Feature request: introduce ALBRouter, etc. to set the type of current_event in the REST API Router

[kmkhr]

Use case

In #761, APIGatewayRestResolver, APIGatewayHttpResolver, ALBResolver, and LambdaFunctionUrlResolver were created to access all properties from current_event.
I would like to access all properties from current_event in router as well.

Solution/User Experience

router = ALBRouter()

@router.get("/todos")
def get_todos():
    router.current_event.request_context.elb_target_group_arn

Alternative solutions

No response

Acknowledgment

• This feature request meets Lambda Powertools Tenets
• Should this be considered in other Lambda Powertools languages? i.e. Java, TypeScript

[heitorlessa]

hey @kt-hr, did you run into any issue when accessing current_event from a Router instance?

It should work, please let us know otherwise with a snippet we can reproduce - Test, Docs Example, API reference

[kmkhr]

hi @heitorlessa , thank you for your confirmation. Sorry, let me correct the content.

I mistakenly thought I could not access properties because the IDE was showing an error.

The type of current_event is BaseProxyEvent, so when I want to access properties such as elb_target_group_arn, the IDE completion does not work.
Although the completion will work by informing the IDE of the type with cast, we think it would be easier to understand if it were ALBRouter, etc.

[heitorlessa]

Ahhh that makes more sense now - thanks for clarifying and updating the title. Let's do it - it should be fairly trivial as you can simply subclass, override the type like we did for each explicit resolver class (ALBResolver), and call out in the docs that each corresponding resolver has a Router for accurate static typing.

Feel free to create a PR and we can review in January after we're back from winter holidays.

Thank you!

[rubenfonseca]

Hi @kt-hr just so I can understand this problem better, why are you not using ALBResolver in your code in the first place? Why are you using the bare Router when you know you're processing ALB events?

[kmkhr]

Hi, @rubenfonseca thank you for checking.

In my use case, I want to access properties such as router.current_event.request_context.authorizer.principal_id when I split it into separate modules as in the Split routes with Router example.
Cast as typed_event = cast(APIGatewayProxyEvent, router.current_event) to enable IDE completion.

_router in APIGatewayRestResolver APIGatewayHttpResolver ALBResolver is List[Route], but _router in Router is Dict[tuple, Callable], so I think they are incompatible.

[rubenfonseca]

Great, I now get the problem! Will work on this today :)