function getAccessToken (bearerToken: string) {
logger.debug('Getting access token (bearerToken: ' + bearerToken + ').')
+ if (!bearerToken) return Bluebird.resolve(undefined)
+
if (accessTokenCache[bearerToken] !== undefined) return Bluebird.resolve(accessTokenCache[bearerToken])
return OAuthTokenModel.getByTokenAndPopulateUser(bearerToken)