DeveloperExceptionPageMiddleware always returns HTML, sometimes JSON would be better

[tjrobinson]

We're using the DeveloperExceptionPageMiddleware and it would be really useful if it could be changed/configured so that AJAX requests to APIs, e.g. from an Angular application were given a JSON response back instead of HTML. This would make the response much more readable when using F12 tools or testing the API through other non-browser tools like Postman.

I hope that's enough information to make sense, let me know if not.

There's a similar problem discussed here: http://stackoverflow.com/questions/35245893/mvc-6-webapi-returning-html-error-page-instead-of-json-version-of-exception-obje

Thanks!

[davidfowl]

Feels like we could do this as part of the new API work @rynowak.

/cc @Eilon

[rynowak]

https://tools.ietf.org/html/rfc7807

And then you want formatters and get bit by the layering bug 😆

[aspnet-hello]

This issue was moved to dotnet/aspnetcore#2590