feat(subscription): add an validateSignature method

src/core/Subscription.ts

@@ -1,3 +1,5 @@
+import { createHmac } from 'crypto';
+
 import { EventName, SubscriptionStatus, ISubscription, PostSubscriptionDTO, PatchSubscriptionDTO } from '../lib';
 import { RequestBuilder } from '../RequestBuilder';
 
@@ -76,4 +78,20 @@ export class Subscription {
 
     this.status = body.status;
   }
+
+  /**
+   * Validates an Algoan Resthook with the "x-hub-signature" header
+   * More information here: https://developers.algoan.com/public/docs/algoan_documentation/resthooks_and_events/resthooks.html#validating-resthook-events
+   * @param signatureHeader Signature header received
+   * @param payload Payload sent
+   */
+  public validateSignature(signatureHeader: string, payload: { [key: string]: string }): boolean {
+    if (this.secret === undefined) {
+      return true;
+    }
+
+    const expectedHash: string = createHmac('sha256', this.secret).update(JSON.stringify(payload)).digest('hex');
+
+    return expectedHash === signatureHeader;
+  }
 }

test/subscription.test.ts

@@ -1,3 +1,4 @@
+import { createHmac } from 'crypto';
 import * as nock from 'nock';
 
 import { RequestBuilder } from '../src/RequestBuilder';
@@ -139,4 +140,69 @@ describe('Tests related to the Subscription class', () => {
       expect(subscription.status).toEqual('ACTIVE');
     });
   });
+
+  describe('validateSignature()', () => {
+    const baseUrl: string = 'http://localhost:3000';
+    let requestBuilder: RequestBuilder;
+    const secret: string = 'random_secret';
+    const fakePayloadSent: {} = {
+      banksUserId: 'id',
+    };
+    const hash: string = createHmac('sha256', secret).update(JSON.stringify(fakePayloadSent)).digest('hex');
+
+    beforeEach(() => {
+      requestBuilder = new RequestBuilder(baseUrl, {
+        clientId: 'a',
+        clientSecret: 's',
+      });
+    });
+
+    afterEach(() => {
+      jest.clearAllMocks();
+      nock.cleanAll();
+    });
+    it('SB030 - should be valid - no secret defined', () => {
+      const subscription: Subscription = new Subscription(
+        {
+          target: baseUrl,
+          id: '1',
+          eventName: EventName.APPLICATION_UPDATED,
+          status: 'DISABLE',
+        },
+        requestBuilder,
+      );
+
+      expect(subscription.validateSignature(hash, fakePayloadSent)).toBeTruthy();
+    });
+
+    it('SB031 - should be valid', () => {
+      const subscription: Subscription = new Subscription(
+        {
+          target: baseUrl,
+          id: '1',
+          eventName: EventName.APPLICATION_UPDATED,
+          status: 'DISABLE',
+          secret,
+        },
+        requestBuilder,
+      );
+
+      expect(subscription.validateSignature(hash, fakePayloadSent)).toBeTruthy();
+    });
+
+    it('SB032 - should not be valid', () => {
+      const subscription: Subscription = new Subscription(
+        {
+          target: baseUrl,
+          id: '1',
+          eventName: EventName.APPLICATION_UPDATED,
+          status: 'DISABLE',
+          secret: 'other_secret',
+        },
+        requestBuilder,
+      );
+
+      expect(subscription.validateSignature(hash, fakePayloadSent)).toBeFalsy();
+    });
+  });
 });