Allow user-level sender addresses for “Share by mail” (file sharing)

Feature Request: Allow user-level sender addresses for “Share by mail” (file sharing)

Problem

When a user sends a file share link via email (Share → “send link via email”, including password mails), the outgoing messages are always sent using the global system email address configured under:

Administration settings → Basic settings → Email server → “From Address / Sender Name”

This results in several issues:

1. Users cannot see the sent email in their own mailbox (“Sent” folder)
   They have no evidence or audit trail that the message was successfully sent.

2. External recipients see the wrong sender
   (Example: admin@company.com instead of the employee who performed the share.)

3. Inconsistent behavior across Nextcloud apps

   • Calendar invitations correctly use the user’s personal email address (via Mail Provider).
   • File sharing emails do not, although they also represent user actions.

4. Compliance and accountability issues
   Especially in business environments where communication must be provable.

Desired Behavior

For “Share by mail” emails (including password-delivery mails):

• Use the user’s own email address as sender, similar to Calendar invitations.
• If available, send through the user’s Mail Provider SMTP configuration.
• Only fall back to the global system email address if:
  • The user has no email configured, or
  • The administrator explicitly disables user-level sending.

Proposed Solution

Add a new admin option under Administration → Sharing or Administration → Basic settings:

• [ ] Use users’ email addresses when sending share links via email (if available)
  Requires Mail Provider or user-level SMTP configuration.

Optional enhancement:

• [ ] Store sent share-emails in users’ “Sent” folder (IMAP)
  If technically possible.

Benefits

• Users regain full visibility and control (“Did my email go out?”).
• Professional appearance: recipient sees the correct sender identity.
• Consistency with Calendar behavior.
• Improved auditability and compliance readiness.
• More intuitive and user-friendly.

Current Workarounds

None truly solve the problem:

• Manually copying the link into an email client → loses convenience.
• Using a neutral global sender → still misleading sender identity.
• No way to sync the real “sent” message to the user’s mailbox.

Environment

• Nextcloud 32.0.2
• Windows Desktop Client 3.17.3
• Windows 11
• Issue reproducible in browser and desktop client.

Summary

File sharing is a user-driven communication action, and should therefore use the user’s personal sender address—not the global system account.
Adding this feature would significantly improve usability, professionalism, and auditability for organizations using Nextcloud.