API-ly Ever After: OpenAPI in .NET 9

In .NET 9, ASP.NET Core ships with built-in support for generating OpenAPI documents from minimal and controller-based APIs. In this session, we'll cover the key features of this new support, explore integration scenarios for OpenAPI, and discuss how your team can make the most of OpenAPI.
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#dotnet

[@d3vil5oldier]

This was awesome. I manage to fix my code where Scalar wouldn't show the authentication type in the drop-down menu. Thank you Safia and Mike.

[@VladyslavHorbachov]

Great demo! I'd like to see some presentation about Kiota and how it's integrated with current open API workflows as well.

[@alexlo5655]

Great demo! Do you have a source code for it on a GitHub?

[@eugene5096]

Thank you guys, just wonder why things that are done in schema transformer could not be done via attributes ?

[@kurumi690]

My first thought is because of NativeAOT friendly, or we need to create some source gen

[@safiaabdalla5656]

There's no out-of-the-box attributes for settings examples for types so we relay on transformers for this. For these kinds of situations, transformers provide more flexibility and reduce the amount of new API that needs to be added.

[@passionblackbay]

@@safiaabdalla5656 Transformers work well for security schemes and requirements, but they feel awkward for defining example values. With the Swashbuckle generator, it's at least possible to use XML comments for classes and route/query params, which is more convenient. However, is there an example available for using transformers specifically with example values for route/query parameters? Having an [Example()] or [Examples()] attribute (like [description()]) would be far more convenient...

[@gibbonaci]

what about fluentvalidation here?

[@safiaabdalla5656]

We don't provide built-in support for mapping FluentValidation configurations to OpenAPI documents but it is something that FluentValidation can provide by building on top of the transformers API in their own packages.

[@andrijs1521]

Could you please provide source code for this presentation?

[@gibbonaci]

There's one thing I would like to point out after initial testing, the `dotnet watch` command is not rebuilding the definitions so hot reloading needs to be turned off!