Add support for creating embeddings with OpenAI API. (#104)

src/ChatGptNet/ChatGptClient.cs

@@ -53,6 +53,25 @@ public async Task<Guid> SetupAsync(Guid conversationId, string message, Cancella
         return conversationId;
     }
 
+    public async Task<ChatGptEmbeddingResponse> CreateEmbeddingAsync(string message, string[]? messages = null, string? model = null, CancellationToken cancellationToken = default)
+    {
+        if (message == null && (messages == null || messages.Length < 1))
+            throw new ArgumentException($"Either ${nameof(message)} or {nameof(messages)} must be supplied");
+        var request = CreateEmbeddingsRequest(message, messages, model);
+        var requestUri = options.ServiceConfiguration.GetEmbeddingsEndpoint(model ?? options.DefaultModel);
+        using var httpResponse = await httpClient.PostAsJsonAsync(requestUri, request, jsonSerializerOptions, cancellationToken);
+
+        var response = await httpResponse.Content.ReadFromJsonAsync<ChatGptEmbeddingResponse>(jsonSerializerOptions, cancellationToken: cancellationToken);
+        NormalizeEmbeddingResponse(httpResponse, response!, model ?? options.DefaultModel);
+
+        if (!response!.IsSuccessful && options.ThrowExceptionOnError)
+        {
+            throw new ChatGptException(response.Error, httpResponse.StatusCode);
+        }
+
+        return response;
+    }
+
     public async Task<ChatGptResponse> AskAsync(Guid conversationId, string message, ChatGptFunctionParameters? functionParameters = null, ChatGptParameters? parameters = null, string? model = null, bool addToConversationHistory = true, CancellationToken cancellationToken = default)
     {
         ArgumentNullException.ThrowIfNull(message);
@@ -301,6 +320,13 @@ private async Task<IList<ChatGptMessage>> CreateMessageListAsync(Guid conversati
         return messages;
     }
 
+    private ChatGptEmbeddingsRequest CreateEmbeddingsRequest(string? message, string[]? messages, string? model = null)
+    => new()
+    {
+        Model = model ?? options.DefaultModel,
+        Input = message != null ? new string[] { message } : messages
+    };
+
     private ChatGptRequest CreateRequest(IEnumerable<ChatGptMessage> messages, ChatGptFunctionParameters? functionParameters, bool stream, ChatGptParameters? parameters, string? model)
         => new()
         {
@@ -379,4 +405,26 @@ private static void NormalizeResponse(HttpResponseMessage httpResponse, ChatGptR
             response.Error.StatusCode = (int)httpResponse.StatusCode;
         }
     }
+
+    private static void NormalizeEmbeddingResponse(HttpResponseMessage httpResponse, ChatGptEmbeddingResponse response, string? model)
+    {
+        if (string.IsNullOrWhiteSpace(response.Model) && model is not null)
+        {
+            response.Model = model;
+        }
+
+        if (!httpResponse.IsSuccessStatusCode && response.Error is null)
+        {
+            response.Error = new ChatGptError
+            {
+                Message = httpResponse.ReasonPhrase ?? httpResponse.StatusCode.ToString(),
+                Code = ((int)httpResponse.StatusCode).ToString()
+            };
+        }
+
+        if (response.Error is not null)
+        {
+            response.Error.StatusCode = (int)httpResponse.StatusCode;
+        }
+    }
 }

src/ChatGptNet/Models/ChatGptEmbedding.cs

@@ -0,0 +1,22 @@
+namespace ChatGptNet.Models;
+
+/// <summary>
+/// Represents an embedding.
+/// </summary>
+public class ChatGptEmbedding
+{
+    /// <summary>
+    /// Gets or sets the index of the embedding.
+    /// </summary>
+    public int Index { get; set; } = 0;
+
+    /// <summary>
+    /// Gets or sets the source object for this response.
+    /// </summary>
+    public string Object { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the embedding data
+    /// </summary>
+    public float[] Embedding { get; set; } = Array.Empty<float>();
+}

src/ChatGptNet/Models/ChatGptEmbeddingResponse.cs

@@ -0,0 +1,48 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace ChatGptNet.Models;
+
+/// <summary>
+/// Represents an embedding response.
+/// </summary>
+public class ChatGptEmbeddingResponse
+{
+    /// <summary>
+    /// Gets or sets the Id of the response.
+    /// </summary>
+    public string Id { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the source object for this response.
+    /// </summary>
+    public string Object { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the model name that has been used to generate the response.
+    /// </summary>
+    public string Model { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the error occurred during the chat completion execution, if any.
+    /// </summary>
+    public ChatGptError? Error { get; set; }
+
+    /// <summary>
+    /// Gets or sets information about token usage.
+    /// </summary>
+    /// <remarks>
+    /// The <see cref="Usage"/> property is always <see langword="null"/> when requesting response streaming with <see cref="ChatGptClient.AskStreamAsync(Guid, string, ChatGptParameters?, string?, bool, CancellationToken)"/>.
+    /// </remarks>
+    public ChatGptUsage? Usage { get; set; }
+
+    /// <summary>
+    /// Gets a value that determines if the response was successful.
+    /// </summary>
+    [MemberNotNullWhen(false, nameof(Error))]
+    public bool IsSuccessful => Error is null;
+
+    /// <summary>
+    /// Array of Embedding objects created by ChatGpt
+    /// </summary>
+    public ChatGptEmbedding[] Data { get; set; } = Array.Empty<ChatGptEmbedding>();
+}

src/ChatGptNet/Models/ChatGptEmbeddingsRequest.cs

@@ -0,0 +1,23 @@
+namespace ChatGptNet.Models;
+
+/// <summary>
+/// Represents a request for create embeddings request.
+/// </summary>
+/// <remarks>
+/// See <see href="https://platform.openai.com/docs/api-reference/embeddings/create">Create embeddings (OpenAI)</see> or <see href="https://learn.microsoft.com/en-us/azure/ai-services/openai/how-to/embeddings?tabs=console">Embeddings basics (Azure)</see> for more information.
+/// </remarks>
+internal class ChatGptEmbeddingsRequest
+{
+    /// <summary>
+    /// Gets or sets the ID of the model to use.
+    /// </summary>
+    public string? Model { get; set; }
+
+    /// <summary>
+    /// Gets or sets the messages array to generate embeddings for.
+    /// </summary>
+    /// <seealso cref="Input"/>
+    public string[]? Input { get; set; }
+
+    public string? User { get; set; }
+}

src/ChatGptNet/ServiceConfigurations/AzureChatGptServiceConfiguration.cs

@@ -84,6 +84,9 @@ public override Uri GetServiceEndpoint(string? modelName)
         return endpoint;
     }
 
+    /// <inheritdoc />
+    public override Uri GetEmbeddingsEndpoint(string? modelName = null) => throw new NotImplementedException();
+
     /// <inheritdoc />
     public override IDictionary<string, string?> GetRequestHeaders()
     {

src/ChatGptNet/ServiceConfigurations/ChatGptServiceConfiguration.cs

@@ -19,6 +19,13 @@ internal abstract class ChatGptServiceConfiguration
     /// <returns>The <see cref="Uri"/> of the service.</returns>
     public abstract Uri GetServiceEndpoint(string? modelName = null);
 
+    /// <summary>
+    /// Returns the <see cref="Uri"/> that creates embeddings.
+    /// </summary>
+    /// <param name="modelName">The name of the model for embeddings.</param>
+    /// <returns>The <see cref="Uri"/> of the service.</returns>
+    public abstract Uri GetEmbeddingsEndpoint(string? modelName = null);
+
     /// <summary>
     /// Returns the headers that are required by the service to complete the request.
     /// </summary>

src/ChatGptNet/ServiceConfigurations/OpenAIChatGptServiceConfiguration.cs

@@ -28,6 +28,9 @@ public OpenAIChatGptServiceConfiguration(IConfiguration configuration)
     /// <inheritdoc />
     public override Uri GetServiceEndpoint(string? _) => new("https://api.openai.com/v1/chat/completions");
 
+    /// <inheritdoc />
+    public override Uri GetEmbeddingsEndpoint(string? _) => new("https://api.openai.com/v1/embeddings");
+
     /// <inheritdoc />
     public override IDictionary<string, string?> GetRequestHeaders()
     {