base on Assembly scanning and decoration extensions for Microsoft.Extensions.DependencyInjection # Scrutor [](https://ci.appveyor.com/project/khellang/scrutor) [](https://www.nuget.org/packages/Scrutor) > Scrutor - I search or examine thoroughly; I probe, investigate or scrutinize > From scrūta, as the original sense of the verb was to search through trash. - https://en.wiktionary.org/wiki/scrutor Assembly scanning and decoration extensions for Microsoft.Extensions.DependencyInjection ## Installation Install the [Scrutor NuGet Package](https://www.nuget.org/packages/Scrutor). ### Package Manager Console ``` Install-Package Scrutor ``` ### .NET Core CLI ``` dotnet add package Scrutor ``` ## Usage The library adds two extension methods to `IServiceCollection`: * `Scan` - This is the entry point to set up your assembly scanning. * `Decorate` - This method is used to decorate already registered services. See **Examples** below for usage examples. ## Examples ### Scanning ```csharp var collection = new ServiceCollection(); collection.Scan(scan => scan // We start out with all types in the assembly of ITransientService .FromAssemblyOf<ITransientService>() // AddClasses starts out with all public, non-abstract types in this assembly. // These types are then filtered by the delegate passed to the method. // In this case, we filter out only the classes that are assignable to ITransientService. .AddClasses(classes => classes.AssignableTo<ITransientService>()) // We then specify what type we want to register these classes as. // In this case, we want to register the types as all of its implemented interfaces. // So if a type implements 3 interfaces; A, B, C, we'd end up with three separate registrations. .AsImplementedInterfaces() // And lastly, we specify the lifetime of these registrations. .WithTransientLifetime() // Here we start again, with a new full set of classes from the assembly above. // This time, filtering out only the classes assignable to IScopedService. .AddClasses(classes => classes.AssignableTo<IScopedService>()) // Now, we just want to register these types as a single interface, IScopedService. .As<IScopedService>() // And again, just specify the lifetime. .WithScopedLifetime() // Generic interfaces are also supported too, e.g. public interface IOpenGeneric<T> .AddClasses(classes => classes.AssignableTo(typeof(IOpenGeneric<>))) .AsImplementedInterfaces() // And you scan generics with multiple type parameters too // e.g. public interface IQueryHandler<TQuery, TResult> .AddClasses(classes => classes.AssignableTo(typeof(IQueryHandler<,>))) .AsImplementedInterfaces()); ``` #### Scanning compiled view (UI) types By default, Scrutor excludes compiler-generated types from the `.AddClasses()` type filters. When loading views from a framework such as [Avalonia UI](https://avaloniaui.net/), we need to opt in to compiler-generated types, like this: ```csharp .AddClasses(classes => classes // Opt-in to compiler-generated types .WithAttribute<CompilerGeneratedAttribute>() // Optionally filter types to reduce number of service registrations. .InNamespaces("MyApp.Desktop.Views") .AssignableToAny( typeof(Window), typeof(UserControl) ) .AsSelf() .WithSingletonLifetime() ``` With some UI frameworks, these compiler-generated views implement quite a few interfaces, so unless you need them, it's probably best to register these classes `.AsSelf()`; in other words, be very precise with your filters that accept compiler generated types. ### Decoration ```csharp var collection = new ServiceCollection(); // First, add our service to the collection. collection.AddSingleton<IDecoratedService, Decorated>(); // Then, decorate Decorated with the Decorator type. collection.Decorate<IDecoratedService, Decorator>(); // Finally, decorate Decorator with the OtherDecorator type. // As you can see, OtherDecorator requires a separate service, IService. We can get that from the provider argument. collection.Decorate<IDecoratedService>((inner, provider) => new OtherDecorator(inner, provider.GetRequiredService<IService>())); var serviceProvider = collection.BuildServiceProvider(); // When we resolve the IDecoratedService service, we'll get the following structure: // OtherDecorator -> Decorator -> Decorated var instance = serviceProvider.GetRequiredService<IDecoratedService>(); ``` ## Sponsors [Entity Framework Extensions](https://entityframework-extensions.net/?utm_source=khellang&utm_medium=Scrutor) and [Dapper Plus](https://dapper-plus.net/?utm_source=khellang&utm_medium=Scrutor) are major sponsors and proud to contribute to the development of Scrutor. [](https://entityframework-extensions.net/bulk-insert?utm_source=khellang&utm_medium=Scrutor) [](https://dapper-plus.net/bulk-insert?utm_source=khellang&utm_medium=Scrutor) ", Assign "at most 3 tags" to the expected json: {"id":"6153","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"