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comparison env/lib/python3.7/site-packages/urllib3/util/connection.py @ 0:26e78fe6e8c4 draft

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"planemo upload commit c699937486c35866861690329de38ec1a5d9f783"
author shellac
date Sat, 02 May 2020 07:14:21 -0400
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-1:000000000000 0:26e78fe6e8c4
1 from __future__ import absolute_import
2 import socket
3 from .wait import NoWayToWaitForSocketError, wait_for_read
4 from ..contrib import _appengine_environ
5
6
7 def is_connection_dropped(conn): # Platform-specific
8 """
9 Returns True if the connection is dropped and should be closed.
10
11 :param conn:
12 :class:`httplib.HTTPConnection` object.
13
14 Note: For platforms like AppEngine, this will always return ``False`` to
15 let the platform handle connection recycling transparently for us.
16 """
17 sock = getattr(conn, "sock", False)
18 if sock is False: # Platform-specific: AppEngine
19 return False
20 if sock is None: # Connection already closed (such as by httplib).
21 return True
22 try:
23 # Returns True if readable, which here means it's been dropped
24 return wait_for_read(sock, timeout=0.0)
25 except NoWayToWaitForSocketError: # Platform-specific: AppEngine
26 return False
27
28
29 # This function is copied from socket.py in the Python 2.7 standard
30 # library test suite. Added to its signature is only `socket_options`.
31 # One additional modification is that we avoid binding to IPv6 servers
32 # discovered in DNS if the system doesn't have IPv6 functionality.
33 def create_connection(
34 address,
35 timeout=socket._GLOBAL_DEFAULT_TIMEOUT,
36 source_address=None,
37 socket_options=None,
38 ):
39 """Connect to *address* and return the socket object.
40
41 Convenience function. Connect to *address* (a 2-tuple ``(host,
42 port)``) and return the socket object. Passing the optional
43 *timeout* parameter will set the timeout on the socket instance
44 before attempting to connect. If no *timeout* is supplied, the
45 global default timeout setting returned by :func:`getdefaulttimeout`
46 is used. If *source_address* is set it must be a tuple of (host, port)
47 for the socket to bind as a source address before making the connection.
48 An host of '' or port 0 tells the OS to use the default.
49 """
50
51 host, port = address
52 if host.startswith("["):
53 host = host.strip("[]")
54 err = None
55
56 # Using the value from allowed_gai_family() in the context of getaddrinfo lets
57 # us select whether to work with IPv4 DNS records, IPv6 records, or both.
58 # The original create_connection function always returns all records.
59 family = allowed_gai_family()
60
61 for res in socket.getaddrinfo(host, port, family, socket.SOCK_STREAM):
62 af, socktype, proto, canonname, sa = res
63 sock = None
64 try:
65 sock = socket.socket(af, socktype, proto)
66
67 # If provided, set socket level options before connecting.
68 _set_socket_options(sock, socket_options)
69
70 if timeout is not socket._GLOBAL_DEFAULT_TIMEOUT:
71 sock.settimeout(timeout)
72 if source_address:
73 sock.bind(source_address)
74 sock.connect(sa)
75 return sock
76
77 except socket.error as e:
78 err = e
79 if sock is not None:
80 sock.close()
81 sock = None
82
83 if err is not None:
84 raise err
85
86 raise socket.error("getaddrinfo returns an empty list")
87
88
89 def _set_socket_options(sock, options):
90 if options is None:
91 return
92
93 for opt in options:
94 sock.setsockopt(*opt)
95
96
97 def allowed_gai_family():
98 """This function is designed to work in the context of
99 getaddrinfo, where family=socket.AF_UNSPEC is the default and
100 will perform a DNS search for both IPv6 and IPv4 records."""
101
102 family = socket.AF_INET
103 if HAS_IPV6:
104 family = socket.AF_UNSPEC
105 return family
106
107
108 def _has_ipv6(host):
109 """ Returns True if the system can bind an IPv6 address. """
110 sock = None
111 has_ipv6 = False
112
113 # App Engine doesn't support IPV6 sockets and actually has a quota on the
114 # number of sockets that can be used, so just early out here instead of
115 # creating a socket needlessly.
116 # See https://github.com/urllib3/urllib3/issues/1446
117 if _appengine_environ.is_appengine_sandbox():
118 return False
119
120 if socket.has_ipv6:
121 # has_ipv6 returns true if cPython was compiled with IPv6 support.
122 # It does not tell us if the system has IPv6 support enabled. To
123 # determine that we must bind to an IPv6 address.
124 # https://github.com/urllib3/urllib3/pull/611
125 # https://bugs.python.org/issue658327
126 try:
127 sock = socket.socket(socket.AF_INET6)
128 sock.bind((host, 0))
129 has_ipv6 = True
130 except Exception:
131 pass
132
133 if sock:
134 sock.close()
135 return has_ipv6
136
137
138 HAS_IPV6 = _has_ipv6("::1")