import type { IncomingMessage, ServerResponse } from "node:http";
export declare const OBSERVER_STATIC_HOST = "127.0.0.1";
export interface ObserverStaticHandlerOptions {
    /** Directory served as the loopback root. Requests can never escape it. */
    root: string;
    /** File served for directory requests. Defaults to `index.html`. */
    indexPath?: string;
    /**
     * When set, an exact `/` request returns a 302 to `/<redirectRootTo>` instead
     * of serving a file. Used to land visitors on `observer/index.html` so the
     * Observer's relative artifact links (`../run.json`, ...) resolve.
     */
    redirectRootTo?: string;
}
export interface ObserverStaticServeOptions extends ObserverStaticHandlerOptions {
    /** TCP port to bind on 127.0.0.1. Defaults to an ephemeral port (0). */
    port?: number;
    /**
     * Relative entry page (e.g. `observer/index.html`). Drives the returned
     * `url` and the `/` -> entry redirect so callers open the page directly.
     */
    entryPath?: string;
}
export interface ObserverStaticServer {
    url: string;
    port: number;
    host: string;
    close(): Promise<void>;
}
export declare function observerStaticContentType(filePath: string): string;
/**
 * Resolve, guard, and serve a single static request from `root`. Never throws:
 * any unexpected failure is reported as a 500 so the connection always closes.
 * Exported directly so the security guards can be unit-tested without binding a
 * socket.
 */
export declare function respondToObserverStaticRequest(options: ObserverStaticHandlerOptions, request: Pick<IncomingMessage, "method" | "url">, response: ServerResponse): Promise<void>;
export declare function createObserverStaticHandler(options: ObserverStaticHandlerOptions): (request: IncomingMessage, response: ServerResponse) => void;
export declare function serveObserverStatic(options: ObserverStaticServeOptions): Promise<ObserverStaticServer>;