Spring cloud gateway filter for adding the original gateway request URL

AddOriginalUrlFilterFactory

package org.example;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;

import java.net.URI;
import java.util.LinkedHashSet;
import java.util.Optional;

/**
 * Filter to add the original gateway URL to the request as a header.
 */
@Component
public class AddOriginalUrlFilterFactory extends AbstractGatewayFilterFactory {

    Logger log = LoggerFactory.getLogger(AddOriginalUrlFilterFactory.class);

    @Override
    public GatewayFilter apply(Object config) {
        return (exchange, chain) -> {

            LinkedHashSet<URI> attr = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR);
            Optional<URI> option = attr.stream().findFirst();

            ServerHttpRequest request = exchange.getRequest();
            if (option.isPresent()) {
                String originalUrl = option.get().toString();
                log.info("Adding original request URL: {}", originalUrl);
                request = request.mutate().header("X-Gateway-Original-Request-Url", originalUrl).build();
            }

            return chain.filter(exchange.mutate().request(request).build());
        };
    }
}

Very helpful, thank you!