aaronjameslang / claudia-api-jwt-authenticator

// tslint:disable-next-line: no-implicit-dependencies

import { APIGatewayProxyEvent } from 'aws-lambda' // @types

import UnauthorisedResponse from './UnauthorisedResponse'

type Token = string

const getToken = (event: APIGatewayProxyEvent): Token | UnauthorisedResponse => {

  const { headers } = event

  if (!headers) {

    return new UnauthorisedResponse('no headers')

  }

  const authHeader = headers.Authorization

  if (!authHeader) {

    return new UnauthorisedResponse('no authorization header')

  }

  const [scheme, token] = authHeader.trim().split(' ')

  if (!scheme || (scheme.toLowerCase() !== 'bearer')) {

    return new UnauthorisedResponse('authorization scheme must be bearer')

  }

  if (!token) {

    return new UnauthorisedResponse('no authorization token')

  }

  return token

}

export default getToken