Allow Anonymous Form Access with Authentication Required on Submission

[ophsr]

Contribution description

Currently, Forms can be configured either for authenticated users or for unauthenticated users.

When a form is available to unauthenticated users, the resulting ticket is generally created without a known requester identity.

This creates a usability issue in organizations using only ticket with requesters

Proposed feature:
Add a new form access mode: A new access option could be added alongside the existing visibility modes:

1. Authenticated users only
2. Anonymous users
3. Anonymous access with authentication required on submission

Public Form with Authentication Required on Submission, behavior:

1. Any user can open and fill the form without authentication.
2. When the user clicks Submit, GLPI checks whether the user is authenticated.
3. If the user is not authenticated:
4. Redirect to the authentication
5. Preserve all entered form data.
6. After successful authentication:
7. Restore the form data.
8. Complete the submission.
9. Create the ticket with the authenticated user as requester.

Example workflow

1. Open form (anonymous)
2. Fill fields
3. Click Submit
4. Authentication required
5. Login through SSO
6. Form data restored
7. Ticket created with authenticated requester

Benefits
Improved user experience.
Allows sharing direct links to forms without forcing authentication before the user knows what information is required.
Guarantees that tickets are always associated with an authenticated requester.
Reduces abandoned submissions caused by early authentication requirements.

Expected result
Users can complete forms immediately while organizations maintain requester identification and traceability requirements.