alexa-verifier/validate-cert-uri.js

Verify HTTP requests sent to an Alexa skill are sent from Amazon

const VALID_CERT_HOSTNAME   = 's3.amazonaws.com'
const VALID_CERT_PATH_START = '/echo.api/'
const VALID_CERT_PORT       = '443'


// parse a certificate and check it's contents for validity
export default function validateCertUri (cert_uri) {
    if (cert_uri.protocol !== 'https:')
        return 'Certificate URI MUST be https: ' + cert_uri

    if (cert_uri.port && (cert_uri.port !== VALID_CERT_PORT))
        return 'Certificate URI port MUST be ' + VALID_CERT_PORT + ', was: ' + cert_uri.port

    if (cert_uri.hostname !== VALID_CERT_HOSTNAME)
        return 'Certificate URI hostname must be ' + VALID_CERT_HOSTNAME + ': ' + cert_uri.hostname

    if (cert_uri.path.indexOf(VALID_CERT_PATH_START) !== 0)
        return 'Certificate URI path must start with ' + VALID_CERT_PATH_START + ': ' + cert_uri

    return true
}