fix(core): Improve error handling on Credentials decryption

packages/core/src/__tests__/credentials.test.ts

@@ -2,6 +2,7 @@ import { Container } from '@n8n/di';
 import { mock } from 'jest-mock-extended';
 import type { CredentialInformation } from 'n8n-workflow';
 
+import { CREDENTIAL_ERRORS } from '@/constants';
 import { Cipher } from '@/encryption/cipher';
 import type { InstanceSettings } from '@/instance-settings';
 
@@ -57,4 +58,38 @@ describe('Credentials', () => {
 			expect(credentials.getData().key1).toEqual(initialData);
 		});
 	});
+
+	describe('getData', () => {
+		const nodeCredentials = { id: '123', name: 'testName' };
+		const credentialType = 'testApi';
+
+		test('should throw an error when data is missing', () => {
+			const credentials = new Credentials(nodeCredentials, credentialType);
+			credentials.data = undefined;
+
+			expect(() => credentials.getData()).toThrow(CREDENTIAL_ERRORS.NO_DATA);
+		});
+
+		test('should throw an error when decryption fails', () => {
+			const credentials = new Credentials(nodeCredentials, credentialType);
+			credentials.data = 'invalid-data';
+
+			expect(() => credentials.getData()).toThrow(CREDENTIAL_ERRORS.DECRYPTION_FAILED);
+		});
+
+		test('should throw an error when JSON parsing fails', () => {
+			const credentials = new Credentials(nodeCredentials, credentialType);
+			credentials.data = cipher.encrypt('invalid-json-string');
+
+			expect(() => credentials.getData()).toThrow(CREDENTIAL_ERRORS.INVALID_JSON);
+		});
+		test('should successfully decrypt and parse valid JSON credentials', () => {
+			const credentials = new Credentials(nodeCredentials, credentialType);
+			credentials.setData({ username: 'testuser', password: 'testpass' });
+
+			const decryptedData = credentials.getData();
+			expect(decryptedData.username).toBe('testuser');
+			expect(decryptedData.password).toBe('testpass');
+		});
+	});
 });

packages/core/src/constants.ts

@@ -14,3 +14,10 @@ export const CONFIG_FILES = 'N8N_CONFIG_FILES';
 export const BINARY_DATA_STORAGE_PATH = 'N8N_BINARY_DATA_STORAGE_PATH';
 export const UM_EMAIL_TEMPLATES_INVITE = 'N8N_UM_EMAIL_TEMPLATES_INVITE';
 export const UM_EMAIL_TEMPLATES_PWRESET = 'N8N_UM_EMAIL_TEMPLATES_PWRESET';
+
+export const CREDENTIAL_ERRORS = {
+	NO_DATA: 'No data is set on this credentials.',
+	DECRYPTION_FAILED:
+		'Credentials could not be decrypted. The likely reason is that a different "encryptionKey" was used to encrypt the data.',
+	INVALID_JSON: 'Decrypted credentials data is not valid JSON.',
+};

packages/core/src/credentials.ts

@@ -2,6 +2,7 @@ import { Container } from '@n8n/di';
 import type { ICredentialDataDecryptedObject, ICredentialsEncrypted } from 'n8n-workflow';
 import { ApplicationError, ICredentials, jsonParse } from 'n8n-workflow';
 
+import { CREDENTIAL_ERRORS } from '@/constants';
 import { Cipher } from '@/encryption/cipher';
 
 export class Credentials<
@@ -21,17 +22,20 @@ export class Credentials<
 	 */
 	getData(): T {
 		if (this.data === undefined) {
-			throw new ApplicationError('No data is set so nothing can be returned.');
+			throw new ApplicationError(CREDENTIAL_ERRORS.NO_DATA);
 		}
 
+		let decryptedData: string;
 		try {
-			const decryptedData = this.cipher.decrypt(this.data);
+			decryptedData = this.cipher.decrypt(this.data);
+		} catch (e) {
+			throw new ApplicationError(CREDENTIAL_ERRORS.DECRYPTION_FAILED, { cause: e });
+		}
 
+		try {
 			return jsonParse(decryptedData);
 		} catch (e) {
-			throw new ApplicationError(
-				'Credentials could not be decrypted. The likely reason is that a different "encryptionKey" was used to encrypt the data.',
-			);
+			throw new ApplicationError(CREDENTIAL_ERRORS.INVALID_JSON, { cause: e });
 		}
 	}