Protecting Worksheets with Node.js via C++

When a worksheet is protected, the actions a user can take are restricted. For example, they cannot input data, insert, or delete rows or columns etc.

Protect Worksheets

Introduction

The general protection options in Microsoft Excel are:

Contents
Objects
Scenarios

Protected worksheets don’t hide or protect sensitive data, so it’s different from file encryption. Generally, worksheet protection is suitable for presentation purposes. It prevents the end user from modifying data, content, and formatting in the worksheet.

Protect a Worksheet

Aspose.Cells provides a class, Workbook that represents a Microsoft Excel file. The Workbook class contains a getWorksheets() collection that allows access to each worksheet in an Excel file. A worksheet is represented by the Worksheet class.

The Worksheet class provides the protect(ProtectionType) method that is used to apply protection on the worksheet. The protect(ProtectionType) method accepts the following parameters:

Protection Type, the type of protection to apply on the worksheet. Protection type is applied with the help of the ProtectionType enumeration.
New Password, the new password used to protect the worksheet.
Old Password, the old password, if the worksheet is already password protected. If the worksheet is not already protected then just pass null.

The ProtectionType enumeration contains the following pre-defined protection types:

Protection Types	Description
All	The user cannot modify anything on this worksheet
Contents	The user cannot enter data in this worksheet
Objects	The user cannot modify drawing objects
Scenarios	The user cannot modify saved scenarios
Structure	The user cannot modify the structure
Windows	Protection is applied to windows
None	No protection is applied

The example below shows how to protect a worksheet with a password.

const path = require("path");
const fs = require("fs");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "book1.xls");

// Instantiating a Workbook object with file buffer
const excel = new AsposeCells.Workbook(fs.readFileSync(filePath));

// Accessing the first worksheet in the Excel file
const worksheet = excel.getWorksheets().get(0);

// Protecting the worksheet with a password
worksheet.protect(AsposeCells.ProtectionType.All, "aspose", null);

// Saving the modified Excel file in default format
excel.save(path.join(dataDir, "output.out.xls"), AsposeCells.SaveFormat.Excel97To2003);

After the above code is used to protect the worksheet, you can check the protection on the worksheet by opening it. Once you open the file and try to add some data to the worksheet, you will see the following dialog:

A dialog warning that a user can’t modify the worksheet

To work on the worksheet, unprotect the worksheet by selecting the Protection, then Unprotect Sheet from the Tools menu item.

After you select Unprotect Sheet menu item, a dialog will open that would prompt you to enter the password so that you may work on the worksheet as shown below:

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Protect a few Cells in the Worksheet Using Microsoft Excel

There might be certain scenarios where you need to lock a few cells only in the worksheet. If you want to lock some specific cells in the worksheet, you have to unlock all the other cells in the worksheet. All the cells in a worksheet are already initialized for locking; you may check this by opening any Excel file in MS Excel and clicking the Format | Cells… to show the Format Cells dialog box and then click the Protection tab and see a checkbox labeled “Locked” is checked by default.

The following points describe how to lock a few cells using MS Excel. This method applies to Microsoft Office Excel 97, 2000, 2002, 2003, and greater versions.

Select the entire worksheet by clicking the Select All button (the gray rectangle directly above the row number for row 1 and to the left of column letter A).
Click Cells on the Format menu, click the Protection tab, and then clear the Locked checkbox. This unlocks all the cells on the worksheet. If the Cells command is not available, parts of the worksheet may already be locked. On the Tools menu, point to Protection, and then click Unprotect Sheet.
Select just the cells you want to lock and repeat step 2, but this time select the Locked checkbox.
On the Tools menu, point to Protection, click Protect Sheet and then click OK.
In the Protect Sheet dialog box, you have the option to specify a password and select the elements that you want users to be able to change.

Protect a few Cells in the Worksheet Using Aspose.Cells

In this method, we use the Aspose.Cells API only to do the task.

Example: The following example exhibits how to protect a few cells in the worksheet. It unlocks all the cells in the worksheet first and then locks 3 cells (A1, B1, C1) in it. Finally, it protects the worksheet. The Style object contains a boolean property, isLocked(). You can set isLocked() property to true or false and apply the Column/Row.applyStyle() method to lock or unlock the row/column with your desired attributes.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");

// Create a new workbook.
const wb = new AsposeCells.Workbook();

// Create a worksheet object and obtain the first sheet.
const sheet = wb.getWorksheets().get(0);

// Define the style object.
let style;

// Define the styleflag object
const styleflag = new AsposeCells.StyleFlag();

// Loop through all the columns in the worksheet and unlock them.
for (let i = 0; i <= 255; i++) {
style = sheet.getCells().getColumns().get((i)).getStyle();
style.setIsLocked(false);
styleflag.setLocked(true);
sheet.getCells().getColumns().get((i)).applyStyle(style, styleflag);
}

// Lock the three cells...i.e. A1, B1, C1.
style = sheet.getCells().get("A1").getStyle();
style.setIsLocked(true);
sheet.getCells().get("A1").setStyle(style);
style = sheet.getCells().get("B1").getStyle();
style.setIsLocked(true);
sheet.getCells().get("B1").setStyle(style);
style = sheet.getCells().get("C1").getStyle();
style.setIsLocked(true);
sheet.getCells().get("C1").setStyle(style);

// Finally, Protect the sheet now.
sheet.protect(AsposeCells.ProtectionType.All);

// Save the excel file.
wb.save(path.join(dataDir, "output.out.xls"), AsposeCells.SaveFormat.Excel97To2003);

Protect a Row in the Worksheet

Aspose.Cells allows you to easily lock any row in the worksheet. Here, we can make use of the applyStyle(Style, StyleFlag) method of Aspose.Cells.Row class to apply Style to a particular row in the worksheet. This method takes two arguments: a Style object and StyleFlag object which has all the members related to applied formatting.

The following example shows how to protect a row in the worksheet. It unlocks all the cells in the worksheet first and then locks the first row in it. Finally, it protects the worksheet. The Style object contains a boolean property, isLocked(). You can set isLocked() property to true or false to lock or unlock the row/column using the StyleFlag object.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");

// Create a new workbook.
const wb = new AsposeCells.Workbook();

// Create a worksheet object and obtain the first sheet.
const sheet = wb.getWorksheets().get(0);

// Define the style object.
let style;

// Define the styleflag object.
const flag = new AsposeCells.StyleFlag();

// Loop through all the columns in the worksheet and unlock them.
for (let i = 0; i <= 255; i++) {
style = sheet.getCells().getColumns().get(i).getStyle();
style.setIsLocked(false);
flag.setLocked(true);
sheet.getCells().getColumns().get(i).applyStyle(style, flag);
}

// Get the first row style.
style = sheet.getCells().getRows().get(0).getStyle();

// Lock it.
style.setIsLocked(true);

// Set the lock setting.
flag.setLocked(true);

// Apply the style to the first row.
sheet.getCells().applyRowStyle(0, style, flag);

// Protect the sheet.
sheet.protect(AsposeCells.ProtectionType.All);

// Save the excel file.
wb.save(path.join(dataDir, "output.out.xls"), AsposeCells.SaveFormat.Excel97To2003);

Protect a Column in the Worksheet

Aspose.Cells allows you to easily lock any column in the worksheet. Here, we can make use of the applyStyle(Style, StyleFlag) method of Aspose.Cells.Column class to apply Style to a particular column in the worksheet. This method takes two arguments: a Style object and StyleFlag object which has all the members related to applied formatting.

The following example shows how to protect a column in the worksheet. It unlocks all the cells in the worksheet first and then locks the first column in it. Finally, it protects the worksheet. The Style object contains a boolean property, isLocked(). You can set isLocked() property to true or false to lock or unlock the row/column using the StyleFlag object.

const AsposeCells = require("aspose.cells.node");
const path = require("path");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");

// Create a new workbook.
const wb = new AsposeCells.Workbook();

// Create a worksheet object and obtain the first sheet.
const sheet = wb.getWorksheets().get(0);

// Define the style object.
let style;

// Define the styleflag object.
const flag = new AsposeCells.StyleFlag();

// Loop through all the columns in the worksheet and unlock them.
for (let i = 0; i <= 255; i++) {
style = sheet.getCells().getColumns().get(i).getStyle();
style.setIsLocked(false);
flag.setLocked(true);
sheet.getCells().getColumns().get(i).applyStyle(style, flag);
}

// Get the first column style.
style = sheet.getCells().getColumns().get(0).getStyle();

// Lock it.
style.setIsLocked(true);

// Apply the style to the first column.
sheet.getCells().getColumns().get(0).applyStyle(style, flag);

// Protect the sheet.
sheet.protect(AsposeCells.ProtectionType.All);

// Save the excel file.
wb.save(path.join(dataDir, "output.out.xls"), AsposeCells.SaveFormat.Excel97To2003);

Allow Users to Edit Ranges

The following example shows how to allow users to edit a range in a protected worksheet.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");

// Instantiate a new Workbook
const book = new AsposeCells.Workbook();

// Get the first (default) worksheet
const sheet = book.getWorksheets().get(0);

// Get the Allow Edit Ranges
const allowRanges = sheet.getAllowEditRanges();

// Define ProtectedRange
let protected_range;

// Create the range
const idx = allowRanges.add("r2", 1, 1, 3, 3);
protected_range = allowRanges.get(idx);

// Specify the password
protected_range.setPassword("123");

// Protect the sheet
sheet.protect(AsposeCells.ProtectionType.All);

// Save the Excel file
book.save(path.join(dataDir, "protectedrange.out.xls"));

Unprotect a Worksheet with Node.js via C++