Say I have a project, I have several CFC's in that project. For the sake of the example, I have a debugging function general.cfc and I want to use that function in mandrill.cfc without having to copy and paste the code into the latter cfc. I've googled this until I can google no more and I know I need to post it here.
Anyone care to take me to school?
This is how I would do it
<cfset var objGeneral = createObject("component","general")>
Then if you have a function in general.cfc called getName() you can call it by saying objGeneral.getName()
You should look at the notion of dependency injection, and you should specifically look at how ColdSpring implements it in the context of ColdFusion (or DI/1).
Basically you have an init() argument in Mandrill which would take a General object, and then you set the General object into the variables scope of the Mandrill object, using its methods via variables.general.
That said, this works best on singleton objects. If you need to do this sort of thing on a transient object, I'd just instantiate the General object as needed within your Mandrill code (ie: now Matt Busche is suggesting).
My solution was to have mandrill.cfc extend the general.cfc component:
<cfcomponent extends="general" name="mandrill" ...>
See also CreateObject
Related
I've been running into endless problems attempting to use Windsor with Web API and injecting HttpRequestMessage into downstream dependencies of a controller. Since I've tried all the matching answers on Stackoverflow, I'd like to ask the question in a different way:
In Castle Windsor, how can I resolve a component instance while supplying a value for a downstream dependency? That is, the supplied value is required by a component that is required by the component being resolved.
For context, I'm trying to inject HttpRequestMessage so that I can use it to resolve the request context (primarily to resolve an absolute URL).
Edit I'd also like to point out that I don't currently have a dependency on Web Host / System.Web and I'd rather not change that.
A proper approach is to
Create IMyDesiredRouteParameterProvider
Implement it. Get the current request inside it and get the url
Register it and inject it in the desired dependent class via constructor.
I made myself such an implementation and I can say that this way it works fine. You can make Web.Infrastructure assembly and put the implementation there. Or put both the interface and the implementation there if you are going to reference it from another web module.
using System;
using System.Web;
namespace RouteParameterProvider
{
interface IMyRouteParameterProvider
{
string GetRouteParameter();
}
public class ControllerActionMethodRouteParameterProvider : IMyRouteParameterProvider
{
public string GetRouteParameter()
{
string Parameter = HttpContext.Current.Request.RequestContext.RouteData.Values["controller"] as string;
if (string.IsNullOrEmpty(Parameter))
{
throw new InvalidOperationException();
}
return Parameter;
}
}
}
You can get every possible thing that the Request Context contains from :
HttpContext.Current.Request.RequestContext
And it will be better if you rethink your design decision :
I need HttpRequestMessage to be regstered prior to creating each
instance of SomethingController so that it will be available down at
the LinkGenerator layer.
Containers are to be initialized at runtime and then used to resolve.
I need HttpRequestMessage to be regstered prior to creating each
instance of SomethingController so that it will be available down at
the LinkGenerator layer.
It sounds like you want to register an item with the container at runtime, post-startup. In general, this is not a good practice--registration should be a discrete event that happens when the app is fired up, and the container's state should not be changed during runtime.
Dependency Injection is about resolving service components, not runtime state--state is generally passed via methods (method injection). In this case it sounds like your LinkGenerator component needs access to the ambient state of the request.
I'm not that familiar with HttpRequestMessage, but this answer seems to show that it is possible to retreive it from HttpContext.Current. You could make this a method on your LinkGenerator class, or wrap this call in a separate component that gets injected into LinkGenerator (HttpRequestMessageProvider?). The latter would be my preferred method, as it allows LinkGenerator to be more testable.
Given the lack of a clean way of doing this and Web API not providing information as to the hosted endpoint beyond per-request context objects, I ended up injecting the base url from configuration.
Is this library by Mark Seemann the answer? In the description he writes explicitly :
This approach enables the use of Dependency Injection (DI) because the
request can be injected into the services which require it.
Then gives an example :
// Inside an ApiController
var uri = this.Url.GetLink(a=> a.GetById(1337));
By which you can then pass the URL down the road in the service that you have injected in the controller.
UPDATE :
Mark Seemann wrote about the same exact problem here:
"Because HttpRequestMessage provides the context you may need to
compose dependency graphs, the best extensibility point is the
extensibility point which provides an HttpRequestMessage every time a
graph should be composed. This extensibility point is the
IHttpControllerActivator interface:..."
This way you can pass request context information to a component deep in the object graph by getting from the HttpRequestMessage and passing it to the DI container.
Just take a look at the interface of IHttpControllerActivator.
The WEB API framework gets the IHttpControllerActivator through DependencyResolver. You probably already replaced it by your CastleWindsorDependencyResolver. Now you have to implement and register your HttpControllerActivator and register it.
When the WEB API framework gets IHttpControllerActivator from DependencyResolver (your Castle Windsor DR) and calls IHttpControllerActivator.Create() it will pass you the HttpRequestMessage. You can get your info from there and pass it to the your CastleDR before you call Resolve(typeof(MyController)) which will resolve the whole object graph - that means you will have MyHttpContextInfo to inject in your XYZComponent deep in the resolution stack.
This way tou are passing the arguments in the last possible moment but it is still possible. In Castle Windsor I make such passing of arguments though CreationContext.AdditionalArguments["myArgument"];.
I have a C++ method that takes variable argument as init param. Something like
MyMethod(std::wchar_t*, ...)
Can someone please let me know how can we write a WinRT component wrapper to expose the variable arguments?
WinRT metadata does not support vararg functions, so there is no good way to do this. The answer therefore depends on what the function actually does. Assuming it is some kind of string formatting function I would suggest wrapping it with something like:-
MyMethod(Platform::String^, Windows::Foundation::Collections::IVector<Platform::Object^>^ params);
This will allow you to take the variable arguments.
The problem of course is that this has completely different semantics from what you have. The caller is going to have to pack up an array, and you won't be able to call your existing method easily with the arguments from the vector.
I'm After several days learning angularJS through converting my standart JS app to a ng one.
I was wondering about this simple scenario:
I have a global function called fb_connect(),
it can be used from any page (or any controller if you like) to make a facebook-based login.
This function makes a simple http call and receives a JSON object contain data to move on (display a pop up, login, etc...)
I read that I can define a Factory or a Service for my app and use it in any controller, which works fine.
So, I created a fb_connect factory function.
The problem is that now, in every page (every controller), I have to define that fb_connect in the constructor of every controller - for example :
function welcome($scope,fb_connect){});
What is the proper way to do this kind of actions using Angular without having to define these functions each and every time in every controller?
Thanks
Setting up factories and services is all part of the dependency injection system of Angular. Using that system is great when you need to create things that depend on other injected things. It's a big tree of dependencies. It's also nice for creating singletons, such that everywhere in your code end up using the same instance of some object.
It sounds to me like neither of these benefits apply in your case. I'd suggest just not using Angular's DI for it. You have some function defined globally, just call it directly and skip the DI. There's nothing wrong with that.
Of course you say it makes an Ajax call, so doesn't depend on the Angular $http service?
Your two options are:
Declare the function on the $rootScope
Inject it as a service
My advice is to go with making it a service. The whole purpose of services is explained in the Angular.js docs, just like this quote:
Angular services are singletons that carry out specific tasks common to web apps... To use an Angular service, you identify it as a dependency for the dependent (a controller, or another service) that depends on the service.
As you mentioned in your question, you'd prefer to not define the service in every controller you wish to use it in. With $rootScope you'll be injecting that also in every controller. So really it's a question of which you prefer, although to answer your question, the proper way of using a factory or service is to inject it into the controller you wish to use it in.
You can always put it in the $rootScope
myApp.run(function($rootScope, fb_connect){
$rootScope.welcome = function(){
};
});
I am trying to use Mootools together with TypeScript. Mootools, and some modern browsers support .bind method, which is polymorphic.
How can I properly declare this feature in a *.d.ts file, to be able to use constructs like [1,2].map(this.foo.bind(this)); ?
I know I can avoid such constructs by using lambdas, but sometimes I do not want to.
Perhaps there is a mootools.d.ts file somewhere which I could download instead of reinventing it myself?
TypeScript's lib.d.ts already defines the bind function's signature in the Function interface as follows:
bind(thisArg: any, ...argArray: any[]): Function;
I don't think there's any better way of doing it until generics get added to the language.
For the time being though, if you want to use bind and the recipient of the resulting function expects a specific signature, you're going to have to cast the function back to that signature:
var bfn : (p: number) => string;
bfn = <(p: number) => string> fn.bind(ctx);
There's a growing list of definition files being tracked here.
As for generating methods pre-bound to their this pointer in TypeScript I've suggested two ways of doing this. 1) a simple base class I defined at the end of this thread. and 2) a more advanced mixin & attribute system here.
How can I pass arguments to a constructor in an IOC-framework?
I want to do something like: (Trying to be IOC-framework agnostic ;) )
object objectToLogFor = xxx;
container.Resolve<ILogging>(objectToLogFor);
public class MyLogging : ILogging
{
public MyLogging(object objectToLogFor){}
}
It seems that this is not possible in StructureMap. But I would love to see someone prove me wrong.
Are other frameworks more feature-rich? Or am I using the IOC-framework in the wrong way?
In structure map you could achieve this using the With method:
string objectToLogFor = "PolicyName";
ObjectFactory.With<string>(objectToLogFor).GetInstance<ILogging>();
See: http://codebetter.com/blogs/jeremy.miller/archive/2008/09/25/using-structuremap-2-5-to-inject-your-entity-objects-into-services.aspx
For Castle Windsor:
var foo = "foo";
var service = this.container.Resolve<TContract>(new { constructorArg1 = foo });
note the use of an anonymous object to specify constructor arguments.
using StructureMap:
var foo = "foo";
var service = container.With(foo).GetInstance<TContract>();
How can this be language-agnostic? This is implementation detail of the framework in question.
Spring alows you to specify c'tor args as a list of values/references, if that's your thing. It's not very readable, though, compared to property injection.
Some people get hot under the collar about this, and insist that c'tor injection is the only thread-safe approach in java. Technically they're correct, but in practice it tends not to matter.
It should not be a very common need, but sometimes it is a valid one. Ninject, which is lighter than StructureMap, allows you to pass parameters when retrieving transient objects from the context. Spring.NET too.
Most of the time, objects declared in an IoC container aren't transient, and accept others non-transient objects through constructors/properties/methods as dependencies.
However, if you really wan't to use the container as a factory, and if you have enough control on the objects you want to resolve, you could use property or method injection even if it sounds less natural and more risky in some way.
Yes, other frameworks are more feature-rich - you need to use an ioc framework that allows for constructor injection. Spring is an example of a multi-language ioc container that allows constructor dependency injection.
Other IoC frameworks are more feature rich.
I.e. check out the ParameterResolution with Autofac
You can also do that with Windsor easily