# Contacts Interaction

The Contacts Interaction app automatically tracks which people a user has recently interacted with and provides this data as a read-only CardDAV address book called **Recently contacted**. This enables autocomplete suggestions in sharing dialogs, email composition, calendar invitations and other places that query the user's address books — even for people who are not saved as explicit contacts.

The app is shipped with Nextcloud and enabled by default. It can be disabled.

## How interactions are tracked

The app listens for `ContactInteractedWithEvent` events dispatched by other Nextcloud apps. The following apps dispatch this event:

- **File sharing**: When a user creates a share with another local user, an email address or a federated remote user.
- **Calendar**: When a user shares a calendar with another user.
- **Mail**: When a user sends an email.

Any app can integrate by dispatching a `ContactInteractedWithEvent` with at least one identifier: a Nextcloud user ID, an email address or a federated cloud ID.

When an interaction is recorded, the app first checks whether the contacted person already exists in one of the user's regular address books. If a match is found, no entry is created in the recently contacted address book since the person is already a known contact. Self-interactions (where the user interacts with themselves) are also ignored.

For new contacts, a minimal vCard is generated containing:

- `FN` (display name): Resolved from the Nextcloud user profile if the person is a local user, falling back to the email address or federated cloud ID.
- `EMAIL`: Included when an email address is known.
- `CLOUD`: Included when a federated cloud ID is known.
- `CATEGORIES`: Set to `Recently contacted`, which allows the Contacts app to identify entries from this address book and offer users the option to copy them to a regular address book.

If the same person is contacted again, the existing entry's timestamp is updated rather than creating a duplicate.

## The recently contacted address book

Each user's recently contacted address book is accessible via CardDAV at:

    /remote.php/dav/addressbooks/users/{userId}/z-app-generated--contactsinteraction--recent/

The `z-app-generated` prefix ensures the address book sorts after user-created address books. Users cannot create their own address books with this reserved prefix.

The address book is **read-only** and **not shareable**. Users cannot create, modify or delete entries. Entries are only removed automatically by the cleanup job or when a user account is deleted.

The address book is visible in:

- **CardDAV clients**: Any client syncing with the user's Nextcloud (e.g., Thunderbird, macOS Contacts, DAVx5) will see the address book.
- **Nextcloud Contacts**: The address book and its entries appear in the Contacts UI if the Contacts app is enabled. Contacts from this address book can be copied to a regular address book.
- **Autocomplete**: Entries are available for recipient suggestions in sharing dialogs and other places across the Nextcloud web interface.

## Data retention

A background job runs every 24 hours and removes entries that have not been updated within the last 7 days. Both the retention period and the cleanup interval are fixed and cannot be configured.

> **提示**
>
> The cleanup job depends on the Nextcloud background job system. Make sure cron is configured correctly for your instance. See [Background jobs](/link/924).

## User deletion

When a user account is deleted, all of that user's recently contacted entries are automatically removed from the database.