1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
import os
import sysconfig
def reset_tzpath(to=None):
global TZPATH
tzpaths = to
if tzpaths is not None:
if isinstance(tzpaths, (str, bytes)):
raise TypeError(
f"tzpaths must be a list or tuple, "
+ f"not {type(tzpaths)}: {tzpaths!r}"
)
if not all(map(os.path.isabs, tzpaths)):
raise ValueError(_get_invalid_paths_message(tzpaths))
base_tzpath = tzpaths
else:
env_var = os.environ.get("PYTHONTZPATH", None)
if env_var is not None:
base_tzpath = _parse_python_tzpath(env_var)
else:
base_tzpath = _parse_python_tzpath(
sysconfig.get_config_var("TZPATH")
)
TZPATH = tuple(base_tzpath)
def _parse_python_tzpath(env_var):
if not env_var:
return ()
raw_tzpath = env_var.split(os.pathsep)
new_tzpath = tuple(filter(os.path.isabs, raw_tzpath))
# If anything has been filtered out, we will warn about it
if len(new_tzpath) != len(raw_tzpath):
import warnings
msg = _get_invalid_paths_message(raw_tzpath)
warnings.warn(
"Invalid paths specified in PYTHONTZPATH environment variable. "
+ msg,
InvalidTZPathWarning,
)
return new_tzpath
def _get_invalid_paths_message(tzpaths):
invalid_paths = (path for path in tzpaths if not os.path.isabs(path))
prefix = "\n "
indented_str = prefix + prefix.join(invalid_paths)
return (
"Paths should be absolute but found the following relative paths:"
+ indented_str
)
def find_tzfile(key):
"""Retrieve the path to a TZif file from a key."""
_validate_tzfile_path(key)
for search_path in TZPATH:
filepath = os.path.join(search_path, key)
if os.path.isfile(filepath):
return filepath
return None
_TEST_PATH = os.path.normpath(os.path.join("_", "_"))[:-1]
def _validate_tzfile_path(path, _base=_TEST_PATH):
if os.path.isabs(path):
raise ValueError(
f"ZoneInfo keys may not be absolute paths, got: {path}"
)
# We only care about the kinds of path normalizations that would change the
# length of the key - e.g. a/../b -> a/b, or a/b/ -> a/b. On Windows,
# normpath will also change from a/b to a\b, but that would still preserve
# the length.
new_path = os.path.normpath(path)
if len(new_path) != len(path):
raise ValueError(
f"ZoneInfo keys must be normalized relative paths, got: {path}"
)
resolved = os.path.normpath(os.path.join(_base, new_path))
if not resolved.startswith(_base):
raise ValueError(
f"ZoneInfo keys must refer to subdirectories of TZPATH, got: {path}"
)
del _TEST_PATH
def available_timezones():
"""Returns a set containing all available time zones.
.. caution::
This may attempt to open a large number of files, since the best way to
determine if a given file on the time zone search path is to open it
and check for the "magic string" at the beginning.
"""
from importlib import resources
valid_zones = set()
# Start with loading from the tzdata package if it exists: this has a
# pre-assembled list of zones that only requires opening one file.
try:
with resources.files("tzdata").joinpath("zones").open("r") as f:
for zone in f:
zone = zone.strip()
if zone:
valid_zones.add(zone)
except (ImportError, FileNotFoundError):
pass
def valid_key(fpath):
try:
with open(fpath, "rb") as f:
return f.read(4) == b"TZif"
except Exception: # pragma: nocover
return False
for tz_root in TZPATH:
if not os.path.exists(tz_root):
continue
for root, dirnames, files in os.walk(tz_root):
if root == tz_root:
# right/ and posix/ are special directories and shouldn't be
# included in the output of available zones
if "right" in dirnames:
dirnames.remove("right")
if "posix" in dirnames:
dirnames.remove("posix")
for file in files:
fpath = os.path.join(root, file)
key = os.path.relpath(fpath, start=tz_root)
if os.sep != "/": # pragma: nocover
key = key.replace(os.sep, "/")
if not key or key in valid_zones:
continue
if valid_key(fpath):
valid_zones.add(key)
if "posixrules" in valid_zones:
# posixrules is a special symlink-only time zone where it exists, it
# should not be included in the output
valid_zones.remove("posixrules")
return valid_zones
class InvalidTZPathWarning(RuntimeWarning):
"""Warning raised if an invalid path is specified in PYTHONTZPATH."""
TZPATH = ()
reset_tzpath()
|
