Fonoster MCP Server

/** * Copyright (C) 2025 by Fonoster Inc (https://fonoster.com) * http://github.com/fonoster/fonoster * * This file is part of Fonoster * * Licensed under the MIT License (the "License"); * you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * https://opensource.org/licenses/MIT * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import { Stream } from "stream"; import { SayOptions } from "@fonoster/common"; import { getLogger } from "@fonoster/logger"; import { AudioStream } from "@fonoster/streams"; import { Client } from "ari-client"; import { SpeechResult } from "../stt/types"; import { AriEvent, SpeechToText, TextToSpeech } from "../types"; const logger = getLogger({ service: "apiserver", filePath: __filename }); class SpeechHandler { private tts: TextToSpeech; private stt: SpeechToText; private ari: Client; private transcriptionsStream: Stream; private audioStream: AudioStream; private sessionRef: string; constructor(params: { tts: TextToSpeech; stt: SpeechToText; ari: Client; transcriptionsStream: Stream; audioStream: AudioStream; sessionRef: string; }) { this.tts = params.tts; this.stt = params.stt; this.ari = params.ari; this.transcriptionsStream = params.transcriptionsStream; this.audioStream = params.audioStream; this.sessionRef = params.sessionRef; } async synthesize(text: string, options: SayOptions): Promise<string> { const { ref, stream } = this.tts.synthesize(text, options); logger.verbose("starting audio synthesis", { ref }); try { // Stop any active stream this.audioStream.stop(); await this.audioStream.playStream(stream); } catch (error) { logger.error(`stream error for ref ${ref}: ${error.message}`, { errorDetails: error.stack || "No stack trace" }); } return ref; } async stopSynthesis(): Promise<void> { this.audioStream.stop(); } async transcribe(): Promise<SpeechResult> { try { return await this.stt.transcribe(this.transcriptionsStream); } catch (e) { logger.warn("transcription error", e); return {} as unknown as SpeechResult; } } startSpeechGather( callback: (stream: { speech: string; responseTime: number }) => void ): void { const out = this.stt.streamTranscribe(this.transcriptionsStream); out.on("data", callback); out.on("error", async (error) => { logger.error("speech recognition error", { error }); await this.ari.channels.hangup({ channelId: this.sessionRef }); }); } async startDtmfGather( callback: (event: { digit: string }) => void ): Promise<void> { const channel = await this.ari.channels.get({ channelId: this.sessionRef }); channel.on(AriEvent.CHANNEL_DTMF_RECEIVED, (event) => { const { digit } = event; callback({ digit }); }); } // Returns a promise that resolves when DTMF collection is complete async waitForDtmf(params: { finishOnKey: string; maxDigits: number; timeout: number; onDigitReceived: () => void; }): Promise<{ digits: string }> { const { onDigitReceived, finishOnKey, maxDigits, timeout } = params; let result = ""; let timeoutId = null; const channel = await this.ari.channels.get({ channelId: this.sessionRef }); return new Promise((resolve) => { const resetTimer = () => { if (timeoutId) { clearTimeout(timeoutId); } timeoutId = setTimeout(() => { channel.removeListener(AriEvent.CHANNEL_DTMF_RECEIVED, dtmfListener); resolve({ digits: result }); }, timeout); }; const dtmfListener = (event) => { const { digit } = event; // Stops the global timeout onDigitReceived(); resetTimer(); if (digit !== finishOnKey) { result += digit; } if (result.length >= maxDigits || digit === finishOnKey) { clearTimeout(timeoutId); channel.removeListener(AriEvent.CHANNEL_DTMF_RECEIVED, dtmfListener); resolve({ digits: result }); } }; channel.on(AriEvent.CHANNEL_DTMF_RECEIVED, dtmfListener); resetTimer(); // Start the initial timeout }); } // Placeholder for future implementation stopStreamGather(): void { throw new Error("Method 'stopStreamGather' not implemented."); } } export { SpeechHandler };