93 |
94 |
97 |
290 |
291 |
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/server/server.py:
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1 | import sys, os.path
2 | import shutil
3 | import sqlite3
4 | import threading
5 | import json
6 |
7 | from http.server import HTTPServer, BaseHTTPRequestHandler, SimpleHTTPRequestHandler
8 | from urllib.parse import urlparse, parse_qs
9 |
10 | from scipy.optimize import minimize
11 | from geopy.distance import distance
12 |
13 | def mse(x, locations, distances):
14 | """
15 | Computes the mean square error for a list of locations
16 | and distances to a point x.
17 |
18 | x -- Target location (lat, lng)
19 | locations -- Reference locations (list of (lat, lng))
20 | distances -- Reference distances (list of int)
21 | """
22 | mse = 0
23 |
24 | for loc, dist in zip(locations, distances):
25 | distance_calculated = distance(x, loc).m
26 | mse += (distance_calculated - dist) ** 2
27 |
28 | return mse / len(distances)
29 |
30 | def make_custom_http_handler(con):
31 |
32 | class CustomHTTPRequestHandler(BaseHTTPRequestHandler):
33 |
34 | def send_json(self, obj):
35 | self.send_response(200)
36 | self.send_header("Content-type", "application/json;charset=utf-8")
37 | self.end_headers()
38 | self.wfile.write(json.dumps(obj).encode("utf-8"))
39 |
40 | def do_GET(self):
41 | url = urlparse(self.path)
42 | res = url.path[1:].split("/")
43 | query = parse_qs(url.query)
44 |
45 | print(url, res, query)
46 |
47 | # show index page
48 | if url.path == "/":
49 | self.send_response(200)
50 | self.send_header("Content-type", "text/html;charset=utf-8")
51 | self.end_headers()
52 |
53 | with open("index.html", "rb") as f:
54 | shutil.copyfileobj(f, self.wfile)
55 |
56 | return
57 |
58 | # handle api calls
59 | if res[0] == "api":
60 | # send user listing
61 | if res[1] == "users":
62 | self.handle_api_users()
63 | return
64 |
65 | # send location listing
66 | if res[1] == "locations":
67 | self.handle_api_locations()
68 | return
69 |
70 | if res[1] == "query":
71 | uid = int(query["id"][0])
72 | max_distance = int(query["mdist"][0])
73 | max_accuracy = float(query["macc"][0])
74 |
75 | self.handle_api_query(uid, max_distance, max_accuracy)
76 | return
77 |
78 | self.send_response(404)
79 | self.send_header("Content-type", "text/plain;charset=utf-8")
80 | self.end_headers()
81 | self.wfile.write("Not found".encode("utf-8"))
82 |
83 | def send_query_response(self, sightings, res_success, res_loc=None, res_reason=None):
84 | self.send_json({
85 | "sightings": sightings,
86 | "guess": {
87 | "success": res_success,
88 | "reason": res_reason if not res_success else "",
89 | "result": {
90 | "latitude": res_loc[0],
91 | "longitude": res_loc[1]
92 | } if res_success else {}
93 | }
94 | })
95 |
96 | def handle_api_query(self, user_id, max_dist, max_acc):
97 | # list of all sightings for the client
98 | all_sightings = []
99 | # list of locations and distances for mse (filtered)
100 | locations = []
101 | distances = []
102 | # min distance to select closest point for initial guess
103 | distance_min = 1e9
104 | initial_guess = None
105 | # locations with distance <= 100, used for initial guess
106 | locations_100 = []
107 |
108 | for row in con.execute("SELECT l.latitude, l.longitude, s.distance, l.accuracy FROM locations l INNER JOIN sightings s ON l.fix_ts = s.fix_ts WHERE s.user_id = ?", [ user_id ]):
109 | loc = ( row[0], row[1] )
110 | dist = row[2]
111 | acc = row[3]
112 |
113 | # check against provided params
114 | if dist > max_dist:
115 | continue
116 |
117 | if acc > max_acc:
118 | continue
119 |
120 | # this'll be provided no matter what
121 | all_sightings.append({
122 | "latitude": loc[0],
123 | "longitude": loc[1],
124 | "distance": dist
125 | })
126 |
127 | # these coords are actually not used in minimization, but
128 | # rather to set an initial guess
129 | if dist <= 100:
130 | locations_100.append(loc)
131 | distance_min = 100
132 | continue
133 |
134 | locations.append(loc)
135 | distances.append(dist)
136 |
137 | # check if initial guess needs to be updated
138 | # this won't happen if 100s have been found
139 | if dist < distance_min:
140 | initial_guess = loc
141 | distance_min = dist
142 |
143 | # check if any locations matched the user specs
144 | if len(all_sightings) == 0:
145 | self.send_query_response([], False, res_reason="No sightings matching given parameters.")
146 | return
147 |
148 | # check if there's even a point in minimizing
149 | if len(all_sightings) > 0 and len(locations) < 3:
150 | self.send_query_response(all_sightings, False, res_reason="Not enough sightings to estimate location, need at least three.")
151 | return
152 |
153 | # if 100s were found, then use those to make
154 | # an initial guess
155 | count_100s = len(locations_100)
156 |
157 | if count_100s > 0:
158 | lat, lng = (0, 0)
159 |
160 | for loc in locations_100:
161 | lat += loc[0]
162 | lng += loc[1]
163 |
164 | # simple average (just a guess)
165 | lat /= count_100s
166 | lng /= count_100s
167 |
168 | initial_guess = (lat, lng)
169 |
170 | result = minimize(
171 | mse,
172 | initial_guess,
173 | args=(locations, distances),
174 | method="L-BFGS-B",
175 | options={
176 | "ftol": 1e-5,
177 | "maxiter": 1e+7
178 | }
179 | )
180 |
181 | self.send_query_response(all_sightings, result.success, result.x, result.message)
182 |
183 | def handle_api_locations(self):
184 | all_locs = []
185 |
186 | for row in con.execute("SELECT fix_ts, latitude, longitude, altitude, accuracy FROM locations"):
187 | all_locs.append({
188 | "timestamp": row[0],
189 | "latitude": row[1],
190 | "longitude": row[2],
191 | "altitude": row[3],
192 | "accuracy": row[4]
193 | })
194 |
195 | self.send_json(all_locs)
196 |
197 | def handle_api_users(self):
198 | all_users = []
199 |
200 | for row in con.execute("SELECT u.id, u.display_name, COUNT(*) AS sighting_count FROM users u INNER JOIN sightings s ON s.user_id = u.id GROUP BY u.id"):
201 | all_users.append({
202 | "id": row[0],
203 | "name": row[1],
204 | "sightingCount": row[2]
205 | })
206 |
207 | self.send_json(all_users)
208 |
209 | return CustomHTTPRequestHandler
210 |
211 | if __name__ == "__main__":
212 | if len(sys.argv) < 2:
213 | print("usage: {} dbfile".format(sys.argv[0]))
214 |
215 | db_path = sys.argv[1]
216 |
217 | if not os.path.exists(db_path):
218 | print("file at path \"{}\" doesn't exist".format(db_path))
219 | exit()
220 |
221 | con = sqlite3.connect(db_path)
222 | srv = HTTPServer(("localhost", 8000), make_custom_http_handler(con))
223 |
224 | try:
225 | print("listening on port {}".format(srv.server_port))
226 | srv.serve_forever()
227 | except KeyboardInterrupt:
228 | print("shutting down")
229 | # pew
230 | t = threading.Thread(target=srv.shutdown)
231 | t.start()
232 | t.join()
233 |
234 | con.close()
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