How to use Application.FileValidation in the xlwings API way

The FileValidation property of the Application object in Excel is a feature designed to manage file validation settings for the application. This property allows developers to control how Excel handles files that originate from potentially unsafe locations, such as those downloaded from the internet or received via email, which may contain macros or other executable content. By using the FileValidation property, you can programmatically adjust Excel’s behavior to either enable or disable validation checks on these files, enhancing security by preventing the automatic execution of potentially harmful code. In xlwings, which provides a Pythonic interface to Excel’s COM automation, accessing this property enables automation of security settings directly from Python scripts, integrating Excel file handling into broader data processing workflows.

Syntax in xlwings:
In xlwings, the Application object is typically accessed through the app object when connecting to an Excel instance. The FileValidation property can be retrieved or set using the following format:

app.api.FileValidation

This property returns or accepts an integer value corresponding to the file validation mode. The values are defined in the Excel object model as follows:

• 0: msoFileValidationDefault – Uses the default file validation behavior.
• 1: msoFileValidationSkip – Skips file validation for the current session.
• 2: msoFileValidationOn – Turns on file validation for the current session.

Note that in xlwings, the api attribute provides direct access to the underlying Excel COM object, allowing you to use properties and methods as documented in the Excel VBA object model. The FileValidation property is read-write, meaning you can both get its current value and set it to change Excel’s behavior.

Code Examples:
Here are practical examples demonstrating how to use the FileValidation property with xlwings:

1. Retrieving the Current File Validation Setting:
   This example connects to an active Excel instance and prints the current file validation mode.

import xlwings as xw

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

# Get the current FileValidation value
validation_mode = app.api.FileValidation
print(f"Current FileValidation mode: {validation_mode}")

2. Setting the File Validation to Skip Validation:
   This example sets the file validation to skip mode, which might be useful when processing trusted files in a controlled environment, and then restores it to the default.

import xlwings as xw

app = xw.apps.active

# Save the current mode for later restoration
original_mode = app.api.FileValidation

# Set to skip validation
app.api.FileValidation = 1 # msoFileValidationSkip
print("File validation set to skip mode.")

# Perform tasks with files (e.g., open a workbook)
# ...

# Restore the original mode
app.api.FileValidation = original_mode
print("File validation restored to original mode.")

3. Enabling File Validation for Enhanced Security:
   This example ensures that file validation is turned on, which is recommended for general use to maintain security.

import xlwings as xw

app = xw.apps.active

# Enable file validation
app.api.FileValidation = 2 # msoFileValidationOn
print("File validation is now enabled.")