Rabid Penguin Rabid Penguin - 1 year ago 90
C# Question

How to resolve instances with Castle Windsor that rely on values from the HttpRequestMessage

I'm using Web Api with the OWIN pipeline.

Startup.cs



public class Startup {
public void Configuration(IAppBuilder app) {
var container = new WindsorContainer().Install(FromAssembly.This());

var config = new HttpConfiguration();
config.MapHttpAttributeRoutes();

// extension method to resolve controllers with Windsor.
app.UseWindsorApi(config, container);
}
}


MyClassInstaller.cs (IWindsorInstaller)



public void Install(IWindsorContainer container, IConfigurationStore store)
{
container.Register(
Component.For<IMyClass>().ImplementedBy<MyClass>()
.LifeStyle.PerWebRequest()
.DependsOn(new {
configSetting = ConfigurationManager.AppSettings["key"],
otherSetting = ???
}));
}


MyClass.cs & IMyClass.cs



public class MyClass : IMyClass {
private readonly string configSetting;
private readonly string otherSetting;

public MyClass(string configSetting, string otherSetting) {
this.configSetting = configSetting;
this.otherSetting = otherSetting;
}

public void DoSomething() {
// method that uses the settings that were set in the constructor.
}
}

public interface IMyClass {
void DoSomething();
}


MyController.cs



public class MyController : ApiController {
private readonly IMyClass myClass;

public MyController(IMyClass myClass) {
this.myClass = myClass;
}

[HttpGet]
[Route("")]
public async Task<IHttpActionResult> GetAsync() {
// uses this.myClass
}
}


Here's where I'm stuck. Whenever an instance of MyClass is resolved the value of otherSetting needs to be assigned.

The value of otherSetting is determined by two things.

1) The client_id claims value from the request.

2) An async call to a method that takes the client_id as a parameter and returns a string value. Which is what gets set into otherSetting

public async Task<string> GetOtherSetting(string client_id) {
return "value";
}


I'm not sure where to even begin to get Castle to inject a value based on those two criteria...

UPDATE:
I've updated to potatopeelings answer with some minor changes and it seems to be working fine.

.DynamicParameters(async (k, p) =>
{
var fundNameProvider = k.Resolve<IFundNameValueProvider>();
p["otherSetting"] = await fundNameProvider.GetFundNameAsync();
k.ReleaseComponent(fundNameProvider);
}))


I changed it to an async lambda so I can await the method.
I also called ReleaseComponent as I was under the impression that objects you manually Resolved with Castle you also needed to manually release.

Answer Source

Use UsingFactoryMethod and DynamicParamters

First, inject the current claims

...
Component.For<ClaimsIdentity>().UsingFactoryMethod(() => HttpContext.Current.User.Identity as ClaimsIdentity).LifestylePerWebRequest()
...

into a service (IOtherValueProvider - PerWebRequest) that has a GetOtherSetting method to wait on an async call (i.e. convert the async call to a synchronous call) to get otherSetting from the client_id extracted from the injected ClaimsIdentity

Then use DynamicParameters to get the value

... register your class ...
.DynamicParameters((kernel, parameters) =>
    {
        parameters["otherSetting"] = kernel.Resolve<IOtherValueProvider>().GetOtherSetting();
    }))
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