Read some System.Text.Json options

[Sinhk]

Get global string enum serialization and casing (#2652) from System.Text.Json options.

When testing this I noticed the GetService<IOptions>() always returns an IOptions, as long as MvcNewtonsoftJsonOptions exists. It didn't have to be registered with the service provider. So I changed some of the code that checks if it should load options for Newtonsoft.Json or System.Text.Json to look for a NewtonsoftJsonOutputFormatter instead.

[Sinhk]

@RicoSuter Finally got around to redoing this. Tried to keep only what’s necessary for reading the options

[RicoSuter]

Looks good. Is there a possibility to add unit tests for that somehow? Just to avoid regressions and have it tested.

[Sinhk]

@RicoSuter Added some tests, checking if the options are set.
I didn't find any test project targeting netcoreapp3 so I added a new one. Is that fine or should the tests rather be added to one of the existing projects?

[RicoSuter]

Sorry for my late reply, added two comments, what do you think?

[RicoSuter]

I think it would make sense to extract a ConvertJsonSettingsToNewtonsoftSettings method and move it to njsonschema.. then we just need to map as good as possible, eventually maybe with a custom contract resolver which reads system.text.json metadata.. i think this would be a good path forward and users of json schema would also benefit.. what do you think?

[Sinhk]

Sounds like a good plan. I'll try to make a PR for that tomorrow.

[RicoSuter]

Another thing: We should somehow turn off reading of newtonsoft attributes - in the newtonsoft settings 😀. See https://github.com/RicoSuter/NSwag/issues/2762

[RicoSuter]

Working on this now in your branch.

[RicoSuter]

Can we merge this?

[Sinhk]

Yes, looks good 🙂