how to do lazy loading in GridJs

about lazy loading

When dealing with a spreadsheet file containing numerous worksheets, we can optimize the loading process by initially loading only the active worksheet.

This strategy ensures that the server-side JSON response initially includes only the data pertaining to the actively selected worksheet.

As a result, the initial web traffic is significantly reduced, enhancing the user experience by minimizing load times.

Furthermore, GridJs is designed to dynamically respond to user interactions. Specifically, when a user clicks on a different worksheet,

GridJs intelligently triggers a request to the server to fetch the data specifically for that worksheet.

This on-demand loading mechanism not only further reduces unnecessary data transfers but also ensures that the user always has access to the most up-to-date information for the worksheet they are currently working on.

By adopting this approach, we not only optimize the initial load time but also maintain a responsive and efficient application that scales well with the increasing number of worksheets in the spreadsheet file.

To implement lazy loading in GridJs ,the steps are

Set Config Option for lazy loading.

for example:

       Config.set_lazy_loading(True)

Set action URL for lazy loading.

for example:

 const lazyLoadingUrl = "/GridJs2/LazyLoading";
 xs.setLazyLoadingUrl(lazyLoadingUrl);

After user click the other worksheet that is not the active one��the action of query data wil be triggered automatically by the spreadsheet application

Implement lazy loading action in Controller in serverside .

for example:

@app.route('/GridJs2/LazyLoading', methods=['POST'])
def lazy_loading():
    sheet_name = request.form.get('name', '')
    uid = request.form.get('uid', '')
    if not sheet_name:
        return jsonify({'error': 'sheet_name is required'}), 400
    if not uid:
        return jsonify({'error': 'uid is required'}), 400

    wbj = GridJsWorkbook()
    try:
        
        output = io.BytesIO()
        with gzip.GzipFile(fileobj=output, mode='wb', compresslevel=9) as gzip_stream:
             wbj.lazy_loading_stream(gzip_stream,uid, sheet_name)
            

        response = Response(output.getvalue(), mimetype='application/json')
        response.headers['Content-Encoding'] = 'gzip'

        return response
    except Exception as e:
        return Response(str(e), status=500)