add "Princeton Users Log in to view" button or banner to unpublished DPUL URL page

[kelea99]

Summary

As a dpul curator, admin, or viewer, I would like to be able to navigate to the URL for my unpublished site and be given a prompt to sign in to view my site, if I am not already signed in to DPUL.

Currently, when folks navigate to an unpublished DPUL URL, they get "Not found. Authentication passthru." via ahttps://dpul.princeton.edu/users/auth/cas redirect (see screenshot). As a work around, I always add directions to every email or slack message, explaining how folks need to navigate to dpul.princeton.edu, sign in, and then look for their site.

Already implemented:
if you look in the princeton sound archive, there is a yellow banner alerting folks to sign in to view all the content (see screenshot). There is also a blue button for items in the catalog "Princeton Users Log in to view" (see screenshot)

Impact

Please include hard deadlines, if the exhibit is part of an event, the issue is stopping work, etc.

Priority recommendation

• asap
• within the next 3 weeks
• PO will prioritize

Sudden Priority Justification

Required if "asap" or "within the next 3 weeks" is checked. Add "Sudden Priority" and "Maintenance/Research labels

Expected behaviour

When I navigate to a URL (example: https://dpul.princeton.edu/test-augustine), I will get either a banner or a button prompting me to sign in or sign up to view my site/content.

Actual behaviour

When I navigate to a URL (example: https://dpul.princeton.edu/test-augustine), I am redirected to https://dpul.princeton.edu/users/auth/cas and "Not found. Authentication passthru." in plaintext in the upper left of the screen.

Steps to reproduce behaviour

Screenshots