Available starting with v3.0.0
Endpoint filters allow intercepting all incoming HTTP requests prior to invoking the composition pipeline.
Defining an endpoint filter requires defining a class that implements the IEndpointFilter interface, like in the following snippet:
class SampleEndpointFilter : IEndpointFilter
{
public async ValueTask<object> InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
{
// Do something meaningful prior to invoking the rest of the pipeline
var response = await next(context);
// Do something meaningful with the response
return response;
}
}
For an endpoint filter to be included in te invocation pipeline, it must be registered at application configuration time:
public void Configure(IApplicationBuilder app)
{
app.UseEndpoints(builder =>
{
builder.MapCompositionHandlers()
.AddEndpointFilter(new SampleEndpointFilter());
});
}
The endpoint filters API exposes through the EndpointFilterInvocationContext the list of arguments that the ASP.Net model binding engire determined as needed by the later invoked controller action. When using regular composition handlers, e.g. by implemeting the ICompositionRequestsHandler interface, ServiceComposer cannot determine which arguments are latwer needed by the user composition code. To overcome this limitation and allow the arguments list to be populated and accessible by filters, it’s required to use a declarative model binding approach.