# Session daemons

ModemManager (or oFono previously) [provides](https://github.com/Neshama1/develop-kde-org/blob/master/content/docs/packaging/plasma-mobile/telephony/system-daemon-userland-dbus-ipc-level/README.md) unified access to different modem devices with different command lists via system D-Bus IPC.

The tasks of the session side daemons are (but not limited to):

* Handle calls and messages
* Provide calls and messages history
* Provide contacts PIM mapping
* Power management
* Notifications
* Interacting with other parts of the user environment
* Filter spam

#### Worth mentioning dependencies

**eg25-manager**

[eg25-manager](https://gitlab.com/mobian1/eg25-manager) is a daemon to handle low-power modes of the Quectel EG25 via ModemManager. It's used for the Pinephone.

**kop316 projects**

* [SMS/MMS Daemon](https://gitlab.com/kop316/mmsd)
* [Visual Voicemail Daemon](https://gitlab.com/kop316/vvmd)

Both projects are developed for Phosh but are [environment-agnostic](https://gitlab.com/kop316/vvmd/-/issues/5). They could be used directly via session-level D-Bus API to implement a Qt/QML library.

If not, at least the D-Bus scheme could be shared among both GNOME and KDE via Freedesktop project. And re-implemented in Qt after that if needed (for example, at *modem-daemon* repository described below). The described approach will provide interoperability on the GUI application level.

**ModemManagerQt**

[ModemManagerQt](https://invent.kde.org/frameworks/modemmanager-qt) is a Qt wrapper for ModemManager DBus API.

**KDE Telephony Meta**

[kde-telephony-meta](https://invent.kde.org/plasma-mobile/plasma-dialer/-/tree/master/kde-telephony-meta/) is KDE Telephony shared data:

* D-Bus XML Interface descriptions
* ready to reuse Qt meta types for complex D-Bus types as a header or a static library

#### Daemons

**Modem Daemon**

[modem-daemon](https://invent.kde.org/plasma-mobile/plasma-dialer/-/tree/master/modem-daemon) is a daemon for background tracking the modem events to:

* Provide access to calls for client applications and daemons via D-Bus session level
* Save the history

The daemon is written in Qt. It is similar to kop316 projects. It's working with the system D-Bus and provides session D-Bus API for applications. It's ModemManagerQt-first, but provides higher-level API so any possible manager switching should be transparent for the application level.

It's not KDE specific (just Qt) and could be used directly in projects like [Nemo Mobile](https://nemomobile.net/) or even [GNOME Phosh](https://gitlab.gnome.org/World/Phosh/phosh).

Work-in-Progress.

**KDE Telephony Daemon**

[kde-telephony-daemon](https://invent.kde.org/plasma-mobile/plasma-dialer/-/tree/master/kde-telephony-daemon) is a daemon for background tracking the modem events to:

* Enable audio channels when needed
* Show notifications
* Automatically launch dialer GUI
* Share KDE-related Telephony services via session DBus

It is KDE-specific and depends on *Modem Daemon*. It's not ModemManagerQt specific. Could also depend on such KF5 libraries as People, Notifications, I18n. Contains *contactphonenumbermapper* — a library to work with KDE KPeople and Google phonenumber libraries.

Work-in-Progress.

#### Relations with Telepathy IM

[Telepathy IM](https://github.com/TelepathyIM/wiki/wiki) is a FreeDesktop project supported by Nokia and Collabora. It's a framework to build instant messaging client applications with interoperability via D-Bus IPC. It could use oFono or ModemManager to implement calls and messaging clients. oFono integration is [already implemented](https://github.com/TelepathyIM/telepathy-qt/wiki/Connection-Managers#gsm).

Telepathy IM could cover both telephony daemons in theory. The project is currently having the contributors' flaws. Telepathy project roots are from the [good](https://translate.yandex.ru/translate?url=https%3A%2F%2Fhabr.com%2Fru%2Fpost%2F171325%2F\&lang=ru-en)-[old](https://en.wikipedia.org/wiki/Peter_principle) days of the Nokia N900/N9 Linux devices and [Collabora](https://mail.gnome.org/archives/desktop-devel-list/2017-September/msg00047.html) team development. A lot of contributors are needed to support such a level of standardization. Right now we have [Kaffeine](https://matrix.to/#/@kaffeine:matrix.org) maintainer who has “picked up the flag” and a few other project sympathizers. It’s the well-known chicken-or-the-egg problem that could be solved step-by-step though. The main weak point of the spec is probably [service-side history](https://github.com/TelepathyIM/wiki/wiki/Specification-TODO-list#service-side-history).

So, the current dialer client implementation is going to be based on the ModemManager without higher-level TelepathyIM usage, while it still could be interesting to have an IM client solution with interoperability in the long-distant future.

#### Conclusion

Session daemons on the user-land level could be used to interact with other parts of the user environment and provide a unified API for GUI applications.

To provide actual developer libraries (environment- and language-specific) is out of the scope for any session-side telephony daemon. The D-Bus API exported via session bus enabling [QML declarative plugin as library side](https://docs.novaflowos.com/start/kde-developer-platform/readme/packaging/plasma-mobile/telephony/_index-3) to handle it.