Jquery BlueImp how to change filename before upload?

require('UploadHandler.php');
class CustomUploadHandler extends UploadHandler {
    protected function trim_file_name($file_path, $name, $size, $type, $error, $index, $content_range) {
            $name = 'First_' . microtime(true);
            $name = str_replace('.', '', $name);
            return $name;
        }
}

$upload_handler = new CustomUploadHandler();

In your custom file index.php initialize this function of UploadHandler.php

This can be achieved with only change the trim_file_name() function to the following in the UploadHandler.php file.

protected function trim_file_name(VARIABLES) {
    $name = uniqid();
    return $name;
}

and that's all

Here's a client-side solution specific to BlueImp. It uses BlueImp's "add" callback. My example will strip commas from the filename.

$('#fileupload').fileupload({
    add: function (e, data) {
        $.each(data.files, function (index, file) {
            //set new name here
            var newname = data.files[index].name.replace(",", "");
            Object.defineProperty(data.files[index], 'name', {
                value: newname
            });
        });
        $.blueimp.fileupload.prototype.options.add.call(this, e, data);
    }
})