Phone Location Logger

If you are using Google Play Services on your Android phone, Google receives and keeps track of your location history. This includes your GPS coordinates and timestamps. Because of the privacy implications, I have revoked pretty much all permissions from Google Play Services and disabled my Location History on my Google settings (as if they would respect that).

But while it might be creepy if a random company has this data, it would be useful if I still have it. After all, who doesn’t want to know the location of a park that they stumbled upon randomly on a vacation 3 years ago.

I remember seeing some location trackers while browsing through F-Droid. I found various applications there, and picked one that was recently updated. The app was a Nextcloud companion app, with support for custom servers. Since I didn’t want a heavy Nextcloud install just to keep track of my location, I decided to go with the custom server approach.

In the end, I decided that the easiest path is to make a small CGI script in Python that appends JSON encoded lines to a text file. Because of this accessible data format, I can process this file in pretty much every programming language, import it to whatever database I want and query it in whatever way I see fit.

The app I went with is called PhoneTrack. You can find the APK and source code links on F-Droid. It replaces the parameters in the URL, logging every parameter looks like this: https://example.com/cgi-bin/locationrecorder.py ?acc=%ACC&alt=%ALT&batt=%BATT&dir=%DIR&lat=%LAT&lon=%LON&sat=%SAT&spd=%SPD &timestamp=%TIMESTAMP

Here’s the script in all it’s glory.

import cgi
import json

PATH = '/home/databases/location.txt'

print('Content-Type: text/plain\n')
form = cgi.FieldStorage()

# Check authentication token
if form.getvalue('token') != 'SECRET_VALUE':
    raise Exception('Nope')

obj = {
    'accuracy':   form.getvalue('acc'),
    'altitude':   form.getvalue('alt'),
    'battery':    form.getvalue('batt'),
    'bearing':    form.getvalue('dir'),
    'latitude':   form.getvalue('lat'),
    'longitude':  form.getvalue('lon'),
    'satellites': form.getvalue('sat'),
    'speed':      form.getvalue('spd'),
    'timestamp':  form.getvalue('timestamp'),
}

with open(PATH, 'a+') as log:
    line = json.dumps(obj)
    log.write(f'{line}\n')