feat: add support for dynamic enum values

Author: r-Larch

OpenAi.JsonSchema.Tests/FluentSchemaBuilderTests.cs

@@ -211,6 +211,44 @@ public void Test_array_anyof()
         Assert.NotNull(json);
         Helper.Assert(json);
     }
+
+
+    [Fact]
+    public void Test_dynamic_enum()
+    {
+        var generator = new DefaultSchemaGenerator();
+        var options = new JsonSchemaOptions(SchemaDefaults.OpenAi, Helper.JsonOptionsSnakeCase);
+
+        var schema = generator.Build(options, _ => _
+            .Object(_ => _
+                .Property("answer", _ => _
+                    .Array(_ => _
+                        .AnyOf(
+                            _ => _.Object("Write markdown text.", _ => _
+                                .Property("$type", _ => _.Const("text"))
+                                .Property("content", _ => _.Value<string>())
+                            ),
+                            _ => _.Object("Show a visually appearing widget.", _ => _
+                                .Property("$type", _ => _.Const("widget"))
+                                .Property("id", "Value form widgetId in context.", _ => _.Enum(["widget1", "widget2", "widget3"]))
+                                .Property("comment", "A user-facing `comment`", _ => _.Value<string>())
+                            ),
+                            _ => _.Object("Add a reference to your statement.", _ => _
+                                .Property("$type", _ => _.Const("citation"))
+                                .Property("title", _ => _.Value<string>())
+                                .Property("url", "URL from context.", _ => _.Value<string>())
+                            )
+                        )
+                    )
+                )
+            )
+        );
+
+        var json = schema.ToJson();
+        output.WriteLine(json);
+        Assert.NotNull(json);
+        Helper.Assert(json);
+    }
 }
 
 public record FluentDocument(

OpenAi.JsonSchema.Tests/Output/FluentSchemaBuilderTests.Test_dynamic_enum.json

@@ -0,0 +1,86 @@
+{
+  "type": "object",
+  "properties": {
+    "answer": {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "object",
+            "description": "Write markdown text.",
+            "properties": {
+              "$type": {
+                "type": "string",
+                "const": "text"
+              },
+              "content": {
+                "type": "string"
+              }
+            },
+            "required": [
+              "$type",
+              "content"
+            ],
+            "additionalProperties": false
+          },
+          {
+            "type": "object",
+            "description": "Show a visually appearing widget.",
+            "properties": {
+              "$type": {
+                "type": "string",
+                "const": "widget"
+              },
+              "id": {
+                "type": "string",
+                "description": "Value form widgetId in context.",
+                "enum": [
+                  "widget1",
+                  "widget2",
+                  "widget3"
+                ]
+              },
+              "comment": {
+                "type": "string",
+                "description": "A user-facing \u0060comment\u0060"
+              }
+            },
+            "required": [
+              "$type",
+              "id",
+              "comment"
+            ],
+            "additionalProperties": false
+          },
+          {
+            "type": "object",
+            "description": "Add a reference to your statement.",
+            "properties": {
+              "$type": {
+                "type": "string",
+                "const": "citation"
+              },
+              "title": {
+                "type": "string"
+              },
+              "url": {
+                "type": "string",
+                "description": "URL from context."
+              }
+            },
+            "required": [
+              "$type",
+              "title",
+              "url"
+            ],
+            "additionalProperties": false
+          }
+        ]
+      }
+    }
+  },
+  "required": [
+    "answer"
+  ],
+  "additionalProperties": false
+}

OpenAi.JsonSchema/Fluent/FluentSchemaBuilder.cs

@@ -1,5 +1,6 @@
 using OpenAi.JsonSchema.Generator.Abstractions;
 using OpenAi.JsonSchema.Nodes;
+using System.Text.Json;
 
 
 namespace OpenAi.JsonSchema.Fluent;
@@ -45,6 +46,11 @@ public SchemaNode Value(Type type)
         return Schema(Resolve(type));
     }
 
+    public SchemaNode Enum<T>(T[] values, bool nullable = false)
+    {
+        return SchemaEnumNode.Create(values, nullable, context.Options.JsonSerializerOptions);
+    }
+
     public SchemaNode Object(Action<IFluentObjectSchemaBuilder> properties)
     {
         var type = Resolve(typeof(object));

OpenAi.JsonSchema/Fluent/IFluentSchemaBuilder.cs

@@ -8,6 +8,8 @@ public interface IFluentSchemaBuilder {
     SchemaNode Value<T>();
     SchemaNode Value(Type type);
 
+    public SchemaNode Enum<T>(T[] values, bool nullable = false);
+
     SchemaNode Object(string description, Action<IFluentObjectSchemaBuilder> properties);
     SchemaNode Object(Action<IFluentObjectSchemaBuilder> properties);
 

OpenAi.JsonSchema/Nodes/SchemaEnumNode.cs

@@ -13,10 +13,15 @@ public record SchemaEnumNode(string Type, string[] Values, bool Nullable) : Sche
     public static SchemaEnumNode Create(Type @enum, bool nullable, JsonSerializerOptions options)
     {
         var values = Enum.GetValues(@enum).Cast<object>().ToArray();
+        return Create(values, nullable, options);
+    }
+
 
+    public static SchemaEnumNode Create<T>(T[] values, bool nullable, JsonSerializerOptions options)
+    {
         var jsonValues = values.Select(value => JsonSerializer.Serialize(value, options)).ToArray();
 
-        var kind = jsonValues.Select(_ => JsonValue.Parse(_)!.GetValueKind()).FirstOrDefault();
+        var kind = jsonValues.Select(_ => JsonNode.Parse(_)!.GetValueKind()).FirstOrDefault();
         var type = kind switch {
             JsonValueKind.String => "string",
             JsonValueKind.Number => "integer",