DotNetStarter: A C# repository from bmcdavid

DotNetStarter is a framework for composing applications where many components are provided by NuGet packages. The main audiences of DotNetStarter are package authors and application developers.

Package authors can depend on either the configuration and startup abstractions or the registration attribute abstractions to create their components. The components can then be designed with constructor dependency injection in mind. These classes can then be registered by using the RegistrationAttribute or in a startup module implementing ILocatorConfigure. Packages may also perform tasks during startup and shutdown using the IStartupModule interface.

Application developers can install the DotNetStarter package, a locator (container wrapper) package, any extension such as MVC for the full .NET framework, and any NuGet packages utilizing the abstractions. Developers have full control over the startup process which can be customized through code configuration at almost every level using a fluent configuration API. The framework also supports a wide variety of .NET frameworks from .NET version 3.5 and up, as well as the .NET Standard starting at 1.0.

Getting Started

To kickoff the startup modules and configure the locator please execute the following early in the project startup, for example global.asax class constructor for .NET Framework web applications.

The StartupBuilder provides a fluent API to change almost every aspect of the startup process, but can also be as simple as:

DotNetStarter.Configure.StartupBuilder.Create().Run();

Or more finely-tuned for assembly scanning and overriding defaults.

var builder = DotNetStarter.Configure.StartupBuilder.Create();
builder
    // configure the assemblies to scan
    .ConfigureAssemblies(assemblies =>
    {
        assemblies
            // Filters assemblies for ones using the [assembly: DotNetStarter.Abstractions.DiscoverableAssembly] 
            .WithDiscoverableAssemblies()
            .WithAssemblyFromType<RegistrationConfiguration>()
            .WithAssembliesFromTypes(typeof(StartupBuilder), typeof(BadStartupModule));
    })
    .ConfigureStartupModules(modules =>
    {
        modules
            // ability to manually add ILocatorConfigure modules after the scanned ones
            .ConfigureLocatorModuleCollection(configureModules =>
            {
                configureModules.Add(sut);
            })
            // ability to manually add IStartupModule modules after the scanned ones
           .ConfigureStartupModuleCollection(collection =>
            {
                collection.AddType<TestStartupModule>();
            })
            // if there are any modules that are acting badly or if you want to customize remove some to insert customized versions.
            .RemoveStartupModule<BadStartupModule>()
            .RemoveConfigureModule<BadConfigureModule>();
    })
    // ability to customize environment object, which can be used make registration decisions based on environment
    .UseEnvironment(new StartupEnvironment("UnitTest1", ""))
    // override default objects
    .OverrideDefaults(defaults =>
    {
        defaults
            .UseLogger(new StringLogger(LogLevel.Info));
    })
    .Build() // configures the ILocator
    .Run() // Runs IStartupModule registrations;

Inversion of Control / Dependency Injection

An IoC/DI package must be installed to enable the ILocator. There are several provided by default:

They can also be swapped at compile time by the application developer by overriding the default:

DotNetStarter.Configure.StartupBuilder.Create()
    .ConfigureAssemblies(a => a.WithDiscoverableAssemblies())
    .OverrideDefaults(d => d.UseLocatorRegistryFactory(new DotNetStarter.Locators.DryIocLocatorFactory())) //uses DryIoc
    .Build()
    .Run();

If the default isn't overridden a locator is discovered at runtime in the configured assemblies by an assembly attribute as noted below for DryIoc.

[assembly: DotNetStarter.Abstractions.LocatorRegistryFactory(typeof(DotNetStarter.DryIocLocatorFactory))]

Examples of DI/IOC

Service Registration

public interface ITest
{
    string SayHi(string n);
}

[Registration(typeof(ITest), Lifecycle.Transient)]
public class Test : ITest
{
    public string SayHi(string n) => "Hello " + n;
}

Usage

Constructor injection is the preferred method of consuming services as shown below.

[Registration(typeof(TestService), Lifecycle.Transient)]
public class TestService
{
    private readonly ITest _test;
    
    public TestService(ITest test)
    {
        _test = test;
    }

    public void ExampleMethod()
    {
        string message = _test.SayHi("User");
    }
}

Cases may exist where constructor injection is not available, in these cases an Import<T> could be used to resolve services. A best practice when using Import <T> is to make the dependency known by using a public property, which may be overridden using Import.Accessor by any consumers.

public class TestService
{
    public Import<ITest> TestImple { get; set; }

    public void ExampleMethod()
    {
        string message = TestImple.Service.SayHi("User");
    }
}

Abstractions