Override Default Services Implementation for AC Gold
Different features in AbleCommerce GOLD are implemented via services, for example coupon calculator service, checkout service, shipping and tax quotes calculation service and etc. CommerceBuilder API makes these services available to be overridden by the custom implementations. Castle Windsor IOC Container is used to resolve the implementation of these services and it is fairly easy to override the default implementations of these services with a custom implementation.
Each service has a defined interface that the service provider class has to implement. For example the default implementation of ship rate calculation service is defined by the interface "CommerceBuilder.Services.IShipRateQuoteCalculator" and is implemented by the class "CommerceBuilder.Services.ShipRateQuoteCalculator". You can provide your own custom implementation by implementing the service interface and update the Windsor config file to make use of use your custom implementation.
It is not required to learn anything about Windsor or any other IOC container to override the default implementation of any service, however some information and help/tutorial links are provided at the end for completion.
How to override the default service implementations
Follow these steps to override a default service implementation with your custom implementation:
1. Implement the respective service interface, and compile the code to some assembly and copy the dll file at "~/App_Data/Bin/" folder under your website.
2. Locate the "~/App_Data/windsor.config" file and open for editing using some text editor.
3. Define your custom service implementations in "~/App_Data/windsor.config" file. For example if you have a custom coupon calculator implementation, you can define it there like this:
<component id="MyCouponCalculator" service="CommerceBuilder.Services.ICouponCalculator, CommerceBuilder" type="MyCustomNamespace.MyCouponCalculator, MyCustomAssembly"/>
The "service" attribute contains the assembly ("CommerceBuilder" in our case) and service interface information, while the "type" attribute contains information about your custom service implementing class and assembly.
After changing/updating the "~/App_Data/windsor.config" file, restart the IIS, and AC Gold will start using your custom service implementation.
Shortcut for websites deployed as web applications :
For store websites configured as web applications, you can implement your custom services under "~/Code/" folder instead creating a separate assembly project for it. In this case you can use "AbleCommerce.Code" namespace. For example:
<component id="MyShipRateQuoteCalculator" service="CommerceBuilder.Services.IShipRateQuoteCalculator, CommerceBuilder" type="AbleCommerce.Code.MyShipRateQuoteCalculator, AbleCommerce"/>
List of services that can be overridden
Interface to be implemented by catalog URL generators
Interface that is to be implemented by URL rewrite providers
Interface to be implemented by URL caching service
Interface to be implemented by store events handler. This could be very useful for your own custom events handling.
Interface that a gift certificate key provider must implement
Interface to be implemented by the coupon calculator service
Interface to be implemented by the inventory management service
Interface to be implemented by the affiliate commissions calculating service
Interface to be implemented by the service used for various basket related calculations
Service interface for pre-checkout logic and basket calculations
Interface to be implemented by the checkout service
Interface to be implemented by the discount calculator service
Interface to be implemented by the user locator service
Interface to be implemented by the service for performing various order calculations
Interface to be implemented by the service for processes business logic related to orders
Interface to be implemented by a service for payment method providers
Interface to be implemented by a service for calculation of ship rate quotes
Interface to be implemented by a service for validating volume discounts
FTS service interface
Interface to be implemented by the service that runs all maintenance routines for the current store context
Interface to be implemented by the page tracking service
SQL Full Text Search (FTS) service interface
Interface to be implemented by the service that provides order status get/update services
Interface to be implemented by the store locator service
Interface to be implemented by the service that provides store settings for a given store
Interface to be implemented by the postal code validator service
Interface to be implemented by the SEO redirect service
Interface to be implemented by the address formatter service
A good example of how default services can be overridden is implementation of a custom event handler for your store. The following article explains how to implement a custom store event handler. Custom Store Event Handler Example
Inversion of Control
Inversion of Control is a principle used by frameworks as a way to allow developers to extend the framework or create applications using it. The basic idea is that the framework is aware of the programmer's objects and makes invocations on them.
This is the opposite of using an API, where the developer's code makes the invocations to the API code. Hence, frameworks invert the control: it is not the developer code that is in charge, instead the framework makes the calls based on some stimulus.
You have probably been in situations where you have developed under the light of this principle, even though you were not aware of it.
Inversion of Control Container
An Inversion of Control Container uses the principle stated above to (in a nutshell) manage classes. That is, their creation, destruction, lifetime, configuration, and dependencies. This way classes do not need to obtain and configure the classes they depend on. This dramatically reduces coupling in a system and, as a consequence, simplifies reuse and testability.
There is some confusion created by people that think that 'Inversion of Control' is a synonym for 'Inversion of Control Container'. As stated, Inversion of control is a broader principle.
Often people think that it is all about "injection", and broadcast that this is the primary purpose of IoC containers. In fact, "injection" is a consequence, a means to decouple, not the primary purpose. http://docs.castleproject.org/Windsor.Inversion-of-Control.ashx
Castle Windsor IOC Container
For information about Castle Windsor IOC Container, help and tutorials check the official documentation: http://docs.castleproject.org/Windsor.MainPage.ashx