middleware.ts

import inputOutputLogger from "@middy/input-output-logger"
import httpHeaderNormalizer from "@middy/http-header-normalizer"
import {injectLambdaContext} from "@aws-lambda-powertools/logger/middleware"
import middy from "@middy/core"
import {Logger} from "@aws-lambda-powertools/logger"
import validator from "@middy/validator"
import {transpileSchema} from "@middy/validator/transpile"
import {validationErrorHandler} from "./errorHandler"

export type MiddlewareGenerator = (logger: Logger, schema?: object) => middy.MiddlewareObj

export const MIDDLEWARE: Record<string, MiddlewareGenerator> = {
  injectLambdaContext: (logger) => injectLambdaContext(logger, {clearState: true}),
  httpHeaderNormalizer: () => httpHeaderNormalizer() as middy.MiddlewareObj,
  inputOutputLogger: (logger) =>
    inputOutputLogger({
      logger: (request) => {
        const response = (request as {response?: unknown} | null | undefined)?.response
        if (response === undefined) {
          logger.info("inputOutputLogger request", {request})
        } else {
          logger.debug("inputOutputLogger response", {response})
        }
      }
    }),
  validator: (logger, schema) => validator({eventSchema: transpileSchema(schema as object)}),
  validationErrorHandler: (logger) => validationErrorHandler({logger: logger})
}

export const DEFAULT_HANDLER_MIDDLEWARE = [
  MIDDLEWARE.injectLambdaContext,
  MIDDLEWARE.httpHeaderNormalizer,
  MIDDLEWARE.inputOutputLogger,
  MIDDLEWARE.validationErrorHandler,
  MIDDLEWARE.validator
]