[Components] Figure out layering on the server

[javiercn]

We want MVC and Components.Server to play nice together.

• MVC has a basic (non-interactive) prerender
• Components.Server has a nicer prerenderer (that supports interactivity).
• We want Components.Server to take over transparently.

They both end up needing some sort of shared abstraction that defines "prerrendering".

• We can leave Components referencing MVC (as it does today).
• We can invert the relationship and have MVC reference components.Server
• We can put the abstractions in Microsoft.AspNetCore.Components but that limits the expressiveness and doesn't apply to WebAssembly scenarios.
• We can create a new assembly that is where the shared abstractions between the server components live.
  • Microsoft.AspNetCore.Components.Http
  • Microsoft.AspNetCore.Components.Core
  • Microsoft.AspNetCore.Components.Html
  • Microsoft.AspNetCore.Components.Prerendering

[javiercn]

We discussed this at length and we decided on the following.

• There will be two separate gestures for rendering components from an MVC page/view:

  • "static rendering": Using a component as a partial.
  • "interactive rendering": Prerending some content + reconnecting to the content.

• MVC will have it's own internal mechanism for performing "static rendering".

• MVC will not have out of the box will not have it's own mechanism for "interactive rendering".

• We will create a new library Microsoft.AspNetCore.Mvc.Prerendering that will reference both MVC and Components.Server and will include a couple of extension methods on HTML Helper that can be used for performing "interactive rendering".

  • This library will be part of the shared framework, so it's available to users without anything magic.
  • This library will simply contain a couple of HTML helpers for doing the interactive prerendering.
  • The html Helpers in this library will rely on an abstraction that lives in Components.Server to perform the prerendering and will resolve it from DI or throw otherwise with a clear exception message informing the user that they need to call AddComponents()

[rynowak]

Sounds right 👍

[mkArtakMSFT]

@javiercn, is there anything pending here? If so, please update the post to reflect on it.