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MVI:最高效、最易于使用的无服务器向量索引,适用于您的数据。要开始使用 MVI,只需注册一个帐户。无需处理基础设施、管理服务器或担心扩展。MVI 是一项根据您的需求自动扩展的服务。无论是在 Node.js、浏览器还是边缘,Momento 都能满足您的需求。 要注册并访问 MVI,请访问 Momento 控制台

设置

  1. Momento 控制台 中注册 API 密钥。
  2. 为您的环境安装 SDK。 2.1. 对于 Node.js
    npm
    npm install @gomomento/sdk
    
    2.2. 对于 浏览器或边缘环境
    npm
    npm install @gomomento/sdk-web
    
  3. 在运行代码之前设置 Momento 的环境变量 3.1 OpenAI
    export OPENAI_API_KEY=YOUR_OPENAI_API_KEY_HERE
    
    3.2 Momento
    export MOMENTO_API_KEY=YOUR_MOMENTO_API_KEY_HERE # https://console.gomomento.com
    

用法

请参阅 此部分 以获取有关安装 LangChain 包的一般说明。
npm
npm install @langchain/openai @langchain/community @langchain/core

使用 fromTexts 索引文档并搜索

此示例演示使用 fromTexts 方法实例化向量存储并索引文档。 如果索引不存在,则会创建它。如果索引已存在,则文档将添加到现有索引中。 ids 是可选的;如果您省略它们,Momento 将为您生成 UUID。
import { MomentoVectorIndex } from "@langchain/community/vectorstores/momento_vector_index";
// For browser/edge, adjust this to import from "@gomomento/sdk-web";
import {
  PreviewVectorIndexClient,
  VectorIndexConfigurations,
  CredentialProvider,
} from "@gomomento/sdk";
import { OpenAIEmbeddings } from "@langchain/openai";
import { sleep } from "@langchain/classic/util/time";

const vectorStore = await MomentoVectorIndex.fromTexts(
  ["hello world", "goodbye world", "salutations world", "farewell world"],
  {},
  new OpenAIEmbeddings(),
  {
    client: new PreviewVectorIndexClient({
      configuration: VectorIndexConfigurations.Laptop.latest(),
      credentialProvider: CredentialProvider.fromEnvironmentVariable({
        environmentVariableName: "MOMENTO_API_KEY",
      }),
    }),
    indexName: "langchain-example-index",
  },
  { ids: ["1", "2", "3", "4"] }
);

// because indexing is async, wait for it to finish to search directly after
await sleep();

const response = await vectorStore.similaritySearch("hello", 2);

console.log(response);

/*
[
  Document { pageContent: 'hello world', metadata: {} },
  Document { pageContent: 'salutations world', metadata: {} }
]
*/

使用 fromDocuments 索引文档并搜索

与上面类似,此示例演示使用 fromDocuments 方法实例化向量存储并索引文档。 如果索引不存在,则会创建它。如果索引已存在,则文档将添加到现有索引中。 使用 fromDocuments 允许您将各种文档加载器与索引无缝链接。
import { MomentoVectorIndex } from "@langchain/community/vectorstores/momento_vector_index";
// For browser/edge, adjust this to import from "@gomomento/sdk-web";
import {
  PreviewVectorIndexClient,
  VectorIndexConfigurations,
  CredentialProvider,
} from "@gomomento/sdk";
import { OpenAIEmbeddings } from "@langchain/openai";
import { TextLoader } from "@langchain/classic/document_loaders/fs/text";
import { sleep } from "@langchain/classic/util/time";

// Create docs with a loader
const loader = new TextLoader("src/document_loaders/example_data/example.txt");
const docs = await loader.load();

const vectorStore = await MomentoVectorIndex.fromDocuments(
  docs,
  new OpenAIEmbeddings(),
  {
    client: new PreviewVectorIndexClient({
      configuration: VectorIndexConfigurations.Laptop.latest(),
      credentialProvider: CredentialProvider.fromEnvironmentVariable({
        environmentVariableName: "MOMENTO_API_KEY",
      }),
    }),
    indexName: "langchain-example-index",
  }
);

// because indexing is async, wait for it to finish to search directly after
await sleep();

// Search for the most similar document
const response = await vectorStore.similaritySearch("hello", 1);

console.log(response);
/*
[
  Document {
    pageContent: 'Foo\nBar\nBaz\n\n',
    metadata: { source: 'src/document_loaders/example_data/example.txt' }
  }
]
*/

从现有集合中搜索

import { MomentoVectorIndex } from "@langchain/community/vectorstores/momento_vector_index";
// For browser/edge, adjust this to import from "@gomomento/sdk-web";
import {
  PreviewVectorIndexClient,
  VectorIndexConfigurations,
  CredentialProvider,
} from "@gomomento/sdk";
import { OpenAIEmbeddings } from "@langchain/openai";

const vectorStore = new MomentoVectorIndex(new OpenAIEmbeddings(), {
  client: new PreviewVectorIndexClient({
    configuration: VectorIndexConfigurations.Laptop.latest(),
    credentialProvider: CredentialProvider.fromEnvironmentVariable({
      environmentVariableName: "MOMENTO_API_KEY",
    }),
  }),
  indexName: "langchain-example-index",
});

const response = await vectorStore.similaritySearch("hello", 1);

console.log(response);
/*
[
  Document {
    pageContent: 'Foo\nBar\nBaz\n\n',
    metadata: { source: 'src/document_loaders/example_data/example.txt' }
  }
]
*/

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