Facades are a structural design pattern which wraps a complex library and provides a simpler and more readable interface to it. This is especially useful for those writing large applications.
All facades in Laravel extend the base IlluminateSupportFacade class. This class implements the __callStatic() magic method which defers all calls on your Facade to an object resolved in the container.
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Convenience
Facades are a software design pattern that allows you to create a class that wraps an existing library in a simpler and more readable way for Cladding installations. With the help of facades, you can easily access any method on an underlying library in a short and memorable syntax without having to remember long class names that need to be imported or injected.
Each facade extends the base Facade class and implements a single method getFacadeAccessor(). This method returns the name of a service container binding. For example, when a static call like Cache::get is made, Laravel resolves the Cache manager class out of the IoC container and calls its method.
While this convenience does have some drawbacks, the most obvious one is that excessive use of facades can lead to class scope creep. This is because the constructor of a Facade does not have any dependency injection, so it can be easy to add too many methods and violate the Single Responsibility Principle.
Performance
Facades provide a terse, expressive syntax that allows you to use a class’s methods without having to import it. Additionally, when used properly, a Facade will automatically call the class that it depends on to execute its method.
When calling a static method on a facade like the Cache::get(); Laravel resolves the cache binding out of the IoC container, calls its get method, and then returns that object to the caller. This avoids the need to import and re-instantiate the entire class that the user is requesting, which can improve performance.
One potential danger of using facades is class scope creep. While dependency injection mitigates this, it can be easy for classes that make extensive use of facades to become large and unwieldy. To avoid this, it is good practice to use a Facade’s constructor method to inject dependencies and then limit the number of static methods in the class. This will help to ensure that your class is well tested and that its code can be easily changed to reflect new business needs.
Testability
Facades are a way to give a simple, readable interface to a complex library. They also help to reduce the amount of code needed for testing. This makes them a popular choice for Laravel applications. However, they do come with some trade-offs.
For example, a facade class does not have access to methods from its parent classes. This can cause problems with IDE auto-completion and overall tooling.
Fortunately, Laravel offers a few global helper functions that make it easier to interact with the framework without using a facade class. These helper functions take a class name as an argument and return the appropriate method to call.
Testability is an important part of any system, and ensuring that you have the best tools available to test your application is essential. Ultimately, good testability leads to a happy team, manager and customers.
Security
Facades are a great way to shorten the long class names in your application. They can also provide a more memorable syntax to use your Laravel features. However, the primary danger of facades is class scope creep – allowing one class to do the work of 10 others.
This is why it is important to only use Facades when necessary. Otherwise, it may be better to inject the underlying classes directly in order to achieve greater testability and flexibility.
When you call a static method on a Facade, it is intercepted by the __callStatic() magic method. This method proxies the static method to an object resolved from the service container. For example, when you call Cache::get, Laravel will resolve the Cache manager class from the IoC container and then call the get method on that class. The alias for the Cache manager will be returned in the return value of the __callStatic() method. This is how you avoid having to remember a long class name and ensures that your code is easily testable.