Exploring Plug&Play Devices (Part 3)

by Jan 3, 2020

In the previous tip we illustrated how to use the UPnP.UPnPDeviceFinder to find devices on your network. You already learned how to enumerate all root devices (“upnp:rootdevice”), and how to directly access a device via its unique device identifier.

$UPnPFinder = New-Object -ComObject UPnP.UPnPDeviceFinder
$UPnPFinder.FindByType("upnp:rootdevice", 0) | Out-GridView 

In this part, let’s complete the search types, and look at how to enumerate all devices (not just root devices), and how to enumerate groups of device types.

To list all devices, use “ssdb:all” instead of “upnp:rootdevice”:

$UPnPFinder = New-Object -ComObject UPnP.UPnPDeviceFinder
$UPnPFinder.FindByType("ssdp:all", 0) | Out-GridView 

The result includes root devices (“IsRootDevice” is $true, and “ParentDevice” is empty) as well as all child devices (“IsRootDevice” is $false and “ParentDevice” points to the device this device is chained to).

In “UniqueDeviceName”, you find the unique device name that can be used to directly access the device:

$UPnPFinder = New-Object -ComObject UPnP.UPnPDeviceFinder
$UPnPFinder.FindByUDN("uuid:...", 0)

Each device belongs to a category which is exposed in “Type”. To see a list of types, try this:

$UPnPFinder = New-Object -ComObject UPnP.UPnPDeviceFinder
$UPnPFinder.FindByType("ssdp:all", 0) |
  Select-Object -ExpandProperty Type |
  Sort-Object -Unique

The result varies depending on the devices found in your network. Here is the list I got:

 
urn:dial-multiscreen-org:device:dial:1
urn:schemas-upnp-org:device:Basic:1
urn:schemas-upnp-org:device:InternetGatewayDevice:1
urn:schemas-upnp-org:device:MediaRenderer:1
urn:schemas-upnp-org:device:WANConnectionDevice:1
urn:schemas-upnp-org:device:WANDevice:1   
 

To find all devices of a specific type, use the type with FindByType():

$UPnPFinder = New-Object -ComObject UPnP.UPnPDeviceFinder
$UPnPFinder.FindByType("urn:schemas-upnp-org:device:InternetGatewayDevice:1", 0)

A final note: whether a device responds to a group search or even “upnp:rootdevice” depends on the device and its implementation. In my scenario, I was unable to get results for the groups “Basic” and “WANDevice” even though there were devices of that type.

If you can’t find a particular device, try the only search that works for all devices, and list them all via “ssdp:all”. If the device shows up now, you can either use “ssdp:all” and client-side filtering via Where-Object, or speed up the search considerably by finding out the unique device identifier and access a particular device via its UDN and FindByUDN() directly.:


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