dbus-fast

4.0.4 · active · verified Sat Apr 11

dbus-fast is a high-performance Python library for interacting with the D-Bus message bus, providing an asynchronous API built on `asyncio`. It aims to be a faster and more modern alternative to older D-Bus libraries, focusing on speed and comprehensive type-hinting support. Currently at version 4.0.4, it maintains a rapid release cadence with frequent updates and bug fixes.

Warnings

breaking The representation of D-Bus STRUCT types changed from Python lists to tuples.
Fix: Update your code to expect and process Python tuples for D-Bus STRUCT types. For example, `(item1, item2)` instead of `[item1, item2]`.
gotcha dbus-fast requires Python 3.10 or newer.
Fix: Ensure your development and deployment environments are running Python 3.10 or a later version. Upgrade Python if necessary.
gotcha dbus-fast is an asynchronous library and requires careful use of `async`/`await` within an `asyncio` event loop. Forgetting `await` or not running in a loop will lead to errors.
Fix: Always `await` calls to `MessageBus` methods (e.g., `bus.connect()`, `bus.call()`) and ensure your main script uses `asyncio.run()` or similar `asyncio` entry points.
gotcha Accessing the D-Bus system bus (BusType.SYSTEM) often requires specific user permissions or group memberships, which can lead to `dbus_fast.errors.DbusError` (e.g., 'org.freedesktop.DBus.Error.AccessDenied').
Fix: For system bus interactions, ensure the running user has the necessary permissions. Test with `BusType.SESSION` if you only need to interact with user-level services.

Install

pip install dbus-fast Install stable version

Imports

MessageBus
```
from dbus_fast.aio import MessageBus
```
The primary entry point for asynchronous D-Bus communication.
BusType
```
from dbus_fast.constants import BusType
```
Used to specify connection type (SESSION or SYSTEM).

ServiceInterface

from dbus_fast.service import ServiceInterface, method, dbus_property, signal

Essential for defining D-Bus services.

Variant
```
from dbus_fast import Variant
```
Represents a D-Bus variant type.

Quickstart

This quickstart demonstrates how to connect to the D-Bus system bus and call the standard `ListNames` method on the D-Bus daemon. It prints the names of currently registered services. Remember to run this in an `asyncio` event loop.

import asyncio
from dbus_fast.aio import MessageBus
from dbus_fast.constants import BusType

async def main():
    # Connect to the system bus. For the user session bus, use BusType.SESSION.
    bus = await MessageBus(bus_type=BusType.SYSTEM).connect()

    try:
        reply = await bus.call(
            bus_name="org.freedesktop.DBus",
            path="/org/freedesktop/DBus",
            interface="org.freedesktop.DBus",
            member="ListNames",
        )
        names = reply.body[0]
        print("D-Bus names on system bus:", names)
    except Exception as e:
        print(f"Error calling ListNames on system bus: {e}")
        print("Note: Access to the system bus typically requires specific permissions (e.g., being in a 'wheel' group or root).")
    finally:
        await bus.disconnect()

if __name__ == "__main__":
    # Ensure this runs in an async context
    asyncio.run(main())

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