Merge pull request #3 from golivecosmos/conversation-summary-memory

Implements conversation summary memory

Author: correa-brian

server/handlers/chat_handler.js

@@ -1,26 +1,27 @@
-import { AgentExecutor, ChatAgent } from 'langchain/agents';
-import { ConversationChain, LLMChain } from 'langchain/chains';
+import { ConversationChain } from 'langchain/chains';
 import { ChatOpenAI } from 'langchain/chat_models/openai';
 import { ChatPromptTemplate, HumanMessagePromptTemplate, MessagesPlaceholder, SystemMessagePromptTemplate } from 'langchain/prompts';
-import { BufferMemory } from 'langchain/memory';
-import { HumanChatMessage, SystemChatMessage } from 'langchain/schema';
-import { SerpAPI } from 'langchain/tools';
+import { ConversationSummaryMemory } from 'langchain/memory';
 
 class ChatService {
-  static async startChat(data) {
-    const chat = new ChatOpenAI({ openAIApiKey: process.env.OPENAI_API_KEY, temperature: 0, verbose: true });
-    const { body: { userInput } } = data;
-
-    const chatPrompt = ChatPromptTemplate.fromPromptMessages([
+  constructor () {
+    this.chat = new ChatOpenAI({ temperature: 0, verbose: true });
+    this.chatPrompt = ChatPromptTemplate.fromPromptMessages([
       SystemMessagePromptTemplate.fromTemplate('The following is a friendly conversation between a human and an AI. The AI is talkative and provides lots of specific details from its context. If the AI does not know the answer to a question, it truthfully says it does not know.'),
       new MessagesPlaceholder('history'),
       HumanMessagePromptTemplate.fromTemplate('{input}'),
     ]);
 
+    this.memory = new ConversationSummaryMemory({ llm: this.chat, returnMessages: true });
+  }
+
+  async startChat(data) {
+    const { body: { userInput } } = data;
+
     const chain = new ConversationChain({
-      memory: new BufferMemory({ returnMessages: true }),
-      prompt: chatPrompt,
-      llm: chat,
+      memory: this.memory,
+      prompt: this.chatPrompt,
+      llm: this.chat,
     });
 
     const response = await chain.call({

server/index.js

@@ -1,5 +1,4 @@
 import 'dotenv/config'
-import * as fs from 'fs';
 import Koa from 'koa';
 import cors from '@koa/cors';
 import { koaBody } from 'koa-body';

server/routers/chat.js

@@ -6,12 +6,14 @@ const router = new Router({
   prefix: '/chat',
 });
 
+const chatService = new ChatService();
+
 router.post('/', async (ctx) => {
   const handlerData = {};
   handlerData.body = ctx.request.body;
   handlerData.user = ctx.state.user;
 
-  const res = await ChatService.startChat(handlerData);
+  const res = await chatService.startChat(handlerData);
   ctx.body = res;
 });