[SOLVED] Which devices are replying to a SSDP discovery datagram

Which devices are replying to a SSDP discovery datagram

I've created a simple Android app to scan my local network; I've used a M-SEARCH with this search target:

  String sentence = "M-SEARCH * HTTP/1.1\r\n"
      + "HOST: 239.255.255.250:1900\r\n"
      + "MAN: \"ssdp:discover\"\r\n"
      + "MX: 10\r\n"
      + "ST: ssdp:all\r\n"
      + "\r\n";

I just need to take care of the TVs on the network, so:

How could I know, from the M-SEARCH response, which of kind of device is replying?
Is there any search target that can match all the TV devices?

Thanks!

Solution

You can search for specific device types (and service types) by setting the ST header to the device or service type urn (e.g. "urn:schemas-upnp-org:device:MediaRenderer:1"). Likewise in the reply, the ST header will tell you what the device/service type is.

There is no search target that can match all TVs because "TV" is not a device defined by UPnP Forum or DLNA: A TV that "supports DLNA" might be just a MediaPlayer and not show up on M-SEARCH at all. If you want to search for UPnP MediaRenderers (a device often implemented by TVs), then the ST I gave above should be useful.