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