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
|
import asyncio
import socket
from typing import Any, Dict, List, Optional, Type, Union
from .abc import AbstractResolver
from .helpers import get_running_loop
__all__ = ("ThreadedResolver", "AsyncResolver", "DefaultResolver")
try:
import aiodns
# aiodns_default = hasattr(aiodns.DNSResolver, 'gethostbyname')
except ImportError: # pragma: no cover
aiodns = None
aiodns_default = False
class ThreadedResolver(AbstractResolver):
"""Threaded resolver.
Uses an Executor for synchronous getaddrinfo() calls.
concurrent.futures.ThreadPoolExecutor is used by default.
"""
def __init__(self, loop: Optional[asyncio.AbstractEventLoop] = None) -> None:
self._loop = get_running_loop(loop)
async def resolve(
self, hostname: str, port: int = 0, family: int = socket.AF_INET
) -> List[Dict[str, Any]]:
infos = await self._loop.getaddrinfo(
hostname,
port,
type=socket.SOCK_STREAM,
family=family,
# flags=socket.AI_ADDRCONFIG,
)
hosts = []
for family, _, proto, _, address in infos:
if family == socket.AF_INET6:
if len(address) < 3:
# IPv6 is not supported by Python build,
# or IPv6 is not enabled in the host
continue
if address[3]: # type: ignore[misc]
# This is essential for link-local IPv6 addresses.
# LL IPv6 is a VERY rare case. Strictly speaking, we should use
# getnameinfo() unconditionally, but performance makes sense.
host, _port = socket.getnameinfo(
address, socket.NI_NUMERICHOST | socket.NI_NUMERICSERV
)
port = int(_port)
else:
host, port = address[:2]
else: # IPv4
assert family == socket.AF_INET
host, port = address # type: ignore[misc]
hosts.append(
{
"hostname": hostname,
"host": host,
"port": port,
"family": family,
"proto": proto,
"flags": socket.AI_NUMERICHOST | socket.AI_NUMERICSERV,
}
)
return hosts
async def close(self) -> None:
pass
class AsyncResolver(AbstractResolver):
"""Use the `aiodns` package to make asynchronous DNS lookups"""
def __init__(
self,
loop: Optional[asyncio.AbstractEventLoop] = None,
*args: Any,
**kwargs: Any
) -> None:
if aiodns is None:
raise RuntimeError("Resolver requires aiodns library")
self._loop = get_running_loop(loop)
self._resolver = aiodns.DNSResolver(*args, loop=loop, **kwargs)
if not hasattr(self._resolver, "gethostbyname"):
# aiodns 1.1 is not available, fallback to DNSResolver.query
self.resolve = self._resolve_with_query # type: ignore
async def resolve(
self, host: str, port: int = 0, family: int = socket.AF_INET
) -> List[Dict[str, Any]]:
try:
resp = await self._resolver.gethostbyname(host, family)
except aiodns.error.DNSError as exc:
msg = exc.args[1] if len(exc.args) >= 1 else "DNS lookup failed"
raise OSError(msg) from exc
hosts = []
for address in resp.addresses:
hosts.append(
{
"hostname": host,
"host": address,
"port": port,
"family": family,
"proto": 0,
"flags": socket.AI_NUMERICHOST | socket.AI_NUMERICSERV,
}
)
if not hosts:
raise OSError("DNS lookup failed")
return hosts
async def _resolve_with_query(
self, host: str, port: int = 0, family: int = socket.AF_INET
) -> List[Dict[str, Any]]:
if family == socket.AF_INET6:
qtype = "AAAA"
else:
qtype = "A"
try:
resp = await self._resolver.query(host, qtype)
except aiodns.error.DNSError as exc:
msg = exc.args[1] if len(exc.args) >= 1 else "DNS lookup failed"
raise OSError(msg) from exc
hosts = []
for rr in resp:
hosts.append(
{
"hostname": host,
"host": rr.host,
"port": port,
"family": family,
"proto": 0,
"flags": socket.AI_NUMERICHOST,
}
)
if not hosts:
raise OSError("DNS lookup failed")
return hosts
async def close(self) -> None:
self._resolver.cancel()
_DefaultType = Type[Union[AsyncResolver, ThreadedResolver]]
DefaultResolver: _DefaultType = AsyncResolver if aiodns_default else ThreadedResolver
|
