Downloading Genesys Cloud Media Recordings via REST API with Node.js

What You Will Build

• This script downloads Genesys Cloud conversation recordings directly to local storage using chunked HTTP range requests and automatic file reassembly.
• It uses the Genesys Cloud REST API endpoints /api/v2/recording/media/{mediaId} and /api/v2/recording/media/{mediaId}/download.
• The implementation uses modern Node.js (ESM) with native fetch, fs, and crypto modules.

Prerequisites

• OAuth 2.0 Client Credentials flow with the recording:read scope
• Genesys Cloud API v2
• Node.js 18.0 or higher (for native fetch support)
• No external npm dependencies required. All logic uses built-in modules.

Authentication Setup

Genesys Cloud requires a valid Bearer token for all API calls. The following client handles token acquisition, caching, and automatic refresh before expiration.

import https from 'node:https';
import { setTimeout } from 'node:timers/promises';

class GenesysAuthClient {
  constructor({ clientId, clientSecret, environment = 'mypurecloud.com' }) {
    this.clientId = clientId;
    this.clientSecret = clientSecret;
    this.baseUrl = `https://api.${environment}`;
    this.token = null;
    this.expiresAt = 0;
  }

  async getAccessToken() {
    if (this.token && Date.now() < this.expiresAt - 60000) {
      return this.token;
    }

    const authHeader = Buffer.from(`${this.clientId}:${this.clientSecret}`).toString('base64');
    const url = `${this.baseUrl}/oauth/token`;
    const params = new URLSearchParams({
      grant_type: 'client_credentials',
      scope: 'recording:read'
    });

    try {
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
          'Authorization': `Basic ${authHeader}`
        },
        body: params
      });

      if (!response.ok) {
        const errorBody = await response.text();
        throw new Error(`OAuth token request failed with status ${response.status}: ${errorBody}`);
      }

      const data = await response.json();
      this.token = data.access_token;
      this.expiresAt = Date.now() + (data.expires_in * 1000);
      return this.token;
    } catch (error) {
      throw new Error(`Authentication failed: ${error.message}`);
    }
  }
}

Required OAuth Scope: recording:read
HTTP Cycle:

• Method: POST
• Path: /oauth/token
• Headers: Authorization: Basic {base64}, Content-Type: application/x-www-form-urlencoded
• Body: grant_type=client_credentials&scope=recording:read
• Response: {"access_token":"eyJhbG...", "expires_in":1800, "token_type":"bearer", "scope":"recording:read"}

Implementation

Step 1: Metadata Retrieval and Schema Validation

Before initiating a download, you must validate the media object against your storage quota, format constraints, and concurrency limits. This step prevents repository exhaustion and ensures the requested format matches Genesys Cloud output capabilities.

class StorageQuotaManager {
  constructor({ maxBytes, maxConcurrent = 3 }) {
    this.maxBytes = maxBytes;
    this.maxConcurrent = maxConcurrent;
    this.usedBytes = 0;
    this.activeDownloads = 0;
  }

  async reserveSpace(sizeInBytes) {
    if (this.activeDownloads >= this.maxConcurrent) {
      throw new Error('Concurrent download limit reached');
    }
    if (this.usedBytes + sizeInBytes > this.maxBytes) {
      throw new Error('Storage quota exceeded');
    }
    this.usedBytes += sizeInBytes;
    this.activeDownloads += 1;
  }

  releaseSpace(sizeInBytes) {
    this.usedBytes -= sizeInBytes;
    this.activeDownloads -= 1;
  }
}

const FORMAT_MATRIX = {
  'audio/wav': { extension: '.wav', supported: true },
  'audio/mpeg': { extension: '.mp3', supported: true },
  'audio/x-wav': { extension: '.wav', supported: true }
};

async function fetchMediaMetadata(authClient, mediaId) {
  const token = await authClient.getAccessToken();
  const response = await fetch(`https://api.mypurecloud.com/api/v2/recording/media/${mediaId}`, {
    headers: { 'Authorization': `Bearer ${token}` }
  });

  if (!response.ok) {
    throw new Error(`Metadata retrieval failed: ${response.status} ${response.statusText}`);
  }

  const metadata = await response.json();
  const formatInfo = FORMAT_MATRIX[metadata.format];

  if (!formatInfo || !formatInfo.supported) {
    throw new Error(`Unsupported recording format: ${metadata.format}`);
  }

  return {
    id: metadata.id,
    format: metadata.format,
    size: metadata.size,
    downloadUrl: metadata.downloadUrl,
    extension: formatInfo.extension
  };
}

Required OAuth Scope: recording:read
Non-obvious parameter: The metadata.size field represents the exact byte count. You must reserve this exact amount before streaming to prevent partial writes that corrupt your storage quota tracking.

Step 2: Streaming Download with Range Requests and Reassembly

Large recordings require chunked retrieval with explicit range directives. The following logic splits the download into configurable chunks, handles HTTP 206 Partial Content responses, and writes bytes to the correct file offsets for automatic reassembly.

import fs from 'node:fs/promises';
import { createWriteStream, openSync, writeSync, closeSync } from 'node:fs';

async function downloadMediaChunks(authClient, downloadUrl, filePath, totalSize, chunkSize = 10 * 1024 * 1024) {
  const fd = openSync(filePath, 'w+');
  let downloadedBytes = 0;

  try {
    while (downloadedBytes < totalSize) {
      const start = downloadedBytes;
      const end = Math.min(start + chunkSize - 1, totalSize - 1);
      const token = await authClient.getAccessToken();

      const response = await fetch(downloadUrl, {
        headers: {
          'Authorization': `Bearer ${token}`,
          'Range': `bytes=${start}-${end}`
        }
      });

      if (response.status === 416) {
        throw new Error('Range not satisfiable. File size may have changed.');
      }
      if (response.status !== 206 && response.status !== 200) {
        throw new Error(`Chunk download failed: ${response.status} ${response.statusText}`);
      }

      const contentLength = response.headers.get('content-length');
      const actualChunkSize = parseInt(contentLength, 10) || (end - start + 1);

      const buffer = Buffer.alloc(actualChunkSize);
      let offset = 0;
      const reader = response.body.getReader();

      while (true) {
        const { done, value } = await reader.read();
        if (done) break;
        buffer.set(value, offset);
        offset += value.length;
      }

      writeSync(fd, buffer, 0, buffer.length, start);
      downloadedBytes += buffer.length;
    }
  } finally {
    closeSync(fd);
  }
}

Required OAuth Scope: recording:read
Edge case handling: Genesys Cloud returns 206 Partial Content for valid range requests. If the server returns 200 OK, it ignores the range header and sends the full file. The code above handles both gracefully by reading the response body into a pre-allocated buffer and writing at the correct offset.

Step 3: Integrity Verification and Webhook Synchronization

After reassembly, you must validate the file against MIME signatures and compute a cryptographic hash. Corruption detection prevents playback failures during quality review. Upon successful validation, the system triggers a webhook to synchronize with external transcription services.

import crypto from 'node:crypto';

const MAGIC_BYTES = {
  'audio/wav': [0x52, 0x49, 0x46, 0x46], // RIFF
  'audio/mpeg': [0x49, 0x44, 0x33, 0x03]  // ID3v2
};

async function validateAndNotify(filePath, format, webhookUrl, metadata) {
  const stats = await fs.stat(filePath);
  const fileBuffer = await fs.readFile(filePath);

  // MIME signature verification
  const expectedMagic = MAGIC_BYTES[format];
  if (expectedMagic && !expectedMagic.every((byte, i) => fileBuffer[i] === byte)) {
    throw new Error('File magic bytes do not match expected format. Recording may be corrupted.');
  }

  // Integrity hash
  const hash = crypto.createHash('sha256').update(fileBuffer).digest('hex');

  // Webhook synchronization
  const payload = {
    event: 'recording_downloaded',
    mediaId: metadata.id,
    filePath: filePath,
    format: format,
    size: stats.size,
    sha256: hash,
    timestamp: new Date().toISOString()
  };

  await fetch(webhookUrl, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(payload)
  });

  return { hash, size: stats.size };
}

Required OAuth Scope: None (local validation and external webhook)
Corruption detection pipeline: The magic byte check catches truncated or mislabeled files immediately. The SHA-256 hash provides a verifiable fingerprint for archival deduplication and compliance audits.

Step 4: Metrics Tracking and Audit Logging

Production downloaders must track latency, success rates, and maintain an immutable audit trail. The following utility manages these metrics without blocking the download pipeline.

class DownloadMetrics {
  constructor() {
    this.logs = [];
  }

  recordEvent(event) {
    this.logs.push({
      ...event,
      recordedAt: new Date().toISOString()
    });
  }

  generateReport() {
    const total = this.logs.length;
    const successes = this.logs.filter(l => l.status === 'success').length;
    const failures = this.logs.filter(l => l.status === 'failure').length;
    const avgLatency = total > 0
      ? this.logs.reduce((acc, l) => acc + (l.latencyMs || 0), 0) / total
      : 0;

    return {
      totalDownloads: total,
      successRate: total > 0 ? (successes / total * 100).toFixed(2) + '%' : '0%',
      averageLatencyMs: avgLatency.toFixed(0),
      failureCount: failures
    };
  }
}

Audit log structure: Each entry contains mediaId, status, latencyMs, error (if applicable), and recordedAt. This structure satisfies compliance verification requirements without requiring external database dependencies.

Complete Working Example

The following script combines all components into a production-ready module. Replace the environment variables with your Genesys Cloud credentials and webhook endpoint.

import fs from 'node:fs/promises';
import path from 'node:path';

// Classes from previous steps would be defined here in a real module
// For this example, they are assumed to be imported or inlined above.

async function main() {
  const CONFIG = {
    clientId: process.env.GENESYS_CLIENT_ID,
    clientSecret: process.env.GENESYS_CLIENT_SECRET,
    environment: process.env.GENESYS_ENV || 'mypurecloud.com',
    mediaId: process.env.TARGET_MEDIA_ID,
    outputDir: process.env.DOWNLOAD_DIR || './recordings',
    webhookUrl: process.env.TRANSCRIPTION_WEBHOOK,
    maxStorageBytes: 10 * 1024 * 1024 * 1024, // 10 GB
    maxConcurrent: 3,
    chunkSize: 10 * 1024 * 1024 // 10 MB chunks
  };

  if (!CONFIG.clientId || !CONFIG.clientSecret || !CONFIG.mediaId) {
    throw new Error('Missing required environment variables');
  }

  const authClient = new GenesysAuthClient(CONFIG);
  const quotaManager = new StorageQuotaManager({
    maxBytes: CONFIG.maxStorageBytes,
    maxConcurrent: CONFIG.maxConcurrent
  });
  const metrics = new DownloadMetrics();

  const startTime = Date.now();
  const eventName = `download_${CONFIG.mediaId}`;

  try {
    await fs.mkdir(CONFIG.outputDir, { recursive: true });

    console.log(`[INFO] Fetching metadata for media ID: ${CONFIG.mediaId}`);
    const metadata = await fetchMediaMetadata(authClient, CONFIG.mediaId);

    console.log(`[INFO] Validating storage quota and format...`);
    await quotaManager.reserveSpace(metadata.size);

    const filePath = path.join(CONFIG.outputDir, `${metadata.id}${metadata.extension}`);
    console.log(`[INFO] Starting chunked download to ${filePath}`);

    await downloadMediaChunks(
      authClient,
      metadata.downloadUrl,
      filePath,
      metadata.size,
      CONFIG.chunkSize
    );

    console.log(`[INFO] Verifying file integrity and triggering webhook...`);
    const { hash, size } = await validateAndNotify(filePath, metadata.format, CONFIG.webhookUrl, metadata);

    const endTime = Date.now();
    const latencyMs = endTime - startTime;

    metrics.recordEvent({
      mediaId: metadata.id,
      status: 'success',
      latencyMs,
      fileSize: size,
      sha256: hash,
      format: metadata.format
    });

    console.log(`[SUCCESS] Download completed. Latency: ${latencyMs}ms. Hash: ${hash}`);
    console.log(JSON.stringify(metrics.generateReport(), null, 2));

  } catch (error) {
    console.error(`[ERROR] Download pipeline failed: ${error.message}`);
    metrics.recordEvent({
      mediaId: CONFIG.mediaId,
      status: 'failure',
      latencyMs: Date.now() - startTime,
      error: error.message
    });
    if (quotaManager.activeDownloads > 0) {
      quotaManager.releaseSpace(metadata?.size || 0);
    }
    process.exit(1);
  }
}

main();

Common Errors & Debugging

Error: 401 Unauthorized

• What causes it: The OAuth token expired, the client credentials are incorrect, or the recording:read scope was omitted during token acquisition.
• How to fix it: Verify GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET match your Genesys Cloud security profile. Ensure the OAuth request body includes scope=recording:read. Implement token refresh logic before expiration as shown in GenesysAuthClient.

Error: 429 Too Many Requests

• What causes it: Genesys Cloud enforces strict rate limits on media downloads. Concurrent streams exceed your organization’s allocation.
• How to fix it: Reduce maxConcurrent in StorageQuotaManager. Implement exponential backoff for retry logic.
• Code showing the fix:

async function fetchWithRetry(url, options, maxRetries = 3) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    const response = await fetch(url, options);
    if (response.status !== 429) return response;
    const retryAfter = parseInt(response.headers.get('retry-after') || '5', 10);
    console.warn(`[WARN] Rate limited. Retrying in ${retryAfter}s (attempt ${attempt})`);
    await setTimeout(retryAfter * 1000);
  }
  throw new Error('Max retries exceeded due to rate limiting');
}

Error: 416 Range Not Satisfiable

• What causes it: The requested byte range exceeds the actual file size, or the file was modified/deleted on the Genesys Cloud side during download.
• How to fix it: Re-fetch metadata to verify metadata.size before retrying. Ensure your range calculation uses Math.min(start + chunkSize - 1, totalSize - 1).

Error: File Magic Bytes Mismatch

• What causes it: The download stream was interrupted, or Genesys Cloud returned an error payload instead of binary audio data.
• How to fix it: Check the HTTP response status before piping to disk. Verify Content-Type matches audio/wav or audio/mpeg. Delete the corrupted file and retry with a fresh token.

Official References

• Genesys Cloud Recording Media API Documentation
• Genesys Cloud OAuth 2.0 Client Credentials Flow
• Node.js Fetch API Reference
• HTTP Range Requests Specification (RFC 7233)