Implement WebhookDispatcherSefeat: Enterprise-grade Resilient Webhook Dispatcher with HMAC Signaturervice for webhook handling

Author: Ingenieralejo

apps/api/src/webhooks/WebhookDispatcherService.ts

@@ -0,0 +1,39 @@
+import { Injectable, Logger } from '@nestjs/common';
+import axios from 'axios';
+import * as crypto from 'crypto';
+
+export interface WebhookPayload {
+    event: string;
+    documentId: string;
+    status: string;
+    timestamp: string;
+    data: any;
+}
+
+@Injectable()
+  export class WebhookDispatcherService {
+    private readonly logger = new Logger(WebhookDispatcherService.name);
+    private readonly MAX_RETRIES = 3;
+    private readonly TIMEOUT_MS = 5000;
+
+  private generateSignature(payload: string, secret: string): string {
+        return crypto.createHmac('sha256', secret).update(payload).digest('hex');
+  }
+
+  async dispatchWithBackoff(url: string, payload: WebhookPayload, secret: string, attempt: number = 1): Promise<boolean> {
+        const payloadString = JSON.stringify(payload);
+        const signature = this.generateSignature(payloadString, secret);
+        try {
+                this.logger.log(`[Attempt ${attempt}] Dispatching webhook to ${url}`);
+                await axios.post(url, payloadString, { headers: { 'Content-Type': 'application/json', 'X-OpenSign-Signature': signature, 'X-OpenSign-Event': payload.event }, timeout: this.TIMEOUT_MS });
+                return true;
+        } catch (error) {
+                if (attempt < this.MAX_RETRIES) {
+                          const backoffDelay = Math.pow(2, attempt) * 1000;
+                          await new Promise(resolve => setTimeout(resolve, backoffDelay));
+                          return this.dispatchWithBackoff(url, payload, secret, attempt + 1);
+                }
+                return false;
+        }
+  }
+}