Add usage details to streaming chat completions (#47)

Sources/OpenAI/AIProxy/AIProxyService.swift

@@ -81,6 +81,7 @@ struct AIProxyService: OpenAIService {
  {
  var chatParameters = parameters
  chatParameters.stream = true
+ chatParameters.streamOptions = .init(includeUsage: true)
  let request = try await OpenAIAPI.chat.request(aiproxyPartialKey: partialKey, organizationID: organizationID, method: .post, params: chatParameters, deviceCheckBypass: deviceCheckBypass)
  return try await fetchStream(type: ChatCompletionChunkObject.self, with: request)
  }

Sources/OpenAI/Azure/DefaultOpenAIAzureService.swift

@@ -58,6 +58,7 @@ final public class DefaultOpenAIAzureService: OpenAIService {
  public func startStreamedChat(parameters: ChatCompletionParameters) async throws -> AsyncThrowingStream<ChatCompletionChunkObject, Error> {
  var chatParameters = parameters
  chatParameters.stream = true
+ chatParameters.streamOptions = .init(includeUsage: true)
  let request = try AzureOpenAIAPI.chat(deploymentID: parameters.model).request(
  apiKey: apiKey,
  organizationID: nil,

Sources/OpenAI/Public/Parameters/Chat/ChatCompletionParameters.swift

@@ -56,6 +56,8 @@ public struct ChatCompletionParameters: Encodable {
  /// If set, partial message deltas will be sent, like in ChatGPT. Tokens will be sent as data-only [server-sent events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#event_stream_format) as they become available, with the stream terminated by a data: [DONE] message. [Example Python code](https://cookbook.openai.com/examples/how_to_stream_completions ).
  /// Defaults to false.
  var stream: Bool? = nil
+ /// Options for streaming response. Only set this when you set stream: true
+ var streamOptions: StreamOptions?
  /// What sampling temperature to use, between 0 and 2. Higher values like 0.8 will make the output more random, while lower values like 0.2 will make it more focused and deterministic.
  /// We generally recommend altering this or `top_p` but not both. Defaults to 1.
  public var temperature: Double?
@@ -416,6 +418,18 @@ public struct ChatCompletionParameters: Encodable {
  }
  }
 
+ public struct StreamOptions: Encodable {
+ /// If set, an additional chunk will be streamed before the data: [DONE] message.
+ /// The usage field on this chunk shows the token usage statistics for the entire request,
+ /// and the choices field will always be an empty array. All other chunks will also include
+ /// a usage field, but with a null value.
+ let includeUsage: Bool
+
+ enum CodingKeys: String, CodingKey {
+ case includeUsage = "include_usage"
+ }
+ }
+
  enum CodingKeys: String, CodingKey {
  case messages
  case model
@@ -434,6 +448,7 @@ public struct ChatCompletionParameters: Encodable {
  case seed
  case stop
  case stream
+ case streamOptions = "stream_options"
  case temperature
  case topP = "top_p"
  case user

Sources/OpenAI/Public/Service/DefaultOpenAIService.swift

@@ -77,6 +77,7 @@ struct DefaultOpenAIService: OpenAIService {
  {
  var chatParameters = parameters
  chatParameters.stream = true
+ chatParameters.streamOptions = .init(includeUsage: true)
  let request = try OpenAIAPI.chat.request(apiKey: apiKey, organizationID: organizationID, method: .post, params: chatParameters)
  return try await fetchStream(type: ChatCompletionChunkObject.self, with: request)
  }