Website Login cgi-script

we need a login for an existing web application. Once login and password is entered and verified, the script should call a given cgi-script that deliveres the application layout. In addition the existing script, that is to be called after login should be extended by a feature that picks up a few parameters from a param-file (e. g. todays date, device,..) and use them in order to select a certain directory tree. Currently website waits until the user has selected manually date and device before it selects the path and shows the data. In the future it shoult already start with a pre-selection from a parameter file.