Getting USB volume serial number from inserted device on OSX

[Sven]

Hello,

I am using Python 2.7 with pyobjc on Lion and NSNotification center to
monitor any inserted USB volumes. This works fine.

I've also got some ideas how to get a device's serial number, but these
involve just parsing all the USB devices ('system_profiler SPUSBDataType'
command). However I'd like to specifically query the inserted device only
(the one creating the notification) rather than checking the entire USB
device list. The latter seems a little inefficient and "wrong".

Can this be accomplished in a sensible way? The NSNotification object
passed to my handler function doesn't have that kind of information and
I've not been able to find any information on doing the above with the
information provided by the NSNotification object.

I've tried DBus (I use this for the linux handler) but I've not had much
luck getting it to work reliably on OS X and installing it wasn't as
straightforward as I hoped.

I have no requirement to use pyobjc so other suggestions welcome as long as
it's straightforward to install and without too many other dependencies.
I'd like to keep installation straightforward for the end users.
Thanks

 

[John Nagle]

Hello,

I am using Python 2.7 with pyobjc on Lion and NSNotification center to
monitor any inserted USB volumes. This works fine.

I've also got some ideas how to get a device's serial number, but these
involve just parsing all the USB devices ('system_profiler SPUSBDataType'
command). However I'd like to specifically query the inserted device only
(the one creating the notification) rather than checking the entire USB
device list. The latter seems a little inefficient and "wrong".

That would be useful to have as a portable function for all USB
devices. Serial port devices are particularly annoying, because their
port number is somewhat random when there's more than one, and changes
on hot-plugging.

John Nagle

 

[Sven]

There is no portable solution. Every operating system handles this kind of
this very differently. Remember, the operating system abstractions are all
designed to hide this from you. When you open a serial port or an audio
device or use a file system, you aren't supposed to KNOW that there is a
USB device behind it

Indeed. Which means I have a working solution under Linux, but I am
struggling to find one under OS X.

Looks like I might have to resort to just parsing the USB tree until I find
the device that was inserted.