--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/gpsd/gpsd.py	Wed May 05 19:38:32 2021 +0200
@@ -0,0 +1,83 @@
+#!/usr/bin/env python
+
+# Collect speed data from a driving ICE/IC train.
+
+import requests
+
+from gps3 import gps3 as gps
+
+import argparse
+import json
+import sys
+import time
+
+def eprint(*args):
+    print(*args, file=sys.stderr)
+
+def send_point(sess, args, info: dict[str, str]):
+    geohub_templ = args.geohub + '/{CLIENT}/log?secret={SECRET}'
+    geohub_url = geohub_templ.format(HOST=args.geohub_host, CLIENT=args.client or info.get('tzn', 'TRAIN'), SECRET=args.secret, PROTOCOL=args.geohub_scheme)
+    additional = '&lat={lat}&longitude={long}&s={spd}&time={ts}'.format(
+            lat=info['lat'], long=info['lon'], spd=info['speed'], ts=info['time'])
+    # Delete unnecessary data.
+    url = geohub_url + additional
+    return sess.post(url, data="")
+
+def fetch_data(datastream, data, seen=set()):
+    if data is None:
+        return None
+    datastream.unpack(data)
+    if datastream.TPV['time'] in seen:
+        return None
+    seen.add(datastream.TPV['time'])
+    return datastream.TPV
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Fetch and send gpsd data')
+    parser.add_argument('--client', default='gpsd', help='Client name.')
+    parser.add_argument('--secret', default='', help='Secret. This protects your current location; to share it, you have to share the secret. By default, the points will be made public on your GeoHub instance.')
+    parser.add_argument('--interval', default=5, type=int, help='Poll interval. If 0, send every point received from gpsd.')
+    parser.add_argument('--outfile', default='data.jsonlines', help='Where to write the JSON data received from the train.')
+    parser.add_argument('--geohub_host', default='example.com', help='Host of your GeoHub. Use this if the URL --geohub works for you.')
+    parser.add_argument('--geohub_scheme', default='https', help='Protocol scheme of the GeoHub instance. Use this if you do not want to specify the entire --geohub URL')
+    parser.add_argument('--geohub', default='{PROTOCOL}://{HOST}/geo/', help='Base URL of Geohub instance. E.g., https://example.com/geo. Use --geohub_host, --geohub_scheme if your URL looks like the example.')
+    return parser.parse_args()
+
+def run(args):
+    session = requests.Session()
+    socket = gps.GPSDSocket()
+    datastream = gps.DataStream()
+    socket.connect()
+    socket.watch()
+
+    geohub_base = args.geohub.format(PROTOCOL=args.geohub_scheme, HOST=args.geohub_host)
+    livemap_url = geohub_base + 'assets/livemap.html?client={client}&secret={secret}'.format(client=args.client, secret=args.secret)
+    eprint('Go to LiveMap:', livemap_url);
+
+    seen = set()
+    last_time = time.time()
+
+    with open(args.outfile, 'w') as outfile:
+        while True:
+            data = socket.next(timeout=5)
+            if data:
+                info = fetch_data(datastream, data, seen=seen)
+                if time.time() - last_time < args.interval:
+                    continue
+                elif info is not None:
+                    last_time = time.time()
+                    eprint('{} :: Sending point ({}, {}) to GeoHub.'.format(info['time'], info['lon'], info['lat']))
+                    send_point(session, args, info)
+                    outfile.write(json.dumps(info))
+                    outfile.write('\n')
+            # Prevent memory leak.
+            if len(seen) > 100:
+                seen = set()
+
+def main():
+    args = parse_args()
+    run(args)
+
+
+if __name__ == '__main__':
+    main()