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| title | author | description | monikerRange | ms.author | ms.custom | ms.date | uid |
|---|---|---|---|---|---|---|---|
| Factory-based middleware activation in ASP.NET Core | guardrex | Learn how to use strongly-typed middleware with a factory-based activation implementation in ASP.NET Core. | >= aspnetcore-2.1 | riande | mvc | 09/22/2019 | fundamentals/middleware/extensibility |
Factory-based middleware activation in ASP.NET Core
By Luke Latham
::: moniker range=">= aspnetcore-3.0"
xref:Microsoft.AspNetCore.Http.IMiddlewareFactory/xref:Microsoft.AspNetCore.Http.IMiddleware is an extensibility point for middleware activation.
xref:Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.UseMiddleware* extension methods check if a middleware's registered type implements xref:Microsoft.AspNetCore.Http.IMiddleware. If it does, the xref:Microsoft.AspNetCore.Http.IMiddlewareFactory instance registered in the container is used to resolve the xref:Microsoft.AspNetCore.Http.IMiddleware implementation instead of using the convention-based middleware activation logic. The middleware is registered as a scoped or transient service in the app's service container.
Benefits:
- Activation per client request (injection of scoped services)
- Strong typing of middleware
xref:Microsoft.AspNetCore.Http.IMiddleware is activated per client request (connection), so scoped services can be injected into the middleware's constructor.
View or download sample code (how to download)
IMiddleware
xref:Microsoft.AspNetCore.Http.IMiddleware defines middleware for the app's request pipeline. The InvokeAsync(HttpContext, RequestDelegate) method handles requests and returns a xref:System.Threading.Tasks.Task that represents the execution of the middleware.
Middleware activated by convention:
Middleware activated by xref:Microsoft.AspNetCore.Http.MiddlewareFactory:
Extensions are created for the middlewares:
It isn't possible to pass objects to the factory-activated middleware with xref:Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.UseMiddleware*:
public static IApplicationBuilder UseFactoryActivatedMiddleware(
this IApplicationBuilder builder, bool option)
{
// Passing 'option' as an argument throws a NotSupportedException at runtime.
return builder.UseMiddleware<FactoryActivatedMiddleware>(option);
}
The factory-activated middleware is added to the built-in container in Startup.ConfigureServices:
Both middlewares are registered in the request processing pipeline in Startup.Configure:
IMiddlewareFactory
xref:Microsoft.AspNetCore.Http.IMiddlewareFactory provides methods to create middleware. The middleware factory implementation is registered in the container as a scoped service.
The default xref:Microsoft.AspNetCore.Http.IMiddlewareFactory implementation, xref:Microsoft.AspNetCore.Http.MiddlewareFactory, is found in the Microsoft.AspNetCore.Http package.
::: moniker-end
::: moniker range="< aspnetcore-3.0"
xref:Microsoft.AspNetCore.Http.IMiddlewareFactory/xref:Microsoft.AspNetCore.Http.IMiddleware is an extensibility point for middleware activation.
xref:Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.UseMiddleware* extension methods check if a middleware's registered type implements xref:Microsoft.AspNetCore.Http.IMiddleware. If it does, the xref:Microsoft.AspNetCore.Http.IMiddlewareFactory instance registered in the container is used to resolve the xref:Microsoft.AspNetCore.Http.IMiddleware implementation instead of using the convention-based middleware activation logic. The middleware is registered as a scoped or transient service in the app's service container.
Benefits:
- Activation per client request (injection of scoped services)
- Strong typing of middleware
xref:Microsoft.AspNetCore.Http.IMiddleware is activated per client request (connection), so scoped services can be injected into the middleware's constructor.
View or download sample code (how to download)
IMiddleware
xref:Microsoft.AspNetCore.Http.IMiddleware defines middleware for the app's request pipeline. The InvokeAsync(HttpContext, RequestDelegate) method handles requests and returns a xref:System.Threading.Tasks.Task that represents the execution of the middleware.
Middleware activated by convention:
Middleware activated by xref:Microsoft.AspNetCore.Http.MiddlewareFactory:
Extensions are created for the middlewares:
It isn't possible to pass objects to the factory-activated middleware with xref:Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.UseMiddleware*:
public static IApplicationBuilder UseFactoryActivatedMiddleware(
this IApplicationBuilder builder, bool option)
{
// Passing 'option' as an argument throws a NotSupportedException at runtime.
return builder.UseMiddleware<FactoryActivatedMiddleware>(option);
}
The factory-activated middleware is added to the built-in container in Startup.ConfigureServices:
Both middlewares are registered in the request processing pipeline in Startup.Configure:
IMiddlewareFactory
xref:Microsoft.AspNetCore.Http.IMiddlewareFactory provides methods to create middleware. The middleware factory implementation is registered in the container as a scoped service.
The default xref:Microsoft.AspNetCore.Http.IMiddlewareFactory implementation, xref:Microsoft.AspNetCore.Http.MiddlewareFactory, is found in the Microsoft.AspNetCore.Http package.
::: moniker-end