serverless-offline/src/events/authFunctionNameExtractor.js

Emulate AWS λ and API Gateway locally when developing your Serverless project

import { log } from "../utils/log.js"

function buildFailureResult(warningMessage) {
  log.warning(warningMessage)

  return {
    unsupportedAuth: true,
  }
}

function buildSuccessResult(authorizerName) {
  return {
    authorizerName,
  }
}

function handleStringAuthorizer(authorizerString) {
  if (authorizerString.toUpperCase() === "AWS_IAM") {
    return buildFailureResult(
      "Serverless Offline does not support the AWS_IAM authorization type",
    )
  }

  return buildSuccessResult(authorizerString)
}

function handleObjectAuthorizer(authorizerObject) {
  const { arn, authorizerId, name, type } = authorizerObject

  if (type && type.toUpperCase() === "AWS_IAM") {
    return buildFailureResult(
      "Serverless Offline does not support the AWS_IAM authorization type",
    )
  }

  if (arn) {
    return buildFailureResult(
      `Serverless Offline does not support non local authorizers (arn): ${arn}`,
    )
  }

  if (authorizerId) {
    return buildFailureResult(
      `Serverless Offline does not support non local authorizers (authorizerId): ${authorizerId}`,
    )
  }

  if (!name) {
    return buildFailureResult(
      "Serverless Offline supports local authorizers but authorizer name is missing",
    )
  }

  return buildSuccessResult(name)
}

export default function authFunctionNameExtractor(endpoint) {
  const { authorizer } = endpoint

  if (!authorizer) {
    return buildSuccessResult(null)
  }

  if (typeof authorizer === "string") {
    return handleStringAuthorizer(authorizer)
  }

  if (typeof authorizer === "object") {
    return handleObjectAuthorizer(authorizer)
  }

  return buildFailureResult(
    "Serverless Offline supports only local authorizers defined as string or object",
  )
}