Expose response format conversions for OpenAI types

src/Libraries/Microsoft.Extensions.AI.OpenAI/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## NOT YET RELEASED
 
+- Added M.E.AI to OpenAI conversions for response format types
+
 ## 9.9.0-preview.1.25458.4
 
 - Updated to depend on OpenAI 2.4.0

src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIChatExtensions.cs

@@ -26,6 +26,15 @@ public static class MicrosoftExtensionsAIChatExtensions
     public static ChatTool AsOpenAIChatTool(this AIFunctionDeclaration function) =>
         OpenAIChatClient.ToOpenAIChatTool(Throw.IfNull(function));
 
+    /// <summary>
+    /// Creates an OpenAI <see cref="ChatResponseFormat"/> from a <see cref="Microsoft.Extensions.AI.ChatResponseFormat"/>.
+    /// </summary>
+    /// <param name="format">The format.</param>
+    /// <param name="options">The options to use when interpreting the format.</param>
+    /// <returns>The converted OpenAI <see cref="ChatResponseFormat"/>.</returns>
+    public static ChatResponseFormat? AsOpenAIChatResponseFormat(this Microsoft.Extensions.AI.ChatResponseFormat? format, ChatOptions? options = null) =>
+        OpenAIChatClient.ToOpenAIChatResponseFormat(format, options);
+
     /// <summary>Creates a sequence of OpenAI <see cref="ChatMessage"/> instances from the specified input messages.</summary>
     /// <param name="messages">The input messages to convert.</param>
     /// <param name="options">The options employed while processing <paramref name="messages"/>.</param>

src/Libraries/Microsoft.Extensions.AI.OpenAI/MicrosoftExtensionsAIResponsesExtensions.cs

@@ -21,6 +21,15 @@ public static class MicrosoftExtensionsAIResponsesExtensions
     public static FunctionTool AsOpenAIResponseTool(this AIFunctionDeclaration function) =>
         OpenAIResponsesChatClient.ToResponseTool(Throw.IfNull(function));
 
+    /// <summary>
+    /// Creates an OpenAI <see cref="ResponseTextFormat"/> from a <see cref="ChatResponseFormat"/>.
+    /// </summary>
+    /// <param name="format">The format.</param>
+    /// <param name="options">The options to use when interpreting the format.</param>
+    /// <returns>The converted OpenAI <see cref="ResponseTextFormat"/>.</returns>
+    public static ResponseTextFormat? AsOpenAIResponseTextFormat(this ChatResponseFormat? format, ChatOptions? options = null) =>
+        OpenAIResponsesChatClient.ToOpenAIResponseTextFormat(format, options);
+
     /// <summary>Creates a sequence of OpenAI <see cref="ResponseItem"/> instances from the specified input messages.</summary>
     /// <param name="messages">The input messages to convert.</param>
     /// <param name="options">The options employed while processing <paramref name="messages"/>.</param>

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIChatClient.cs

@@ -582,27 +582,28 @@ private ChatCompletionOptions ToOpenAIOptions(ChatOptions? options)
             }
         }
 
-        if (result.ResponseFormat is null)
-        {
-            if (options.ResponseFormat is ChatResponseFormatText)
-            {
-                result.ResponseFormat = OpenAI.Chat.ChatResponseFormat.CreateTextFormat();
-            }
-            else if (options.ResponseFormat is ChatResponseFormatJson jsonFormat)
-            {
-                result.ResponseFormat = OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema ?
-                    OpenAI.Chat.ChatResponseFormat.CreateJsonSchemaFormat(
-                        jsonFormat.SchemaName ?? "json_schema",
-                        BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, OpenAIJsonContext.Default.JsonElement)),
-                        jsonFormat.SchemaDescription,
-                        OpenAIClientExtensions.HasStrict(options.AdditionalProperties)) :
-                    OpenAI.Chat.ChatResponseFormat.CreateJsonObjectFormat();
-            }
-        }
+        result.ResponseFormat ??= ToOpenAIChatResponseFormat(options.ResponseFormat, options);
 
         return result;
     }
 
+    internal static OpenAI.Chat.ChatResponseFormat? ToOpenAIChatResponseFormat(ChatResponseFormat? format, ChatOptions? options) =>
+        format switch
+        {
+            ChatResponseFormatText => OpenAI.Chat.ChatResponseFormat.CreateTextFormat(),
+
+            ChatResponseFormatJson jsonFormat when OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema =>
+                 OpenAI.Chat.ChatResponseFormat.CreateJsonSchemaFormat(
+                    jsonFormat.SchemaName ?? "json_schema",
+                    BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, OpenAIJsonContext.Default.JsonElement)),
+                    jsonFormat.SchemaDescription,
+                    OpenAIClientExtensions.HasStrict(options?.AdditionalProperties)),
+
+            ChatResponseFormatJson => OpenAI.Chat.ChatResponseFormat.CreateJsonObjectFormat(),
+
+            _ => null
+        };
+
     private static UsageDetails FromOpenAIUsage(ChatTokenUsage tokenUsage)
     {
         var destination = new UsageDetails

src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs

@@ -520,33 +520,32 @@ private ResponseCreationOptions ToOpenAIResponseCreationOptions(ChatOptions? opt
             }
         }
 
-        if (result.TextOptions is null)
+        if (result.TextOptions?.TextFormat is null &&
+            ToOpenAIResponseTextFormat(options.ResponseFormat, options) is { } newFormat)
         {
-            if (options.ResponseFormat is ChatResponseFormatText)
-            {
-                result.TextOptions = new()
-                {
-                    TextFormat = ResponseTextFormat.CreateTextFormat()
-                };
-            }
-            else if (options.ResponseFormat is ChatResponseFormatJson jsonFormat)
-            {
-                result.TextOptions = new()
-                {
-                    TextFormat = OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema ?
-                        ResponseTextFormat.CreateJsonSchemaFormat(
-                            jsonFormat.SchemaName ?? "json_schema",
-                            BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, OpenAIJsonContext.Default.JsonElement)),
-                            jsonFormat.SchemaDescription,
-                            OpenAIClientExtensions.HasStrict(options.AdditionalProperties)) :
-                        ResponseTextFormat.CreateJsonObjectFormat(),
-                };
-            }
+            (result.TextOptions ??= new()).TextFormat = newFormat;
         }
 
         return result;
     }
 
+    internal static ResponseTextFormat? ToOpenAIResponseTextFormat(ChatResponseFormat? format, ChatOptions? options = null) =>
+        format switch
+        {
+            ChatResponseFormatText => ResponseTextFormat.CreateTextFormat(),
+
+            ChatResponseFormatJson jsonFormat when OpenAIClientExtensions.StrictSchemaTransformCache.GetOrCreateTransformedSchema(jsonFormat) is { } jsonSchema =>
+                ResponseTextFormat.CreateJsonSchemaFormat(
+                    jsonFormat.SchemaName ?? "json_schema",
+                    BinaryData.FromBytes(JsonSerializer.SerializeToUtf8Bytes(jsonSchema, OpenAIJsonContext.Default.JsonElement)),
+                    jsonFormat.SchemaDescription,
+                    OpenAIClientExtensions.HasStrict(options?.AdditionalProperties)),
+
+            ChatResponseFormatJson => ResponseTextFormat.CreateJsonObjectFormat(),
+
+            _ => null,
+        };
+
     /// <summary>Convert a sequence of <see cref="ChatMessage"/>s to <see cref="ResponseItem"/>s.</summary>
     internal static IEnumerable<ResponseItem> ToOpenAIResponseItems(IEnumerable<ChatMessage> inputs, ChatOptions? options)
     {

test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs

@@ -2,10 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.ClientModel.Primitives;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
 using System.Text.Json;
+using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 using OpenAI.Assistants;
 using OpenAI.Chat;
@@ -22,6 +24,75 @@ public class OpenAIConversionTests
         "test_function",
         "A test function for conversion");
 
+    [Fact]
+    public void AsOpenAIChatResponseFormat_HandlesVariousFormats()
+    {
+        Assert.Null(MicrosoftExtensionsAIChatExtensions.AsOpenAIChatResponseFormat(null));
+
+        var text = MicrosoftExtensionsAIChatExtensions.AsOpenAIChatResponseFormat(ChatResponseFormat.Text);
+        Assert.NotNull(text);
+        Assert.Equal("""{"type":"text"}""", ((IJsonModel<OpenAI.Chat.ChatResponseFormat>)text).Write(ModelReaderWriterOptions.Json).ToString());
+
+        var json = MicrosoftExtensionsAIChatExtensions.AsOpenAIChatResponseFormat(ChatResponseFormat.Json);
+        Assert.NotNull(json);
+        Assert.Equal("""{"type":"json_object"}""", ((IJsonModel<OpenAI.Chat.ChatResponseFormat>)json).Write(ModelReaderWriterOptions.Json).ToString());
+
+        var jsonSchema = ChatResponseFormat.ForJsonSchema(typeof(int), schemaName: "my_schema", schemaDescription: "A test schema").AsOpenAIChatResponseFormat();
+        Assert.NotNull(jsonSchema);
+        Assert.Equal(RemoveWhitespace("""
+            {"type":"json_schema","json_schema":{"description":"A test schema","name":"my_schema","schema":{
+              "$schema": "https://json-schema.org/draft/2020-12/schema",
+              "type": "integer"
+            }}}
+            """), RemoveWhitespace(((IJsonModel<OpenAI.Chat.ChatResponseFormat>)jsonSchema).Write(ModelReaderWriterOptions.Json).ToString()));
+
+        jsonSchema = ChatResponseFormat.ForJsonSchema(typeof(int), schemaName: "my_schema", schemaDescription: "A test schema").AsOpenAIChatResponseFormat(
+            new() { AdditionalProperties = new AdditionalPropertiesDictionary { ["strictJsonSchema"] = true } });
+        Assert.NotNull(jsonSchema);
+        Assert.Equal(RemoveWhitespace("""
+            {
+            "type":"json_schema","json_schema":{"description":"A test schema","name":"my_schema","schema":{
+              "$schema": "https://json-schema.org/draft/2020-12/schema",
+              "type": "integer"
+            },"strict":true}}
+            """), RemoveWhitespace(((IJsonModel<OpenAI.Chat.ChatResponseFormat>)jsonSchema).Write(ModelReaderWriterOptions.Json).ToString()));
+    }
+
+    [Fact]
+    public void AsOpenAIResponseTextFormat_HandlesVariousFormats()
+    {
+        Assert.Null(MicrosoftExtensionsAIResponsesExtensions.AsOpenAIResponseTextFormat(null));
+
+        var text = MicrosoftExtensionsAIResponsesExtensions.AsOpenAIResponseTextFormat(ChatResponseFormat.Text);
+        Assert.NotNull(text);
+        Assert.Equal(ResponseTextFormatKind.Text, text.Kind);
+
+        var json = MicrosoftExtensionsAIResponsesExtensions.AsOpenAIResponseTextFormat(ChatResponseFormat.Json);
+        Assert.NotNull(json);
+        Assert.Equal(ResponseTextFormatKind.JsonObject, json.Kind);
+
+        var jsonSchema = ChatResponseFormat.ForJsonSchema(typeof(int), schemaName: "my_schema", schemaDescription: "A test schema").AsOpenAIResponseTextFormat();
+        Assert.NotNull(jsonSchema);
+        Assert.Equal(ResponseTextFormatKind.JsonSchema, jsonSchema.Kind);
+        Assert.Equal(RemoveWhitespace("""
+            {"type":"json_schema","description":"A test schema","name":"my_schema","schema":{
+              "$schema": "https://json-schema.org/draft/2020-12/schema",
+              "type": "integer"
+            }}
+            """), RemoveWhitespace(((IJsonModel<ResponseTextFormat>)jsonSchema).Write(ModelReaderWriterOptions.Json).ToString()));
+
+        jsonSchema = ChatResponseFormat.ForJsonSchema(typeof(int), schemaName: "my_schema", schemaDescription: "A test schema").AsOpenAIResponseTextFormat(
+            new() { AdditionalProperties = new AdditionalPropertiesDictionary { ["strictJsonSchema"] = true } });
+        Assert.NotNull(jsonSchema);
+        Assert.Equal(ResponseTextFormatKind.JsonSchema, jsonSchema.Kind);
+        Assert.Equal(RemoveWhitespace("""
+            {"type":"json_schema","description":"A test schema","name":"my_schema","schema":{
+              "$schema": "https://json-schema.org/draft/2020-12/schema",
+              "type": "integer"
+            },"strict":true}
+            """), RemoveWhitespace(((IJsonModel<ResponseTextFormat>)jsonSchema).Write(ModelReaderWriterOptions.Json).ToString()));
+    }
+
     [Fact]
     public void AsOpenAIChatTool_ProducesValidInstance()
     {
@@ -1113,4 +1184,6 @@ private static async IAsyncEnumerable<T> CreateAsyncEnumerable<T>(IEnumerable<T>
             yield return item;
         }
     }
+
+    private static string RemoveWhitespace(string input) => Regex.Replace(input, @"\s+", "");
 }