5141\u8bb8\u7684\u8bf7\u6c42\u5934<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>4.3 \u751f\u4ea7\u73af\u5883\u5efa\u8bae<\/h4>\n<p># \u5f00\u53d1\u73af\u5883<br \/>\nCORS_ORIGINS&#061;http:\/\/localhost:3000,http:\/\/localhost:5173<\/p>\n<p># \u751f\u4ea7\u73af\u5883&#xff08;\u53ea\u653e\u5b9e\u9645\u57df\u540d&#xff09;<br \/>\nCORS_ORIGINS&#061;https:\/\/your-domain.com<\/p>\n<hr \/>\n<h3>5. \u8def\u7531\u62c6\u5206\u4e0e API \u6a21\u5757\u5316<\/h3>\n<h4>5.1 \u4e3a\u4ec0\u4e48\u8981\u62c6\u5206\u8def\u7531<\/h4>\n<p>\u5c0f\u578b\u9879\u76ee\u628a\u6240\u6709\u63a5\u53e3\u5199\u5728 main.py \u4e2d\u6ca1\u95ee\u9898\u3002\u4f46\u9879\u76ee\u53d8\u5927\u540e&#xff1a;<\/p>\n<ul>\n<li>\u6587\u4ef6\u8fc7\u957f&#xff0c;\u96be\u4ee5\u7ef4\u62a4<\/li>\n<li>\u591a\u4eba\u534f\u4f5c\u5bb9\u6613\u51b2\u7a81<\/li>\n<li>\u6d4b\u8bd5\u65f6\u96be\u4ee5\u9694\u79bb<\/li>\n<\/ul>\n<p>APIRouter \u5141\u8bb8\u628a\u8def\u7531\u6309\u529f\u80fd\u62c6\u5206\u5230\u4e0d\u540c\u6a21\u5757\u3002<\/p>\n<h4>5.2 \u8def\u7531\u62c6\u5206\u7ed3\u6784<\/h4>\n<p>backend\/<br \/>\n\u251c\u2500\u2500 api\/<br \/>\n\u2502   \u251c\u2500\u2500 __init__.py<br \/>\n\u2502   \u251c\u2500\u2500 routes.py          # \u603b\u8def\u7531\u5165\u53e3<br \/>\n\u2502   \u251c\u2500\u2500 endpoints\/<br \/>\n\u2502   \u2502   \u251c\u2500\u2500 __init__.py<br \/>\n\u2502   \u2502   \u251c\u2500\u2500 upload.py      # \u6587\u4ef6\u4e0a\u4f20\u63a5\u53e3<br \/>\n\u2502   \u2502   \u2514\u2500\u2500 chat.py        # \u95ee\u7b54\u63a5\u53e3<\/p>\n<h4>5.3 \u521b\u5efa\u5b50\u8def\u7531<\/h4>\n<p>\u521b\u5efa backend\/api\/endpoints\/upload.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> APIRouter<span class=\"token punctuation\">,<\/span> UploadFile<span class=\"token punctuation\">,<\/span> File<span class=\"token punctuation\">,<\/span> HTTPException<br \/>\n<span class=\"token keyword\">from<\/span> pathlib <span class=\"token keyword\">import<\/span> Path<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<\/p>\n<p>router <span class=\"token operator\">&#061;<\/span> APIRouter<span class=\"token punctuation\">(<\/span>prefix<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/upload&#034;<\/span><span class=\"token punctuation\">,<\/span> tags<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;\u6587\u4ef6\u4e0a\u4f20&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;router<span class=\"token punctuation\">.<\/span>post<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">upload_file<\/span><span class=\"token punctuation\">(<\/span><span class=\"token builtin\">file<\/span><span class=\"token punctuation\">:<\/span> UploadFile <span class=\"token operator\">&#061;<\/span> File<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u4e0a\u4f20\u653f\u7b56\u6587\u6863&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token comment\"># \u6821\u9a8c\u6587\u4ef6\u7c7b\u578b<\/span><br \/>\n    allowed_extensions <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;.pdf&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;.txt&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;.md&#034;<\/span><span class=\"token punctuation\">}<\/span><br \/>\n    file_ext <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span><span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>filename<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span>suffix<span class=\"token punctuation\">.<\/span>lower<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> file_ext <span class=\"token keyword\">not<\/span> <span class=\"token keyword\">in<\/span> allowed_extensions<span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">raise<\/span> HTTPException<span class=\"token punctuation\">(<\/span><br \/>\n            status_code<span class=\"token operator\">&#061;<\/span><span class=\"token number\">400<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            detail<span class=\"token operator\">&#061;<\/span><span class=\"token string-interpolation\"><span class=\"token string\">f&#034;\u4e0d\u652f\u6301\u7684\u6587\u4ef6\u7c7b\u578b&#xff1a;<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span>file_ext<span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\">&#xff0c;\u4ec5\u652f\u6301 <\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span>allowed_extensions<span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\">&#034;<\/span><\/span><br \/>\n        <span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># \u4fdd\u5b58\u6587\u4ef6<\/span><br \/>\n    upload_path <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span>settings<span class=\"token punctuation\">.<\/span>upload_dir<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">\/<\/span> <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>filename<br \/>\n    content <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">await<\/span> <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>read<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    upload_path<span class=\"token punctuation\">.<\/span>write_bytes<span class=\"token punctuation\">(<\/span>content<span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token string\">&#034;filename&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>filename<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token string\">&#034;size&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">len<\/span><span class=\"token punctuation\">(<\/span>content<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token string\">&#034;path&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><span class=\"token punctuation\">(<\/span>upload_path<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token string\">&#034;message&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;\u4e0a\u4f20\u6210\u529f&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>\u521b\u5efa backend\/api\/endpoints\/chat.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> APIRouter<span class=\"token punctuation\">,<\/span> HTTPException<br \/>\n<span class=\"token keyword\">from<\/span> pydantic <span class=\"token keyword\">import<\/span> BaseModel<\/p>\n<p>router <span class=\"token operator\">&#061;<\/span> APIRouter<span class=\"token punctuation\">(<\/span>prefix<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/chat&#034;<\/span><span class=\"token punctuation\">,<\/span> tags<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;\u667a\u80fd\u95ee\u7b54&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChatRequest<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    question<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><br \/>\n    session_id<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;default&#034;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChatResponse<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    answer<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><br \/>\n    sources<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">list<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><br \/>\n    session_id<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;router<span class=\"token punctuation\">.<\/span>post<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/&#034;<\/span><span class=\"token punctuation\">,<\/span> response_model<span class=\"token operator\">&#061;<\/span>ChatResponse<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">chat<\/span><span class=\"token punctuation\">(<\/span>request<span class=\"token punctuation\">:<\/span> ChatRequest<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token comment\"># \u8fd9\u91cc\u5148\u8fd4\u56de\u5360\u4f4d\u56de\u7b54&#xff0c;\u540e\u9762\u96c6\u6210 RAG<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> ChatResponse<span class=\"token punctuation\">(<\/span><br \/>\n        answer<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\u6b63\u5728\u5efa\u8bbe\u4e2d&#xff0c;\u8bf7\u7a0d\u540e\u91cd\u8bd5&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        sources<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        session_id<span class=\"token operator\">&#061;<\/span>request<span class=\"token punctuation\">.<\/span>session_id<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<h4>5.4 \u6ce8\u518c\u603b\u8def\u7531<\/h4>\n<p>\u521b\u5efa backend\/api\/routes.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> APIRouter<br \/>\n<span class=\"token keyword\">from<\/span> api<span class=\"token punctuation\">.<\/span>endpoints <span class=\"token keyword\">import<\/span> upload<span class=\"token punctuation\">,<\/span> chat<\/p>\n<p>router <span class=\"token operator\">&#061;<\/span> APIRouter<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\nrouter<span class=\"token punctuation\">.<\/span>include_router<span class=\"token punctuation\">(<\/span>upload<span class=\"token punctuation\">.<\/span>router<span class=\"token punctuation\">)<\/span><br \/>\nrouter<span class=\"token punctuation\">.<\/span>include_router<span class=\"token punctuation\">(<\/span>chat<span class=\"token punctuation\">.<\/span>router<span class=\"token punctuation\">)<\/span><\/p>\n<p>\u5728 factory.py \u4e2d\u6ce8\u518c&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> api<span class=\"token punctuation\">.<\/span>routes <span class=\"token keyword\">import<\/span> router<\/p>\n<p>app<span class=\"token punctuation\">.<\/span>include_router<span class=\"token punctuation\">(<\/span>router<span class=\"token punctuation\">,<\/span> prefix<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/api\/v1&#034;<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<h4>5.5 \u8bbf\u95ee\u8def\u5f84<\/h4>\n<table>\n<tr>\u63a5\u53e3\u8def\u5f84\u65b9\u6cd5<\/tr>\n<tbody>\n<tr>\n<td>\u6839\u8def\u5f84<\/td>\n<td>GET \/<\/td>\n<td>GET<\/td>\n<\/tr>\n<tr>\n<td>\u4e0a\u4f20\u6587\u6863<\/td>\n<td>\/api\/v1\/upload\/<\/td>\n<td>POST<\/td>\n<\/tr>\n<tr>\n<td>\u667a\u80fd\u95ee\u7b54<\/td>\n<td>\/api\/v1\/chat\/<\/td>\n<td>POST<\/td>\n<\/tr>\n<tr>\n<td>Swagger<\/td>\n<td>\/docs<\/td>\n<td>GET<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3>6. Pydantic \u6570\u636e\u6a21\u578b<\/h3>\n<h4>6.1 \u4e3a\u4ec0\u4e48\u7528 Pydantic<\/h4>\n<p>FastAPI \u4f7f\u7528 Pydantic \u505a\u6570\u636e\u6821\u9a8c\u3001\u5e8f\u5217\u5316\u3001\u6587\u6863\u751f\u6210\u3002\u8bf7\u6c42\u53c2\u6570\u548c\u54cd\u5e94\u6570\u636e\u901a\u8fc7 Pydantic \u6a21\u578b\u81ea\u52a8\u6821\u9a8c\u7c7b\u578b\u3002<\/p>\n<h4>6.2 \u8bf7\u6c42\u6a21\u578b<\/h4>\n<p><span class=\"token keyword\">from<\/span> pydantic <span class=\"token keyword\">import<\/span> BaseModel<span class=\"token punctuation\">,<\/span> Field<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChatRequest<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    question<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> Field<span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">,<\/span>  <span class=\"token comment\"># \u5fc5\u586b<\/span><br \/>\n        min_length<span class=\"token operator\">&#061;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        max_length<span class=\"token operator\">&#061;<\/span><span class=\"token number\">500<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        description<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\u7528\u6237\u95ee\u9898&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n    session_id<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> Field<span class=\"token punctuation\">(<\/span><br \/>\n        default<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;default&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        description<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\u4f1a\u8bdd ID&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<h4>6.3 \u54cd\u5e94\u6a21\u578b<\/h4>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">DocumentSource<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    file_name<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><br \/>\n    page<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">int<\/span><br \/>\n    content<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChatResponse<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    answer<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> Field<span class=\"token punctuation\">(<\/span>description<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\u6a21\u578b\u56de\u7b54&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    sources<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">list<\/span><span class=\"token punctuation\">[<\/span>DocumentSource<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> Field<span class=\"token punctuation\">(<\/span><br \/>\n        default<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        description<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\u5f15\u7528\u6765\u6e90&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><br \/>\n    session_id<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><\/p>\n<h4>6.4 \u81ea\u52a8\u6821\u9a8c\u6548\u679c<\/h4>\n<p>\u5982\u679c\u8bf7\u6c42\u53c2\u6570\u4e0d\u5408\u6cd5&#xff0c;FastAPI \u81ea\u52a8\u8fd4\u56de 422 \u9519\u8bef&#xff1a;<\/p>\n<p><span class=\"token punctuation\">{<\/span><br \/>\n  <span class=\"token string-property property\">&#034;detail&#034;<\/span><span class=\"token operator\">:<\/span> <span class=\"token punctuation\">[<\/span><br \/>\n    <span class=\"token punctuation\">{<\/span><br \/>\n      <span class=\"token string-property property\">&#034;loc&#034;<\/span><span class=\"token operator\">:<\/span> <span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;body&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;question&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n      <span class=\"token string-property property\">&#034;msg&#034;<\/span><span class=\"token operator\">:<\/span> <span class=\"token string\">&#034;ensure this value has at least 1 characters&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n      <span class=\"token string-property property\">&#034;type&#034;<\/span><span class=\"token operator\">:<\/span> <span class=\"token string\">&#034;value_error.any_str.min_length&#034;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n  <span class=\"token punctuation\">]<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<h3>7. \u4f9d\u8d56\u6ce8\u5165<\/h3>\n<h4>7.1 \u4ec0\u4e48\u662f\u4f9d\u8d56\u6ce8\u5165<\/h4>\n<p>\u4f9d\u8d56\u6ce8\u5165&#xff08;DI&#xff09;\u662f\u628a\u9700\u8981\u7684\u8d44\u6e90&#xff08;\u6570\u636e\u5e93\u8fde\u63a5\u3001\u914d\u7f6e\u3001\u670d\u52a1\u7b49&#xff09;\u901a\u8fc7\u53c2\u6570\u4f20\u5165&#xff0c;\u800c\u4e0d\u662f\u5728\u51fd\u6570\u5185\u90e8\u521b\u5efa\u3002<\/p>\n<h4>7.2 FastAPI \u4e2d\u5b9a\u4e49\u4f9d\u8d56<\/h4>\n<p>\u521b\u5efa backend\/core\/deps.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> Depends<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>rag_service <span class=\"token keyword\">import<\/span> RAGService<\/p>\n<p><span class=\"token comment\"># \u5168\u5c40\u5355\u4f8b<\/span><br \/>\n_rag_service<span class=\"token punctuation\">:<\/span> RAGService <span class=\"token operator\">|<\/span> <span class=\"token boolean\">None<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">None<\/span><\/p>\n<p><span class=\"token keyword\">def<\/span> <span class=\"token function\">get_settings<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u83b7\u53d6\u914d\u7f6e&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> settings<\/p>\n<p><span class=\"token keyword\">def<\/span> <span class=\"token function\">get_rag_service<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token operator\">&gt;<\/span> RAGService<span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u83b7\u53d6 RAG \u670d\u52a1&#xff08;\u61d2\u52a0\u8f7d\u5355\u4f8b&#xff09;&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token keyword\">global<\/span> _rag_service<br \/>\n    <span class=\"token keyword\">if<\/span> _rag_service <span class=\"token keyword\">is<\/span> <span class=\"token boolean\">None<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        _rag_service <span class=\"token operator\">&#061;<\/span> RAGService<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> _rag_service<\/p>\n<h4>7.3 \u5728\u8def\u7531\u4e2d\u4f7f\u7528\u4f9d\u8d56<\/h4>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> APIRouter<span class=\"token punctuation\">,<\/span> Depends<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>deps <span class=\"token keyword\">import<\/span> get_rag_service<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>rag_service <span class=\"token keyword\">import<\/span> RAGService<\/p>\n<p>router <span class=\"token operator\">&#061;<\/span> APIRouter<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;router<span class=\"token punctuation\">.<\/span>post<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">chat<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    request<span class=\"token punctuation\">:<\/span> ChatRequest<span class=\"token punctuation\">,<\/span><br \/>\n    rag_service<span class=\"token punctuation\">:<\/span> RAGService <span class=\"token operator\">&#061;<\/span> Depends<span class=\"token punctuation\">(<\/span>get_rag_service<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u95ee\u7b54\u63a5\u53e3&#034;&#034;&#034;<\/span><br \/>\n    answer <span class=\"token operator\">&#061;<\/span> rag_service<span class=\"token punctuation\">.<\/span>ask<span class=\"token punctuation\">(<\/span>request<span class=\"token punctuation\">.<\/span>question<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> ChatResponse<span class=\"token punctuation\">(<\/span><br \/>\n        answer<span class=\"token operator\">&#061;<\/span>answer<span class=\"token punctuation\">,<\/span><br \/>\n        sources<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        session_id<span class=\"token operator\">&#061;<\/span>request<span class=\"token punctuation\">.<\/span>session_id<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<p>\u4f18\u70b9&#xff1a;<\/p>\n<ul>\n<li>\u6d4b\u8bd5\u65f6\u53ef\u4ee5 mock \u4f9d\u8d56<\/li>\n<li>\u4f9d\u8d56\u7684\u751f\u547d\u5468\u671f\u7531 FastAPI \u7ba1\u7406<\/li>\n<li>\u4ee3\u7801\u89e3\u8026&#xff0c;\u804c\u8d23\u6e05\u6670<\/li>\n<\/ul>\n<hr \/>\n<h3>8. \u6587\u4ef6\u4e0a\u4f20\u4e0e\u5904\u7406<\/h3>\n<h4>8.1 \u4e0a\u4f20\u63a5\u53e3<\/h4>\n<p>\u524d\u9762\u5df2\u7ecf\u521b\u5efa\u4e86 upload.py&#xff0c;\u73b0\u5728\u8865\u5145\u6587\u6863\u89e3\u6790\u548c\u5411\u91cf\u5165\u5e93\u3002<\/p>\n<h4>8.2 \u6587\u6863\u89e3\u6790\u670d\u52a1<\/h4>\n<p>\u521b\u5efa backend\/services\/document_service.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> pathlib <span class=\"token keyword\">import<\/span> Path<br \/>\n<span class=\"token keyword\">from<\/span> typing <span class=\"token keyword\">import<\/span> List<br \/>\n<span class=\"token keyword\">from<\/span> langchain_core<span class=\"token punctuation\">.<\/span>documents <span class=\"token keyword\">import<\/span> Document<br \/>\n<span class=\"token keyword\">from<\/span> langchain_community<span class=\"token punctuation\">.<\/span>document_loaders <span class=\"token keyword\">import<\/span> PyPDFLoader<span class=\"token punctuation\">,<\/span> TextLoader<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">DocumentService<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token keyword\">def<\/span> <span class=\"token function\">__init__<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">,<\/span> upload_dir<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        self<span class=\"token punctuation\">.<\/span>upload_dir <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span>upload_dir<span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">def<\/span> <span class=\"token function\">parse_file<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">,<\/span> file_path<span class=\"token punctuation\">:<\/span> Path<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token operator\">&gt;<\/span> List<span class=\"token punctuation\">[<\/span>Document<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u89e3\u6790\u6587\u6863\u4e3a\u6587\u672c\u5757&#034;&#034;&#034;<\/span><br \/>\n        suffix <span class=\"token operator\">&#061;<\/span> file_path<span class=\"token punctuation\">.<\/span>suffix<span class=\"token punctuation\">.<\/span>lower<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> suffix <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token string\">&#034;.pdf&#034;<\/span><span class=\"token punctuation\">:<\/span><br \/>\n            loader <span class=\"token operator\">&#061;<\/span> PyPDFLoader<span class=\"token punctuation\">(<\/span><span class=\"token builtin\">str<\/span><span class=\"token punctuation\">(<\/span>file_path<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">elif<\/span> suffix <span class=\"token keyword\">in<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;.txt&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;.md&#034;<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">:<\/span><br \/>\n            loader <span class=\"token operator\">&#061;<\/span> TextLoader<span class=\"token punctuation\">(<\/span><span class=\"token builtin\">str<\/span><span class=\"token punctuation\">(<\/span>file_path<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> encoding<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;utf-8&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">else<\/span><span class=\"token punctuation\">:<\/span><br \/>\n            <span class=\"token keyword\">raise<\/span> ValueError<span class=\"token punctuation\">(<\/span><span class=\"token string-interpolation\"><span class=\"token string\">f&#034;\u4e0d\u652f\u6301\u7684\u6587\u4ef6\u7c7b\u578b&#xff1a;<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span>suffix<span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\">&#034;<\/span><\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token keyword\">return<\/span> loader<span class=\"token punctuation\">.<\/span>load<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">def<\/span> <span class=\"token function\">get_file_path<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">,<\/span> filename<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token operator\">&gt;<\/span> Path<span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> self<span class=\"token punctuation\">.<\/span>upload_dir <span class=\"token operator\">\/<\/span> filename<\/p>\n<h4>8.3 \u5b8c\u6574\u4e0a\u4f20\u6d41\u7a0b<\/h4>\n<p>\u4fee\u6539 upload.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> APIRouter<span class=\"token punctuation\">,<\/span> UploadFile<span class=\"token punctuation\">,<\/span> File<span class=\"token punctuation\">,<\/span> HTTPException<span class=\"token punctuation\">,<\/span> Depends<br \/>\n<span class=\"token keyword\">from<\/span> pathlib <span class=\"token keyword\">import<\/span> Path<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>deps <span class=\"token keyword\">import<\/span> get_document_service<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>document_service <span class=\"token keyword\">import<\/span> DocumentService<\/p>\n<p>router <span class=\"token operator\">&#061;<\/span> APIRouter<span class=\"token punctuation\">(<\/span>prefix<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/upload&#034;<\/span><span class=\"token punctuation\">,<\/span> tags<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;\u6587\u4ef6\u4e0a\u4f20&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;router<span class=\"token punctuation\">.<\/span>post<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">upload_file<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">:<\/span> UploadFile <span class=\"token operator\">&#061;<\/span> File<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    doc_service<span class=\"token punctuation\">:<\/span> DocumentService <span class=\"token operator\">&#061;<\/span> Depends<span class=\"token punctuation\">(<\/span>get_document_service<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u4e0a\u4f20\u5e76\u89e3\u6790\u653f\u7b56\u6587\u6863&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token comment\"># \u6821\u9a8c\u6587\u4ef6\u7c7b\u578b<\/span><br \/>\n    allowed_extensions <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;.pdf&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;.txt&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;.md&#034;<\/span><span class=\"token punctuation\">}<\/span><br \/>\n    file_ext <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span><span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>filename<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span>suffix<span class=\"token punctuation\">.<\/span>lower<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> file_ext <span class=\"token keyword\">not<\/span> <span class=\"token keyword\">in<\/span> allowed_extensions<span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">raise<\/span> HTTPException<span class=\"token punctuation\">(<\/span><br \/>\n            status_code<span class=\"token operator\">&#061;<\/span><span class=\"token number\">400<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            detail<span class=\"token operator\">&#061;<\/span><span class=\"token string-interpolation\"><span class=\"token string\">f&#034;\u4e0d\u652f\u6301\u7684\u6587\u4ef6\u7c7b\u578b&#xff1a;<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span>file_ext<span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\">&#034;<\/span><\/span><br \/>\n        <span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># \u4fdd\u5b58\u6587\u4ef6<\/span><br \/>\n    upload_path <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span>settings<span class=\"token punctuation\">.<\/span>upload_dir<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">\/<\/span> <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>filename<br \/>\n    content <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">await<\/span> <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>read<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    upload_path<span class=\"token punctuation\">.<\/span>write_bytes<span class=\"token punctuation\">(<\/span>content<span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token comment\"># \u89e3\u6790\u6587\u6863<\/span><br \/>\n    <span class=\"token keyword\">try<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        documents <span class=\"token operator\">&#061;<\/span> doc_service<span class=\"token punctuation\">.<\/span>parse_file<span class=\"token punctuation\">(<\/span>upload_path<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token string\">&#034;filename&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">file<\/span><span class=\"token punctuation\">.<\/span>filename<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;size&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">len<\/span><span class=\"token punctuation\">(<\/span>content<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;pages&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">len<\/span><span class=\"token punctuation\">(<\/span>documents<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;message&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;\u4e0a\u4f20\u5e76\u89e3\u6790\u6210\u529f&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">except<\/span> Exception <span class=\"token keyword\">as<\/span> e<span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">raise<\/span> HTTPException<span class=\"token punctuation\">(<\/span>status_code<span class=\"token operator\">&#061;<\/span><span class=\"token number\">500<\/span><span class=\"token punctuation\">,<\/span> detail<span class=\"token operator\">&#061;<\/span><span class=\"token string-interpolation\"><span class=\"token string\">f&#034;\u89e3\u6790\u5931\u8d25&#xff1a;<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span><span class=\"token builtin\">str<\/span><span class=\"token punctuation\">(<\/span>e<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\">&#034;<\/span><\/span><span class=\"token punctuation\">)<\/span><\/p>\n<hr \/>\n<h3>9. LangChain \u96c6\u6210&#xff1a;\u6a21\u578b\u4e0e Embedding<\/h3>\n<h4>9.1 \u6a21\u578b\u5de5\u5382<\/h4>\n<p>\u521b\u5efa backend\/services\/model_factory.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> langchain_openai <span class=\"token keyword\">import<\/span> ChatOpenAI<br \/>\n<span class=\"token keyword\">from<\/span> langchain_community<span class=\"token punctuation\">.<\/span>embeddings <span class=\"token keyword\">import<\/span> DashScopeEmbeddings<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<\/p>\n<p><span class=\"token keyword\">def<\/span> <span class=\"token function\">get_chat_model<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u83b7\u53d6\u804a\u5929\u6a21\u578b&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> ChatOpenAI<span class=\"token punctuation\">(<\/span><br \/>\n        model<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;deepseek-chat&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        api_key<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>deepseek_api_key<span class=\"token punctuation\">,<\/span><br \/>\n        base_url<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>deepseek_base_url<span class=\"token punctuation\">,<\/span><br \/>\n        temperature<span class=\"token operator\">&#061;<\/span><span class=\"token number\">0.7<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<p><span class=\"token keyword\">def<\/span> <span class=\"token function\">get_embedding_model<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u83b7\u53d6 Embedding \u6a21\u578b&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> DashScopeEmbeddings<span class=\"token punctuation\">(<\/span><br \/>\n        model<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;text-embedding-v4&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        dashscope_api_key<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>deepseek_api_key<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<h4>9.2 \u5411\u91cf\u6570\u636e\u5e93\u8fde\u63a5<\/h4>\n<p>\u521b\u5efa backend\/services\/vector_store.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> langchain_community<span class=\"token punctuation\">.<\/span>vectorstores <span class=\"token keyword\">import<\/span> Milvus<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>model_factory <span class=\"token keyword\">import<\/span> get_embedding_model<br \/>\n<span class=\"token keyword\">from<\/span> pymilvus <span class=\"token keyword\">import<\/span> connections<span class=\"token punctuation\">,<\/span> utility<\/p>\n<p><span class=\"token keyword\">def<\/span> <span class=\"token function\">get_vector_store<\/span><span class=\"token punctuation\">(<\/span>collection_name<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">None<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u83b7\u53d6 Milvus \u5411\u91cf\u5e93\u5b9e\u4f8b&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> collection_name <span class=\"token keyword\">is<\/span> <span class=\"token boolean\">None<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        collection_name <span class=\"token operator\">&#061;<\/span> settings<span class=\"token punctuation\">.<\/span>milvus_collection_name<\/p>\n<p>    <span class=\"token comment\"># \u8fde\u63a5 Milvus<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token keyword\">not<\/span> connections<span class=\"token punctuation\">.<\/span>has_connection<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;default&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        connections<span class=\"token punctuation\">.<\/span>connect<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;default&#034;<\/span><span class=\"token punctuation\">,<\/span> uri<span class=\"token operator\">&#061;<\/span>settings<span class=\"token punctuation\">.<\/span>milvus_uri<span class=\"token punctuation\">)<\/span><\/p>\n<p>    embeddings <span class=\"token operator\">&#061;<\/span> get_embedding_model<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> Milvus<span class=\"token punctuation\">(<\/span><br \/>\n        embedding_function<span class=\"token operator\">&#061;<\/span>embeddings<span class=\"token punctuation\">,<\/span><br \/>\n        collection_name<span class=\"token operator\">&#061;<\/span>collection_name<span class=\"token punctuation\">,<\/span><br \/>\n        connection_args<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;uri&#034;<\/span><span class=\"token punctuation\">:<\/span> settings<span class=\"token punctuation\">.<\/span>milvus_uri<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        index_params<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token string\">&#034;index_type&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;HNSW&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;metric_type&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;COSINE&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;params&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token string\">&#034;M&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token number\">16<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;efConstruction&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token number\">128<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        auto_id<span class=\"token operator\">&#061;<\/span><span class=\"token boolean\">True<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<hr \/>\n<h3>10. RAG \u77e5\u8bc6\u5e93\u95ee\u7b54 API<\/h3>\n<h4>10.1 RAG \u670d\u52a1<\/h4>\n<p>\u521b\u5efa backend\/services\/rag_service.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> langchain_text_splitters <span class=\"token keyword\">import<\/span> RecursiveCharacterTextSplitter<br \/>\n<span class=\"token keyword\">from<\/span> langchain_core<span class=\"token punctuation\">.<\/span>documents <span class=\"token keyword\">import<\/span> Document<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>vector_store <span class=\"token keyword\">import<\/span> get_vector_store<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>model_factory <span class=\"token keyword\">import<\/span> get_chat_model<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>document_service <span class=\"token keyword\">import<\/span> DocumentService<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>config <span class=\"token keyword\">import<\/span> settings<br \/>\n<span class=\"token keyword\">from<\/span> pathlib <span class=\"token keyword\">import<\/span> Path<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">RAGService<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token keyword\">def<\/span> <span class=\"token function\">__init__<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        self<span class=\"token punctuation\">.<\/span>vector_store <span class=\"token operator\">&#061;<\/span> get_vector_store<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        self<span class=\"token punctuation\">.<\/span>chat_model <span class=\"token operator\">&#061;<\/span> get_chat_model<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        self<span class=\"token punctuation\">.<\/span>document_service <span class=\"token operator\">&#061;<\/span> DocumentService<span class=\"token punctuation\">(<\/span>settings<span class=\"token punctuation\">.<\/span>upload_dir<span class=\"token punctuation\">)<\/span><br \/>\n        self<span class=\"token punctuation\">.<\/span>text_splitter <span class=\"token operator\">&#061;<\/span> RecursiveCharacterTextSplitter<span class=\"token punctuation\">(<\/span><br \/>\n            chunk_size<span class=\"token operator\">&#061;<\/span><span class=\"token number\">500<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            chunk_overlap<span class=\"token operator\">&#061;<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">,<\/span><br \/>\n            separators<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;\\\\n\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;\u3002&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;&#xff01;&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;&#xff1f;&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">def<\/span> <span class=\"token function\">build_index<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">,<\/span> file_path<span class=\"token punctuation\">:<\/span> Path<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u6784\u5efa\u77e5\u8bc6\u5e93\u7d22\u5f15&#034;&#034;&#034;<\/span><br \/>\n        <span class=\"token comment\"># 1. \u89e3\u6790\u6587\u6863<\/span><br \/>\n        documents <span class=\"token operator\">&#061;<\/span> self<span class=\"token punctuation\">.<\/span>document_service<span class=\"token punctuation\">.<\/span>parse_file<span class=\"token punctuation\">(<\/span>file_path<span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token comment\"># 2. \u5207\u5206\u6587\u6863<\/span><br \/>\n        chunks <span class=\"token operator\">&#061;<\/span> self<span class=\"token punctuation\">.<\/span>text_splitter<span class=\"token punctuation\">.<\/span>split_documents<span class=\"token punctuation\">(<\/span>documents<span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token comment\"># 3. \u5199\u5165\u5411\u91cf\u5e93<\/span><br \/>\n        self<span class=\"token punctuation\">.<\/span>vector_store<span class=\"token punctuation\">.<\/span>add_documents<span class=\"token punctuation\">(<\/span>chunks<span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token keyword\">return<\/span> <span class=\"token builtin\">len<\/span><span class=\"token punctuation\">(<\/span>chunks<span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">def<\/span> <span class=\"token function\">ask<\/span><span class=\"token punctuation\">(<\/span>self<span class=\"token punctuation\">,<\/span> question<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token operator\">&gt;<\/span> <span class=\"token builtin\">str<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u95ee\u7b54&#034;&#034;&#034;<\/span><br \/>\n        <span class=\"token comment\"># 1. \u68c0\u7d22\u76f8\u5173\u6587\u6863<\/span><br \/>\n        results <span class=\"token operator\">&#061;<\/span> self<span class=\"token punctuation\">.<\/span>vector_store<span class=\"token punctuation\">.<\/span>similarity_search<span class=\"token punctuation\">(<\/span>question<span class=\"token punctuation\">,<\/span> k<span class=\"token operator\">&#061;<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token keyword\">not<\/span> results<span class=\"token punctuation\">:<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token string\">&#034;\u672a\u627e\u5230\u76f8\u5173\u653f\u7b56\u5185\u5bb9&#xff0c;\u8bf7\u5c1d\u8bd5\u5176\u4ed6\u95ee\u9898\u3002&#034;<\/span><\/p>\n<p>        <span class=\"token comment\"># 2. \u6784\u5efa\u4e0a\u4e0b\u6587<\/span><br \/>\n        context <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;\\\\n\\\\n&#034;<\/span><span class=\"token punctuation\">.<\/span>join<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">[<\/span>doc<span class=\"token punctuation\">.<\/span>page_content <span class=\"token keyword\">for<\/span> doc <span class=\"token keyword\">in<\/span> results<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>        <span class=\"token comment\"># 3. \u8c03\u7528\u6a21\u578b<\/span><br \/>\n        prompt <span class=\"token operator\">&#061;<\/span> <span class=\"token string-interpolation\"><span class=\"token string\">f&#034;&#034;&#034;\u57fa\u4e8e\u4ee5\u4e0b\u653f\u7b56\u8d44\u6599\u56de\u7b54\u95ee\u9898&#xff1a;<\/p>\n<p>\u8d44\u6599&#xff1a;<br \/>\n<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span>context<span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\"><\/p>\n<p>\u95ee\u9898&#xff1a;<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span>question<span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\"><\/p>\n<p>\u8bf7\u6839\u636e\u8d44\u6599\u56de\u7b54&#xff0c;\u5982\u679c\u8d44\u6599\u4e2d\u6ca1\u6709\u76f8\u5173\u4fe1\u606f&#xff0c;\u8bf7\u8bf4\u660e\u3002&#034;&#034;&#034;<\/span><\/span><\/p>\n<p>        response <span class=\"token operator\">&#061;<\/span> self<span class=\"token punctuation\">.<\/span>chat_model<span class=\"token punctuation\">.<\/span>invoke<span class=\"token punctuation\">(<\/span>prompt<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> response<span class=\"token punctuation\">.<\/span>content<\/p>\n<h4>10.2 \u95ee\u7b54\u63a5\u53e3<\/h4>\n<p>\u4fee\u6539 chat.py&#xff1a;<\/p>\n<p><span class=\"token keyword\">from<\/span> fastapi <span class=\"token keyword\">import<\/span> APIRouter<span class=\"token punctuation\">,<\/span> Depends<br \/>\n<span class=\"token keyword\">from<\/span> pydantic <span class=\"token keyword\">import<\/span> BaseModel<span class=\"token punctuation\">,<\/span> Field<br \/>\n<span class=\"token keyword\">from<\/span> core<span class=\"token punctuation\">.<\/span>deps <span class=\"token keyword\">import<\/span> get_rag_service<br \/>\n<span class=\"token keyword\">from<\/span> services<span class=\"token punctuation\">.<\/span>rag_service <span class=\"token keyword\">import<\/span> RAGService<\/p>\n<p>router <span class=\"token operator\">&#061;<\/span> APIRouter<span class=\"token punctuation\">(<\/span>prefix<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\/chat&#034;<\/span><span class=\"token punctuation\">,<\/span> tags<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token string\">&#034;\u667a\u80fd\u95ee\u7b54&#034;<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChatRequest<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    question<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> Field<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">,<\/span> min_length<span class=\"token operator\">&#061;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> max_length<span class=\"token operator\">&#061;<\/span><span class=\"token number\">500<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    session_id<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token string\">&#034;default&#034;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">DocumentSource<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    file_name<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><br \/>\n    content<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChatResponse<\/span><span class=\"token punctuation\">(<\/span>BaseModel<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    answer<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><br \/>\n    sources<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">list<\/span><span class=\"token punctuation\">[<\/span>DocumentSource<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><br \/>\n    session_id<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;router<span class=\"token punctuation\">.<\/span>post<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/&#034;<\/span><span class=\"token punctuation\">,<\/span> response_model<span class=\"token operator\">&#061;<\/span>ChatResponse<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">chat<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    request<span class=\"token punctuation\">:<\/span> ChatRequest<span class=\"token punctuation\">,<\/span><br \/>\n    rag_service<span class=\"token punctuation\">:<\/span> RAGService <span class=\"token operator\">&#061;<\/span> Depends<span class=\"token punctuation\">(<\/span>get_rag_service<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54&#034;&#034;&#034;<\/span><br \/>\n    answer <span class=\"token operator\">&#061;<\/span> rag_service<span class=\"token punctuation\">.<\/span>ask<span class=\"token punctuation\">(<\/span>request<span class=\"token punctuation\">.<\/span>question<span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> ChatResponse<span class=\"token punctuation\">(<\/span><br \/>\n        answer<span class=\"token operator\">&#061;<\/span>answer<span class=\"token punctuation\">,<\/span><br \/>\n        sources<span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        session_id<span class=\"token operator\">&#061;<\/span>request<span class=\"token punctuation\">.<\/span>session_id<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">)<\/span><\/p>\n<h4>10.3 \u7d22\u5f15\u6784\u5efa\u63a5\u53e3<\/h4>\n<p>\u5728 upload.py \u4e2d\u6dfb\u52a0\u6784\u5efa\u7d22\u5f15\u903b\u8f91&#xff1a;<\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;router<span class=\"token punctuation\">.<\/span>post<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/{filename}\/index&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">build_index<\/span><span class=\"token punctuation\">(<\/span><br \/>\n    filename<span class=\"token punctuation\">:<\/span> <span class=\"token builtin\">str<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    rag_service<span class=\"token punctuation\">:<\/span> RAGService <span class=\"token operator\">&#061;<\/span> Depends<span class=\"token punctuation\">(<\/span>get_rag_service<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u4e3a\u5df2\u4e0a\u4f20\u7684\u6587\u6863\u6784\u5efa\u5411\u91cf\u7d22\u5f15&#034;&#034;&#034;<\/span><br \/>\n    file_path <span class=\"token operator\">&#061;<\/span> Path<span class=\"token punctuation\">(<\/span>settings<span class=\"token punctuation\">.<\/span>upload_dir<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">\/<\/span> filename<\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token keyword\">not<\/span> file_path<span class=\"token punctuation\">.<\/span>exists<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">raise<\/span> HTTPException<span class=\"token punctuation\">(<\/span>status_code<span class=\"token operator\">&#061;<\/span><span class=\"token number\">404<\/span><span class=\"token punctuation\">,<\/span> detail<span class=\"token operator\">&#061;<\/span><span class=\"token string\">&#034;\u6587\u4ef6\u4e0d\u5b58\u5728&#034;<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<p>    <span class=\"token keyword\">try<\/span><span class=\"token punctuation\">:<\/span><br \/>\n        chunk_count <span class=\"token operator\">&#061;<\/span> rag_service<span class=\"token punctuation\">.<\/span>build_index<span class=\"token punctuation\">(<\/span>file_path<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token string\">&#034;filename&#034;<\/span><span class=\"token punctuation\">:<\/span> filename<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;chunks&#034;<\/span><span class=\"token punctuation\">:<\/span> chunk_count<span class=\"token punctuation\">,<\/span><br \/>\n            <span class=\"token string\">&#034;message&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;\u7d22\u5f15\u6784\u5efa\u6210\u529f&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">except<\/span> Exception <span class=\"token keyword\">as<\/span> e<span class=\"token punctuation\">:<\/span><br \/>\n        <span class=\"token keyword\">raise<\/span> HTTPException<span class=\"token punctuation\">(<\/span>status_code<span class=\"token operator\">&#061;<\/span><span class=\"token number\">500<\/span><span class=\"token punctuation\">,<\/span> detail<span class=\"token operator\">&#061;<\/span><span class=\"token string-interpolation\"><span class=\"token string\">f&#034;\u7d22\u5f15\u6784\u5efa\u5931\u8d25&#xff1a;<\/span><span class=\"token interpolation\"><span class=\"token punctuation\">{<\/span><span class=\"token builtin\">str<\/span><span class=\"token punctuation\">(<\/span>e<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">}<\/span><\/span><span class=\"token string\">&#034;<\/span><\/span><span class=\"token punctuation\">)<\/span><\/p>\n<hr \/>\n<h3>11. \u5065\u5eb7\u68c0\u67e5\u4e0e\u4f18\u96c5\u5173\u95ed<\/h3>\n<h4>11.1 \u5065\u5eb7\u68c0\u67e5\u63a5\u53e3<\/h4>\n<p>\u5728 factory.py \u4e2d\u6dfb\u52a0&#xff1a;<\/p>\n<p><span class=\"token decorator annotation punctuation\">&#064;app<span class=\"token punctuation\">.<\/span>get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\/health&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">health_check<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token string\">&#034;status&#034;<\/span><span class=\"token punctuation\">:<\/span> <span class=\"token string\">&#034;healthy&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token string\">&#034;version&#034;<\/span><span class=\"token punctuation\">:<\/span> settings<span class=\"token punctuation\">.<\/span>app_version<span class=\"token punctuation\">,<\/span><br \/>\n        <span class=\"token string\">&#034;timestamp&#034;<\/span><span class=\"token punctuation\">:<\/span> datetime<span class=\"token punctuation\">.<\/span>now<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span>isoformat<span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<h4>11.2 \u4f18\u96c5\u5173\u95ed<\/h4>\n<p><span class=\"token decorator annotation punctuation\">&#064;app<span class=\"token punctuation\">.<\/span>on_event<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;shutdown&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token keyword\">async<\/span> <span class=\"token keyword\">def<\/span> <span class=\"token function\">shutdown_event<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">:<\/span><br \/>\n    <span class=\"token triple-quoted-string string\">&#034;&#034;&#034;\u5e94\u7528\u5173\u95ed\u65f6\u6e05\u7406\u8d44\u6e90&#034;&#034;&#034;<\/span><br \/>\n    <span class=\"token keyword\">from<\/span> pymilvus <span class=\"token keyword\">import<\/span> connections<br \/>\n    connections<span class=\"token punctuation\">.<\/span>disconnect<span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;default&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token keyword\">print<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\u5df2\u65ad\u5f00 Milvus \u8fde\u63a5&#034;<\/span><span class=\"token punctuation\">)<\/span><\/p>\n<hr \/>\n<h3>12. \u9879\u76ee\u5b8c\u6574\u7ed3\u6784<\/h3>\n<p>policy-rag-backend\/<br \/>\n\u251c\u2500\u2500 .env                          # \u73af\u5883\u53d8\u91cf&#xff08;\u5bc6\u94a5&#xff09;<br \/>\n\u251c\u2500\u2500 .gitignore                    # Git \u5ffd\u7565\u6587\u4ef6<br \/>\n\u251c\u2500\u2500 requirements.txt              # \u4f9d\u8d56\u6e05\u5355<br \/>\n\u251c\u2500\u2500 backend\/<br \/>\n\u2502   \u251c\u2500\u2500 main.py                   # \u542f\u52a8\u5165\u53e3<br \/>\n\u2502   \u251c\u2500\u2500 app\/<br \/>\n\u2502   \u2502   \u2514\u2500\u2500 factory.py            # \u5e94\u7528\u5de5\u5382<br \/>\n\u2502   \u251c\u2500\u2500 api\/<br \/>\n\u2502   \u2502   \u251c\u2500\u2500 __init__.py<br \/>\n\u2502   \u2502   \u251c\u2500\u2500 routes.py             # \u603b\u8def\u7531\u5165\u53e3<br \/>\n\u2502   \u2502   \u2514\u2500\u2500 endpoints\/<br \/>\n\u2502   \u2502       \u251c\u2500\u2500 __init__.py<br \/>\n\u2502   \u2502       \u251c\u2500\u2500 upload.py         # \u6587\u4ef6\u4e0a\u4f20<br \/>\n\u2502   \u2502       \u2514\u2500\u2500 chat.py           # \u667a\u80fd\u95ee\u7b54<br \/>\n\u2502   \u251c\u2500\u2500 core\/<br \/>\n\u2502   \u2502   \u251c\u2500\u2500 __init__.py<br \/>\n\u2502   \u2502   \u251c\u2500\u2500 config.py             # \u914d\u7f6e\u7ba1\u7406<br \/>\n\u2502   \u2502   \u2514\u2500\u2500 deps.py               # \u4f9d\u8d56\u6ce8\u5165<br \/>\n\u2502   \u2514\u2500\u2500 services\/<br \/>\n\u2502       \u251c\u2500\u2500 __init__.py<br \/>\n\u2502       \u251c\u2500\u2500 model_factory.py      # \u6a21\u578b\u5de5\u5382<br \/>\n\u2502       \u251c\u2500\u2500 vector_store.py       # \u5411\u91cf\u5e93\u8fde\u63a5<br \/>\n\u2502       \u251c\u2500\u2500 document_service.py   # \u6587\u6863\u89e3\u6790<br \/>\n\u2502       \u2514\u2500\u2500 rag_service.py        # RAG \u670d\u52a1<br \/>\n\u2514\u2500\u2500 uploads\/                      # \u4e0a\u4f20\u6587\u4ef6\u76ee\u5f55<\/p>\n<hr \/>\n<h3>13. \u8e29\u5751\u6e05\u5355<\/h3>\n<table>\n<tr>\u95ee\u9898\u539f\u56e0\u89e3\u51b3\u65b9\u6848<\/tr>\n<tbody>\n<tr>\n<td>ModuleNotFoundError: No module named &#039;app&#039;<\/td>\n<td>\u542f\u52a8\u547d\u4ee4\u4e0d\u5728 backend \u76ee\u5f55<\/td>\n<td>\u786e\u4fdd\u5728 backend\/ \u76ee\u5f55\u6267\u884c uvicorn main:app<\/td>\n<\/tr>\n<tr>\n<td>ImportError: cannot import name &#039;Settings&#039;<\/td>\n<td>pydantic-settings \u672a\u5b89\u88c5<\/td>\n<td>pip install pydantic-settings<\/td>\n<\/tr>\n<tr>\n<td>CORS \u62a5\u9519&#xff0c;\u524d\u7aef\u65e0\u6cd5\u8c03\u7528<\/td>\n<td>allow_origins \u914d\u7f6e\u9519\u8bef<\/td>\n<td>\u786e\u4fdd\u5305\u542b http:\/\/localhost:3000&#xff0c;\u6ce8\u610f\u65e0\u659c\u6760<\/td>\n<\/tr>\n<tr>\n<td>\u4e0a\u4f20\u5927\u6587\u4ef6\u5931\u8d25<\/td>\n<td>\u9ed8\u8ba4\u8bf7\u6c42\u4f53\u5927\u5c0f\u9650\u5236<\/td>\n<td>\u542f\u52a8\u65f6\u52a0 &#8211;limit-max-request-body-size 100000000<\/td>\n<\/tr>\n<tr>\n<td>Milvus \u8fde\u63a5\u8d85\u65f6<\/td>\n<td>\u670d\u52a1\u672a\u542f\u52a8\u6216 URI \u9519\u8bef<\/td>\n<td>\u786e\u8ba4 Milvus Docker \u5bb9\u5668\u8fd0\u884c&#xff0c;docker ps \u68c0\u67e5<\/td>\n<\/tr>\n<tr>\n<td>TypeError: &#039;NoneType&#039; object is not callable<\/td>\n<td>\u4f9d\u8d56\u6ce8\u5165\u51fd\u6570\u672a\u6b63\u786e\u8fd4\u56de<\/td>\n<td>\u68c0\u67e5 Depends() \u4e2d\u7684\u51fd\u6570\u662f\u5426\u6b63\u786e\u8fd4\u56de\u5b9e\u4f8b<\/td>\n<\/tr>\n<tr>\n<td>.env \u914d\u7f6e\u4e0d\u751f\u6548<\/td>\n<td>\u8def\u5f84\u9519\u8bef\u6216\u7f16\u7801\u95ee\u9898<\/td>\n<td>\u786e\u8ba4 .env \u5728 backend \u540c\u7ea7\u6216\u4e0a\u7ea7\u76ee\u5f55&#xff0c;\u4f7f\u7528 UTF-8 \u7f16\u7801<\/td>\n<\/tr>\n<tr>\n<td>\u6a21\u578b\u8c03\u7528\u8fd4\u56de 401<\/td>\n<td>API Key \u9519\u8bef\u6216\u672a\u914d\u7f6e<\/td>\n<td>\u68c0\u67e5 .env \u4e2d DEEPSEEK_API_KEY \u662f\u5426\u6b63\u786e<\/td>\n<\/tr>\n<tr>\n<td>RAG \u68c0\u7d22\u4e0d\u5230\u5185\u5bb9<\/td>\n<td>\u672a\u6784\u5efa\u7d22\u5f15\u6216\u7d22\u5f15\u4e3a\u7a7a<\/td>\n<td>\u5148\u8c03\u7528 \/upload\/{filename}\/index \u6784\u5efa\u7d22\u5f15<\/td>\n<\/tr>\n<tr>\n<td>Pydantic \u6821\u9a8c\u9519\u8bef<\/td>\n<td>\u8bf7\u6c42\u53c2\u6570\u7c7b\u578b\u4e0d\u5339\u914d<\/td>\n<td>\u5bf9\u7167 Swagger \/docs \u4e2d\u7684\u8bf7\u6c42\u6a21\u578b\u68c0\u67e5\u53c2\u6570<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3>14. \u672c\u7ae0\u91cd\u70b9<\/h3>\n<p>\u672c\u7ae0\u9700\u8981\u91cd\u70b9\u638c\u63e1&#xff1a;<\/p>\n<ul>\n<li>\u5e94\u7528\u5de5\u5382&#xff1a;create_app() \u5c01\u88c5\u521b\u5efa\u903b\u8f91&#xff0c;\u652f\u6301\u914d\u7f6e\u6ce8\u5165\u548c\u7075\u6d3b\u6269\u5c55<\/li>\n<li>\u914d\u7f6e\u7ba1\u7406&#xff1a;Pydantic Settings \u81ea\u52a8\u8bfb\u53d6 .env&#xff0c;\u5f00\u53d1\/\u751f\u4ea7\u73af\u5883\u5207\u6362<\/li>\n<li>\u8def\u7531\u62c6\u5206&#xff1a;APIRouter \u6309\u529f\u80fd\u6a21\u5757\u62c6\u5206&#xff0c;\u4ee3\u7801\u7ed3\u6784\u6e05\u6670<\/li>\n<li>Pydantic \u6a21\u578b&#xff1a;\u8bf7\u6c42\/\u54cd\u5e94\u81ea\u52a8\u6821\u9a8c&#xff0c;\u7c7b\u578b\u5b89\u5168<\/li>\n<li>\u4f9d\u8d56\u6ce8\u5165&#xff1a;Depends() \u89e3\u8026\u670d\u52a1&#xff0c;\u652f\u6301\u6d4b\u8bd5 mock<\/li>\n<li>\u6587\u4ef6\u4e0a\u4f20&#xff1a;UploadFile \u5904\u7406\u5927\u6587\u4ef6&#xff0c;\u652f\u6301\u6d41\u5f0f\u8bfb\u53d6<\/li>\n<li>CORS \u914d\u7f6e&#xff1a;\u524d\u540e\u7aef\u8054\u8c03\u5fc5\u5907&#xff0c;\u751f\u4ea7\u73af\u5883\u4e25\u683c\u9650\u5236\u57df\u540d<\/li>\n<li>LangChain \u96c6\u6210&#xff1a;\u6a21\u578b\u5de5\u5382 &#043; Embedding &#043; \u5411\u91cf\u5e93&#xff0c;\u6784\u5efa RAG \u670d\u52a1<\/li>\n<\/ul>\n<p>\u5b8c\u6574\u540e\u7aef\u95ee\u7b54\u6d41\u7a0b&#xff1a;<\/p>\n<p>\u7528\u6237\u4e0a\u4f20\u6587\u6863<br \/>\n  -&gt; \u89e3\u6790\u4e3a\u6587\u672c\u5757<br \/>\n  -&gt; Embedding \u5411\u91cf\u5316<br \/>\n  -&gt; \u5b58\u5165 Milvus<\/p>\n<p>\u7528\u6237\u63d0\u95ee<br \/>\n  -&gt; Embedding \u5411\u91cf\u5316<br \/>\n  -&gt; Milvus \u76f8\u4f3c\u5ea6\u68c0\u7d22<br \/>\n  -&gt; \u83b7\u53d6\u4e0a\u4e0b\u6587<br \/>\n  -&gt; DeepSeek \u751f\u6210\u56de\u7b54<br \/>\n  -&gt; \u8fd4\u56de JSON \u54cd\u5e94<\/p>\n<hr \/>\n<p>\u5982\u679c\u672c\u6587\u5bf9\u4f60\u6709\u5e2e\u52a9&#xff0c;\u6b22\u8fce\u70b9\u8d5e\u6536\u85cf\u3002\u5982\u6709\u95ee\u9898&#xff0c;\u6b22\u8fce\u5728\u8bc4\u8bba\u533a\u7559\u8a00\u4ea4\u6d41\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>FastAPI  LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218&#xff1a;\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf \u6458\u8981&#xff1a;\u672c\u6587\u57fa\u4e8e FastAPI \u6846\u67b6\u548c LangChain&#xff0c;\u624b\u628a\u624b\u6559\u4f60\u4ece\u96f6\u6784\u5efa\u4e00\u4e2a\u5b8c\u6574\u7684\u653f\u52a1\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54\u540e\u7aef\u7cfb\u7edf\u3002\u6db5\u76d6\u5e94\u7528\u5de5\u5382\u6a21\u5f0f\u3001Pydantic \u6570\u636e\u6a21\u578b\u3001\u4f9d\u8d56\u6ce8\u5165\u3001\u6587\u4ef6\u4e0a\u4f20\u3001CORS \u914d\u7f6e\u3001\u8def\u7531\u62c6\u5206\u3001LangChain \u96c6\u6210\u3001Embedding \u5411\u91cf\u68c0\u7d22\u3001RAG \u95ee\u7b54 API \u7b49\u5b8c\u6574\u751f\u4ea7\u7ea7\u80fd\u529b\u3002\u6240\u6709\u4ee3\u7801\u53ef\u76f4\u63a5\u590d\u5236\u8fd0\u884c&amp;#xff0c<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[10187,8980,72,997,50,100],"topic":[],"class_list":["post-89783","post","type-post","status-publish","format-standard","hentry","category-server","tag-codingplan","tag-8980","tag-fastapi","tag-langchain","tag-50","tag-100"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title># FastAPI + LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218\uff1a\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/89783.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"# FastAPI + LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218\uff1a\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"FastAPI LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218&#xff1a;\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf \u6458\u8981&#xff1a;\u672c\u6587\u57fa\u4e8e FastAPI \u6846\u67b6\u548c LangChain&#xff0c;\u624b\u628a\u624b\u6559\u4f60\u4ece\u96f6\u6784\u5efa\u4e00\u4e2a\u5b8c\u6574\u7684\u653f\u52a1\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54\u540e\u7aef\u7cfb\u7edf\u3002\u6db5\u76d6\u5e94\u7528\u5de5\u5382\u6a21\u5f0f\u3001Pydantic \u6570\u636e\u6a21\u578b\u3001\u4f9d\u8d56\u6ce8\u5165\u3001\u6587\u4ef6\u4e0a\u4f20\u3001CORS \u914d\u7f6e\u3001\u8def\u7531\u62c6\u5206\u3001LangChain \u96c6\u6210\u3001Embedding \u5411\u91cf\u68c0\u7d22\u3001RAG \u95ee\u7b54 API \u7b49\u5b8c\u6574\u751f\u4ea7\u7ea7\u80fd\u529b\u3002\u6240\u6709\u4ee3\u7801\u53ef\u76f4\u63a5\u590d\u5236\u8fd0\u884c&amp;#xff0c\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/89783.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-08-03T10:16:42+00:00\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"10 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/89783.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/89783.html\",\"name\":\"# FastAPI + LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218\uff1a\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf - 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\u540e\u7aef\u9879\u76ee\u5b9e\u6218\uff1a\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\",\"url\":\"https:\/\/www.wsisp.com\/helps\/\",\"name\":\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"description\":\"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}\"},\"query-input\":\"required 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\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.wsisp.com\/helps\/89783.html","og_locale":"zh_CN","og_type":"article","og_title":"# FastAPI + LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218\uff1a\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"FastAPI LangChain \u653f\u52a1\u653f\u7b56 RAG \u540e\u7aef\u9879\u76ee\u5b9e\u6218&#xff1a;\u4ece\u96f6\u6784\u5efa\u751f\u4ea7\u7ea7\u667a\u80fd\u95ee\u7b54\u7cfb\u7edf \u6458\u8981&#xff1a;\u672c\u6587\u57fa\u4e8e FastAPI \u6846\u67b6\u548c LangChain&#xff0c;\u624b\u628a\u624b\u6559\u4f60\u4ece\u96f6\u6784\u5efa\u4e00\u4e2a\u5b8c\u6574\u7684\u653f\u52a1\u653f\u7b56\u77e5\u8bc6\u5e93\u95ee\u7b54\u540e\u7aef\u7cfb\u7edf\u3002\u6db5\u76d6\u5e94\u7528\u5de5\u5382\u6a21\u5f0f\u3001Pydantic \u6570\u636e\u6a21\u578b\u3001\u4f9d\u8d56\u6ce8\u5165\u3001\u6587\u4ef6\u4e0a\u4f20\u3001CORS \u914d\u7f6e\u3001\u8def\u7531\u62c6\u5206\u3001LangChain \u96c6\u6210\u3001Embedding \u5411\u91cf\u68c0\u7d22\u3001RAG \u95ee\u7b54 API \u7b49\u5b8c\u6574\u751f\u4ea7\u7ea7\u80fd\u529b\u3002\u6240\u6709\u4ee3\u7801\u53ef\u76f4\u63a5\u590d\u5236\u8fd0\u884c&amp;#xff0c","og_url":"https:\/\/www.wsisp.com\/helps\/89783.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-08-03T10:16:42+00:00","author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"10 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