How to use Application.RTD in the xlwings API way

The Application.RTD property in Excel, accessed via the xlwings API, provides a powerful interface for working with Real-Time Data (RTD) servers. RTD enables Excel to receive live, continuously updated data from external sources, such as financial market feeds, sensor data, or custom server applications, without manual refreshes. This functionality is essential for building dynamic dashboards and monitoring systems directly within Excel workbooks.

Functionality
The primary purpose of the RTD property is to instantiate an IRTDUpdateEvent object. This object acts as the core event handler for the RTD server communication within Excel. It manages the update notifications, telling Excel when new data is available from the server. Through xlwings, developers can integrate Python-based logic to act as or interact with RTD servers, enabling real-time data processing and visualization directly from Python scripts.

Syntax and Parameters
In xlwings, you access this property through the Application object. The typical call pattern is:

import xlwings as xw
rtd_event = xw.apps.active.api.RTD

Here, rtd_event becomes a COM object representing Excel’s IRTDUpdateEvent interface. The key method of this interface is UpdateNotify(), which you would call from your RTD server code to signal Excel that fresh data is ready. The RTD property itself does not take parameters; its value is the event object.

Example: Simulating an RTD Update Trigger
The following xlwings code snippet demonstrates how to acquire the RTD event object and use it to manually trigger a data update notification in Excel. This is useful when you have a Python script acting as a data source.

import xlwings as xw
import time

# Connect to the active Excel instance
app = xw.apps.active

# Access the RTD UpdateEvent object
rtd_update_event = app.api.RTD

# Simulate a background data-fetching loop
print("RTD server simulation started. Updates will be triggered every 5 seconds.")
try:
    while True:
        # ... (Your code here would fetch new real-time data)
        # Notify Excel that new data is available for any RTD-linked cells
        rtd_update_event.UpdateNotify()
        print(f"Update notification sent at {time.strftime('%H:%M:%S')}")
        time.sleep(5)
except KeyboardInterrupt:
    print("RTD update simulation stopped.")