Fix OpenAPI to skip SecurityScheme for [AllowAnonymous] controllers

src/OpenApi/src/PACKAGE.md

@@ -47,6 +47,48 @@ The main types provided by this library are:
 * `OpenApiOptions`: Options for configuring OpenAPI document generation.
 * `IDocumentTransformer`: Transformer that modifies the OpenAPI document generated by the library.
 
+## Customizing Security Schemes
+
+When using `[AllowAnonymous]` on a controller or action, you may want to skip adding security scheme requirements to the OpenAPI document for those endpoints. You can achieve this by implementing a custom `IOpenApiDocumentTransformer` that removes security requirements from endpoints marked with `[AllowAnonymous]`.
+
+### Example
+
+```csharp
+public class SkipAnonymousSecurityTransformer : IOpenApiDocumentTransformer
+{
+    public async Task TransformAsync(
+        OpenApiDocument document,
+        OpenApiDocumentTransformerContext context,
+        CancellationToken cancellationToken)
+    {
+        var allowAnonymousEndpoints = context.EndpointMetadata
+            .OfType<Microsoft.AspNetCore.Authorization.IAllowAnonymous>();
+
+        if (allowAnonymousEndpoints.Any())
+        {
+            foreach (var path in document.Paths.Values)
+            {
+                foreach (var operation in path.Operations.Values)
+                {
+                    operation.Security = null;
+                }
+            }
+        }
+    }
+}
+```
+
+Register this transformer in your `Program.cs`:
+
+```csharp
+builder.Services.AddOpenApi(options =>
+{
+    options.AddDocumentTransformer<SkipAnonymousSecurityTransformer>();
+});
+```
+
+For more information on customizing OpenAPI documents, refer to the [official documentation](https://learn.microsoft.com/aspnet/core/fundamentals/minimal-apis/openapi).
+
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