protected function merge_query_args( $base_args, $request_args ) {

		$args = array();

		// date
		if ( ! empty( $request_args['created_at_min'] ) || ! empty( $request_args['created_at_max'] ) || ! empty( $request_args['updated_at_min'] ) || ! empty( $request_args['updated_at_max'] ) ) {

			$args['date_query'] = array();

			// resources created after specified date
			if ( ! empty( $request_args['created_at_min'] ) ) {
				$args['date_query'][] = array( 'column' => 'post_date_gmt', 'after' => $this->server->parse_datetime( $request_args['created_at_min'] ), 'inclusive' => true );
			}

			// resources created before specified date
			if ( ! empty( $request_args['created_at_max'] ) ) {
				$args['date_query'][] = array( 'column' => 'post_date_gmt', 'before' => $this->server->parse_datetime( $request_args['created_at_max'] ), 'inclusive' => true );
			}

			// resources updated after specified date
			if ( ! empty( $request_args['updated_at_min'] ) ) {
				$args['date_query'][] = array( 'column' => 'post_modified_gmt', 'after' => $this->server->parse_datetime( $request_args['updated_at_min'] ), 'inclusive' => true );
			}

			// resources updated before specified date
			if ( ! empty( $request_args['updated_at_max'] ) ) {
				$args['date_query'][] = array( 'column' => 'post_modified_gmt', 'before' => $this->server->parse_datetime( $request_args['updated_at_max'] ), 'inclusive' => true );
			}
		}

		// search
		if ( ! empty( $request_args['q'] ) ) {
			$args['s'] = $request_args['q'];
		}

		// resources per response
		if ( ! empty( $request_args['limit'] ) ) {
			$args['posts_per_page'] = $request_args['limit'];
		}

		// resource offset
		if ( ! empty( $request_args['offset'] ) ) {
			$args['offset'] = $request_args['offset'];
		}

		// order (ASC or DESC, ASC by default)
		if ( ! empty( $request_args['order'] ) ) {
			$args['order'] = $request_args['order'];
		}

		// orderby
		if ( ! empty( $request_args['orderby'] ) ) {
			$args['orderby'] = $request_args['orderby'];

			// allow sorting by meta value
			if ( ! empty( $request_args['orderby_meta_key'] ) ) {
				$args['meta_key'] = $request_args['orderby_meta_key'];
			}
		}

		// allow post status change
		if ( ! empty( $request_args['post_status'] ) ) {
			$args['post_status'] = $request_args['post_status'];
			unset( $request_args['post_status'] );
		}

		// filter by a list of post id
		if ( ! empty( $request_args['in'] ) ) {
			$args['post__in'] = explode( ',', $request_args['in'] );
			unset( $request_args['in'] );
		}

		// filter by a list of post id
		if ( ! empty( $request_args['in'] ) ) {
			$args['post__in'] = explode( ',', $request_args['in'] );
			unset( $request_args['in'] );
		}

		// resource page
		$args['paged'] = ( isset( $request_args['page'] ) ) ? absint( $request_args['page'] ) : 1;

		$args = apply_filters( 'woocommerce_api_query_args', $args, $request_args );

		return array_merge( $base_args, $args );
	}