AWS Amplify提供了几种不同的Lambda函数模板，每个模板都有不同的用途和参数。以下是三种常见的Lambda函数模板：

1. REST API：这个模板用于创建REST API，它包含一个简单的Express应用程序，可以处理HTTP GET / POST请求，并从AWS提供的API网关接收输入。以下是创建REST API模板的示例代码：

exports.handler = async (event, context) => {
  const { httpMethod, body } = event;
  const response = {
    statusCode: 200,
    headers: {
      'Access-Control-Allow-Origin': '*'
    },
    body: JSON.stringify({ message: "Hello World" })
  };
  
  if (httpMethod === 'GET') {
    return response;
  } else if (httpMethod === 'POST') {
    // Process POST request body
    return response;
  }
};

2. 使用Cognito验证的REST API：这个模板与REST API模板非常类似，但它包括使用Cognito用户池验证用户的过程。以下是使用Cognito验证的REST API模板的示例代码：

const AmazonCognitoIdentity = require('amazon-cognito-identity-js');
global.fetch = require('node-fetch');

exports.handler = async (event) => {
  const poolData = {
    UserPoolId: process.env.USER_POOL_ID,
    ClientId: process.env.APP_CLIENT_ID,
  };
  const userPool = new AmazonCognitoIdentity.CognitoUserPool(poolData);

  const { httpMethod, body } = event;
  const response = {
    statusCode: 200,
    headers: {
      'Access-Control-Allow-Origin': '*'
    },
    body: JSON.stringify({ message: "Hello World" })
  };

  if (httpMethod === 'GET') {
    return response;
  } else if (httpMethod === 'POST') {
    // Verify user token
    const token = event.headers.Authorization;
    const cognitoUser = getTokenUser(userPool, token);
    if (cognitoUser) {
      // Process POST request body
      return