import { type AxiosResponseHeaders, type RawAxiosResponseHeaders } from 'axios';
/**
 * Check to see if the given URL is 'secure'. This assumes:
 *
 * - `https` URLs are always secure
 * - `http` URLS are allowed for localhost
 * - And also for '`svc.cluster.local` and `.internal` URLs
 *
 * Note that this does not resolve the URL, so it is possible this could
 * resolve to some other internal URL, and may return `false` on non-fully
 * qualified internal URLs.
 *
 * @param url remote service to validate
 * @returns the url is local or `https`
 */
export declare function validateSecureUrl(url: string): boolean;
export declare function padSlashToUrl(u: string): string;
/**
 * Checks that `testUrl` is prefixed with one of the given origin + path fragment URIs in urlPrefixes.
 *
 * Note this doesn't do anything special to queries or fragments and will fail to work properly if those are present on the prefixes
 * @param urlPrefixes a list of origin parts of urls, possibly including some path fragment as well
 * @param testUrl a url to see if it is prefixed by one or more of the `urlPrefixes` values
 * @throws Error when testUrl is not present
 */
export declare const safeUrlCheck: (urlPrefixes: string[], testUrl: string) => void | never;
export declare function isBrowser(): boolean;
export declare const isFirefox: () => boolean;
export declare const rstrip: (str: string, suffix?: string) => string;
/**
 * Rough estimate of number of seconds to add to the current system clock time
 * to get the clock time on the given server, or origin if not specified
 * @param server a server to compute skew with
 * @returns the number of seconds to add to the current local system clock time
 * to get an rough guess of the time on the given server
 */
export declare const estimateSkew: (serverEndpoint?: string) => Promise<number>;
export type AnyHeaders = AxiosResponseHeaders | RawAxiosResponseHeaders | Headers;
/**
 * Rough estimate of number of seconds to add to the curren time to get
 * the clock time on the server that responded with the headers object.
 * @param headers A set of headers, which must include the `date` header
 * @param dateNowBefore time before initiating the request, usually by calling
 * `Date.now()`. Note this is in milliseconds since the epoch, while the
 * estimate is given in seconds.
 * @returns the number of seconds to add to the current local system clock time
 * to get an rough guess of the time on the server that was used
 */
export declare const estimateSkewFromHeaders: (headers: AnyHeaders, dateNowBefore?: number) => number;
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