Different behaviour from .Use(Func<T>) and .Use(Func<IContext, Func<T>>) when using custom lifecycle

[Peter McEvoy]

I am using a custom lifecycle to enable a "multi tenant" style web application.  In particular, I want certain objects to be associated with a particular URL Domain, where a domain is a function of an incoming HttpRequest.  Thus, I am able to make a declaration like this:

For<ISupportedLocalizations>()

.LifecycleIs(new DomainLifecycle())

.ConditionallyUse(c =>

{

c.TheDefault.IsThis(

new SupportedLocalizations(

CultureInfo.GetCultureInfo("es-ES"),

new List<CultureInfo> { CultureInfo.GetCultureInfo("en-US"), CultureInfo.GetCultureInfo("ro-RO") })

);

c.If(RequestIsForDomain("www.xxx.yyy")).ThenIt.IsThis(

new SupportedLocalizations(

      CultureInfo.GetCultureInfo("en-US"),

       new List<CultureInfo> {CultureInfo.GetCultureInfo("ro-RO")})

);

});

Now, there are situations (application startup) where I need objects to be resolved by structuremap, but I do not have access to the domain, because there is no RequestContext.  In these cases, I usually inject a factory method that will have access to Request Context at runtime:

For<Func<ISupportedLocalizations>>()

.Singleton()

.Use(() => ObjectFactory.GetInstance<ISupportedLocalizations>());

I don't really like this syntax, because everywhere I am reading that one should not use ObjectFactory.GetInstance.  So I figured out that the following _should_ be equivalent:

For<Func<ISupportedLocalizations>>()

.Singleton()

.Use(ctx => () => ctx.GetInstance<ISupportedLocalizations>());

In the first declaration, I am seeing the expected behaviour  - namely the factory method is getting called and the ISuportLocaliztions instance that gets resolved is appropriate to the incoming request.   

However, if I use the second version, I am NOT seeing that behaviour - I get the FIRST ISupportedLocalizations instance that was created.

I'm baffled and will need to stick with the first syntax until I understand a bit more.

I know I will probably be asked for the definition of DomainLifecycle so here it is:

public class DomainLifecycle : ILifecycle

{

private static readonly ConcurrentDictionary<string, MainObjectCache> _tenantCaches = new ConcurrentDictionary<string, MainObjectCache>();

public IObjectCache FindCache()

{

var domain = GetDomainLower();

var cache = _tenantCaches.GetOrAdd(domain, new MainObjectCache());

return cache;

}

public void EjectAll()

{

FindCache().DisposeAndClear();

}

public string Scope

{

get { return "Domain"; }

}

private static string GetDomainLower()

{

var requestDomain = HttpContext.Current.Request.Headers["host"];

if (!string.IsNullOrEmpty(requestDomain))

{

var indexOfPortSeparator = requestDomain.IndexOf(":", StringComparison.Ordinal);

if (indexOfPortSeparator > 0)

requestDomain = requestDomain.Substring(0, indexOfPortSeparator);

}

else

//HTTP spec says that HOST header MUST be specified, we are unlikely to get to this line (maybe in an incorrect Unit test tho)

requestDomain = HttpContext.Current.Request.Url.Host;

return requestDomain.ToLower();

}

}