BearerTokenAuthenticator is not extendable

[laurentschoelens]

Is your feature request related to a problem? Please describe.

BearerTokenAuthenticator is marked as final and could not be extended to provide extra informations / headers in Stripe request

Describe the solution you'd like

Make BearerTokenAuthenticator extendable by removing the final keyword or close only methods that are not extendable

Describe alternatives you've considered

No response

Additional context

No response

[jar-stripe]

Hi @laurentschoelens , thanks for submitting the feature request! Can you give me some more information about what kinds of additional information or headers you would like to add to the Stripe request?

[laurentschoelens]

It's technical informations for internal gateway like internal authentication informations

[jar-stripe]

Thanks for the response! Is that information added to the Authorization header? Or additional headers?

[laurentschoelens]

Custom header to not conflict w/ Authentication header which contains Bearer informations

[laurentschoelens]

Currently if we want to achieve that, we need to declare custom class which does both adds headers and code which use instanceof on class won't work as expected

[jar-stripe]

Gotcha, thank you! Last question for now, do you need to set these headers on every request? or on just a few requests?

[laurentschoelens]

Since it's authentication information for internal gateway, it's on every request that these headers should be sent

[mbroshi-stripe]

Are you able to create your own Authenticator that delegates to the BearerTokenAuthenticator and then use setAuthenticator on a per-request basis?

[laurentschoelens]

No I dont want to use a per-request based code since I have to do that for every request.

It's a one-time config I need

[mbroshi-stripe]

OK, thanks for the clarification! Do I understand correctly then that you're instead using StripeClientBuilder#setAuthenticator at a client-level? That should work. As you point out, it will break the StripeClient#getApiKey method, but that isn't used anywhere in our SDK.

[laurentschoelens]

OK, thanks for the clarification! Do I understand correctly then that you're instead using StripeClientBuilder#setAuthenticator at a client-level? That should work.

Yes but that's a bit hacky

As you point out, it will break the StripeClient#getApiKey method, but that isn't used anywhere in our SDK.

Maybe if not used you should deprecate the method and remove it later. From what I remember, it was mandatory but I'll double check that point

[mbroshi-stripe]

Maybe if not used you should deprecate the method and remove it later.

Agreed. I'll add that to our backlog.

Yes but that's a bit hacky

Can you expand on that? Is there something else you have in mind?

[laurentschoelens]

Yes but that's a bit hacky

Can you expand on that? Is there something else you have in mind?

When you want or need to extend something to change current behavior, the best way to do is to extend existing class to add specific technical or business code, not generating a new class that will do both the existing code and your needs.
Here if you change something in the library class, the changes won't be catched up by the custom class and may break somehow in a near future when updating the library version...

[mbroshi-stripe]

When you want or need to extend something to change current behavior, the best way to do is to extend existing class to add specific technical or business code

I respectfully disagree with you here. Item 18 of Joshua Bloch's Effective Java is: "Prefer composition over inheritance" and Item 19 is "Design and document for inheritance or else prohibit it." In our case, we've followed Item 19, and marked the class final to prevent inheriting from it. For your use case, you can follow Item 18, and use composition to get the desired behavior plus whatever additional behavior you want:

public class InternalGatewayAuthenticator implements Authenticator {
    private final Authenticator delegate;

    public InternalGatewayAuthenticator(Stripe apiKey) { 
        this.delegate = new BearerTokenAuthenticator(apiKey);
    }

    @Override
    public StripeRequest authenticate(StripeRequest request) throws StripeException {
        request = addCustomerHeaders(request);
        return delegate.authenticate(request);
    }
}

Excuse me if I'm missing something, but I fail to see how this does not meet your use case.