First of all, is there a complete reference on Microsoft Unity?
I noticed today that, when I call "Configure" on the "UnityConfigurationSection" it configures and prepares all configuration mappings.
What if a class has a dependency on an object registered inside Unity. Does this class itself needs to be registered by Unity so that, Unity injects its dependency?
I am afraid that Unity would not inject a dependency on an Object, if that object is not registered into Unity. This is the case with "Page" class in ASP.NET.
Thanks
Unity has some well defined default behavior when working on classes that aren't registered ahead of time.
In the absence of registration, the container will look for the longest constructor, and it'll also look for attributes on the type ([Dependency] being the main one) to figure out what properties to inject.
If you don't want to use the attributes or the defaults don't match what you want, you'll need to configure the container to do the what you want.
Related
The project I'm on requires we use Unity. The lifetime managers are correctly set so this is not an issue with setting a lifetime manager. We have a special case where I need to resolve a service but it needs to freshly resolve every dependency as if it was the original request. In Autofac I can do this by injecting an Owned. Does Unity support anything like that or is there a way I can call Resolve and get a fresh set of injections?
Unity doesn't have equivalent of Autofac's Owned<> feature.
As for your problem, I think factories could solve it. You can write your own factory or use Unity Automatic Factories feature. More info on msdn.
I ended up using a Marker interface and registering that interface with a different scope. Then when I must have a new instance and not a shared instance I use the other interface.
Currently I've got a Symfony2 DI container instance ready with a service and all it's dependencies. Lets say for example I have a Car class and it has Engine and Lights as dependencies.
In my current setup both these dependencies are automatically created through setter injection when the Car object is created, but it might very well be that my Car object won't need it's lights this time around thus it doesn't explicitly need to create an instance of this dependency.
Is there a way to achieve this in Symfony DI? Thus only creating an instance of the Lights object when needed? My guess is it'll be some sort of Proxy implementation like Doctrine has but as far as i've seen it doesn't exist in Symfony DI.
Inject the dedendencies that are mandatory through the Constructor via your services.yml, automatically.
If you have optional dependencies inject them through a setter in your Controller when you need them.
$this->container->get('cars')->setLights(new \Namespace\Lights());
Of course your Cars class must be designed like so and you have to direct the injections yourself in your controller, or whereever needed, code.
Question is already answered, but for who needs this functionality, lazy services are implemented in Symfony 2.3.
You need to install the ProxyManager bridge.
You can find official documentation here.
A very interesting question, but I don't think it's possible within Symfony2's Dependency Injection Container. The container is only aware of what you tell it - in this case, you have a dependency that's conditional on a specific use-case. Plus, the registration of services happens early on in the app's life, so I don't see how you could get this to work.
Maybe you should use the Factory pattern. Register a CarFactory as a service, and then when fetching a Car instance, you can specify that it should include a Light dependency.
Can I ask why you want to achieve this? There may be a simpler solution.
It's not a pretty workaround, but you can try injecting the whole DIC, then getting the Light and Engine services when neccessary.
I was thinking about something like this method in the Car class:
protected function getLightService()
{
if (!$this->light) { //so we reuse the first instance
$this->light = $this->dic->get("car.light");
}
return $this->light;
}
I'm starting with a Symfony2 project. I know the framework basics but I have a question:
Where is the right place to pot those helper classes I create for help or for the business logic?
Max's answer is correct. However I question the path he recommends for your code.
The following classes and files have specific emplacements:
Service Container Extensions (belong in) DependencyInjection/
from http://symfony.com/doc/current/cookbook/bundles/best_practices.html
That says your Services should be placed in a folder called 'DependencyInjection', not 'Services'. In full, it should be src/Foo/BarBundle/DependencyInjection
I say this as someone that had the former and has just finished moving them all to the latter (!)
What #Adam says is wrong, you have to store your Dependency Injection Extensions in DependecyInjection directory, not the services itself. In the documentation says that you can store your (custom) business logic classes in any place you like.
http://symfony.com/doc/current/best_practices/business-logic.html
The best way to keep the business logic is create service to handle all the logic. So it will be in:
src/Foo/BarBundle/Service
and you need to call the service in the services.yml.
I recently did some small work on an existing Symfony2 project. As described by answer from Tuong Le, I created my Helper classes under the Helper directory of the bundle and class name with Helper suffix i.e. the helper class is located at:
src/MyBundle/Helper/MyUtilHelper.php
I can use MyUtilHelper class in my bundle without calling the service container i.e. I didn't need to call.
$container->get('my_util');
I don't really know whether there is some special config. in my setup; someone already got it setup and I was just adding new functionality.
You can create the custom classes under your Bundle, such as under a folder Helper/..
However, to use those helper in your code, you'll need to define those Helper(s) in your service description file (such as services.xml)... Then you can use $container->get('your_helper')->
According to official documentation - in particular - Symfony Best Practices - you should store your services in Utils folder under the src. I belive, that this is correct way regardless of whether you want or don't wont to make the functionality provided by services of your bundle available to other parts of application via Service Container. Furthermore, you can store helper classes in any place you consider suitable. Concerning #Adam Knowles and #PachinSV answers - they are not quite right because they do not answer your question - "Where is the right place to pot those helper classes I create for help or for the business logic?" or "Where to store classes which I want to register and use via Service Container" - but not where to put bundle Extension class - which main purpose is to provide information about configuration which should be automatically loaded from your bundle to apps Service Container during the process of booting the Kernel.
I'm working with Orchard CMS and it is better CMS for me. I want to understand how it does the logging and whether I can add my own logging or not. I saw that Orchard uses NullLogger class and it does no work. I've opened the App_Data.Logs folder and have seen that there are the log files. But how? I searched in code where is the trick that replaces NullLogger with log4net (I guess this is log4net, because the log format and the formatting for log4net.config are very similar) but I haven't found this.
Can somebody answer me:
How Orchard does the logging?
Whether I can add my own logger and if yes what best practices exist to do this?
Thanks, Andrey.
An Autofac module (Orchard.Logging.LoggerModule to be precise) handles that. Basically - it scans each dependency and fills all properties of type ILogger with a reference to appropriate logger instance. Each dependency gets its own logger with name equal to full type name (including namespace) of a containing class.
The NullLogger is just a placeholder so accessing the property would not throw NullReferenceExceptions before the property is being set by Autofac.
Extending the default logging is a rather complicated task as it would involve doing three things:
create a custom implementation of ILoggerFactory (just like the default Orchard.Logging.CastleLoggerFactory) and
create an Autofac module that registers that implementation in the container (like the mentioned LoggerModule does)
suppress the current default logging module by decorating your new one with [OrchardSuppressDependency("Orchard.Logging.LoggingModule")]
UPDATE
Just realized I haven't addressed the most important part of the question here:)
Yes, Orchard uses log4net so you may alter the default settings via Config/log4net.config file.
There is a great article on how Orchard Logging works. (I am not sure if it is ok to copy and paste the entire article). This is the link: Injection Logger in Orchard
So the trick is this:
Whenever a class requires a Logger instance, all it needs to do is to
declare a ILogger property, that’s it. And later, in your class, you
can use this property to Logging at anytime
And how is this done?
When Orchard web application startup, the OrchardStarter will be used
to do most of the registration work.
In a few words, it looks all the code in all projects, gets all the classes that use an ILogger property, and implements it for you (if not implemented), using Castle's logger factory.
Can anyone help point me to some good resources for working with Unity 2.0 in an ASP.NET that doesn't talk about ASP.NET MVC?!?
We are not using MVC and I am struggling to get Unity to inject dependencies into my pages following the couple of examples I've read (which are all based on David Hayden's work so they are all presenting the same examples and code).
UPDATE
I tried to go the PageHandlerFactory route but the example (here) is incomplete and no source code is available to accompany the article.
So, I decided to try the custom HttpModule approach described here and here. Again, no source code is available beyond what is shown so it is difficult to troubleshoot issues.
The problem I have now is that all of the plumbing appears to be wiring up correctly but the Buildup method does nothing to my page. I can see all of the types are registered in the container when I set a break-point in the module code and the code is executing as expected. But a break-point in the Page_Load event handler shows that the dependencies are all null.
The property in question is public, with a setter and getter, and is marked with the Dependency attribute. I've tried with and without the attribute, with and without a mapping name, ... every combination I could think of and nothing works.
What am I missing???
It depends what you expect. Most exemples targeting MVC present custom controller factory which allows creating controllers with dependency injection. This is indeed also possible with web forms but instead of controller you must inject dependencies into pages. To do this you must replace PageHandlerFactory with custom implementation.
You can create your own implementation of PageHandlerFactory which will be able to resolve pages directly and inject dependencies defined in constructor or you can use one of these (here, here and here) which instead uses stantandard PageHandlerFactory and builds page instance (resolve property dependencies).