87240238cc
OpenAI gpt-4o-mini-tts (female voice nova by default; TTS_MODEL/TTS_VOICE) renders OGG/Opus, sent with sendVoice in order with rendered output. Up to 4500 characters per call, split into 1500-character parts at paragraph/sentence/word boundaries; all parts are synthesized before any is sent, and API errors come back to the agent as text with the key hidden. On whenever OPENAI_API_KEY is set.
70 lines
3.3 KiB
C#
70 lines
3.3 KiB
C#
using System.Net.Http.Headers;
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using System.Net.Http.Json;
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namespace Volcanic.AgenticCore.Telegram.Speech;
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/// <summary>OpenAI's <c>/audio/speech</c> with <c>response_format=opus</c>, which Telegram shows as a voice note.</summary>
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public sealed class OpenAiTextToSpeech(HttpClient http, SpeechOptions options) : ITextToSpeech
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{
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private const string Prefix = "OpenAI speech synthesis failed: ";
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private const int MaxExcerpt = 200;
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public async Task<byte[]> SynthesizeAsync(string text, string? voice, string? instructions, CancellationToken cancellationToken)
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{
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for (var attempt = 1; ; attempt++)
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{
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try
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{
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return await SynthesizeOnceAsync(text, voice, instructions, cancellationToken).ConfigureAwait(false);
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}
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catch (TextToSpeechException ex) when (ex.IsTransient && attempt < SpeechOptions.MaxAttempts)
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{
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await Task.Delay(options.RetryDelay * (1 << (attempt - 1)), cancellationToken).ConfigureAwait(false);
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}
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}
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}
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private async Task<byte[]> SynthesizeOnceAsync(string text, string? voice, string? instructions, CancellationToken cancellationToken)
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{
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var body = new Dictionary<string, string>
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{
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["model"] = options.ResolvedTtsModel,
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["input"] = text,
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["voice"] = string.IsNullOrWhiteSpace(voice) ? options.ResolvedTtsVoice : voice.Trim(),
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["response_format"] = "opus",
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};
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var tone = string.IsNullOrWhiteSpace(instructions) ? options.TtsInstructions : instructions.Trim();
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if (!string.IsNullOrWhiteSpace(tone)) body["instructions"] = tone.Trim();
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using var request = new HttpRequestMessage(HttpMethod.Post, options.BaseUrl.TrimEnd('/') + "/audio/speech")
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{
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Content = JsonContent.Create(body),
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};
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request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", options.ApiKey);
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try
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{
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using var response = await http.SendAsync(request, cancellationToken).ConfigureAwait(false);
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if (response.IsSuccessStatusCode)
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{
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var audio = await response.Content.ReadAsByteArrayAsync(cancellationToken).ConfigureAwait(false);
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return audio.Length > 0 ? audio : throw new TextToSpeechException(Prefix + "the response is empty.");
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}
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var error = Hide(await response.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false)); // hide before cutting
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var excerpt = error.Length > MaxExcerpt ? error[..MaxExcerpt] : error;
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var status = (int)response.StatusCode;
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throw new TextToSpeechException($"{Prefix}HTTP {status} {excerpt}".TrimEnd()) { IsTransient = status is 408 or 429 or >= 500 };
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}
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catch (OperationCanceledException ex) when (!cancellationToken.IsCancellationRequested) // HttpClient.Timeout
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{
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throw new TextToSpeechException(Prefix + "the request timed out.", ex) { IsTransient = true };
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}
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catch (HttpRequestException ex)
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{
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throw new TextToSpeechException(Prefix + Hide(ex.Message), ex) { IsTransient = true };
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}
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}
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private string Hide(string text) =>
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string.IsNullOrEmpty(options.ApiKey) ? text : text.Replace(options.ApiKey, "[REDACTED]", StringComparison.Ordinal);
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}
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