feat: yield events for streaming including custom message complete event
This commit is contained in:
Stevan Freeborn
@@ -0,0 +1,233 @@
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using System.Net.Http.Headers;
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using System.Text;
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using System.Text.Json;
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using AnthropicClient.Json;
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using AnthropicClient.Utils;
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using AnthropicClient.Models;
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namespace AnthropicClient;
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/// <summary>
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/// Represents a client for interacting with the Anthropic API.
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/// </summary>
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public interface IAnthropicApiClient
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{
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/// <summary>
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/// Creates a chat message asynchronously.
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/// </summary>
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/// <param name="request">The chat message request to create.</param>
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/// <returns>A task that represents the asynchronous operation. The task result contains the chat response as an <see cref="AnthropicResult{T}"/>.</returns>
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Task<AnthropicResult<ChatResponse>> CreateChatMessageAsync(ChatMessageRequest request);
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/// <summary>
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/// Creates a chat message asynchronously and streams the response.
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/// </summary>
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/// <param name="request">The chat message request to create.</param>
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/// <returns>An asynchronous enumerable that yields the chat response line by line.</returns>
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IAsyncEnumerable<AnthropicEvent> CreateChatMessageAsync(StreamChatMessageRequest request);
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}
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/// <inheritdoc cref="IAnthropicApiClient"/>
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public class AnthropicApiClient : IAnthropicApiClient
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{
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private const string BaseUrl = "https://api.anthropic.com/v1/";
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private const string ApiKeyHeader = "x-api-key";
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private const string MessagesEndpoint = "messages";
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private const string JsonContentType = "application/json";
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private const string RequestIdHeader = "request-id";
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private const string EventPrefix = "event:";
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private const string DataPrefix = "data:";
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private readonly Dictionary<string, string> _defaultHeaders = new()
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{
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{ "anthropic-version", "2023-06-01" },
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};
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private readonly HttpClient _httpClient;
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/// <summary>
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/// Initializes a new instance of the <see cref="AnthropicApiClient"/> class.
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/// </summary>
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/// <param name="apiKey">The API key to use for the client.</param>
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/// <param name="httpClient">The HTTP client to use for the client.</param>
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/// <exception cref="ArgumentNullException">Thrown when the API key or HTTP client is null.</exception>
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/// <returns>A new instance of the <see cref="AnthropicApiClient"/> class.</returns>
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public AnthropicApiClient(string apiKey, HttpClient httpClient)
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{
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ArgumentValidator.ThrowIfNull(apiKey, nameof(apiKey));
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ArgumentValidator.ThrowIfNull(httpClient, nameof(httpClient));
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_httpClient = httpClient;
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_httpClient.BaseAddress = new Uri(BaseUrl);
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_httpClient.DefaultRequestHeaders.Add(ApiKeyHeader, apiKey);
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_httpClient.DefaultRequestHeaders
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.Accept
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.Add(new MediaTypeWithQualityHeaderValue(JsonContentType));
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foreach (var pair in _defaultHeaders)
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{
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_httpClient.DefaultRequestHeaders.Add(pair.Key, pair.Value);
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}
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}
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/// <inheritdoc />
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public async Task<AnthropicResult<ChatResponse>> CreateChatMessageAsync(ChatMessageRequest request)
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{
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var response = await SendRequestAsync(request);
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var anthropicHeaders = new AnthropicHeaders(response.Headers);
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var responseContent = await response.Content.ReadAsStringAsync();
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if (response.IsSuccessStatusCode is false)
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{
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var error = Deserialize<AnthropicError>(responseContent) ?? new AnthropicError();
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return AnthropicResult<ChatResponse>.Failure(error, anthropicHeaders);
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}
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var chatResponse = Deserialize<ChatResponse>(responseContent) ?? new ChatResponse();
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return AnthropicResult<ChatResponse>.Success(chatResponse, anthropicHeaders);
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}
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/// <inheritdoc />
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public async IAsyncEnumerable<AnthropicEvent> CreateChatMessageAsync(StreamChatMessageRequest request)
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{
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var response = await SendRequestAsync(request);
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var anthropicHeaders = new AnthropicHeaders(response.Headers);
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using var responseContent = await response.Content.ReadAsStreamAsync();
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using var streamReader = new StreamReader(responseContent);
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ChatResponse? chatResponse = null;
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Content? content = null;
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var toolInputJsonStringBuilder = new StringBuilder();
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var currentEvent = new AnthropicEvent();
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do
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{
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var line = await streamReader.ReadLineAsync();
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// I know...this is not pretty, but here is why...
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// as events are being yielded I want to also
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// build up the complete chat response
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// so I can yield it as a special event to make tool
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// calling easier to handle
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// initialize chat response on message start
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if (currentEvent.Type is EventType.MessageStart && currentEvent.Data is MessageStartEventData msgStartData)
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{
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chatResponse = msgStartData.Message;
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}
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// initialize content block on content block start
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if (currentEvent.Type is EventType.ContentBlockStart && currentEvent.Data is ContentStartEventData contentStartData)
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{
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content = contentStartData.ContentBlock;
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}
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// update content block with deltas based on
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// current content type and delta type
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if (currentEvent.Type is EventType.ContentBlockDelta && currentEvent.Data is ContentDeltaEventData contentDeltaData)
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{
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if (content is TextContent textContent && contentDeltaData.Delta is TextDelta textDelta)
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{
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var newText = textContent.Text + textDelta.Text;
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content = new TextContent(newText);
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}
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if (content is ToolUseContent toolUseContent && contentDeltaData.Delta is JsonDelta jsonDelta)
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{
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toolInputJsonStringBuilder.Append(jsonDelta.PartialJson);
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}
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}
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// finalize content block on content block stop
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// and add it to the chat response
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if (currentEvent.Type is EventType.ContentBlockStop)
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{
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if (content is not null && chatResponse is not null)
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{
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if (content is TextContent textContent)
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{
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chatResponse.Content.Add(textContent);
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}
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if (content is ToolUseContent toolUseContent)
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{
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var input = Deserialize<Dictionary<string, object?>>(toolInputJsonStringBuilder.ToString());
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var newToolUseContent = new ToolUseContent()
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{
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Id = toolUseContent.Id,
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Name = toolUseContent.Name,
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Input = input!,
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};
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chatResponse.Content.Add(newToolUseContent);
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}
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content = null;
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}
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}
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// update chat response with message delta data
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if (
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currentEvent.Type is EventType.MessageDelta &&
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currentEvent.Data is MessageDeltaEventData msgDeltaData &&
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chatResponse is not null
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)
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{
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chatResponse = new ChatResponse()
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{
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Id = chatResponse.Id,
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Model = chatResponse.Model,
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Role = chatResponse.Role,
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StopReason = msgDeltaData.Delta.StopReason,
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StopSequence = msgDeltaData.Delta.StopSequence,
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Type = chatResponse.Type,
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Usage = msgDeltaData.Usage,
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Content = chatResponse.Content,
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};
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}
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// yield chat response on message stop
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if (currentEvent.Type is EventType.MessageStop && chatResponse is not null)
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{
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var eventData = new MessageCompleteEventData(chatResponse, anthropicHeaders);
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yield return new AnthropicEvent(EventType.MessageComplete, eventData);
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chatResponse = null;
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}
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if (line is null)
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{
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break;
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}
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if (line == string.Empty)
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{
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yield return currentEvent;
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currentEvent = new AnthropicEvent();
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}
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if (line.StartsWith(EventPrefix))
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{
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var eventType = line.Substring(EventPrefix.Length).Trim();
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currentEvent = new AnthropicEvent(eventType, currentEvent.Data);
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continue;
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}
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if (line.StartsWith(DataPrefix))
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{
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var eventData = line.Substring(DataPrefix.Length).Trim();
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var eventDataJson = Deserialize<EventData>(eventData);
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currentEvent = new AnthropicEvent(currentEvent.Type, eventDataJson!);
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continue;
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}
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} while (true);
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}
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private async Task<HttpResponseMessage> SendRequestAsync(MessageRequest request)
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{
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var requestContent = new StringContent(Serialize(request), Encoding.UTF8, JsonContentType);
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return await _httpClient.PostAsync(MessagesEndpoint, requestContent);
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}
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private string Serialize<T>(T obj) => JsonSerializer.Serialize(obj, JsonSerializationOptions.DefaultOptions);
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private T? Deserialize<T>(string json) => JsonSerializer.Deserialize<T>(json, JsonSerializationOptions.DefaultOptions);
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}
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