Support XML-based OpenAPI docs for minimal APIs

Is there an existing issue for this?

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Describe the bug

Swashbuckle currently supports reading the XML doc string associated with an action’s method to derive the description, summary, example, etc for an action.

We need to add similar support for minimal endpoints where the documentation might be on a referenced method group or (maybe) on a Map* invocation.

Expected Behavior

/// <summary>
/// This is a foo.
/// </summary>
string GetFoo() => "This is a test";

Should resolve the correct summary info.

[mholec]

I consider this functionality unnecessary. Given the way REST APIs are created and the constant proliferation of approaches like microservices and API gateways, generating documentation in general makes no sense. The documentation generated falls short of the quality of the specification and reflects implementation errors. Generated documentation is unusable in practice for automation, mocking and testing. The specification first approach has been a trend for several years.

[andrewlock]

Just FYI, this already works, as long as you

• Setup Documentation generation
• Configure IncludeXmlComments in AddSwaggerGen()
• Use MethodGroup endpoint handlers.

That last point is the biggest sticking point - it would be great if you could use lambdas too, but at least this partially works 🙂

One observation (I’m not sure if it’s a bug or expected behaviour). If you use WithOpenApi(), it wipes out any existing documentation of the parameters that comes from XML