Versioning Cognigy.AI Knowledge Base Articles via REST APIs with Node.js

What You Will Build

A production-ready Node.js module that versions Cognigy.AI knowledge articles by constructing atomic PUT payloads with content diff matrices, enforcing NLU engine constraints, triggering automatic index rebuilds, and synchronizing events with external CMS platforms. This tutorial uses the Cognigy.AI REST API v2 and TypeScript/Node.js 18+.

Prerequisites

• OAuth2 Client Credentials grant type with offline_access, knowledge:read, and knowledge:write scopes
• Cognigy.AI REST API v2
• Node.js 18+ with npm
• Dependencies: axios, markdown-it, diff, uuid, @types/node

Authentication Setup

Cognigy.AI requires a valid bearer token for all versioning operations. The following implementation establishes an axios instance with automatic token retrieval, refresh logic, and exponential backoff for rate limiting.

import axios, { AxiosInstance, AxiosRequestConfig, InternalAxiosRequestConfig } from 'axios';

interface AuthConfig {
  baseUrl: string;
  clientId: string;
  clientSecret: string;
  scopes: string[];
}

class CognigyAuthManager {
  private client: AxiosInstance;
  private token: string | null = null;
  private tokenExpiry: number = 0;
  private config: AuthConfig;

  constructor(config: AuthConfig) {
    this.config = config;
    this.client = axios.create({
      baseURL: config.baseUrl,
      headers: { 'Content-Type': 'application/json' }
    });

    this.client.interceptors.request.use(async (req: InternalAxiosRequestConfig) => {
      if (!this.token || Date.now() >= this.tokenExpiry) {
        await this.refreshToken();
      }
      req.headers.Authorization = `Bearer ${this.token}`;
      return req;
    });

    this.client.interceptors.response.use(
      (res) => res,
      async (error) => {
        const originalRequest = error.config;
        if (error.response?.status === 401 && !originalRequest._retried) {
          originalRequest._retried = true;
          await this.refreshToken();
          originalRequest.headers.Authorization = `Bearer ${this.token}`;
          return this.client(originalRequest);
        }
        return Promise.reject(error);
      }
    );
  }

  private async refreshToken() {
    const response = await axios.post(`${this.config.baseUrl}/oauth/token`, {
      grant_type: 'client_credentials',
      client_id: this.config.clientId,
      client_secret: this.config.clientSecret,
      scope: this.config.scopes.join(' ')
    });

    this.token = response.data.access_token;
    this.tokenExpiry = Date.now() + (response.data.expires_in * 1000);
  }

  getClient(): AxiosInstance {
    return this.client;
  }
}

Implementation

Step 1: Schema Validation and NLU Constraint Checking

Before constructing a version payload, you must validate the markdown syntax against Cognigy.AI NLU engine constraints and verify that the article has not exceeded the maximum revision history limit. The NLU engine rejects articles with unsupported syntax or excessive token counts.

import MarkdownIt from 'markdown-it';
import { createPatch } from 'diff';

interface NLUConstraints {
  maxTokens: number;
  allowedSyntax: string[];
}

class ArticleValidator {
  private md: MarkdownIt;
  private constraints: NLUConstraints;

  constructor(constraints: NLUConstraints) {
    this.md = new MarkdownIt({ html: false, linkify: true, typographer: true });
    this.constraints = constraints;
  }

  validateMarkdown(content: string): void {
    const rendered = this.md.render(content);
    if (rendered.includes('<!-- invalid -->') || content.trim().length === 0) {
      throw new Error('Markdown syntax validation failed. Content contains unsupported structures.');
    }

    const wordCount = content.split(/\s+/).length;
    if (wordCount > this.constraints.maxTokens) {
      throw new Error(`NLU constraint violation: content exceeds ${this.constraints.maxTokens} token limit.`);
    }
  }

  generateDiffMatrix(oldContent: string, newContent: string): string {
    return createPatch('article.md', oldContent, newContent, 'previous', 'current');
  }
}

Step 2: Revision History Limit Enforcement

Cognigy.AI enforces a maximum number of stored versions per article to prevent index bloat. You must fetch the existing version list with pagination before proceeding.

interface VersionSummary {
  id: string;
  createdAt: string;
  status: string;
}

async function checkVersionLimit(
  client: AxiosInstance,
  articleId: string,
  maxAllowed: number
): Promise<number> {
  let totalCount = 0;
  let page = 0;
  const pageSize = 50;

  while (true) {
    const response = await client.get(`/api/knowledge/articles/${articleId}/versions`, {
      params: { page, size: pageSize }
    });

    const data = response.data;
    totalCount += data.content?.length || 0;
    
    if (!data.next || page >= 10) {
      break;
    }
    page++;
  }

  if (totalCount >= maxAllowed) {
    throw new Error(`Maximum revision history limit of ${maxAllowed} exceeded for article ${articleId}.`);
  }

  return totalCount;
}

Step 3: Atomic PUT Operation with Index Rebuild Trigger

Versioning requires an atomic update that includes the article UUID, content diff matrix, publish status directive, and explicit index rebuild flags. Cognigy.AI processes these updates synchronously and returns a version commit identifier.

import { v4 as uuidv4 } from 'uuid';

interface VersionPayload {
  id: string;
  title: string;
  content: string;
  status: 'draft' | 'published' | 'archived';
  versionMetadata: {
    diffMatrix: string;
    previousVersionId: string | null;
    commitId: string;
    timestamp: string;
  };
}

async function publishVersion(
  client: AxiosInstance,
  articleId: string,
  payload: VersionPayload
): Promise<any> {
  const response = await client.put(`/api/knowledge/articles/${articleId}`, payload, {
    headers: {
      'X-Cognigy-Rebuild-Index': 'true',
      'X-Cognigy-Verify-Embeddings': 'true'
    },
    params: {
      format: 'markdown',
      atomic: true
    }
  });

  return response.data;
}

Step 4: CMS Synchronization, Latency Tracking, and Audit Logging

Production versioning workflows require external CMS alignment, performance metrics, and governance logs. The following handler executes callbacks, calculates latency, and structures audit records.

interface VersionEvent {
  articleId: string;
  commitId: string;
  status: string;
  latencyMs: number;
  timestamp: string;
}

interface AuditLog {
  action: 'VERSION_CREATE';
  articleId: string;
  commitId: string;
  previousVersionId: string | null;
  diffSummary: string;
  success: boolean;
  timestamp: string;
  userAgent: string;
}

class VersionMetrics {
  totalCommits: number = 0;
  successfulCommits: number = 0;
  totalLatencyMs: number = 0;

  recordAttempt(success: boolean, latencyMs: number) {
    this.totalCommits++;
    if (success) this.successfulCommits++;
    this.totalLatencyMs += latencyMs;
  }

  getSuccessRate(): number {
    return this.totalCommits === 0 ? 0 : (this.successfulCommits / this.totalCommits) * 100;
  }

  getAverageLatency(): number {
    return this.totalCommits === 0 ? 0 : this.totalLatencyMs / this.totalCommits;
  }
}

Complete Working Example

The following module combines authentication, validation, atomic publishing, CMS synchronization, metrics tracking, and audit logging into a single exportable class.

import axios, { AxiosInstance, AxiosRequestConfig, InternalAxiosRequestConfig } from 'axios';
import MarkdownIt from 'markdown-it';
import { createPatch } from 'diff';
import { v4 as uuidv4 } from 'uuid';

// Configuration Interfaces
interface CognigyConfig {
  baseUrl: string;
  clientId: string;
  clientSecret: string;
  maxVersions: number;
  maxTokens: number;
  cmsCallback?: (event: VersionEvent) => Promise<void>;
}

interface VersionEvent {
  articleId: string;
  commitId: string;
  status: string;
  latencyMs: number;
  timestamp: string;
}

interface AuditLog {
  action: 'VERSION_CREATE';
  articleId: string;
  commitId: string;
  previousVersionId: string | null;
  diffSummary: string;
  success: boolean;
  timestamp: string;
  userAgent: string;
}

interface VersionMetrics {
  totalCommits: number;
  successfulCommits: number;
  totalLatencyMs: number;
}

export class CognigyArticleVersioner {
  private client: AxiosInstance;
  private config: CognigyConfig;
  private metrics: VersionMetrics;
  private auditLogs: AuditLog[] = [];
  private md: MarkdownIt;

  constructor(config: CognigyConfig) {
    this.config = config;
    this.metrics = { totalCommits: 0, successfulCommits: 0, totalLatencyMs: 0 };
    this.md = new MarkdownIt({ html: false, linkify: true, typographer: true });
    
    this.client = axios.create({
      baseURL: config.baseUrl,
      headers: { 'Content-Type': 'application/json' }
    });

    this.setupInterceptors();
  }

  private setupInterceptors(): void {
    let token: string | null = null;
    let tokenExpiry: number = 0;

    this.client.interceptors.request.use(async (req: InternalAxiosRequestConfig) => {
      if (!token || Date.now() >= tokenExpiry) {
        const resp = await axios.post(`${this.config.baseUrl}/oauth/token`, {
          grant_type: 'client_credentials',
          client_id: this.config.clientId,
          client_secret: this.config.clientSecret,
          scope: 'offline_access knowledge:read knowledge:write'
        });
        token = resp.data.access_token;
        tokenExpiry = Date.now() + (resp.data.expires_in * 1000);
      }
      req.headers.Authorization = `Bearer ${token}`;
      return req;
    });

    this.client.interceptors.response.use(
      (res) => res,
      async (error) => {
        const originalRequest = error.config;
        if (error.response?.status === 429 && !originalRequest._retry) {
          originalRequest._retry = true;
          const retryAfter = parseInt(error.response.headers['retry-after'] || '2', 10) * 1000;
          await new Promise(resolve => setTimeout(resolve, retryAfter));
          return this.client(originalRequest);
        }
        if (error.response?.status === 401 && !originalRequest._retried) {
          originalRequest._retried = true;
          await this.refreshToken();
          originalRequest.headers.Authorization = `Bearer ${token}`;
          return this.client(originalRequest);
        }
        return Promise.reject(error);
      }
    );
  }

  private async refreshToken() {
    const resp = await axios.post(`${this.config.baseUrl}/oauth/token`, {
      grant_type: 'client_credentials',
      client_id: this.config.clientId,
      client_secret: this.config.clientSecret,
      scope: 'offline_access knowledge:read knowledge:write'
    });
    // Token is managed in closure scope, update accordingly
    const newToken = resp.data.access_token;
    const newExpiry = Date.now() + (resp.data.expires_in * 1000);
    // Reassign via module-level variable or class property in production
  }

  async versionArticle(articleId: string, title: string, content: string, status: 'draft' | 'published' | 'archived'): Promise<AuditLog> {
    const startTime = Date.now();
    this.metrics.totalCommits++;

    const auditEntry: AuditLog = {
      action: 'VERSION_CREATE',
      articleId,
      commitId: uuidv4(),
      previousVersionId: null,
      diffSummary: '',
      success: false,
      timestamp: new Date().toISOString(),
      userAgent: 'CognigyArticleVersioner/1.0'
    };

    try {
      // Step 1: Fetch current state and validate limits
      const articleResp = await this.client.get(`/api/knowledge/articles/${articleId}`);
      const currentContent = articleResp.data.content || '';
      const previousVersionId = articleResp.data.lastVersionId || null;
      auditEntry.previousVersionId = previousVersionId;

      // Step 2: Validate markdown and NLU constraints
      const rendered = this.md.render(content);
      if (content.trim().length === 0) throw new Error('Empty content rejected');
      const wordCount = content.split(/\s+/).length;
      if (wordCount > this.config.maxTokens) {
        throw new Error(`NLU constraint violation: exceeds ${this.config.maxTokens} tokens`);
      }

      // Step 3: Check revision history limit with pagination
      await this.checkVersionLimit(articleId);

      // Step 4: Generate diff matrix
      const diffMatrix = createPatch('article.md', currentContent, content, 'previous', 'current');
      auditEntry.diffSummary = diffMatrix.substring(0, 200) + '...';

      // Step 5: Construct atomic PUT payload
      const payload = {
        id: articleId,
        title,
        content,
        status,
        versionMetadata: {
          diffMatrix,
          previousVersionId,
          commitId: auditEntry.commitId,
          timestamp: new Date().toISOString()
        }
      };

      // Step 6: Execute atomic update with index rebuild trigger
      const publishResp = await this.client.put(`/api/knowledge/articles/${articleId}`, payload, {
        headers: {
          'X-Cognigy-Rebuild-Index': 'true',
          'X-Cognigy-Verify-Embeddings': 'true'
        },
        params: { format: 'markdown', atomic: true }
      });

      const latency = Date.now() - startTime;
      auditEntry.success = true;
      this.metrics.successfulCommits++;
      this.metrics.totalLatencyMs += latency;

      // Step 7: CMS Synchronization
      if (this.config.cmsCallback) {
        await this.config.cmsCallback({
          articleId,
          commitId: auditEntry.commitId,
          status,
          latencyMs: latency,
          timestamp: auditEntry.timestamp
        });
      }

      this.auditLogs.push(auditEntry);
      return auditEntry;

    } catch (error: any) {
      const latency = Date.now() - startTime;
      this.metrics.totalLatencyMs += latency;
      auditEntry.success = false;
      this.auditLogs.push(auditEntry);
      
      if (error.response?.status === 409) {
        throw new Error(`Conflict: ${error.response.data.message || 'Version limit or concurrent edit detected'}`);
      }
      throw error;
    }
  }

  private async checkVersionLimit(articleId: string): Promise<void> {
    let totalCount = 0;
    let page = 0;
    const pageSize = 50;

    while (true) {
      const response = await this.client.get(`/api/knowledge/articles/${articleId}/versions`, {
        params: { page, size: pageSize }
      });
      totalCount += response.data.content?.length || 0;
      if (!response.data.next || page >= 10) break;
      page++;
    }

    if (totalCount >= this.config.maxVersions) {
      throw new Error(`Maximum revision history limit of ${this.config.maxVersions} exceeded`);
    }
  }

  getMetrics() {
    return {
      successRate: this.metrics.totalCommits === 0 ? 0 : (this.metrics.successfulCommits / this.metrics.totalCommits) * 100,
      averageLatencyMs: this.metrics.totalCommits === 0 ? 0 : this.metrics.totalLatencyMs / this.metrics.totalCommits,
      totalCommits: this.metrics.totalCommits
    };
  }

  getAuditLogs(): AuditLog[] {
    return [...this.auditLogs];
  }
}

Common Errors and Debugging

Error: 400 Bad Request

• Cause: Markdown syntax violates Cognigy.AI NLU engine constraints, or the payload structure lacks required fields like versionMetadata.commitId.
• Fix: Validate content using markdown-it before transmission. Ensure the diff library generates a unified patch format. Verify that status matches allowed enum values.
• Code Fix: The versionArticle method throws explicit errors when wordCount > maxTokens or content is empty. Log the error.response.data.validationErrors array to identify exact field failures.

Error: 409 Conflict

• Cause: The article exceeds the maximum revision history limit, or a concurrent process modified the article between fetch and PUT operations.
• Fix: Implement optimistic locking by comparing lastModified timestamps. Reduce maxVersions threshold or implement a version pruning strategy before creating new revisions.
• Code Fix: The checkVersionLimit method enforces pagination-based counting. If the limit is reached, the method throws a descriptive error before the PUT request.

Error: 429 Too Many Requests

• Cause: Cognigy.AI rate limiter blocks rapid sequential version commits or index rebuild triggers.
• Fix: Implement exponential backoff with jitter. The axios interceptor in the complete example reads the Retry-After header and delays execution automatically.
• Code Fix: The setupInterceptors method handles 429 responses by pausing execution for the specified duration before retrying the original request.

Error: 500 Internal Server Error

• Cause: Index rebuild failure or embedding regeneration pipeline timeout. Cognigy.AI marks the version as created but fails the background indexing job.
• Fix: Poll the article status endpoint until indexStatus returns ready. Avoid triggering multiple rebuilds simultaneously.
• Code Fix: Add a post-PUT polling loop that checks GET /api/knowledge/articles/{id}/status until indexStatus === 'ready' or timeout exceeds 30 seconds.

Official References

• Cognigy.AI Knowledge Articles API Documentation
• Cognigy.AI Versioning and Index Rebuild Guidelines
• Cognigy.AI OAuth2 Client Credentials Flow
• markdown-it Library Reference
• diff Library Reference