make pc sync with phone via phone's wifi hotspot

thank you for the great work. i have a laptop at work environment without wifi ap. i want to sync folder between laptop and my phone1 via wifi. i have successfully done it by using another phone2 as wifi ap by enabling its wifi hotspot, and make laptop and phone1 connect to phone2. but would it be simpler if laptop just connect to phone1’s wifi hotspot without using phone2? which appears impossible for now.

Hi,

Phone 1 isn’t as good as phone 2… ?

phone2 is not desired. that is a spare phone i use to reach my goal for the time being. not sure if i were using this tool properly. my goal is just to sync the work laptop and phone1. without the help of phone2, phone1’s syncthing app refuses to work by enabling phone1’s wifi hotspot,to which the laptop can connect. hope it clarifies.

Sorry to insist asking further: Which model, os, make is phone1?

mi8,a chinese phone brand,running android 9 with its rom called miui 10.

Cool, I have that model too and it works fine with hotspot. You’ll need to manually enable autostart/Background execution in MIUI so the app may monitor run conditions.

Just for reference, I have a Pixel 2 XL and Syncthing works fine when I connect my MacBook Pro to its hotspot. It’s also, expectedly, much faster than going through a router.

I would also suggest looking into the run conditions. When you turn on hotspot, you, technically, disconnect from Wi-Fi so you’d be using “mobile data”, which may be the culprit.

I have tried a few syncthing app’s connection options. This is probably to do with how the phone’s wifi hotspot works. If I turn on hotspot and turn off mobile data and wifi at same time, which means the phone has no access to other data link but its own hotspot, syncthing app will not run. It runs only if either mobile data is on, or wifi is connected to some existing wifi access point(be it another phone’s hotspot or a normal wifi router). This suggests syncthing app will not discover/connect devices within hotspot connection itself. It actualy does it via either mobile data or wifi. Anyone can confirm this limitation?

My intention is to use the phone without mobile data and no wifi, only via hotspot connection with the laptop.

I actually encountered this exact scenario yesterday. I was in a place without any cell phone reception, I wanted to sync my phone with my laptop and Syncthing didn’t start on my phone. I am using @Catfriend1’s fork so it tells me why it wasn’t working:

  • Syncthing is allowed to run on mobile data connection but mobile data isn’t connected.
  • Syncthing is allowed to run on WiFi but WiFi isn’t connected or the phone is in flight mode.

I was able to “force start, ignore run conditions”, which I believe is only an option in the @Catfriend1’s fork, and it worked fine from that point on but it’s still a bug IMHO.

@Catfriend1, let me know if you’d like me to open an issue on Github. I’m not sure if it’s possible to detect whether we are in hotspot mode but it’s worth giving it a thought.