Middy 是一个非常简单的中间件引擎，可让你在使用 Node.js 时简化 AWS Lambda 代码。
如果你使用过 Express 等 Web 框架，那么你将熟悉 Middy 中采用的概念，你将能够很快上手。
中间件引擎允许你专注于 Lambda 的严格业务逻辑，然后通过装饰主要业务逻辑，以模块化和可重用的方式附加额外的通用元素，如认证、授权、验证、序列化等。
//# handler.js #
// import core
import middy from '@middy/core' // esm Node v14+
//const middy = require('@middy/core') // commonjs Node v12+
// import some middlewares
import jsonBodyParser from '@middy/http-json-body-parser'
import httpErrorHandler from '@middy/http-error-handler'
import validator from '@middy/validator'
// This is your common handler, in no way different than what you are used to doing every day in AWS Lambda
const baseHandler = async (event, context, callback) => {
// we don't need to deserialize the body ourself as a middleware will be used to do that
const { creditCardNumber, expiryMonth, expiryYear, cvc, nameOnCard, amount } = event.body
// do stuff with this data
// ...
const response = { result: 'success', message: 'payment processed correctly'}
return {statusCode: 200, body: JSON.stringify(response)}
}
// Notice that in the handler you only added base business logic (no deserialization,
// validation or error handler), we will add the rest with middlewares
const inputSchema = {
type: 'object',
properties: {
body: {
type: 'object',
properties: {
creditCardNumber: { type: 'string', minLength: 12, maxLength: 19, pattern: '\d+' },
expiryMonth: { type: 'integer', minimum: 1, maximum: 12 },
expiryYear: { type: 'integer', minimum: 2017, maximum: 2027 },
cvc: { type: 'string', minLength: 3, maxLength: 4, pattern: '\d+' },
nameOnCard: { type: 'string' },
amount: { type: 'number' }
},
required: ['creditCardNumber'] // Insert here all required event properties
}
}
}
// Let's "middyfy" our handler, then we will be able to attach middlewares to it
const handler = middy(baseHandler)
.use(jsonBodyParser()) // parses the request body when it's a JSON and converts it to an object
.use(validator({inputSchema})) // validates the input
.use(httpErrorHandler()) // handles common http errors and returns proper responses
module.exports = { handler }
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