import { GrpcEvent, GrpcMessage, GrpcRequest } from '@ngx-grpc/common';
import { Observable } from 'rxjs';
import { GrpcHandler } from './grpc-handler';
/**
 * Interceptor interface which should be implemented for custom interceptors
 */
export interface GrpcInterceptor {
    /**
     * Interceptor entry point
     *
     * Example:
     *
     * ```
     *  intercept<Q extends GrpcMessage, S extends GrpcMessage>(request: GrpcRequest<Q, S>, next: GrpcHandler): Observable<GrpcEvent<S>> {
     *    // here do something before request, e.g. patch messages, metadata, etc
     *
     *    return next.handle(request).pipe(
     *      // here handle all messages, status codes, metadata, errors, retries etc
     *    );
     *  }
     * ```
     *
     * @param request intercepted request
     * @param next current GrpcHandler to pass the messages through
     */
    intercept<Q extends GrpcMessage, S extends GrpcMessage>(request: GrpcRequest<Q, S>, next: GrpcHandler): Observable<GrpcEvent<S>>;
}