How to multi-upload a file?

Question

Django

@csrf_exempt
def upload_file(request):
    if request.method == 'POST':
        try:
            file = request.FILES['data']
            destination = open(upload_dir + file.name, 'wb+')
            for chunk in file.chunks():
                destination.write(chunk)
                destination.close()
            return JSONResponse({
                'success': True,
                'message': 'File upload successful',
                'path': upload_dir+file.name
            })
        except Exception as e:
            return JSONResponse({
                'success': False,
                'message': "fail to upload file"
            })

this way I get the file, but how to check how many files have arrived and then save them all?