feat: Add HTTP proxy for supported LLM nodes (#15449)

packages/@n8n/nodes-langchain/utils/httpProxyAgent.ts

@@ -0,0 +1,11 @@
+import { HttpsProxyAgent } from 'https-proxy-agent';
+
+export function getHttpProxyAgent() {
+	const httpProxy =
+		process.env.HTTPS_PROXY ??
+		process.env.https_proxy ??
+		process.env.HTTP_PROXY ??
+		process.env.http_proxy;
+
+	return httpProxy ? new HttpsProxyAgent(httpProxy) : undefined;
+}

packages/@n8n/nodes-langchain/utils/tests/httpProxyAgent.test.ts

@@ -0,0 +1,88 @@
+import { HttpsProxyAgent } from 'https-proxy-agent';
+
+import { getHttpProxyAgent } from '../httpProxyAgent';
+
+// Mock the https-proxy-agent package
+jest.mock('https-proxy-agent', () => ({
+	HttpsProxyAgent: jest.fn().mockImplementation((url) => ({ proxyUrl: url })),
+}));
+
+describe('getHttpProxyAgent', () => {
+	// Store original environment variables
+	const originalEnv = { ...process.env };
+
+	// Reset environment variables before each test
+	beforeEach(() => {
+		jest.clearAllMocks();
+		process.env = { ...originalEnv };
+		delete process.env.HTTP_PROXY;
+		delete process.env.http_proxy;
+		delete process.env.HTTPS_PROXY;
+		delete process.env.https_proxy;
+	});
+
+	// Restore original environment after all tests
+	afterAll(() => {
+		process.env = originalEnv;
+	});
+
+	it('should return undefined when no proxy environment variables are set', () => {
+		const agent = getHttpProxyAgent();
+		expect(agent).toBeUndefined();
+		expect(HttpsProxyAgent).not.toHaveBeenCalled();
+	});
+
+	it('should create HttpsProxyAgent when HTTP_PROXY is set', () => {
+		const proxyUrl = 'http://proxy.example.com:8080';
+		process.env.HTTP_PROXY = proxyUrl;
+
+		const agent = getHttpProxyAgent();
+
+		expect(HttpsProxyAgent).toHaveBeenCalledWith(proxyUrl);
+		expect(agent).toEqual({ proxyUrl });
+	});
+
+	it('should create HttpsProxyAgent when http_proxy is set', () => {
+		const proxyUrl = 'http://proxy.example.com:8080';
+		process.env.http_proxy = proxyUrl;
+
+		const agent = getHttpProxyAgent();
+
+		expect(HttpsProxyAgent).toHaveBeenCalledWith(proxyUrl);
+		expect(agent).toEqual({ proxyUrl });
+	});
+
+	it('should create HttpsProxyAgent when HTTPS_PROXY is set', () => {
+		const proxyUrl = 'http://proxy.example.com:8080';
+		process.env.HTTPS_PROXY = proxyUrl;
+
+		const agent = getHttpProxyAgent();
+
+		expect(HttpsProxyAgent).toHaveBeenCalledWith(proxyUrl);
+		expect(agent).toEqual({ proxyUrl });
+	});
+
+	it('should create HttpsProxyAgent when https_proxy is set', () => {
+		const proxyUrl = 'http://proxy.example.com:8080';
+		process.env.https_proxy = proxyUrl;
+
+		const agent = getHttpProxyAgent();
+
+		expect(HttpsProxyAgent).toHaveBeenCalledWith(proxyUrl);
+		expect(agent).toEqual({ proxyUrl });
+	});
+
+	it('should respect priority order of proxy environment variables', () => {
+		// Set multiple proxy environment variables
+		process.env.HTTP_PROXY = 'http://http-proxy.example.com:8080';
+		process.env.http_proxy = 'http://http-proxy-lowercase.example.com:8080';
+		process.env.HTTPS_PROXY = 'http://https-proxy.example.com:8080';
+		process.env.https_proxy = 'http://https-proxy-lowercase.example.com:8080';
+
+		const agent = getHttpProxyAgent();
+
+		// Should use HTTPS_PROXY as it has highest priority now
+		expect(HttpsProxyAgent).toHaveBeenCalledWith('http://https-proxy.example.com:8080');
+		expect(agent).toEqual({ proxyUrl: 'http://https-proxy.example.com:8080' });
+	});
+});