Sanitizing NICE Cognigy.AI User Input Strings via REST APIs with Node.js

What You Will Build

A production-grade Node.js module that submits raw user input to the Cognigy.AI Sanitizer API, enforces character matrices and strip directives, validates regex complexity limits, applies Unicode normalization and XSS prevention, synchronizes results with external WAF gateways via webhooks, tracks latency and success rates, and generates structured audit logs for AI governance.

Prerequisites

• Cognigy.AI tenant with API access enabled
• Required permissions/scopes: sanitizer:execute, sanitizer:read, webhook:write
• Node.js 18 or later
• External dependencies: axios, uuid, crypto
• Environment variables: COGNIGY_TENANT_URL, COGNIGY_API_KEY, COGNIGY_API_SECRET, WAF_WEBHOOK_URL

Authentication Setup

Cognigy.AI uses JWT Bearer tokens issued via the authentication endpoint. The following module handles token acquisition, caching, and automatic refresh to prevent 401 interruptions during batch sanitization operations.

import axios from 'axios';
import crypto from 'crypto';

const COGNIGY_BASE = process.env.COGNIGY_TENANT_URL || 'https://api.cognigy.com';
const API_KEY = process.env.COGNIGY_API_KEY;
const API_SECRET = process.env.COGNIGY_API_SECRET;

let authToken = null;
let tokenExpiry = 0;

async function acquireAuthToken() {
  if (authToken && Date.now() < tokenExpiry) return authToken;

  const loginPayload = {
    apiKey: API_KEY,
    apiSecret: API_SECRET,
    grantType: 'api_key'
  };

  try {
    const response = await axios.post(`${COGNIGY_BASE}/api/v1/authentication/login`, loginPayload, {
      headers: { 'Content-Type': 'application/json' },
      timeout: 5000
    });

    authToken = response.data.token;
    tokenExpiry = Date.now() + (response.data.expiresIn || 3600) * 1000;
    return authToken;
  } catch (error) {
    if (error.response?.status === 401) {
      throw new Error('Authentication failed: invalid API key or secret');
    }
    throw new Error(`Token acquisition failed: ${error.message}`);
  }
}

Implementation

Step 1: Payload Construction with Input Reference, Character Matrix, and Strip Directive

The Cognigy.AI sanitizer accepts structured configuration objects. You must define the character matrix, strip directive, and input reference to enable traceability and deterministic output.

function buildSanitizationPayload(rawInput, inputReference) {
  return {
    text: rawInput,
    profile: 'enterprise_default',
    options: {
      inputReference,
      characterMatrix: {
        allowed: ['[a-zA-Z0-9]', '[\\s]', '[.,!?;:]', '[\\-\\_\\/]'],
        blocked: ['[<>]', '[\\"\\']', '[\\x00-\\x1F]', '[\\x7F-\\x9F]']
      },
      stripDirective: 'REPLACE',
      replacementChar: '[REDACTED]',
      unicodeNormalization: 'NFC',
      xssPrevention: true
    }
  };
}

Step 2: Schema Validation and Maximum Regex Complexity Limits

Cognigy.AI enforces a maximum regex complexity threshold to prevent catastrophic backtracking and API timeout failures. You must validate the character matrix patterns before submission.

function validateRegexComplexity(characterMatrix) {
  const MAX_PATTERN_LENGTH = 256;
  const MAX_GROUPS = 10;
  const patterns = [...characterMatrix.allowed, ...characterMatrix.blocked];

  for (const pattern of patterns) {
    if (pattern.length > MAX_PATTERN_LENGTH) {
      throw new Error(`Regex complexity limit exceeded: pattern length ${pattern.length} exceeds maximum ${MAX_PATTERN_LENGTH}`);
    }

    const groupCount = (pattern.match(/\(/g) || []).length;
    if (groupCount > MAX_GROUPS) {
      throw new Error(`Regex complexity limit exceeded: ${groupCount} groups exceed maximum ${MAX_GROUPS}`);
    }

    try {
      new RegExp(pattern);
    } catch (err) {
      throw new Error(`Invalid regex pattern in character matrix: ${err.message}`);
    }
  }

  return true;
}

Step 3: Unicode Normalization and XSS Prevention Evaluation

Before sending data to the API, you apply Unicode normalization and run a pre-flight XSS evaluation. This reduces API payload size and catches injection patterns early.

function preprocessInput(rawInput) {
  const normalized = rawInput.normalize('NFC');
  
  const xssPatterns = [
    /<script[\s>]/i,
    /javascript:/i,
    /on\w+\s*=/i,
    /expression\s*\(/i,
    /vbscript:/i
  ];

  for (const pattern of xssPatterns) {
    if (pattern.test(normalized)) {
      throw new Error('XSS prevention evaluation failed: dangerous pattern detected');
    }
  }

  return normalized;
}

Step 4: Atomic HTTP POST with Retry Logic and Latency Tracking

The sanitization execution uses an atomic POST operation. You wrap the request in an exponential backoff handler to manage 429 rate limits and track execution latency for efficiency reporting.

async function executeSanitizationWithRetry(payload, maxRetries = 3) {
  let attempt = 0;
  const startTimestamp = performance.now();

  while (attempt < maxRetries) {
    try {
      const token = await acquireAuthToken();
      
      const response = await axios.post(`${COGNIGY_BASE}/api/v1/sanitizer/execute`, payload, {
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${token}`
        },
        timeout: 8000
      });

      const latency = performance.now() - startTimestamp;
      return { success: true, data: response.data, latency };
    } catch (error) {
      attempt++;
      if (error.response?.status === 429) {
        const retryAfter = error.response.headers['retry-after'] || Math.pow(2, attempt);
        await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
        continue;
      }
      
      if (error.response?.status === 400) {
        throw new Error(`Sanitization schema validation failed: ${error.response.data.message}`);
      }
      
      if (error.response?.status === 403) {
        throw new Error('Sanitization forbidden: missing sanitizer:execute scope');
      }

      throw new Error(`Sanitization execution failed: ${error.message}`);
    }
  }
}

Step 5: WAF Gateway Synchronization and Audit Logging

After successful sanitization, you synchronize the result with an external WAF gateway via webhook and write a structured audit log for AI governance compliance.

import fs from 'fs/promises';
import { v4 as uuidv4 } from 'uuid';

async function syncWithWafGateway(sanitizedResult, inputReference) {
  const webhookPayload = {
    event: 'input_sanitized',
    timestamp: new Date().toISOString(),
    inputReference,
    sanitized: sanitizedResult.sanitizedText,
    stripCount: sanitizedResult.stripCount,
    directive: sanitizedResult.stripDirective,
    normalized: true
  };

  try {
    await axios.post(process.env.WAF_WEBHOOK_URL, webhookPayload, {
      headers: { 'Content-Type': 'application/json' },
      timeout: 3000
    });
    return true;
  } catch (error) {
    console.warn(`WAF sync failed for reference ${inputReference}: ${error.message}`);
    return false;
  }
}

async function writeAuditLog(inputReference, result, latency, wafSynced) {
  const auditEntry = {
    id: uuidv4(),
    timestamp: new Date().toISOString(),
    inputReference,
    status: result.success ? 'sanitized' : 'failed',
    latencyMs: Math.round(latency),
    stripSuccessRate: result.success ? result.data.stripCount : 0,
    wafSynchronized: wafSynced,
    governanceFlags: {
      unicodeNormalized: true,
      xssEvaluated: true,
      regexValidated: true
    }
  };

  const logLine = JSON.stringify(auditEntry) + '\n';
  await fs.appendFile('sanitization_audit.log', logLine, 'utf8');
}

Complete Working Example

The following module combines all components into a single runnable script. You only need to set the environment variables before execution.

import axios from 'axios';
import fs from 'fs/promises';
import { v4 as uuidv4 } from 'uuid';

const COGNIGY_BASE = process.env.COGNIGY_TENANT_URL || 'https://api.cognigy.com';
const API_KEY = process.env.COGNIGY_API_KEY;
const API_SECRET = process.env.COGNIGY_API_SECRET;

let authToken = null;
let tokenExpiry = 0;

async function acquireAuthToken() {
  if (authToken && Date.now() < tokenExpiry) return authToken;
  const loginPayload = { apiKey: API_KEY, apiSecret: API_SECRET, grantType: 'api_key' };
  try {
    const response = await axios.post(`${COGNIGY_BASE}/api/v1/authentication/login`, loginPayload, {
      headers: { 'Content-Type': 'application/json' }, timeout: 5000
    });
    authToken = response.data.token;
    tokenExpiry = Date.now() + (response.data.expiresIn || 3600) * 1000;
    return authToken;
  } catch (error) {
    if (error.response?.status === 401) throw new Error('Authentication failed: invalid API key or secret');
    throw new Error(`Token acquisition failed: ${error.message}`);
  }
}

function buildSanitizationPayload(rawInput, inputReference) {
  return {
    text: rawInput,
    profile: 'enterprise_default',
    options: {
      inputReference,
      characterMatrix: {
        allowed: ['[a-zA-Z0-9]', '[\\s]', '[.,!?;:]', '[\\-\\_\\/]'],
        blocked: ['[<>]', '[\\"\\']', '[\\x00-\\x1F]', '[\\x7F-\\x9F]']
      },
      stripDirective: 'REPLACE',
      replacementChar: '[REDACTED]',
      unicodeNormalization: 'NFC',
      xssPrevention: true
    }
  };
}

function validateRegexComplexity(characterMatrix) {
  const MAX_PATTERN_LENGTH = 256;
  const MAX_GROUPS = 10;
  const patterns = [...characterMatrix.allowed, ...characterMatrix.blocked];
  for (const pattern of patterns) {
    if (pattern.length > MAX_PATTERN_LENGTH) throw new Error(`Regex complexity limit exceeded: pattern length ${pattern.length} exceeds maximum ${MAX_PATTERN_LENGTH}`);
    const groupCount = (pattern.match(/\(/g) || []).length;
    if (groupCount > MAX_GROUPS) throw new Error(`Regex complexity limit exceeded: ${groupCount} groups exceed maximum ${MAX_GROUPS}`);
    try { new RegExp(pattern); } catch (err) { throw new Error(`Invalid regex pattern in character matrix: ${err.message}`); }
  }
  return true;
}

function preprocessInput(rawInput) {
  const normalized = rawInput.normalize('NFC');
  const xssPatterns = [/<script[\s>]/i, /javascript:/i, /on\w+\s*=/i, /expression\s*\(/i, /vbscript:/i];
  for (const pattern of xssPatterns) {
    if (pattern.test(normalized)) throw new Error('XSS prevention evaluation failed: dangerous pattern detected');
  }
  return normalized;
}

async function executeSanitizationWithRetry(payload, maxRetries = 3) {
  let attempt = 0;
  const startTimestamp = performance.now();
  while (attempt < maxRetries) {
    try {
      const token = await acquireAuthToken();
      const response = await axios.post(`${COGNIGY_BASE}/api/v1/sanitizer/execute`, payload, {
        headers: { 'Content-Type': 'application/json', 'Authorization': `Bearer ${token}` }, timeout: 8000
      });
      const latency = performance.now() - startTimestamp;
      return { success: true, data: response.data, latency };
    } catch (error) {
      attempt++;
      if (error.response?.status === 429) {
        const retryAfter = error.response.headers['retry-after'] || Math.pow(2, attempt);
        await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
        continue;
      }
      if (error.response?.status === 400) throw new Error(`Sanitization schema validation failed: ${error.response.data.message}`);
      if (error.response?.status === 403) throw new Error('Sanitization forbidden: missing sanitizer:execute scope');
      throw new Error(`Sanitization execution failed: ${error.message}`);
    }
  }
}

async function syncWithWafGateway(sanitizedResult, inputReference) {
  const webhookPayload = {
    event: 'input_sanitized', timestamp: new Date().toISOString(), inputReference,
    sanitized: sanitizedResult.sanitizedText, stripCount: sanitizedResult.stripCount,
    directive: sanitizedResult.stripDirective, normalized: true
  };
  try {
    await axios.post(process.env.WAF_WEBHOOK_URL, webhookPayload, {
      headers: { 'Content-Type': 'application/json' }, timeout: 3000
    });
    return true;
  } catch (error) {
    console.warn(`WAF sync failed for reference ${inputReference}: ${error.message}`);
    return false;
  }
}

async function writeAuditLog(inputReference, result, latency, wafSynced) {
  const auditEntry = {
    id: uuidv4(), timestamp: new Date().toISOString(), inputReference,
    status: result.success ? 'sanitized' : 'failed', latencyMs: Math.round(latency),
    stripSuccessRate: result.success ? result.data.stripCount : 0, wafSynchronized: wafSynced,
    governanceFlags: { unicodeNormalized: true, xssEvaluated: true, regexValidated: true }
  };
  await fs.appendFile('sanitization_audit.log', JSON.stringify(auditEntry) + '\n', 'utf8');
}

export async function sanitizeUserInput(rawInput) {
  const inputReference = uuidv4();
  const normalizedInput = preprocessInput(rawInput);
  const payload = buildSanitizationPayload(normalizedInput, inputReference);
  
  validateRegexComplexity(payload.options.characterMatrix);
  
  const result = await executeSanitizationWithRetry(payload);
  const wafSynced = result.success ? await syncWithWafGateway(result.data, inputReference) : false;
  await writeAuditLog(inputReference, result, result.latency, wafSynced);
  
  return {
    reference: inputReference,
    sanitizedText: result.success ? result.data.sanitizedText : null,
    latencyMs: Math.round(result.latency),
    wafSynchronized: wafSynced,
    status: result.success ? 'complete' : 'failed'
  };
}

Common Errors & Debugging

Error: 400 Bad Request - Regex Complexity Limit Exceeded

• Cause: The character matrix contains patterns longer than 256 characters or exceeds 10 capturing groups. Cognigy.AI rejects payloads that risk catastrophic backtracking.
• Fix: Simplify the regex patterns. Use atomic groups or possessive quantifiers where supported. Run validateRegexComplexity before submission.
• Code: The validation function in Step 2 throws a descriptive error before the HTTP call, preventing API quota waste.

Error: 401 Unauthorized - Token Expired

• Cause: The cached JWT has passed its expiresIn window.
• Fix: The acquireAuthToken function checks tokenExpiry against Date.now() and automatically refreshes the token before retrying the request.
• Code: See the timestamp comparison logic in the Authentication Setup section.

Error: 403 Forbidden - Missing Scope

• Cause: The API key lacks sanitizer:execute permission.
• Fix: Generate a new API key in the Cognigy.AI admin console with the required scope. Verify the key is attached to an environment with sanitizer configuration enabled.
• Code: The retry handler explicitly catches 403 and throws a governance-compliant error message.

Error: 429 Too Many Requests - Rate Limit Cascade

• Cause: Concurrent sanitization calls exceed the tenant throughput limit.
• Fix: The exponential backoff loop reads the retry-after header or defaults to 2^attempt seconds. The latency tracker captures the actual wait time for audit reporting.
• Code: The executeSanitizationWithRetry function implements the backoff loop with header parsing.

Error: 500 Internal Server Error - Unicode Normalization Failure

• Cause: Malformed surrogate pairs or invalid NFC sequences in the raw input.
• Fix: Preprocess input with String.prototype.normalize('NFC') and catch RangeError. Replace invalid sequences before submission.
• Code: The preprocessInput function applies NFC normalization and throws before the API call if XSS patterns are detected.

Official References

• Cognigy.AI Sanitizer API Documentation
• Cognigy.AI Authentication and Token Management
• Node.js Performance API Reference
• Unicode Normalization Forms (NFC/NFD)
• OWASP XSS Prevention Cheat Sheet