/**
 * URL helpers shared across packages.
 *
 * @module
 */
/**
 * Returns true when the hostname is a loopback, private, link-local, or
 * otherwise non-routable literal that should not be fetched from untrusted
 * input.
 */
export declare function isPrivateHostname(hostname: string): boolean;
/**
 * Thrown by {@link assertPublicUrl} (and surfaced by {@link fetchPublicUrl}) when a URL — or a
 * redirect target — fails public-URL validation. Distinct from generic `Error` so callers can
 * map validation failures to a specific error code (e.g. `invalidGatewayUri`) without
 * accidentally also mapping unrelated network failures.
 */
export declare class PublicUrlValidationError extends Error {
    constructor(message: string);
}
/**
 * Parses and validates that a URL targets a routable public host over an allowed network scheme.
 *
 * Rejects:
 * - URLs whose protocol is not in `allowedProtocols` (defaults to `http:` / `https:`), so callers
 *   cannot smuggle `file:`, `javascript:`, `data:`, `ws:`, etc. past a downstream `fetch()`.
 * - URLs without a hostname.
 * - URLs whose hostname is a loopback, private, link-local, or otherwise non-routable literal per
 *   {@link isPrivateHostname}, unless `allowPrivateHosts` explicitly permits trusted local targets.
 *
 * This intentionally does not perform DNS resolution, so callers handling high-risk server-side
 * fetches should still consider DNS rebinding defenses (and use {@link fetchPublicUrl} to also
 * validate every redirect target).
 */
export declare function assertPublicUrl(url: string | URL, description?: string, options?: {
    allowedProtocols?: readonly string[];
    allowPrivateHosts?: boolean;
}): URL;
/**
 * Performs a `fetch()` whose target — and every subsequent redirect target — is validated by
 * {@link assertPublicUrl}. Defends against SSRF via redirect-based bypasses where a public
 * gateway returns `Location: http://127.0.0.1/...` after the initial validation succeeded.
 *
 * Manually drives the redirect loop so each `Location` is re-validated. A 3xx response without a
 * `Location` header (e.g. `304 Not Modified`) is returned to the caller unchanged.
 */
export declare function fetchPublicUrl(url: string | URL, init?: RequestInit, options?: {
    description?: string;
    allowedProtocols?: readonly string[];
    /** Allow trusted local targets without bypassing scheme validation or redirect limits. */
    allowPrivateHosts?: boolean;
    maxRedirects?: number;
    /** Wrap each validated hop's fetch independently of URL and redirect handling. */
    fetchFn?: (url: string, init: RequestInit) => Promise<Response>;
}): Promise<Response>;
/**
 * Concatenates a base URL and a path ensuring that there is exactly one slash between them.
 *
 * The `path` argument must be a pure URL pathname — raw `?` (query) and `#` (fragment) delimiters
 * are rejected because they are silently percent-encoded by the WHATWG URL parser when assigned
 * to `pathname`, which would otherwise change the endpoint a caller meant to reach. Callers that
 * need to attach a query string or fragment should construct the URL explicitly. Percent-encoded
 * `%3F` / `%23` are preserved so genuine path segments containing those characters work.
 */
export declare function concatenateUrl(baseUrl: string, path: string): string;
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