Update the book (F.Promise to CompletionStage)

[eximius313]

Here: https://leanpub.com/deadbolt-2/read it would be good to replace F.Promise<Optional<Result>> with CompletionStage<Optional<Result>>

[schaloner]

I'm in the process of updating everything to be Play 2.5 compliant. I'm aiming to publish the latest version in the next two weeks.

Thanks!

[skiotterjeffa]

Hi Steve

I've used your auth0-integration example for Java from the book and am updating it for Deadbolt 2 2.5.1 and CompletionStage. I'm struggling with onAuthFailure, but everything else seems to compile. I haven't developed anything in over a decade, so I'm having to learn Lambdas, Futures, etc. I'm sure it is something simple. I'm happy to contribute the updates to this example if that is of value to you once I have it working.

Here is what I have.

public CompletionStage<Result> onAuthFailure(final Http.Context context,
                                           final Optional<String> s) {
        return getSubject(context)
                .thenApplyAsync(maybeSubject ->
                             maybeSubject.thenApplyAsync(subject -> Optional.of((User)subject))
                                         .thenApplyAsync(user -> new F.Tuple<>(true,
                                                                    denied.render(user)))
                                         .orElse(() -> new F.Tuple<>(false,  //orElseGet?
                                                                        login.render(clientId,
                                                                                     domain,
                                                                                     redirectUri))))
                .thenApplyAsync(subjectPresentAndContent -> subjectPresentAndContent._1
                                                 ? Results.forbidden(subjectPresentAndContent._2)
                                                 : Results.unauthorized(subjectPresentAndContent._2));
    }

Eclipse is telling me Type mismatch: cannot convert from CompletionStage to .

[schaloner]

Hi,

if it's been a while since you developed anything, it might be easier to use anonymous classes to get started. When using lambdas and chained calls, it can be really easy to lose what you're doing.

Alternatively, use local variables instead of chaining the calls. This will make it far easier to read.

For example, maybeSubject is an Optional, which does not have thenApplyAsync, etc, method - those belong to futures.

Here's the corrected example:

public CompletionStage<Result> onAuthFailure(final Http.Context context,
                                             final Optional<String> s) {
    return getSubject(context)
            .thenApplyAsync(maybeSubject ->
                                    maybeSubject.map(subject -> new F.Tuple<>(true,
                                                                              denied.render(subject)))
                                                .orElseGet(() -> new F.Tuple<>(false,
                                                                               login.render(clientId,
                                                                                            domain,
                                                                                            redirectUri))))
            .thenApplyAsync(subjectPresentAndContent -> subjectPresentAndContent._1
                                                        ? Results.forbidden(subjectPresentAndContent._2)
                                                        : Results.unauthorized(subjectPresentAndContent._2));
}

I didn't include the cast of subject to User to keep it simple, but let me know if you have issues with that.

I'm (slowly) updating the book for Play 2.5, including CompletionStage instead of Play's Future, Java's Optional instead of Play's F.Option, etc, and hope to have a new version out shortly.

Regards,
Steve

[skiotterjeffa]

Thanks Steve. Your suggestion of using local variables helped.

[eximius313]

@schaloner, I see that in most sections there is CompletionStage already, but in section 7 there are still F.Promise<Boolean>. Is it on purpose?

[schaloner]

No, the revision is an ongoing process so there are a few hold-overs. I need to start working on the book again.

[mkurz]

We are tracking all documentation related issues in #89 now.