150 lines
4.8 KiB
Python
150 lines
4.8 KiB
Python
from __future__ import absolute_import
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import socket
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from ..contrib import _appengine_environ
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from ..exceptions import LocationParseError
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from ..packages import six
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from .wait import NoWayToWaitForSocketError, wait_for_read
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def is_connection_dropped(conn): # Platform-specific
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"""
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Returns True if the connection is dropped and should be closed.
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:param conn:
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:class:`http.client.HTTPConnection` object.
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Note: For platforms like AppEngine, this will always return ``False`` to
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let the platform handle connection recycling transparently for us.
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"""
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sock = getattr(conn, "sock", False)
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if sock is False: # Platform-specific: AppEngine
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return False
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if sock is None: # Connection already closed (such as by httplib).
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return True
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try:
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# Returns True if readable, which here means it's been dropped
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return wait_for_read(sock, timeout=0.0)
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except NoWayToWaitForSocketError: # Platform-specific: AppEngine
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return False
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# This function is copied from socket.py in the Python 2.7 standard
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# library test suite. Added to its signature is only `socket_options`.
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# One additional modification is that we avoid binding to IPv6 servers
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# discovered in DNS if the system doesn't have IPv6 functionality.
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def create_connection(
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address,
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timeout=socket._GLOBAL_DEFAULT_TIMEOUT,
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source_address=None,
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socket_options=None,
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):
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"""Connect to *address* and return the socket object.
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Convenience function. Connect to *address* (a 2-tuple ``(host,
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port)``) and return the socket object. Passing the optional
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*timeout* parameter will set the timeout on the socket instance
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before attempting to connect. If no *timeout* is supplied, the
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global default timeout setting returned by :func:`socket.getdefaulttimeout`
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is used. If *source_address* is set it must be a tuple of (host, port)
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for the socket to bind as a source address before making the connection.
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An host of '' or port 0 tells the OS to use the default.
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"""
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host, port = address
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if host.startswith("["):
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host = host.strip("[]")
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err = None
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# Using the value from allowed_gai_family() in the context of getaddrinfo lets
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# us select whether to work with IPv4 DNS records, IPv6 records, or both.
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# The original create_connection function always returns all records.
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family = allowed_gai_family()
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try:
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host.encode("idna")
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except UnicodeError:
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return six.raise_from(
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LocationParseError(u"'%s', label empty or too long" % host), None
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)
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for res in socket.getaddrinfo(host, port, family, socket.SOCK_STREAM):
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af, socktype, proto, canonname, sa = res
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sock = None
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try:
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sock = socket.socket(af, socktype, proto)
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# If provided, set socket level options before connecting.
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_set_socket_options(sock, socket_options)
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if timeout is not socket._GLOBAL_DEFAULT_TIMEOUT:
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sock.settimeout(timeout)
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if source_address:
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sock.bind(source_address)
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sock.connect(sa)
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return sock
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except socket.error as e:
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err = e
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if sock is not None:
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sock.close()
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sock = None
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if err is not None:
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raise err
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raise socket.error("getaddrinfo returns an empty list")
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def _set_socket_options(sock, options):
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if options is None:
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return
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for opt in options:
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sock.setsockopt(*opt)
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def allowed_gai_family():
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"""This function is designed to work in the context of
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getaddrinfo, where family=socket.AF_UNSPEC is the default and
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will perform a DNS search for both IPv6 and IPv4 records."""
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family = socket.AF_INET
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if HAS_IPV6:
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family = socket.AF_UNSPEC
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return family
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def _has_ipv6(host):
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"""Returns True if the system can bind an IPv6 address."""
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sock = None
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has_ipv6 = False
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# App Engine doesn't support IPV6 sockets and actually has a quota on the
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# number of sockets that can be used, so just early out here instead of
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# creating a socket needlessly.
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# See https://github.com/urllib3/urllib3/issues/1446
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if _appengine_environ.is_appengine_sandbox():
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return False
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if socket.has_ipv6:
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# has_ipv6 returns true if cPython was compiled with IPv6 support.
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# It does not tell us if the system has IPv6 support enabled. To
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# determine that we must bind to an IPv6 address.
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# https://github.com/urllib3/urllib3/pull/611
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# https://bugs.python.org/issue658327
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try:
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sock = socket.socket(socket.AF_INET6)
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sock.bind((host, 0))
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has_ipv6 = True
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except Exception:
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pass
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if sock:
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sock.close()
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return has_ipv6
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HAS_IPV6 = _has_ipv6("::1")
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