feat: Respond to chat and wait for response (#12546)

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>
Co-authored-by: Shireen Missi <94372015+ShireenMissi@users.noreply.github.com>

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

@@ -117,6 +117,20 @@ export function getSessionId(
 			sessionId = bodyData.sessionId as string;
 		} else {
 			sessionId = ctx.evaluateExpression('{{ $json.sessionId }}', itemIndex) as string;
+
+			// try to get sessionId from chat trigger
+			if (!sessionId || sessionId === undefined) {
+				try {
+					const chatTrigger = ctx.getChatTrigger();
+
+					if (chatTrigger) {
+						sessionId = ctx.evaluateExpression(
+							`{{ $('${chatTrigger.name}').first().json.sessionId }}`,
+							itemIndex,
+						) as string;
+					}
+				} catch (error) {}
+			}
 		}
 
 		if (sessionId === '' || sessionId === undefined) {

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

@@ -10,6 +10,7 @@ import {
 	getConnectedTools,
 	hasLongSequentialRepeat,
 	unwrapNestedOutput,
+	getSessionId,
 } from '../helpers';
 import { N8nTool } from '../N8nTool';
 
@@ -376,6 +377,52 @@ describe('unwrapNestedOutput', () => {
 	});
 });
 
+describe('getSessionId', () => {
+	let mockCtx: any;
+
+	beforeEach(() => {
+		mockCtx = {
+			getNodeParameter: jest.fn(),
+			evaluateExpression: jest.fn(),
+			getChatTrigger: jest.fn(),
+			getNode: jest.fn(),
+		};
+	});
+
+	it('should retrieve sessionId from bodyData', () => {
+		mockCtx.getBodyData = jest.fn();
+		mockCtx.getNodeParameter.mockReturnValue('fromInput');
+		mockCtx.getBodyData.mockReturnValue({ sessionId: '12345' });
+
+		const sessionId = getSessionId(mockCtx, 0);
+		expect(sessionId).toBe('12345');
+	});
+
+	it('should retrieve sessionId from chat trigger', () => {
+		mockCtx.getNodeParameter.mockReturnValue('fromInput');
+		mockCtx.evaluateExpression.mockReturnValueOnce(undefined);
+		mockCtx.getChatTrigger.mockReturnValue({ name: 'chatTrigger' });
+		mockCtx.evaluateExpression.mockReturnValueOnce('67890');
+		const sessionId = getSessionId(mockCtx, 0);
+		expect(sessionId).toBe('67890');
+	});
+
+	it('should throw error if sessionId is not found', () => {
+		mockCtx.getNodeParameter.mockReturnValue('fromInput');
+		mockCtx.evaluateExpression.mockReturnValue(undefined);
+		mockCtx.getChatTrigger.mockReturnValue(undefined);
+
+		expect(() => getSessionId(mockCtx, 0)).toThrow(NodeOperationError);
+	});
+
+	it('should use custom sessionId if provided', () => {
+		mockCtx.getNodeParameter.mockReturnValueOnce('custom').mockReturnValueOnce('customSessionId');
+
+		const sessionId = getSessionId(mockCtx, 0);
+		expect(sessionId).toBe('customSessionId');
+	});
+});
+
 describe('hasLongSequentialRepeat', () => {
 	it('should return false for text shorter than threshold', () => {
 		const text = 'a'.repeat(99);