From 82642f25bc72c004ddb3be23238f6dedd5950285 Mon Sep 17 00:00:00 2001
From: Marcello Lamonaca <marcello@lamonaca.eu>
Date: Fri, 13 May 2022 19:50:12 +0200
Subject: [PATCH] Add minimal api filter notes

---
 dotnet/asp.net/minimal-api.md | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/dotnet/asp.net/minimal-api.md b/dotnet/asp.net/minimal-api.md
index b05da45..07d6143 100644
--- a/dotnet/asp.net/minimal-api.md
+++ b/dotnet/asp.net/minimal-api.md
@@ -139,6 +139,25 @@ app.MapGet("/todos/{id}", async Results<Ok<Todo>, NotFound> (int id, TodoDb db)
 });
 ```
 
+## Filters
+
+```cs
+public class ExampleFilter : IRouteHandlerFilter
+{
+    public async ValueTask<object?> InvokeAsync(RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next)
+    {
+        // before endpoint call
+        var result = next(context);
+        /// after endpoint call
+        return result;
+    }
+}
+```
+
+```cs
+app.MapPost("/route", Handler).AddFilter<ExampleFilter>();
+```
+
 ## Context
 
 With Minimal APIs it's possible to access the contextual information by passing one of the following types as a parameter to your handler delegate: