Hi, @marktheknife. Thank you for posting this. I did actually see this and I use it. It's a good suggestion and will work for a lot of people. It's very simple to install, setup and use and that is perfect. I think it needs more recognition for how simple and straightforward it is compared to some of the other smart phone presence sensors. This is the type of solution that I would prefer to create over one that requires JFFS support and a script to be running on a router or any of the other things I mentioned above.
Also, it drives me a little crazy that it is called "iPhone" anything so my device driver is modified to be a "HTTP Request Presence Sensor" since it works on more than iPhone and Android or phones. In rare cases even an iPhone or an Android phone could be running something on port 80 that would respond to throw this off (like some of the camera restreaming apps for Android, etc).
At any rate, it was sort of this presence sensor that prompted my request. Since I'm a sane person and I don't purchase enterprise level switches for my home I am limited to 128 static IPs in my reservation list. That's not a lot by the time you put a static IP on all of the Christmas light controllers, Google products (Nest, Homes, etc), Ring Products (cameras, chimes, etc.), Alexa products, TVs, Receivers, Streaming Devices, Gaming Consoles, HDHomeRuns, miscellaneous IP cameras, garage controller, sprinkler controller, and desktops/servers.
I'm out of space in the table. I could run a separate DHCP and DNS server but again... when I can consolidate I try to. I have had in the past a separate server or router that doesn't route but just handles DHCP and DNS from time to time. I've just recently gotten rid of it this time because I am trying to consolidate. I have way too much crap. Things like phones, laptops, tablets, smart watches, are what's left off static IP reservation. Our electricity bills (at least mine) are ridiculous. All of these always on devices add up.
My phone's IP address can and sometimes change because of that. There are other ways around this and I am capable of doing them. Some people might not have the skills though. The easiest way to get the IP address (from a MAC address) to me seemed to be to ask the router. I heard or saw somewhere maybe that HE didn't suport ARP pinging. Phones won't respond to UPNP, bonjour and that sort of thing when they're asleep either. The device that knows the new IP is the router (hopefully).
And I'll admit... this and all of the above uses cases I mentioned are probably fringe uses cases. I'm only approaching these fringe cases because I have already established most of the base functionality I desire out of HE without needing a SSH client. This is definitely on my nice-to-have list.