How to Detect a File Format and Check if the File is Encrypted with Node.js via C++

Sometimes you need to detect a file’s format before opening it because the file extension does not guarantee that the file content is appropriate. The file might be encrypted (a password-protected file) so it can’t be read directly, or we should not read it. Aspose.Cells for Node.js via C++ provides the FileFormatUtil.detectFileFormat(Uint8Array) static method and some relevant APIs that you can use to process documents.

The following sample code illustrates how to detect a file format (using the file path) and check its extension. You can also determine whether the file is encrypted.

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

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "Book1.xlsx");

// Detect file format
const info = AsposeCells.FileFormatUtil.detectFileFormat(new Uint8Array(require("fs").readFileSync(filePath)));

// Gets the detected load format
console.log("The spreadsheet format is: " + AsposeCells.FileFormatUtil.loadFormatToExtension(info.getLoadFormat()));

// Check if the file is encrypted.
console.log("The file is encrypted: " + info.isEncrypted());