export declare const TARGET_URL_HEADER = "x-fal-target-url";
export declare const DEFAULT_PROXY_ROUTE = "/api/fal/proxy";
export type HeaderValue = string | string[] | undefined | null;
/**
 * The proxy behavior that is passed to the proxy handler. This is a subset of
 * request objects that are used by different frameworks, like Express and NextJS.
 */
export interface ProxyBehavior<ResponseType> {
    id: string;
    method: string;
    respondWith(status: number, data: string | any): ResponseType;
    sendResponse(response: Response): Promise<ResponseType>;
    getHeaders(): Record<string, HeaderValue>;
    getHeader(name: string): HeaderValue;
    sendHeader(name: string, value: string): void;
    getRequestBody(): Promise<string | undefined>;
    resolveApiKey?: () => Promise<string | undefined>;
}
/**
 * A request handler that proxies the request to the fal API
 * endpoint. This is useful so client-side calls to the fal endpoint
 * can be made without CORS issues and the correct credentials can be added
 * effortlessly.
 *
 * @param behavior the request proxy behavior.
 * @returns Promise<any> the promise that will be resolved once the request is done.
 */
export declare function handleRequest<ResponseType>(behavior: ProxyBehavior<ResponseType>): Promise<ResponseType>;
export declare function fromHeaders(headers: Headers): Record<string, string | string[]>;
export declare const responsePassthrough: (res: Response) => Promise<Response>;
export declare const resolveApiKeyFromEnv: () => Promise<string>;