New Post: Well-Known Boundaries

What's the deal with Microsoft.Composition.Demos.Web.Mvc.Boundaries?

It says it defines [w]ell-known sharing boundary names. The composition provider uses all of these when handling a web request and then goes on to define three:

// The boundary within which a
// current HTTP request is accessible.
public const string HttpRequest = "HttpRequest";

// The boundary within which a
// consistent view of persistent data is available.
public const string DataConsistency = "DataConsistency";

// The boundary within which a
// single user can be identified.
public const string UserIdentity = "UserIdentity";

As far as I can tell, these aren't "well-known" to anything, and at the end of the day they're all per-request care of CompositionProvider.CurrentInitialisedScope leaning on HttpContext.Current.

Which is to say, they might as well be called PerRequestBoundary1, PerRequestBoundary2, and PerRequestBoundary3.

Boundaries.cs hints at as much with: The composition provider uses all of these when handling a web request.

But basically it looks like everything but HttpRequest are misnomers: there's nothing about the string "UserIdentity" that actually links a part's lifetime to the request's user identity.