Can I add some actions after file is uploaded? like send an email notification or change the file-name?
Yes, look for this line in filegator/include/blueimp/server/php/upload.class.php
and add you custom code after or before that line, something like this email notification:
mail('email@example.com', 'Subject', 'New file uploaded');
You can access current user’s parameters such as username, email, homedir or permissions via $_SESSION[‘simple_auth’] variable. See this example:
mail('firstname.lastname@example.org', 'Subject', 'New file uploaded by the user: '.$_SESSION['simple_auth']['username']);