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DynamoDB支持的聊天记录

如果需要在聊天进程之间进行更长期的持久化，您可以将默认的内存chatHistory替换为DynamoDB实例，作为支持BufferMemory等聊天记录类的后端。，注意：chatHistory指聊天记录类，BufferMemory指缓存存储器类。

设置​

首先，在您的项目中安装AWS DynamoDB客户端

npm install @aws-sdk/client-dynamodb

接下来，登录您的AWS帐户并创建一个DynamoDB表格。将表格命名为langchain，指定您的分区键为id，分区键必须是字符串类型，其他设置保持默认即可。

您还需要检索一个AWS访问密钥和密钥，以便拥有访问该表格的角色或用户，并将它们添加到环境变量中。

使用方法​

import { BufferMemory } from "langchain/memory";
import { DynamoDBChatMessageHistory } from "langchain/stores/message/dynamodb";
import { ChatOpenAI } from "langchain/chat_models/openai";
import { ConversationChain } from "langchain/chains";

const memory = new BufferMemory({
  chatHistory: new DynamoDBChatMessageHistory({
    tableName: "langchain",
    partitionKey: "id",
    sessionId: new Date().toISOString(), // Or some other unique identifier for the conversation
    config: {
      region: "us-east-2",
      credentials: {
        accessKeyId: "<your AWS access key id>",
        secretAccessKey: "<your AWS secret access key>",
      },
    },
  }),
});

const model = new ChatOpenAI();
const chain = new ConversationChain({ llm: model, memory });

const res1 = await chain.call({ input: "Hi! I'm Jim." });
console.log({ res1 });
/*
{
  res1: {
    text: "Hello Jim! It's nice to meet you. My name is AI. How may I assist you today?"
  }
}
*/

const res2 = await chain.call({ input: "What did I just say my name was?" });
console.log({ res2 });

/*
{
  res1: {
    text: "You said your name was Jim."
  }
}
*/