From 3b79e9cf7ef6355251a927529e9c105f39c314d5 Mon Sep 17 00:00:00 2001
From: Mads Larsen <hylkegaard@gmail.com>
Date: Sat, 20 Sep 2025 16:50:09 +0200
Subject: [PATCH] feat: configure enum as string

---
 .../Extensions/OpenApiOptionsExtensions.cs    | 18 ++++++++++++-
 ...beAllEnumsAsStringsSchemaTransformation.cs | 27 +++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 src/OpenApi.Extensions/Schemas/DescribeAllEnumsAsStringsSchemaTransformation.cs

diff --git a/src/OpenApi.Extensions/Extensions/OpenApiOptionsExtensions.cs b/src/OpenApi.Extensions/Extensions/OpenApiOptionsExtensions.cs
index 67f8ecb..7175a6b 100644
--- a/src/OpenApi.Extensions/Extensions/OpenApiOptionsExtensions.cs
+++ b/src/OpenApi.Extensions/Extensions/OpenApiOptionsExtensions.cs
@@ -8,6 +8,7 @@
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Models;
 using OpenApi.Extensions.Options;
+using OpenApi.Extensions.Schemas;
 using OpenApi.Extensions.Transformers;
 using OpenApi.Extensions.Transformers.Documents;
 using OpenApi.Extensions.Transformers.Operations;
@@ -42,7 +43,11 @@ public static OpenApiOptions AddOAuth2ImplicitFlow(this OpenApiOptions options,
         var opt = new ImplicitFlowOptions();
         configure(opt);
 
-        options.AddDocumentTransformer(new OAuth2ImplicitFlowDocumentTransformation(opt.SecurityScheme, opt.TokenEndpoint, opt.AuthorizationEndpoint, opt.Description, opt.Scopes));
+        options.AddDocumentTransformer(new OAuth2ImplicitFlowDocumentTransformation(opt.SecurityScheme,
+            opt.TokenEndpoint,
+            opt.AuthorizationEndpoint,
+            opt.Description,
+            opt.Scopes));
         return options;
     }
 
@@ -495,6 +500,17 @@ public static OpenApiOptions AddType<TConcrete, TType>(this OpenApiOptions optio
         return options;
     }
 
+    /// <summary>
+    /// Instructs the generator to represent all enum values as strings rather than their numeric values in the generated OpenAPI specification.
+    /// </summary>
+    /// <param name="options">The OpenAPI options to configure.</param>
+    /// <returns>The updated <see cref="OpenApiOptions"/> instance.</returns>
+    public static OpenApiOptions DescribeAllEnumsAsStrings(this OpenApiOptions options)
+    {
+        options.AddSchemaTransformer<DescribeAllEnumsAsStringsSchemaTransformation>();
+        return options;
+    }
+
     private static string FormatJson<T>(T obj, JsonSerializerOptions? jsonSerializerOptions)
     {
         var formatToJson = JsonSerializer.Serialize(obj, jsonSerializerOptions);
diff --git a/src/OpenApi.Extensions/Schemas/DescribeAllEnumsAsStringsSchemaTransformation.cs b/src/OpenApi.Extensions/Schemas/DescribeAllEnumsAsStringsSchemaTransformation.cs
new file mode 100644
index 0000000..def2295
--- /dev/null
+++ b/src/OpenApi.Extensions/Schemas/DescribeAllEnumsAsStringsSchemaTransformation.cs
@@ -0,0 +1,27 @@
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.OpenApi;
+using Microsoft.OpenApi.Any;
+using Microsoft.OpenApi.Models;
+
+namespace OpenApi.Extensions.Schemas;
+
+public class DescribeAllEnumsAsStringsSchemaTransformation : IOpenApiSchemaTransformer
+{
+    public Task TransformAsync(OpenApiSchema schema, OpenApiSchemaTransformerContext context, CancellationToken cancellationToken)
+    {
+        if (context.JsonTypeInfo.Type is { IsEnum: true })
+        {
+            schema.Enum.Clear();
+            Enum.GetNames(context.JsonTypeInfo.Type)
+                .ToList()
+                .ForEach(name => schema.Enum.Add(new OpenApiString($"{name}")));
+
+            schema.Type = "string";
+        }
+
+        return Task.CompletedTask;
+    }
+}