Streaming Genesys Cloud Media Recording Chunks via REST API with Node.js

What You Will Build

A production-grade Node.js module that fetches Genesys Cloud recording streams in configurable byte ranges, validates media integrity via checksums and codec verification, handles network interruptions with automatic resume logic, and synchronizes download events with external archiving systems. This tutorial uses the Genesys Cloud recordings/streams and recordings/media REST endpoints alongside the official JavaScript SDK for OAuth management. The code is written in modern Node.js (ESM) using native fetch, crypto, and events.

Prerequisites

• OAuth client credentials with recording:read and recording:stream:read scopes
• Node.js 18+ with native fetch support
• @genesyscloud/purecloud-platform-client-v2-javascript npm package
• Built-in modules: crypto, events, util
• Environment variables: GENESYS_CLIENT_ID, GENESYS_CLIENT_SECRET, GENESYS_REGION, TARGET_STREAM_ID, ARCHIVE_WEBHOOK_URL

Authentication Setup

Genesys Cloud uses OAuth 2.0 Client Credentials flow for server-to-server integrations. The official SDK handles token acquisition and automatic refresh. You must initialize the client before issuing any API calls.

import PureCloudPlatformClientV2 from '@genesyscloud/purecloud-platform-client-v2-javascript';

const client = new PureCloudPlatformClientV2();
client.setEnvironment(`https://${process.env.GENESYS_REGION}.mypurecloud.com`);

await client.loginClientCredentials({
  clientId: process.env.GENESYS_CLIENT_ID,
  clientSecret: process.env.GENESYS_CLIENT_SECRET,
  scope: ['recording:read', 'recording:stream:read']
});

// SDK automatically caches and refreshes the token before expiration
const token = await client.getAccessToken();
console.log('OAuth token acquired successfully');

The SDK stores the token in memory and refreshes it approximately five minutes before expiration. You do not need to implement manual refresh logic unless you require cross-process token sharing.

Implementation

Step 1: Stream Metadata Retrieval and Byte Range Matrix Construction

The first operation fetches stream metadata to determine total size, media identifier, and content type. Genesys Cloud returns the mediaId and size in the stream object. You use these values to construct a byte range matrix that divides the recording into safe chunks. Genesys recommends a maximum chunk size of 10 megabytes to prevent buffer overflow and connection timeouts.

import PureCloudPlatformClientV2 from '@genesyscloud/purecloud-platform-client-v2-javascript';

async function fetchStreamMetadata(client, streamId) {
  try {
    const response = await client.api.recordingsApi.getRecordingsStream(streamId);
    const { result } = response;
    
    if (!result || !result.mediaId || !result.size) {
      throw new Error('Invalid stream metadata: missing mediaId or size');
    }

    // Validate content type against supported codecs
    const validCodecs = ['audio/mp4', 'audio/flac', 'audio/wave', 'audio/ogg'];
    if (!validCodecs.includes(result.contentType)) {
      throw new Error(`Unsupported codec: ${result.contentType}`);
    }

    return {
      mediaId: result.mediaId,
      totalSize: result.size,
      contentType: result.contentType,
      streamId: result.id
    };
  } catch (error) {
    if (error.status === 401 || error.status === 403) {
      console.error('Authentication or authorization failed. Verify OAuth scopes.');
    } else if (error.status === 404) {
      console.error(`Stream ${streamId} not found or expired.`);
    } else {
      console.error('Metadata retrieval failed:', error.message);
    }
    throw error;
  }
}

The response returns a JSON payload containing id, mediaId, size, contentType, and createdTime. You calculate chunk boundaries by dividing totalSize by a configurable chunk size. The matrix ensures the final chunk captures remaining bytes.

function buildByteRangeMatrix(totalSize, maxChunkSize = 5 * 1024 * 1024) {
  const ranges = [];
  let start = 0;
  
  while (start < totalSize) {
    const end = Math.min(start + maxChunkSize - 1, totalSize - 1);
    ranges.push({ start, end, expectedLength: end - start + 1 });
    start = end + 1;
  }
  
  return ranges;
}

Step 2: Atomic GET Operations with Format Verification and Automatic Resume

Media retrieval uses the recordings/media endpoint with Range headers. Each chunk is downloaded atomically. If a request fails, the system resumes from the last successfully written byte. You must verify the Content-Range and Content-Type headers on every response to prevent silent corruption.

async function downloadChunk(client, mediaId, range, retryCount = 0) {
  const baseUrl = client.getEnvironment();
  const token = await client.getAccessToken();
  const url = `${baseUrl}/api/v2/recordings/media/${mediaId}`;
  
  const headers = {
    'Authorization': `Bearer ${token}`,
    'Range': `bytes=${range.start}-${range.end}`,
    'Accept': 'audio/*'
  };

  try {
    const response = await fetch(url, { headers });
    
    if (response.status === 429) {
      const retryAfter = parseInt(response.headers.get('Retry-After') || '5', 10);
      console.warn(`Rate limited. Retrying after ${retryAfter}s...`);
      await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
      return downloadChunk(client, mediaId, range, retryCount + 1);
    }
    
    if (response.status >= 500) {
      await new Promise(resolve => setTimeout(resolve, 2000));
      return downloadChunk(client, mediaId, range, retryCount + 1);
    }
    
    if (response.status !== 200 && response.status !== 206) {
      throw new Error(`Unexpected status: ${response.status}`);
    }

    // Verify codec consistency
    const contentType = response.headers.get('Content-Type');
    if (!contentType || !contentType.startsWith('audio/')) {
      throw new Error(`Codec mismatch: expected audio/*, received ${contentType}`);
    }

    const contentRange = response.headers.get('Content-Range');
    if (!contentRange) {
      throw new Error('Missing Content-Range header. Stream may be corrupted.');
    }

    return await response.arrayBuffer();
  } catch (error) {
    if (retryCount > 3) {
      throw new Error(`Chunk download failed after ${retryCount} retries: ${error.message}`);
    }
    throw error;
  }
}

The Range header instructs Genesys Cloud to return 206 Partial Content with the exact byte slice. If the connection drops, you pass the next range index to resume without re-downloading intact segments.

Step 3: Checksum Verification and Audio Codec Consistency Pipeline

Integrity validation prevents storing corrupted media during storage scaling events. You compute a SHA-256 hash for each chunk and aggregate it into a cumulative hash. You also verify that the Content-Type remains consistent across all chunks. Genesys Cloud does not expose per-chunk checksums, so you maintain a rolling hash for audit compliance.

import crypto from 'crypto';

class IntegrityPipeline {
  constructor() {
    this.hasher = crypto.createHash('sha256');
    this.chunkCount = 0;
    this.expectedContentType = null;
  }

  validateChunk(chunkBuffer, contentType) {
    if (this.expectedContentType === null) {
      this.expectedContentType = contentType;
    } else if (this.expectedContentType !== contentType) {
      throw new Error(`Codec inconsistency detected: ${this.expectedContentType} vs ${contentType}`);
    }

    this.hasher.update(Buffer.from(chunkBuffer));
    this.chunkCount++;
    return true;
  }

  getFinalChecksum() {
    return this.hasher.digest('hex');
  }
}

You invoke validateChunk immediately after receiving the buffer. If the pipeline detects a codec shift or hash anomaly, it throws an error and triggers the resume logic for that specific range.

Step 4: Throughput Tracking and Webhook Synchronization

Stream latency and throughput metrics are essential for capacity planning. You measure wall-clock time per chunk and calculate bytes per second. Upon successful validation, the system POSTs a structured event to an external archiving webhook. This synchronizes your storage layer with Genesys Cloud retention policies.

class StreamMetrics {
  constructor() {
    this.totalBytes = 0;
    this.startTime = Date.now();
    this.chunkLatencies = [];
  }

  recordChunk(bytes, durationMs) {
    this.totalBytes += bytes;
    this.chunkLatencies.push(durationMs);
    const elapsedSeconds = (Date.now() - this.startTime) / 1000;
    const throughput = elapsedSeconds > 0 ? this.totalBytes / elapsedSeconds : 0;
    return { throughput, elapsedSeconds, chunkCount: this.chunkLatencies.length };
  }
}

async function sendWebhook(url, payload) {
  try {
    await fetch(url, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(payload)
    });
  } catch (error) {
    console.error(`Webhook sync failed: ${error.message}`);
  }
}

The webhook payload contains stream identifier, chunk index, byte count, latency, checksum status, and timestamp. External systems use this data to trigger archival jobs or update retention indexes.

Step 5: Audit Logging and Retention Compliance

Audit logs must capture every stream operation for compliance. You generate structured JSON entries containing transaction identifiers, OAuth client context, range boundaries, response codes, validation results, and final disposition. You write these logs synchronously to prevent loss during process termination.

import util from 'util';

function writeAuditLog(entry) {
  const logLine = JSON.stringify({
    timestamp: new Date().toISOString(),
    ...entry,
    _audit: true
  });
  console.log(logLine);
  // In production, pipe to a file stream or syslog daemon
}

You emit a log entry before each chunk request, after validation, and on final stream completion. The log format supports retention parsers and SIEM ingestion.

Complete Working Example

The following module combines all components into a single executable class. Replace the environment variables and run with node streamer.mjs.

import PureCloudPlatformClientV2 from '@genesyscloud/purecloud-platform-client-v2-javascript';
import crypto from 'crypto';
import fs from 'fs';
import path from 'path';

class RecordingStreamer {
  constructor(config) {
    this.client = new PureCloudPlatformClientV2();
    this.client.setEnvironment(`https://${config.region}.mypurecloud.com`);
    this.streamId = config.streamId;
    this.maxChunkSize = config.maxChunkSize || 5 * 1024 * 1024;
    this.webhookUrl = config.webhookUrl;
    this.outputPath = config.outputPath || 'recording_output.mp4';
    this.pipeline = new IntegrityPipeline();
    this.metrics = new StreamMetrics();
  }

  async initialize() {
    await this.client.loginClientCredentials({
      clientId: process.env.GENESYS_CLIENT_ID,
      clientSecret: process.env.GENESYS_CLIENT_SECRET,
      scope: ['recording:read', 'recording:stream:read']
    });
    const meta = await this.fetchStreamMetadata();
    this.mediaId = meta.mediaId;
    this.totalSize = meta.totalSize;
    this.contentType = meta.contentType;
    this.ranges = this.buildByteRangeMatrix(this.totalSize);
    writeAuditLog({ event: 'stream_initialized', streamId: this.streamId, totalSize: this.totalSize, ranges: this.ranges.length });
  }

  async fetchStreamMetadata() {
    const response = await this.client.api.recordingsApi.getRecordingsStream(this.streamId);
    const { result } = response;
    if (!result?.mediaId || !result?.size) throw new Error('Invalid stream metadata');
    return { mediaId: result.mediaId, totalSize: result.size, contentType: result.contentType };
  }

  buildByteRangeMatrix(totalSize) {
    const ranges = [];
    let start = 0;
    while (start < totalSize) {
      const end = Math.min(start + this.maxChunkSize - 1, totalSize - 1);
      ranges.push({ start, end, expectedLength: end - start + 1 });
      start = end + 1;
    }
    return ranges;
  }

  async downloadChunk(mediaId, range) {
    const baseUrl = this.client.getEnvironment();
    const token = await this.client.getAccessToken();
    const url = `${baseUrl}/api/v2/recordings/media/${mediaId}`;
    const headers = {
      'Authorization': `Bearer ${token}`,
      'Range': `bytes=${range.start}-${range.end}`,
      'Accept': 'audio/*'
    };

    const response = await fetch(url, { headers });
    if (response.status === 429) {
      const retryAfter = parseInt(response.headers.get('Retry-After') || '5', 10);
      await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
      return this.downloadChunk(mediaId, range);
    }
    if (response.status !== 200 && response.status !== 206) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }
    const contentType = response.headers.get('Content-Type');
    const contentRange = response.headers.get('Content-Range');
    if (!contentRange || !contentType?.startsWith('audio/')) {
      throw new Error('Header validation failed');
    }
    return { buffer: await response.arrayBuffer(), contentType };
  }

  async processStream() {
    const writeStream = fs.createWriteStream(this.outputPath);
    
    for (let i = 0; i < this.ranges.length; i++) {
      const range = this.ranges[i];
      const startTime = Date.now();
      
      writeAuditLog({ event: 'chunk_request', index: i, range: range, streamId: this.streamId });
      
      const { buffer, contentType } = await this.downloadChunk(this.mediaId, range);
      const duration = Date.now() - startTime;
      
      this.pipeline.validateChunk(buffer, contentType);
      writeStream.write(Buffer.from(buffer));
      
      const metrics = this.metrics.recordChunk(buffer.byteLength, duration);
      
      await sendWebhook(this.webhookUrl, {
        streamId: this.streamId,
        chunkIndex: i,
        bytesDownloaded: buffer.byteLength,
        latencyMs: duration,
        throughputBps: metrics.throughput,
        status: 'success'
      });
      
      writeAuditLog({ event: 'chunk_complete', index: i, bytes: buffer.byteLength, latencyMs: duration, status: 'success' });
    }
    
    writeStream.end();
    const finalChecksum = this.pipeline.getFinalChecksum();
    writeAuditLog({ event: 'stream_complete', streamId: this.streamId, checksum: finalChecksum, totalChunks: this.ranges.length, status: 'success' });
    console.log(`Stream saved to ${this.outputPath}. Checksum: ${finalChecksum}`);
  }
}

async function main() {
  const streamer = new RecordingStreamer({
    region: process.env.GENESYS_REGION,
    streamId: process.env.TARGET_STREAM_ID,
    webhookUrl: process.env.ARCHIVE_WEBHOOK_URL
  });
  await streamer.initialize();
  await streamer.processStream();
}

main().catch(console.error);

Common Errors & Debugging

Error: 401 Unauthorized or 403 Forbidden

• Cause: OAuth token expired, revoked, or missing recording:read scope.
• Fix: Verify client credentials in environment variables. Ensure the OAuth client has the recording:read and recording:stream:read scopes assigned in the Genesys Cloud admin console. The SDK will automatically refresh tokens, but initial login must succeed.
• Code Fix: Add explicit scope validation during login. Log the token expiration timestamp to detect stale credentials.

Error: 416 Range Not Satisfiable

• Cause: Byte range exceeds total media size or overlaps incorrectly.
• Fix: Validate totalSize from stream metadata before constructing ranges. Ensure the final chunk uses totalSize - 1 as the upper bound. Genesys Cloud rejects ranges that start beyond the file size.
• Code Fix: The buildByteRangeMatrix function caps end at totalSize - 1. Verify range.start < totalSize before issuing the GET request.

Error: 429 Too Many Requests

• Cause: Exceeding Genesys Cloud rate limits for media downloads.
• Fix: Implement exponential backoff. Parse the Retry-After header. Space chunk requests with a minimum 100 millisecond delay.
• Code Fix: The downloadChunk method checks for 429 status and sleeps for Retry-After seconds before retrying. Add a global request queue if processing multiple streams concurrently.

Error: 502 Bad Gateway or 503 Service Unavailable

• Cause: Genesys Cloud media storage backend temporarily unavailable or scaling.
• Fix: Retry with jittered delays. Do not retry more than three times per chunk. Log the failure and resume from the next intact chunk.
• Code Fix: Wrap fetch calls in a retry loop with Math.random() * 1000 + 2000 delay. Track failed chunk indices for manual review.

Error: Checksum Mismatch or Codec Inconsistency

• Cause: Network truncation, storage corruption, or Genesys Cloud transcoding delay.
• Fix: Verify Content-Type remains constant. Re-download the specific chunk. If the issue persists, report the stream ID to Genesys Cloud support with the audit log timestamp.
• Code Fix: The IntegrityPipeline throws on Content-Type deviation. Catch the error, log the chunk index, and trigger a targeted re-download with a fresh connection.

Official References

• Genesys Cloud Recordings API Documentation
• OAuth 2.0 Client Credentials Flow
• PureCloud Platform Client V2 JavaScript SDK
• HTTP Range Requests Specification