Junior — Middle
What approaches and techniques will you use when creating your own container for dependency injection?
sobes.tech AI
Answer from AI
When creating a custom dependency injection container, the following approaches and techniques should be considered:
- Dependency registration: implement methods for registering types and their implementations, for example, with different lifecycles (singleton, transient).
- Dependency resolution: the container should be able to create objects, automatically resolving their dependencies through constructors (constructor injection).
- Recursive resolution: when creating an object, the container should recursively create all necessary dependencies.
- Handling cyclic dependencies: provide protection against infinite recursion.
- Configuration: ability to configure dependencies through code or configuration files.
Example of a simplified container in C#:
public class SimpleContainer
{
private readonly Dictionary<Type, Type> _registrations = new();
public void Register<TService, TImplementation>()
{
_registrations[typeof(TService)] = typeof(TImplementation);
}
public TService Resolve<TService>()
{
return (TService)Resolve(typeof(TService));
}
private object Resolve(Type serviceType)
{
if (!_registrations.ContainsKey(serviceType))
throw new Exception($"Service {serviceType.Name} not registered");
var implementationType = _registrations[serviceType];
var constructor = implementationType.GetConstructors().First();
var parameters = constructor.GetParameters()
.Select(p => Resolve(p.ParameterType))
.ToArray();
return Activator.CreateInstance(implementationType, parameters);
}
}
This container allows registering dependencies and automatically creating objects with their dependencies.