import { ExpressRequest, Response } from '../v1';
/** Key-value metadata to pass to a function. */
export declare type AuthMiddlewareMetadata = any;
/**
 * Middleware to authenticate the request and provide extra metadata once authenticated.
 * @param req The request object.
 * @param res The response object.
 * @param required If true, the middleware is encouraged to send an unauthorized response
 * if the request is not authenticated. Otherwise, the middleware can do whatever the hell it
 * wants.
 */
export declare type AuthMetadataMiddlewareFunction = (req: ExpressRequest, res: Response<any, any>, required: boolean) => Promise<any>;