ServiceComposer leverages the Endpoints support to plug into the request handling pipeline. ServiceComposer can be added to existing or new ASP.NET Core projects or hosted in .NET console applications.
Starting with version 5.0, ServiceComposer targets .NET 10 only.
New to ServiceComposer and ViewModel Composition? Start with the getting started guide.
[!NOTE] If resources are shared across more than one handler, they must be thread-safe.
Contract-less composition handlers allow writing composition handlers without implementing a specific interface, using a syntax similar to ASP.NET controller actions. For more information, refer to the contract-less composition handlers section.
ServiceComposer can enhance existing MVC web applications by adding composition support to Controllers. For more information, refer to the composition over controllers section.
When handling composition requests, there are scenarios in which request handlers need to offload some composition concerns to other handlers. That can be done by publishing events.
By default, ServiceComposer uses C# dynamic object instances to serve view models to request handlers. It’s possible to use strongly typed view models by defining view model factories.
When handling composition requests, it is possible to leverage ASP.NET Model Binding to bind incoming form data, request bodies, query string parameters, or route data to strongly typed C# models. For more information on model binding, refer to the Model Binding section.
The response status code can be set in composition handlers. For more information, refer to the custom HTTP status codes section.
MVC Action results support allows composition handlers to set custom response results for specific scenarios, like, for example, handling bad requests or validation errors. For more information on action results, refer to the MVC Action results section.
By default, ServiceComposer serializes responses using System.Text.Json. The built-in serialization support can be configured to serialize responses using a camel case or pascal case approach on a per-request basis by adding to the request an Accept-Casing custom HTTP header. For more information, refer to the response serialization casing section. Or it’s possible to take full control over the response serialization settings on a case-by-case by supplying at configuration time a customization function.
Starting with version 1.9.0, regular MVC Output Formatters can be used to serialize the response model and honor the Accept HTTP header set by clients. When using output formatters, the serialization casing is controlled by the formatter configuration and not by ServiceComposer. For more information on using output formatters refers to the output formatters serialization section.
By leveraging ASP.NET Core Endpoints, ServiceComposer automatically supports authentication and authorization metadata attributes to express authentication and authorization requirements for routes. For more information, refer to the Authentication and Authorization section.
Endpoint filters allow intercepting all incoming HTTP requests before they reach the composition stage. For more information, refer to the endpoint filters documentation.
Composition request filters allow intercepting composition requests before they are dispatched to composition handlers. For more information, refer to the Composition requests filters documentation.
It’s possible to access and customize ViewModel Composition options at application startup by defining types that implement the IViewModelCompositionOptionsCustomization interface.
ServiceComposer natively supports scatter/gather scenarios through a fanout approach. For more information, refer to the Scatter/Gather section.
ServiceComposer emits OpenTelemetry traces for ViewModel Composition and Scatter/Gather. For more information, refer to the OpenTelemetry section.
Upgrade guides are available to ease the migration from one version to another.