[Question] Optional with CompletableFuture?

Hello,

I am using retrofit 2.5.0 and have an API like:

CompletableFuture<Optional<String>> getCustomer(int customerId)

But the response is null instead of Optional.empty().

Here’s my retrofit builder:

new Retrofit.Builder()
                .baseUrl(getBaseUrl())
                .addConverterFactory(new NullOnEmptyConverterFactory())
                .client(getOkHttpClient(getOAuthInterceptor(decrypter())))
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .addConverterFactory(ScalarsConverterFactory.create())
                .addConverterFactory(create(objectMapper))
                .build();

[JakeWharton]

NullOnEmpty is for broken servers who return 0-length bodies instead of JSON literals of null for an absent body.

Right now there’s not a good way to differentiate this case because the HTTP status code bypasses the converter. If you don’t care about distinguishing between 204 and 205 you can use an OkHttp interceptor to rewrite them to 200’s with a null literal as the root element.

Beyond that, we probably need to add a method to Converter.Factory for handling HTTP 204/205 since there is no body but the user requested an instance of a particular type. I need to think about it more.

[RaviH]

Great. I might have a question later but thank you for the explanation.