Check if Digital Signature of VBA Code is Valid with JavaScript via C++

Check if Digital Signature of VBA Code is Valid in JavaScript

The following code demonstrates the usage of this property using the sample excel file which you can download from the provided link. The same excel file has a valid signature but when we modify its VBA code and save the workbook and then recheck, we find its signature has become invalid.

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells VBA Signature Example</title>
    </head>
    <body>
        <h1>VBA Signature Example</h1>
        <input type="file" id="fileInput" accept=".xls,.xlsx,.xlsm,.csv" />
        <button id="runExample">Run Example</button>
        <a id="downloadLink" style="display: none;">Download Result</a>
        <div id="result"></div>
    </body>

    <script src="aspose.cells.js.min.js"></script>
    <script type="text/javascript">
        const { Workbook, SaveFormat, Utils } = AsposeCells;
        
        AsposeCells.onReady({
            license: "/lic/aspose.cells.enc",
            fontPath: "/fonts/",
            fontList: [
                "arial.ttf",
                "NotoSansSC-Regular.ttf"
            ]
        }).then(() => {
            console.log("Aspose.Cells initialized");
        });

        document.getElementById('runExample').addEventListener('click', async () => {
            const fileInput = document.getElementById('fileInput');
            const resultEl = document.getElementById('result');
            if (!fileInput.files.length) {
                resultEl.innerHTML = '<p style="color: red;">Please select an Excel file (preferably .xlsm).</p>';
                return;
            }

            const file = fileInput.files[0];
            const arrayBuffer = await file.arrayBuffer();

            // Loads the workbook which contains the VBA project
            const workbook = new Workbook(new Uint8Array(arrayBuffer));

            // Signature status before modification
            const isSignedBefore = workbook.vbaProject.isValidSigned();
            console.log("Is VBA Code Project Valid Signed: " + isSignedBefore);

            // Modify the VBA Code, save the workbook then reload
            // VBA Code Signature will now be invalid
            let code = workbook.vbaProject.modules.get(1).codes;
            code = code.replace("Welcome to Aspose", "Welcome to Aspose.Cells");
            workbook.vbaProject.modules.get(1).codes = code;

            // Save the modified workbook to a downloadable blob
            const outputData = workbook.save(SaveFormat.Xlsm);
            const blob = new Blob([outputData], { type: 'application/vnd.ms-excel.sheet.macroEnabled.12' });
            const downloadLink = document.getElementById('downloadLink');
            downloadLink.href = URL.createObjectURL(blob);
            downloadLink.download = 'output_out.xlsm';
            downloadLink.style.display = 'block';
            downloadLink.textContent = 'Download Modified Excel File';

            // Reload from the saved output data to verify signature status
            const reloadedWorkbook = new Workbook(new Uint8Array(outputData));
            const isSignedAfter = reloadedWorkbook.vbaProject.isValidSigned();
            console.log("Is VBA Code Project Valid Signed: " + isSignedAfter);

            // Update result UI
            resultEl.innerHTML = `
                <p style="color: green;">Operation completed successfully!</p>
                <p>Signature valid before modification: <strong>${isSignedBefore}</strong></p>
                <p>Signature valid after modification: <strong>${isSignedAfter}</strong></p>
                <p>Click the download link to get the modified file.</p>
            `;
        });
    </script>
</html>