CODEWITHSUNDEEP
monospring-webflux
Vinod Kumar
Vinod Kumar

Reputation: 675

How to call a private method from reactive subscribe of Mono and return a specific type in Spring 5?

I have a main method whose return type WebClient. In this method I get a Mono object and using subscribe I'm trying to call another method which returns webclient object. Now within subscribe, I have webclient object which I want to return. I'm blocked here as I'm not sure how to return the object and where to put the return keyword.

Main method:-

public WebClient getWebClientWithAuthorization(String t) {
-----
----

    Mono<AccessToken> accessToken = authenticationProvider.getUserAccessToken(serviceConnectionDetails, queryParams);

    Disposable disposable = accessToken.subscribe(
        value -> getWebClientBuilder(t, value.getAccessToken()),
        error -> error.printStackTrace(),
        () -> System.out.println("completed without a value")
    );

}

Below getWebClientBuilder method returns webclient object:-

private WebClient getWebClientBuilder(String tenantDomain, String accessToken) {
        //TODO Logic for Saving the Token using Caching/Redis mechanism will be taken up from here and implemented in future Sprints
        logger.info("Bearer token received: "+ CommerceConnectorConstants.REQUEST_HEADER_AUTHORIZATION_BEARER +" "+ accessToken);

        if (null != proxyHost) {
            return utilsbuilder.baseUrl(tenantDomain).filter(oauth2Credentials(accessToken)).clientConnector(getHttpConnector()).build();

        } else {
            return utilsbuilder
                    .baseUrl(tenantDomain)
                    .filter(oauth2Credentials(accessToken))
                    .build();

        }
    }

Now in getWebClientWithAuthorization method, where to put the return keyword inside subscribe or outside subscribe.

Upvotes: 0

Views: 1913

Answers (1)

Oleh Dokuka
Oleh Dokuka

Reputation: 12184

Think "Reactive" end to end

In my opinion, what is the most important when star building application using Reactive Programming is treating any call as asynchronous hence providing end to end asynchronous and non-blocking communication.

Thus, what I suggest you is providing instead of synchronous type a Mono<WebClient> in the following way:

public Mono<WebClient> getWebClientWithAuthorization(String t) {
-----
----

    Mono<AccessToken> accessToken = authenticationProvider.getUserAccessToken(serviceConnectionDetails, queryParams);

    return accessToken.map(value -> getWebClientBuilder(t, value.getAccessToken()))
                      .doOnError(error -> error.printStackTrace())
                      .doOnComplete(() -> System.out.println("completed without a value"))
    );

}

So, now you may easily map value to the WebClient's instance and send it to the downstream. In turn, your downstream may react to that value and transform WebClient to the execution of HTTP call as it is shown in the following example:

getWebClientWithAuthorization("some magic string here")
        .flatMapMany(webClient -> webClient.get()
                                       .uri("some uri here")
                                       .retrieve()
                                       .bodyToFlux(MessageResponse.class))
        // operate with downstream items somehow
        // .map
        // .filter
        // .etc
        // and return Mono or Flux again to just continue the flow

And remember, just continue the flow and everywhere specify reactive types if async communication is supposed. There is no sense to subscribe to the source until you met some network boundary or some logical end of the stream where you do not have to return something back.

Upvotes: 1

Related Questions