Spring WebClient Wrapper allowing for redirects

RedirectingWebClient.java

package se.cygni.bootcamp.mashup.core;

import java.util.Optional;

import org.springframework.http.HttpHeaders;
import org.springframework.web.reactive.function.client.ClientResponse;
import org.springframework.web.reactive.function.client.WebClient;

import reactor.core.publisher.Mono;

public final class RedirectingWebClient {

    private static final int MAX_REDIRECTS = 5;
    private final WebClient webClient;

    public RedirectingWebClient(final String url) {
        webClient = WebClient.create(url);
    }

    public Mono<ClientResponse> get(final String uri) {
        return redirectingRequest(uri, 0);
    }

    private Mono<ClientResponse> redirectingRequest(final String uri, final int redirects) {

        Optional.of(redirects)
                .filter(red -> red <= MAX_REDIRECTS)
                .orElseThrow(TooManyRedirectsException::new);

        return webClient
                .get()
                .uri(uri)
                .exchange()
                .flatMap(response -> Optional.of(response)
                        .filter(r -> r.statusCode().is3xxRedirection())
                        .map(r -> redirect(r, redirects))
                        .orElse(Mono.just(response)));
    }

    private Mono<ClientResponse> redirect(final ClientResponse r, final int redirects) {

        String u = r.headers().header(HttpHeaders.LOCATION).get(0);
        return redirectingRequest(u, redirects + 1);
    }
}

Spring 5.0.5 and Spring Boot 2.0.3 relies on a version of Netty that can't handle redirects. Therefore Spring's WebClient can't handle redirects neither. The fix is at the earliest released in the end of 2018 (Spring 5.1) and until we can rely on that version this is a wrapped Webclient that takes care of redirects.

When running Revision 2 (Typed Webclient):

    var wc = new RedirectingWebClient<String>("http://redirect.org", String.class)
                .get("/old")
                .block();

    var dataMappedObject = new RedirectingWebClient<DataMapObject>("http://redirect.org", DataMapObject.class)
                .get("/old")
                .block(); 

When running Revision 3 (You handle the typing, not WebClient, and the client can be re-used for different calls):

    var client = new RedirectingWebClient("http://redirect.org");

    var wc = client.get("/whatever/uri/")
                .block()
                .bodyToMono(String.class)
                .block();

    var dataMappedObject = client.get("/another/uri")
                .block()
                .bodyToMono(DataMapObject.class)
                .block();