feat(OpenAI Node): Support custom headers for model requests (#17835)

Co-authored-by: Idir Ouhab <ouhab.idir@gmail.com>
Co-authored-by: Oleg Ivaniv <me@olegivaniv.com>

packages/nodes-base/credentials/test/OpenAiApi.credentials.test.ts

@@ -0,0 +1,155 @@
+import type { ICredentialDataDecryptedObject, IHttpRequestOptions } from 'n8n-workflow';
+
+import { OpenAiApi } from '../OpenAiApi.credentials';
+
+describe('OpenAiApi Credential', () => {
+	const openAiApi = new OpenAiApi();
+
+	it('should have correct properties', () => {
+		expect(openAiApi.name).toBe('openAiApi');
+		expect(openAiApi.displayName).toBe('OpenAi');
+		expect(openAiApi.documentationUrl).toBe('openAi');
+		expect(openAiApi.properties).toHaveLength(6);
+		expect(openAiApi.test.request.baseURL).toBe('={{$credentials?.url}}');
+		expect(openAiApi.test.request.url).toBe('/models');
+	});
+
+	describe('authenticate', () => {
+		it('should add Authorization header with API key only', async () => {
+			const credentials: ICredentialDataDecryptedObject = {
+				apiKey: 'sk-test123456789',
+			};
+
+			const requestOptions: IHttpRequestOptions = {
+				headers: {},
+				url: '/models',
+				baseURL: 'https://api.openai.com/v1',
+			};
+
+			const result = await openAiApi.authenticate(credentials, requestOptions);
+
+			expect(result.headers).toEqual({
+				Authorization: 'Bearer sk-test123456789',
+				'OpenAI-Organization': undefined,
+			});
+		});
+
+		it('should add Authorization and Organization headers', async () => {
+			const credentials: ICredentialDataDecryptedObject = {
+				apiKey: 'sk-test123456789',
+				organizationId: 'org-123',
+			};
+
+			const requestOptions: IHttpRequestOptions = {
+				headers: {},
+				url: '/models',
+				baseURL: 'https://api.openai.com/v1',
+			};
+
+			const result = await openAiApi.authenticate(credentials, requestOptions);
+
+			expect(result.headers).toEqual({
+				Authorization: 'Bearer sk-test123456789',
+				'OpenAI-Organization': 'org-123',
+			});
+		});
+
+		it('should add custom header when header toggle is enabled', async () => {
+			const credentials: ICredentialDataDecryptedObject = {
+				apiKey: 'sk-test123456789',
+				organizationId: 'org-123',
+				header: true,
+				headerName: 'X-Custom-Header',
+				headerValue: 'custom-value-123',
+			};
+
+			const requestOptions: IHttpRequestOptions = {
+				headers: {},
+				url: '/models',
+				baseURL: 'https://api.openai.com/v1',
+			};
+
+			const result = await openAiApi.authenticate(credentials, requestOptions);
+
+			expect(result.headers).toEqual({
+				Authorization: 'Bearer sk-test123456789',
+				'OpenAI-Organization': 'org-123',
+				'X-Custom-Header': 'custom-value-123',
+			});
+		});
+
+		it('should not add custom header when header toggle is disabled', async () => {
+			const credentials: ICredentialDataDecryptedObject = {
+				apiKey: 'sk-test123456789',
+				header: false,
+				headerName: 'X-Custom-Header',
+				headerValue: 'custom-value-123',
+			};
+
+			const requestOptions: IHttpRequestOptions = {
+				headers: {},
+				url: '/models',
+				baseURL: 'https://api.openai.com/v1',
+			};
+
+			const result = await openAiApi.authenticate(credentials, requestOptions);
+
+			expect(result.headers).toEqual({
+				Authorization: 'Bearer sk-test123456789',
+				'OpenAI-Organization': undefined,
+			});
+			expect(result.headers?.['X-Custom-Header']).toBeUndefined();
+		});
+
+		it('should preserve existing headers', async () => {
+			const credentials: ICredentialDataDecryptedObject = {
+				apiKey: 'sk-test123456789',
+				header: true,
+				headerName: 'X-Custom-Header',
+				headerValue: 'custom-value-123',
+			};
+
+			const requestOptions: IHttpRequestOptions = {
+				url: '/models',
+				baseURL: 'https://api.openai.com/v1',
+			};
+
+			const result = await openAiApi.authenticate(credentials, requestOptions);
+
+			const raw =
+				typeof (result.headers as any)?.get === 'function'
+					? Object.fromEntries((result.headers as unknown as Headers).entries())
+					: (result.headers as Record<string, string | undefined>);
+
+			const headers = Object.fromEntries(Object.entries(raw).map(([k, v]) => [k.toLowerCase(), v]));
+
+			expect(headers).toEqual(
+				expect.objectContaining({
+					authorization: 'Bearer sk-test123456789',
+					'x-custom-header': 'custom-value-123',
+					'openai-organization': undefined,
+				}),
+			);
+		});
+
+		it('should handle empty organization ID', async () => {
+			const credentials: ICredentialDataDecryptedObject = {
+				apiKey: 'sk-test123456789',
+				organizationId: '',
+			};
+
+			const requestOptions: IHttpRequestOptions = {
+				headers: {},
+				url: '/models',
+				baseURL: 'https://api.openai.com/v1',
+			};
+
+			const result = await openAiApi.authenticate(credentials, requestOptions);
+
+			expect(result.headers).toEqual({
+				Authorization: 'Bearer sk-test123456789',
+				'OpenAI-Organization': '',
+			});
+		});
+	});
+});