Move IUrlHelper to an abstractions assembly

[strohhut]

I have a standard class library that provides ASP.NET specific utility methods that are independent from the app specific logic of concrete ASP.NET projects. For example I have a bunch of extension methods for HttpRequest.

Would it be possible to move IUrlHelper to an abstractions assembly so I can implement utility methods outside of the web project that require an IUrlHelper? Otherwise I have to implement my own IUrlHelper interface in my class library and then a class in my web project that implements it and that is a wrapper around the real IUrlHelper.

I can use IActionResult in a standard class library for instance. It would be nice if this was possible with IUrlHelper too.

[rynowak]

@strohhut - are you talking about moving it to Microsoft.AspNetCore.Mvc.Abstractions?

/cc @Eilon - I don't really see any reason why we couldn't do this.

[strohhut]

@rynowak Yes that's what I'm talking about.

I just saw that UrlRouteContext and UrlActionContext which IUrlHelper uses are also not inside Microsoft.AspNetCore.Mvc.Abstractions so my wrapper workaround cannot be implemented that easily. Also this means moving only IUrlHelper into Microsoft.AspNetCore.Mvc.Abstractions won't work then I guess.

[rynowak]

We would move all three types. Those two contexts are just parameter-objects they don't have any behavior.

[strohhut]

Sounds great. It would make it a lot easier for helper libraries.