PrivateChat/server/dist/whisper-transcriber.js

import { spawn } from 'node:child_process';
import { createInterface } from 'node:readline';
export class WhisperTranscriber {
    options;
    logger;
    worker = null;
    readyPromise = null;
    resolveReady = null;
    rejectReady = null;
    pendingRequests = new Map();
    constructor(options, logger) {
        this.options = options;
        this.logger = logger;
    }
    async transcribe(requestId, audioPath) {
        await this.ensureWorker();
        if (!this.worker || this.worker.stdin.destroyed) {
            throw new Error('The Whisper worker is not available.');
        }
        return new Promise((resolve, reject) => {
            this.pendingRequests.set(requestId, { resolve, reject });
            try {
                this.worker?.stdin.write(`${JSON.stringify({ type: 'transcribe', requestId, audioPath })}\n`);
            }
            catch (error) {
                this.pendingRequests.delete(requestId);
                reject(error);
            }
        });
    }
    async ensureWorker() {
        if (this.readyPromise) {
            return this.readyPromise;
        }
        this.worker = spawn(this.options.pythonExecutable, [
            this.options.scriptPath,
            '--model',
            this.options.model,
            '--device',
            this.options.device,
            '--compute-type',
            this.options.computeType,
        ], { stdio: ['pipe', 'pipe', 'pipe'] });
        this.readyPromise = new Promise((resolve, reject) => {
            this.resolveReady = resolve;
            this.rejectReady = reject;
        });
        const stdout = createInterface({ input: this.worker.stdout });
        stdout.on('line', (line) => {
            this.handleWorkerLine(line);
        });
        this.worker.stderr.on('data', (chunk) => {
            const message = chunk.toString().trim();
            if (message) {
                this.logger.warn({ whisperStderr: message }, 'Whisper worker stderr');
            }
        });
        this.worker.on('error', (error) => {
            this.failWorker(error instanceof Error ? error : new Error('The Whisper worker could not start.'));
        });
        this.worker.on('exit', (code, signal) => {
            this.failWorker(new Error(`The Whisper worker exited unexpectedly (code=${code ?? 'null'}, signal=${signal ?? 'null'}).`));
        });
        return this.readyPromise;
    }
    handleWorkerLine(line) {
        let payload;
        try {
            payload = JSON.parse(line);
        }
        catch {
            this.logger.warn({ whisperStdout: line }, 'Ignored non-JSON Whisper worker output');
            return;
        }
        if (payload.type === 'ready') {
            this.logger.info({ model: payload.model }, 'Whisper worker ready');
            this.resolveReady?.();
            this.resolveReady = null;
            this.rejectReady = null;
            return;
        }
        if (payload.type === 'fatal') {
            this.failWorker(new Error(payload.message));
            return;
        }
        if (payload.type === 'error') {
            if (!payload.requestId) {
                this.failWorker(new Error(payload.message));
                return;
            }
            const pendingRequest = this.pendingRequests.get(payload.requestId);
            if (!pendingRequest) {
                return;
            }
            this.pendingRequests.delete(payload.requestId);
            pendingRequest.reject(new Error(payload.message));
            return;
        }
        const pendingRequest = this.pendingRequests.get(payload.requestId);
        if (!pendingRequest) {
            return;
        }
        this.pendingRequests.delete(payload.requestId);
        pendingRequest.resolve(payload.text.trim());
    }
    failWorker(error) {
        if (this.worker) {
            this.worker.removeAllListeners();
            this.worker = null;
        }
        this.rejectReady?.(error);
        this.resolveReady = null;
        this.rejectReady = null;
        this.readyPromise = null;
        for (const { reject } of this.pendingRequests.values()) {
            reject(error);
        }
        this.pendingRequests.clear();
        this.logger.error({ err: error }, 'Whisper worker failed');
    }
}