[Bug]: Sharing a photo album via public link does not work

[brawlins]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• Nextcloud Server is running on 64bit capable CPU, PHP and OS.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When you share a photo album via public link, the receiver cannot see the photos and is asked to log in. I would assume that a public link would be viewable by anyone who has the link, even if they do not have a login to your Nextcloud server.

When you load the link in your browser (in incognito mode - to simulate a user who is not logged in), you see thumbnails of the photos in the album. As soon as you click an image, you see a blank photo viewer with a spinner, and a login window pops up. If you cancel the login window, the spinner goes away and you see an error message: "Error loading [filename].jpg".

Steps to reproduce

1. Select some photos and add them to a new album.
2. Open your new album and click on the "share" icon.
3. Click "Share via public link" and then "Copy public link".
4. Paste the link from your clipboard into a new incognito window in your browser.
5. You should see the album name and some thumbnail images. Click an image.
6. Now you see a blank image viewer with a spinner and a login window.
7. If you cancel the login, you see an error message "Error loading [filename]".

Expected behavior

Should be able to view photos in the shared album without being logged in.

Installation method

Community Docker image

Operating system

Debian/Ubuntu

PHP engine version

PHP 7.4

Web server

Nginx

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "memcache.local": "\\OC\\Memcache\\APCu",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "overwriteprotocol": "https",
        "overwritehost": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***"
        ],
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "25.0.3.2",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "maintenance": false,
        "default_phone_region": "US",
        "theme": "",
        "loglevel": 0,
        "updater.release.channel": "beta",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp"
    }
}

List of activated Apps

Enabled:
  - activity: 2.17.0
  - bookmarks: 12.0.0
  - circles: 25.0.0
  - cloud_federation_api: 1.8.0
  - comments: 1.15.0
  - contacts: 5.0.2
  - contactsinteraction: 1.6.0
  - dashboard: 7.5.0
  - dav: 1.24.0
  - federatedfilesharing: 1.15.0
  - federation: 1.15.0
  - files: 1.20.1
  - files_pdfviewer: 2.6.0
  - files_rightclick: 1.4.0
  - files_sharing: 1.17.0
  - files_trashbin: 1.15.0
  - files_versions: 1.18.0
  - firstrunwizard: 2.14.0
  - logreader: 2.10.0
  - lookup_server_connector: 1.13.0
  - nextcloud_announcements: 1.14.0
  - notes: 4.6.0
  - notifications: 2.13.1
  - oauth2: 1.13.0
  - password_policy: 1.15.0
  - photos: 2.0.1
  - privacy: 1.9.0
  - provisioning_api: 1.15.0
  - recognize: 3.3.6
  - recommendations: 1.4.0
  - related_resources: 1.0.3
  - serverinfo: 1.15.0
  - settings: 1.7.0
  - sharebymail: 1.15.0
  - spreed: 15.0.2
  - support: 1.8.0
  - survey_client: 1.13.0
  - systemtags: 1.15.0
  - tasks: 0.14.5
  - text: 3.6.0
  - theming: 2.0.1
  - twofactor_backupcodes: 1.14.0
  - updatenotification: 1.15.0
  - user_status: 1.5.0
  - viewer: 1.9.0
  - weather_status: 1.5.0
  - workflowengine: 2.7.0
Disabled:
  - admin_audit
  - bruteforcesettings
  - encryption
  - files_external
  - suspicious_login
  - twofactor_totp
  - user_ldap

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

No response

Additional info

No response

[brawlins]

Screenshot of the error message:

[g-work]

Duplicate of #1452 ?

[brawlins]

Yes, this is a duplicate of #1452. Good catch. Thank you.