Coverage for src/couchers/utils.py: 94%
127 statements
« prev ^ index » next coverage.py v7.5.0, created at 2024-10-15 13:03 +0000
1import http.cookies
2import re
3from datetime import date, datetime, timedelta
4from email.utils import formatdate
5from typing import List
6from zoneinfo import ZoneInfo
8import pytz
9from geoalchemy2.shape import from_shape, to_shape
10from geoalchemy2.types import Geography, Geometry
11from google.protobuf.duration_pb2 import Duration
12from google.protobuf.timestamp_pb2 import Timestamp
13from shapely.geometry import Point, Polygon, shape
14from sqlalchemy.sql import cast, func
15from sqlalchemy.types import DateTime
17from couchers.config import config
18from couchers.constants import EMAIL_REGEX
19from couchers.crypto import decrypt_page_token, encrypt_page_token
21utc = pytz.UTC
24# When a user logs in, they can basically input one of three things: user id, username, or email
25# These are three non-intersecting sets
26# * user_ids are numeric representations in base 10
27# * usernames are alphanumeric + underscores, at least 2 chars long, and don't start with a number, and don't start or end with underscore
28# * emails are just whatever stack overflow says emails are ;)
31def is_valid_user_id(field):
32 """
33 Checks if it's a string representing a base 10 integer not starting with 0
34 """
35 return re.match(r"[1-9][0-9]*$", field) is not None
38def is_valid_username(field):
39 """
40 Checks if it's an alphanumeric + underscore, lowercase string, at least
41 two characters long, and starts with a letter, ends with alphanumeric
42 """
43 return re.match(r"[a-z][0-9a-z_]*[a-z0-9]$", field) is not None
46def is_valid_name(field):
47 """
48 Checks if it has at least one non-whitespace character
49 """
50 return re.match(r"\S+", field) is not None
53def is_valid_email(field):
54 return re.match(EMAIL_REGEX, field) is not None
57def Timestamp_from_datetime(dt: datetime):
58 pb_ts = Timestamp()
59 pb_ts.FromDatetime(dt)
60 return pb_ts
63def Duration_from_timedelta(dt: datetime):
64 pb_d = Duration()
65 pb_d.FromTimedelta(dt)
66 return pb_d
69def parse_date(date_str: str):
70 """
71 Parses a date-only string in the format "YYYY-MM-DD" returning None if it fails
72 """
73 try:
74 return date.fromisoformat(date_str)
75 except ValueError:
76 return None
79def date_to_api(date: date):
80 return date.isoformat()
83def to_aware_datetime(ts: Timestamp):
84 """
85 Turns a protobuf Timestamp object into a timezone-aware datetime
86 """
87 return utc.localize(ts.ToDatetime())
90def now():
91 return datetime.now(utc)
94def minimum_allowed_birthdate():
95 """
96 Most recent birthdate allowed to register (must be 18 years minimum)
98 This approximation works on leap days!
99 """
100 return today() - timedelta(days=365.25 * 18)
103def today():
104 """
105 Date only in UTC
106 """
107 return now().date()
110def now_in_timezone(tz):
111 """
112 tz should be tzdata identifier, e.g. America/New_York
113 """
114 return datetime.now(pytz.timezone(tz))
117def today_in_timezone(tz):
118 """
119 tz should be tzdata identifier, e.g. America/New_York
120 """
121 return now_in_timezone(tz).date()
124# Note: be very careful with ordering of lat/lng!
125# In a lot of cases they come as (lng, lat), but us humans tend to use them from GPS as (lat, lng)...
126# When entering as EPSG4326, we also need it in (lng, lat)
129def create_coordinate(lat, lng):
130 """
131 Creates a WKT point from a (lat, lng) tuple in EPSG4326 coordinate system (normal GPS-coordinates)
132 """
133 wkb_point = from_shape(Point(lng, lat), srid=4326)
135 # Casting to Geography and back here to ensure coordinate wrapping
136 return cast(
137 cast(wkb_point, Geography(geometry_type="POINT", srid=4326)), Geometry(geometry_type="POINT", srid=4326)
138 )
141def create_polygon_lat_lng(points):
142 """
143 Creates a EPSG4326 WKT polygon from a list of (lat, lng) tuples
144 """
145 return from_shape(Polygon([(lng, lat) for (lat, lng) in points]), srid=4326)
148def create_polygon_lng_lat(points):
149 """
150 Creates a EPSG4326 WKT polygon from a list of (lng, lat) tuples
151 """
152 return from_shape(Polygon(points), srid=4326)
155def geojson_to_geom(geojson):
156 """
157 Turns GeoJSON to PostGIS geom data in EPSG4326
158 """
159 return from_shape(shape(geojson), srid=4326)
162def to_multi(polygon):
163 return func.ST_Multi(polygon)
166def get_coordinates(geom):
167 """
168 Returns EPSG4326 (lat, lng) pair for a given WKT geom point
169 """
170 shp = to_shape(geom)
171 # note the funiness with 4326 normally being (x, y) = (lng, lat)
172 return (shp.y, shp.x)
175def http_date(dt=None):
176 """
177 Format the datetime for HTTP cookies
178 """
179 if not dt:
180 dt = now()
181 return formatdate(dt.timestamp(), usegmt=True)
184def _create_tasty_cookie(name: str, value, expiry: datetime, httponly: bool):
185 cookie = http.cookies.Morsel()
186 cookie.set(name, str(value), str(value))
187 # tell the browser when to stop sending the cookie
188 cookie["expires"] = http_date(expiry)
189 # restrict to our domain, note if there's no domain, it won't include subdomains
190 cookie["domain"] = config["COOKIE_DOMAIN"]
191 # path so that it's accessible for all API requests, otherwise defaults to something like /org.couchers.auth/
192 cookie["path"] = "/"
193 if config["DEV"]:
194 # send only on requests from first-party domains
195 cookie["samesite"] = "Strict"
196 else:
197 # send on all requests, requires Secure
198 cookie["samesite"] = "None"
199 # only set cookie on HTTPS sites in production
200 cookie["secure"] = True
201 # not accessible from javascript
202 cookie["httponly"] = httponly
204 return cookie.OutputString()
207def create_session_cookies(token, user_id, expiry) -> List[str]:
208 """
209 Creates our session cookies.
211 We have two: the secure session token (in couchers-sesh) that's inaccessible to javascript, and the user id (in couchers-user-id) which the javascript frontend can access, so that it knows when it's logged in/out
212 """
213 return [
214 _create_tasty_cookie("couchers-sesh", token, expiry, httponly=True),
215 _create_tasty_cookie("couchers-user-id", user_id, expiry, httponly=False),
216 ]
219def parse_session_cookie(headers):
220 """
221 Returns our session cookie value (aka token) or None
222 """
223 if "cookie" not in headers:
224 return None
226 # parse the cookie
227 cookie = http.cookies.SimpleCookie(headers["cookie"]).get("couchers-sesh")
229 if not cookie:
230 return None
232 return cookie.value
235def parse_user_id_cookie(headers):
236 """
237 Returns our session cookie value (aka token) or None
238 """
239 if "cookie" not in headers:
240 return None
242 # parse the cookie
243 cookie = http.cookies.SimpleCookie(headers["cookie"]).get("couchers-user-id")
245 if not cookie:
246 return None
248 return cookie.value
251def parse_api_key(headers):
252 """
253 Returns a bearer token (API key) from the `authorization` header, or None if invalid/not present
254 """
255 if "authorization" not in headers:
256 return None
258 authorization = headers["authorization"]
259 if not authorization.startswith("Bearer "):
260 return None
262 return authorization[7:]
265def remove_duplicates_retain_order(list_):
266 out = []
267 for item in list_:
268 if item not in out:
269 out.append(item)
270 return out
273def date_in_timezone(date_, timezone):
274 """
275 Given a naive postgres date object (postgres doesn't have tzd dates), returns a timezone-aware timestamp for the
276 start of that date in that timezone. E.g. if postgres is in 'America/New_York',
278 SET SESSION TIME ZONE 'America/New_York';
280 CREATE TABLE tz_trouble (to_date date, timezone text);
282 INSERT INTO tz_trouble(to_date, timezone) VALUES
283 ('2021-03-10'::date, 'Australia/Sydney'),
284 ('2021-03-20'::date, 'Europe/Berlin'),
285 ('2021-04-15'::date, 'America/New_York');
287 SELECT timezone(timezone, to_date::timestamp) FROM tz_trouble;
289 The result is:
291 timezone
292 ------------------------
293 2021-03-09 08:00:00-05
294 2021-03-19 19:00:00-04
295 2021-04-15 00:00:00-04
296 """
297 return func.timezone(timezone, cast(date_, DateTime(timezone=False)))
300def millis_from_dt(dt):
301 return round(1000 * dt.timestamp())
304def dt_from_millis(millis):
305 return datetime.fromtimestamp(millis / 1000, tz=utc)
308def dt_to_page_token(dt):
309 """
310 Python has datetime resolution equal to 1 micro, as does postgres
312 We pray to deities that this never changes
313 """
314 assert datetime.resolution == timedelta(microseconds=1)
315 return encrypt_page_token(str(round(1_000_000 * dt.timestamp())))
318def dt_from_page_token(page_token):
319 # see above comment
320 return datetime.fromtimestamp(int(decrypt_page_token(page_token)) / 1_000_000, tz=utc)
323def last_active_coarsen(dt):
324 """
325 Coarsens a "last active" time to the accuracy we use for last active times, currently to the last hour, e.g. if the current time is 27th June 2021, 16:53 UTC, this returns 27th June 2021, 16:00 UTC
326 """
327 return dt.replace(minute=0, second=0, microsecond=0)
330def get_tz_as_text(tz_name):
331 return datetime.now(tz=ZoneInfo(tz_name)).strftime("%Z/UTC%z")