openhomedevice

Library to provide an API to an existing openhome device. The device needs to have been discovered first by something like netdisco (https://github.com/home-assistant/netdisco).

The underlying UPnP client library used is https://github.com/StevenLooman/async_upnp_client

• Tested against Linn Products Ltd devices running Davaar 80 (thought expected to work on earlier variants)
• Tested against OpenHome Player devices

Installation

pip install openhomedevice

API

Constructor

device = Device(location)
await device.init()

Pass an existing aiohttp.ClientSession to reuse it and its connection pool. Without one, every request opens and closes a session of its own, which is wasteful when polling a device:

device = Device(location, session=session)
await device.init()

The session is never closed by this library. Whoever created it owns it.

Pass an event_handler to receive events through a notify server you already run, rather than letting the device start one of its own. See Sharing a notify server.

Errors

Every method that talks to the device raises one of these, so callers do not need to know that async_upnp_client is underneath:

from openhomedevice.exceptions import (
    OpenhomeError,             # base class for all of the below
    OpenhomeConnectionError,   # device could not be reached
    OpenhomeTimeoutError,      # device did not answer in time
    OpenhomeDeviceError,       # device answered, but refused or replied unusably
)

OpenhomeTimeoutError is a subclass of OpenhomeConnectionError, so catching the latter covers a device that is off or unreachable for any reason. OpenhomeDeviceError means the device is reachable but something else is wrong: a SOAP fault, an HTTP error status, or a response that could not be parsed. The original exception is kept as __cause__.

try:
    await device.init()
except OpenhomeConnectionError:
    ...  # device is off or off the network
except OpenhomeDeviceError:
    ...  # device answered with something unusable

Events

Rather than polling, a device can be asked to push its changes. subscribe takes a callback and returns the lease the device granted:

def on_event(changes):
    print(changes)  # {"volume": 42, "is_muted": False}

lease = await device.subscribe(on_event)
...
await device.unsubscribe()

The callback may be a plain function or a coroutine function. It is given a dictionary holding only what changed, using the same keys and the same types the matching method would have returned:

The first callback after subscribing carries the device's whole state, because that is what a device sends when a subscription begins. After that only the values that actually changed are present, so check for a key rather than assuming it is there.

A callback that raises is logged and otherwise ignored: the notify server behind a subscription may be shared with other devices, and one broken callback must not stop the rest of them receiving anything.

Keeping a subscription

A subscription lasts as long as the lease subscribe returned, and nothing here renews it for you. Call renew before the lease runs out, on whatever schedule suits you, and renew against what it returns rather than what you asked for: a device caps the lease at its own maximum.

lease = await device.subscribe(on_event)
while True:
    await asyncio.sleep(lease.total_seconds() - 60)
    try:
        lease = await device.renew()
    except OpenhomeError:
        lease = await device.subscribe(on_event)

Renewing is also what puts a lost subscription right. A device that restarted, or that gave up on an event it could not deliver, is not obliged to say so and does not: it answers every other request exactly as before, and simply never sends another event. Renewing takes the subscription out again, transparently where the device is there to answer, so events resume without the caller being told anything happened.

renew raises OpenhomeDeviceError only where that cannot be done at all, which in practice means the device is unreachable. It releases everything first, so is_subscribed is already False and subscribe is what picks the device back up.

Renewing is all or nothing: one subscription that cannot be renewed ends them all, because holding half a subscription is worse than holding none. Some values would go stale while others kept arriving, with no way to tell which were which.

Devices that cannot be subscribed to

Subscribing needs the Product, Transport and Info services. Check events_enabled before subscribing; subscribe() raises OpenhomeDeviceError on a device that has not got them:

if device.events_enabled:
    await device.subscribe(on_event)
else:
    ...  # poll instead

Older firmware and some third party renderers have no Transport service and report transport state through Radio or Playlist instead. Which of the two is authoritative depends on the source selected, so neither can be subscribed to, and transport state is the one value a caller is least able to do without. Rather than offer a subscription that leaves it behind, none is offered: a caller polling transport_state() on a timer may as well poll the rest and skip the listener entirely.

A device with no Volume service is still served. Volume control can be switched off, leaving the device at unity gain with no service to advertise, so there is no volume for a caller to miss.

Sharing a notify server

Events arrive over HTTP, so a subscription needs something listening. By default the device starts a listener of its own on subscribe and stops it again on unsubscribe. When several devices are involved it is better to run one listener and hand it to each of them:

from async_upnp_client.aiohttp import AiohttpNotifyServer, AiohttpRequester
from async_upnp_client.utils import async_get_local_ip

_, local_ip = await async_get_local_ip(location)
server = AiohttpNotifyServer(requester=AiohttpRequester(), source=(local_ip, 0))
await server.async_start_server()

device = Device(location, event_handler=server.event_handler)

As with the session, a notify server you supply is never stopped by this library. Whoever created it owns it.

When events do not arrive

A subscription only works if the device can reach the listener, which puts two requirements on the host running this library.

The callback address must be on the device's own subnet. A device refuses one that is not, and subscribe() raises OpenhomeDeviceError carrying HTTP 412. Hosts behind NAT, such as some container and virtual machine setups, advertise an address the device cannot route to and are refused for this reason.

The device must also be able to open a connection back to the listener. Nothing reports a problem here: the subscription is accepted, subscribe() returns, is_subscribed is True, and no events ever arrive. A firewall that permits outbound but blocks inbound connections produces exactly this, so it is worth ruling out first when a subscription looks healthy but is silent.

Methods

Control

    await subscribe(callback) #push changes to callback instead of polling
    await unsubscribe() #stop receiving changes
    await set_standby(standbyRequested) #bool
    await play() #starts playback
    await play_media(track_details) #start playing `track_details`
    await stop() #stops playback
    await pause() #pauses playback
    await skip(offset) #positive or negative integer
    await set_volume(volume_level) #positive number
    await increase_volume() #increase volume by 1
    await decrease_volume() #decrease volume by 1
    await set_mute(muteRequested) #bool
    await set_source(index) #positive integer (use Sources() for indices)
    await invoke_pin(index) #positive integer (use Pins() for indices)

Songcast

    await songcast_receiver_join(sender) #follow a sender from songcast_sender()
    await songcast_receiver_leave() #stop following and clear the sender

Firmware

    await check_latest_firmware() #check for the latest firmware
    await update_firmware() #update the device firmware
    await software_status() #returns a dictionary with information about the current software

Informational

    uuid() #Unique identifier
    manufacturer() #Manufacturer
    model_name() #Model Name
    friendly_name() #Friendly Name
    await name() #Name of device
    await room() #Name of room
    await is_in_standby() #returns true if in standby
    await transport_state() #returns one of Stopped, Playing, Paused or Buffering.
    await can_pause() #true if what is playing can be paused, None if unknown
    await can_skip_next() #true if the next track can be skipped to
    await can_skip_previous() #true if the previous track can be skipped to
<<<<<<< HEAD
=======
    is_subscribed #property true while subscribed to the device's events
    events_enabled #property true if this device can be subscribed to
>>>>>>> 9f27828 (Subscribe to device events instead of polling)
    volume_enabled #property true if the volume service is available
    await volume() #returns the volume setting or None if disabled
    await is_muted() #returns true if muted or None if disabled
    await source() #returns the currently connected source as a dictionary
    await sources() #returns an array of source dictionaries with indices
    await track_info() #returns a track dictionary
    await pins() #returns an array of pin dictionaries with indices
    pins_enabled #property true if the pins service is available
    songcast_sender_enabled #property true if the sender service is available
    songcast_receiver_enabled #property true if the receiver service is available
    await songcast_sender_status() #Enabled, Disabled or Blocked, or None if unavailable
    await songcast_sender_audio() #true if this device is broadcasting audio
    await songcast_sender() #this device as a sender, or None if it cannot send
    await songcast_receiver_sender() #the sender being followed, or None
    await songcast_receiver_transport_state() #Stopped, Waiting, Playing or Buffering

Source Response

{
    'type': 'Playlist',
    'name': 'Playlist'
}

Sources Response

[
    { 'index': 0, 'type': 'Playlist', 'name': 'Playlist' },
    { 'index': 1, 'type': 'Radio', 'name': 'Radio' },
    { 'index': 3, 'type': 'Receiver', 'name': 'Songcast' },
    { 'index': 6, 'type': 'Analog', 'name': 'Front Aux' }
]

Pins Response

[
  {'index': 1, 'title': 'Playstation 4', 'artworkUri': 'external:///source?type=Hdmi&systemName=HDMI3'}
  {'index': 4, 'title': 'Classic FM', 'artworkUri': 'http://cdn-profiles.tunein.com/s8439/images/logoq.png?t=1'}
  {'index': 6, 'title': 'Chillout Playlist', 'artworkUri': 'http://media/artwork/chillout-playlist.png'}
]

Songcast Sender Response

Returned by songcast_sender(), and by songcast_receiver_sender() for the sender a device is currently following. None when the device cannot send, or when it is not following anyone.

{
    'uri': 'ohz://239.255.255.250:51972/4c494e4e-0026-0f21-1234-01234567013f',
    'metadata': '<DIDL-Lite ...><item id="0" restricted="True">...</item></DIDL-Lite>'
}

TrackInfo Response

{
  "mimeType": "http-get:*:audio/x-flac:DLNA.ORG_OP=01;DLNA.ORG_FLAGS=01700000000000000000000000000000",
  "rating": None,
  "performer": [
    "Fahmi Alqhai, Performer - Johann Sebastian Bach, Composer"
  ],
  "bitDepth": 16,
  "channels": 2,
  "disc": None,
  "composer": [],
  "year": 2017,
  "duration": 460,
  "author": [],
  "albumArtist": [],
  "type": "object.item.audioItem.musicTrack",
  "narrator": [],
  "description": None,
  "conductor": [],
  "albumArtwork": "http://static.qobuz.com/images/covers/58/20/8424562332058_600.jpg",
  "track": 2,
  "tracks": None,
  "artwork": None,
  "genre": [
    "Klassiek"
  ],
  "publisher": "Glossa",
  "albumGenre": [
    "Klassiek"
  ],
  "artist": [
    "Fahmi Alqhai"
  ],
  "bitRate": None,
  "albumTitle": "The Bach Album",
  "uri": "http://192.168.0.110:58050/stream/audio/b362f0f7a1ff33b176bcf2adde75af96.flac",
  "discs": None,
  "published": None,
  "title": "Violin Sonata No. 2 in A Minor, BWV 1003 (Arr. for Viola da gamba) : Violin Sonata No. 2 in A Minor, BWV 1003 (Arr. for Viola da gamba): II. Fuga",
  "sampleRate": 44100
}

SoftwareStatus response

When an update is available:

{
   "status":"update_available",
   "current_software":{
      "version":"4.99.491",
      "topic":"main",
      "channel":"release"
   },
   "update_info":{
      "legal":{
         "licenseurl":"http://products.linn.co.uk/VersionInfo/licenseV2.txt",
         "privacyurl":"https://www.linn.co.uk/privacy",
         "privacyuri":"https://products.linn.co.uk/VersionInfo/PrivacyV1.json",
         "privacyversion":1
      },
      "releasenotesuri":"http://docs.linn.co.uk/wiki/index.php/ReleaseNotes",
      "updates":[
         {
            "channel":"release",
            "date":"07 Jun 2023 12:29:48",
            "description":"Release build version 4.100.502 (07 Jun 2023 12:29:48)",
            "exaktlink":"3",
            "manifest":"https://cloud.linn.co.uk/update/components/836/4.100.502/manifest.json",
            "topic":"main",
            "variant":"836",
            "version":"4.100.502"
         }
      ],
      "exaktUpdates":[]
   }
}

When the system is on the latest firmware:

{
   "status":"on_latest",
   "current_software":{
      "version":"4.100.502",
      "topic":"main",
      "channel":"release"
   }
}

Upgrading Firmware

Use this to check if an update is required and then instruct the device to apply it

    await openhome_device.check_latest_firmware()
    await openhome_device.update_firmware()

Playing A Track

Use this to play a short audio track, a podcast Uri or radio station Uri. The audio will be played using the radio source of the device. The trackDetails object should be the same as the one described in the TrackInfo section above.

    track_details = {}
    track_details["uri"] = "http://opml.radiotime.com/Tune.ashx?id=s122119"
    track_details["title"] = 'Linn Radio (Eclectic Music)'
    track_details["albumArtwork"] = 'http://cdn-radiotime-logos.tunein.com/s122119q.png'

    await openhome_device.play_media(track_details)

Grouping Rooms With Songcast

One device broadcasts its audio as a Songcast sender, and others follow it as receivers, so several rooms play the same thing in sync.

songcast_receiver_join sets the sender and starts the receiver playing. Linn firmware selects the Songcast source itself in response, so there is no need to call set_source first. songcast_receiver_leave stops the receiver and clears the sender, rather than leaving a stale one configured.

    sender = await kitchen.songcast_sender()

    if sender is not None:
        await living_room.songcast_receiver_join(sender)

    # ... later
    await living_room.songcast_receiver_leave()

A receiver reports Waiting from songcast_receiver_transport_state() when it is following a sender that is not currently broadcasting any audio. Use songcast_sender_audio() on the sender to tell that apart from a sender that is genuinely playing.

Not every device can send: songcast_sender() returns None when the sender service is missing or reports no metadata, and songcast_sender_status() distinguishes Enabled from Disabled and Blocked.

Example

python3 demo.py

The addresses in demo.py are hardcoded. To find the devices on your network:

python3 tools/discovery.py

Running Tests

Install the package and the test dependencies, then run the suite:

python3 -m pip install . -r requirements-test.txt
PYTHONPATH=. pytest ./tests/*

The same suite runs on GitHub Actions against Python 3.10 to 3.14 for every push and pull request, so a proposed change shows a pass or fail on the pull request itself. The workflow is .github/workflows/tests.yml.

requirements-test.txt holds aiohttp<3.14: aioresponses, which the tests use to mock the device, constructs an aiohttp ClientResponse by hand and aiohttp 3.14 added a required argument to that constructor. Without the pin every mocked request fails. The pin can go once aioresponses catches up.

Releasing

Update version in setup.py and merge that, then tag and release:

gh release create <version> --generate-notes

Tagging is what publishes: .github/workflows/publish.yml builds, tests and uploads to PyPI, using the Trusted Publisher registered at https://pypi.org/manage/project/openhomedevice/settings/publishing/.

--generate-notes writes the release notes from the pull requests and commits merged since the previous release, so contributions that arrived as PRs are listed and credited without anything being written by hand. Review the generated notes afterwards and add a line about anything a consumer of the library has to act on, such as a changed method signature.

Pushing the tag is not enough on its own: a tag does not appear on the releases page, and a release created later will only generate notes back to the previous release, not for work the tag has already gone out with. Create the release at the same time as the tag. If a tag was already pushed without one, the release can still be created against it, and the notes filled in by hand where the generated set is incomplete.

Release notes matter beyond this repository. Home Assistant reviews a dependency bump by reading what changed between the old and new versions, so a version with no release is extra work for whoever is handling the bump.

The description shown on PyPI is baked into each release from this file, so a README change only appears there once a new version is published.