🔥 refactor: remove langchain

README.md

@@ -8,9 +8,7 @@
 
 <h1>Lobe Chat</h1>
 
-Lobe Chat is an open-source chatbot client using LangChain
-
-Typescript and Next.js
+Lobe Chat is an open-source chatbot client using OpenAI and Next.js
 
 [Changelog](./CHANGELOG.md) · [Report Bug][issues-url] · [Request Feature][issues-url]
 

package.json

@@ -76,7 +76,6 @@
     "gpt-tokenizer": "^2",
     "i18next": "^23",
     "immer": "^10",
-    "langchain": "latest",
     "lodash-es": "^4",
     "lucide-react": "latest",
     "nanoid": "^4",

src/pages/api/LangChainStream.ts

@@ -1,95 +0,0 @@
-import { LLMChain } from 'langchain/chains';
-import { ChatOpenAI } from 'langchain/chat_models/openai';
-import {
-  AIMessagePromptTemplate,
-  ChatPromptTemplate,
-  HumanMessagePromptTemplate,
-  SystemMessagePromptTemplate,
-} from 'langchain/prompts';
-
-import { LangChainParams } from '@/types/langchain';
-
-const isDev = process.env.NODE_ENV === 'development';
-const OPENAI_PROXY_URL = process.env.OPENAI_PROXY_URL;
-
-export function LangChainStream(payload: LangChainParams) {
-  const { prompts, vars, llm } = payload;
-
-  // 将 payload 中的消息转换为 ChatOpenAI 所需的 HumanChatMessage、SystemChatMessage 和 AIChatMessage 类型
-  const chatPrompt = ChatPromptTemplate.fromPromptMessages(
-    prompts.map((m) => {
-      switch (m.role) {
-        default:
-        case 'user': {
-          return HumanMessagePromptTemplate.fromTemplate(m.content);
-        }
-        case 'system': {
-          return SystemMessagePromptTemplate.fromTemplate(m.content);
-        }
-
-        case 'assistant': {
-          return AIMessagePromptTemplate.fromTemplate(m.content);
-        }
-      }
-    }),
-  );
-
-  // 使用 TextEncoder 将字符串转换为字节数组，以便在 ReadableStream 中发送
-  const encoder = new TextEncoder();
-
-  // 初始化换行符计数器
-
-  return new ReadableStream({
-    async start(controller) {
-      let newlineCounter = 0;
-
-      const chat = new ChatOpenAI(
-        {
-          streaming: true,
-          ...llm,
-
-          callbacks: [
-            {
-              handleLLMNewToken(token) {
-                // 如果 message 是换行符，且 newlineCounter 小于 2，那么跳过该换行符
-                if (newlineCounter < 2 && token === '\n') {
-                  return;
-                }
-
-                // 将 message 编码为字节并添加到流中
-                const queue = encoder.encode(token);
-                controller.enqueue(queue);
-                newlineCounter++;
-              },
-            },
-          ],
-          // 暂时设定不重试 ，后续看是否需要支持重试
-          maxRetries: 0,
-        },
-        isDev && OPENAI_PROXY_URL ? { basePath: OPENAI_PROXY_URL } : undefined,
-      );
-
-      const chain = new LLMChain({
-        callbacks: [
-          {
-            handleChainError(err: Error): Promise<void> | void {
-              console.log(err.message);
-            },
-          },
-        ],
-        llm: chat,
-        prompt: chatPrompt,
-        verbose: true,
-      });
-      try {
-        // 使用转换后的聊天消息作为输入开始聊天
-        await chain.call(vars);
-        // 完成后，关闭流
-        controller.close();
-      } catch (error) {
-        // 如果在执行过程中发生错误，向流发送错误
-        controller.error(error);
-      }
-    },
-  });
-}

src/pages/api/chain.api.ts

@@ -1,17 +0,0 @@
-import { LangChainParams } from '@/types/langchain';
-
-import { LangChainStream } from './LangChainStream';
-
-if (!process.env.OPENAI_API_KEY) {
-  throw new Error('Missing env var from OpenAI');
-}
-
-export const config = {
-  runtime: 'edge',
-};
-
-export default async function handler(request: Request) {
-  const payload = (await request.json()) as LangChainParams;
-
-  return new Response(LangChainStream(payload));
-}

src/services/langChain.ts

@@ -1,18 +0,0 @@
-import { URLS } from '@/services/url';
-import { LangChainParams } from '@/types/langchain';
-import { fetchAIFactory } from '@/utils/fetch';
-
-/**
- * 专门用于 FlowChain 的 fetch
- */
-export const fetchLangChain = fetchAIFactory(
-  (params: LangChainParams, signal?: AbortSignal | undefined) =>
-    fetch(URLS.chain, {
-      body: JSON.stringify(params),
-      headers: {
-        'Content-Type': 'application/json',
-      },
-      method: 'POST',
-      signal,
-    }),
-);

src/services/url.ts

@@ -3,6 +3,5 @@ const isDev = process.env.NODE_ENV === 'development';
 const prefix = isDev ? '-dev' : '';
 
 export const URLS = {
-  chain: '/api/chain' + prefix,
   openai: '/api/openai' + prefix,
 };

src/types/langchain.ts

@@ -1,34 +0,0 @@
-import { ChatMessage } from '@lobehub/ui';
-
-export interface LangChainParams {
-  llm: {
-    /**
-     *  控制生成文本中的惩罚系数，用于减少重复性
-     */
-    frequency_penalty?: number;
-    /**
-     *  生成文本的最大长度
-     */
-    max_tokens?: number;
-    model: string;
-    /**
-     *  控制生成文本中的惩罚系数，用于减少主题的变化
-     */
-    presence_penalty?: number;
-    /**
-     *  生成文本的随机度量，用于控制文本的创造性和多样性
-     * @default 0.6
-     */
-    temperature: number;
-    /**
-     *  控制生成文本中最高概率的单个令牌
-     */
-    top_p?: number;
-  };
-
-  /**
-   *  聊天信息列表
-   */
-  prompts: ChatMessage[];
-  vars: Record<string, string>;
-}