Use persistent connections

10 files changed, 1828 insertions, 0 deletions

diff --git a/python/urllib3/util/__init__.py b/python/urllib3/util/__init__.py
new file mode 100644
index 0000000..2f2770b
--- /dev/null
+++ b/python/urllib3/util/__init__.py
@@ -0,0 +1,54 @@
+from __future__ import absolute_import
+# For backwards compatibility, provide imports that used to be here.
+from .connection import is_connection_dropped
+from .request import make_headers
+from .response import is_fp_closed
+from .ssl_ import (
+    SSLContext,
+    HAS_SNI,
+    IS_PYOPENSSL,
+    IS_SECURETRANSPORT,
+    assert_fingerprint,
+    resolve_cert_reqs,
+    resolve_ssl_version,
+    ssl_wrap_socket,
+)
+from .timeout import (
+    current_time,
+    Timeout,
+)
+
+from .retry import Retry
+from .url import (
+    get_host,
+    parse_url,
+    split_first,
+    Url,
+)
+from .wait import (
+    wait_for_read,
+    wait_for_write
+)
+
+__all__ = (
+    'HAS_SNI',
+    'IS_PYOPENSSL',
+    'IS_SECURETRANSPORT',
+    'SSLContext',
+    'Retry',
+    'Timeout',
+    'Url',
+    'assert_fingerprint',
+    'current_time',
+    'is_connection_dropped',
+    'is_fp_closed',
+    'get_host',
+    'parse_url',
+    'make_headers',
+    'resolve_cert_reqs',
+    'resolve_ssl_version',
+    'split_first',
+    'ssl_wrap_socket',
+    'wait_for_read',
+    'wait_for_write'
+)
diff --git a/python/urllib3/util/connection.py b/python/urllib3/util/connection.py
new file mode 100644
index 0000000..5ad70b2
--- /dev/null
+++ b/python/urllib3/util/connection.py
@@ -0,0 +1,134 @@
+from __future__ import absolute_import
+import socket
+from .wait import NoWayToWaitForSocketError, wait_for_read
+from ..contrib import _appengine_environ
+
+
+def is_connection_dropped(conn):  # Platform-specific
+    """
+    Returns True if the connection is dropped and should be closed.
+
+    :param conn:
+        :class:`httplib.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:`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()
+
+    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/shazow/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')
diff --git a/python/urllib3/util/queue.py b/python/urllib3/util/queue.py
new file mode 100644
index 0000000..d3d379a
--- /dev/null
+++ b/python/urllib3/util/queue.py
@@ -0,0 +1,21 @@
+import collections
+from ..packages import six
+from ..packages.six.moves import queue
+
+if six.PY2:
+    # Queue is imported for side effects on MS Windows. See issue #229.
+    import Queue as _unused_module_Queue  # noqa: F401
+
+
+class LifoQueue(queue.Queue):
+    def _init(self, _):
+        self.queue = collections.deque()
+
+    def _qsize(self, len=len):
+        return len(self.queue)
+
+    def _put(self, item):
+        self.queue.append(item)
+
+    def _get(self):
+        return self.queue.pop()
diff --git a/python/urllib3/util/request.py b/python/urllib3/util/request.py
new file mode 100644
index 0000000..3ddfcd5
--- /dev/null
+++ b/python/urllib3/util/request.py
@@ -0,0 +1,118 @@
+from __future__ import absolute_import
+from base64 import b64encode
+
+from ..packages.six import b, integer_types
+from ..exceptions import UnrewindableBodyError
+
+ACCEPT_ENCODING = 'gzip,deflate'
+_FAILEDTELL = object()
+
+
+def make_headers(keep_alive=None, accept_encoding=None, user_agent=None,
+                 basic_auth=None, proxy_basic_auth=None, disable_cache=None):
+    """
+    Shortcuts for generating request headers.
+
+    :param keep_alive:
+        If ``True``, adds 'connection: keep-alive' header.
+
+    :param accept_encoding:
+        Can be a boolean, list, or string.
+        ``True`` translates to 'gzip,deflate'.
+        List will get joined by comma.
+        String will be used as provided.
+
+    :param user_agent:
+        String representing the user-agent you want, such as
+        "python-urllib3/0.6"
+
+    :param basic_auth:
+        Colon-separated username:password string for 'authorization: basic ...'
+        auth header.
+
+    :param proxy_basic_auth:
+        Colon-separated username:password string for 'proxy-authorization: basic ...'
+        auth header.
+
+    :param disable_cache:
+        If ``True``, adds 'cache-control: no-cache' header.
+
+    Example::
+
+        >>> make_headers(keep_alive=True, user_agent="Batman/1.0")
+        {'connection': 'keep-alive', 'user-agent': 'Batman/1.0'}
+        >>> make_headers(accept_encoding=True)
+        {'accept-encoding': 'gzip,deflate'}
+    """
+    headers = {}
+    if accept_encoding:
+        if isinstance(accept_encoding, str):
+            pass
+        elif isinstance(accept_encoding, list):
+            accept_encoding = ','.join(accept_encoding)
+        else:
+            accept_encoding = ACCEPT_ENCODING
+        headers['accept-encoding'] = accept_encoding
+
+    if user_agent:
+        headers['user-agent'] = user_agent
+
+    if keep_alive:
+        headers['connection'] = 'keep-alive'
+
+    if basic_auth:
+        headers['authorization'] = 'Basic ' + \
+            b64encode(b(basic_auth)).decode('utf-8')
+
+    if proxy_basic_auth:
+        headers['proxy-authorization'] = 'Basic ' + \
+            b64encode(b(proxy_basic_auth)).decode('utf-8')
+
+    if disable_cache:
+        headers['cache-control'] = 'no-cache'
+
+    return headers
+
+
+def set_file_position(body, pos):
+    """
+    If a position is provided, move file to that point.
+    Otherwise, we'll attempt to record a position for future use.
+    """
+    if pos is not None:
+        rewind_body(body, pos)
+    elif getattr(body, 'tell', None) is not None:
+        try:
+            pos = body.tell()
+        except (IOError, OSError):
+            # This differentiates from None, allowing us to catch
+            # a failed `tell()` later when trying to rewind the body.
+            pos = _FAILEDTELL
+
+    return pos
+
+
+def rewind_body(body, body_pos):
+    """
+    Attempt to rewind body to a certain position.
+    Primarily used for request redirects and retries.
+
+    :param body:
+        File-like object that supports seek.
+
+    :param int pos:
+        Position to seek to in file.
+    """
+    body_seek = getattr(body, 'seek', None)
+    if body_seek is not None and isinstance(body_pos, integer_types):
+        try:
+            body_seek(body_pos)
+        except (IOError, OSError):
+            raise UnrewindableBodyError("An error occurred when rewinding request "
+                                        "body for redirect/retry.")
+    elif body_pos is _FAILEDTELL:
+        raise UnrewindableBodyError("Unable to record file position for rewinding "
+                                    "request body during a redirect/retry.")
+    else:
+        raise ValueError("body_pos must be of type integer, "
+                         "instead it was %s." % type(body_pos))
diff --git a/python/urllib3/util/response.py b/python/urllib3/util/response.py
new file mode 100644
index 0000000..3d54864
--- /dev/null
+++ b/python/urllib3/util/response.py
@@ -0,0 +1,87 @@
+from __future__ import absolute_import
+from ..packages.six.moves import http_client as httplib
+
+from ..exceptions import HeaderParsingError
+
+
+def is_fp_closed(obj):
+    """
+    Checks whether a given file-like object is closed.
+
+    :param obj:
+        The file-like object to check.
+    """
+
+    try:
+        # Check `isclosed()` first, in case Python3 doesn't set `closed`.
+        # GH Issue #928
+        return obj.isclosed()
+    except AttributeError:
+        pass
+
+    try:
+        # Check via the official file-like-object way.
+        return obj.closed
+    except AttributeError:
+        pass
+
+    try:
+        # Check if the object is a container for another file-like object that
+        # gets released on exhaustion (e.g. HTTPResponse).
+        return obj.fp is None
+    except AttributeError:
+        pass
+
+    raise ValueError("Unable to determine whether fp is closed.")
+
+
+def assert_header_parsing(headers):
+    """
+    Asserts whether all headers have been successfully parsed.
+    Extracts encountered errors from the result of parsing headers.
+
+    Only works on Python 3.
+
+    :param headers: Headers to verify.
+    :type headers: `httplib.HTTPMessage`.
+
+    :raises urllib3.exceptions.HeaderParsingError:
+        If parsing errors are found.
+    """
+
+    # This will fail silently if we pass in the wrong kind of parameter.
+    # To make debugging easier add an explicit check.
+    if not isinstance(headers, httplib.HTTPMessage):
+        raise TypeError('expected httplib.Message, got {0}.'.format(
+            type(headers)))
+
+    defects = getattr(headers, 'defects', None)
+    get_payload = getattr(headers, 'get_payload', None)
+
+    unparsed_data = None
+    if get_payload:
+        # get_payload is actually email.message.Message.get_payload;
+        # we're only interested in the result if it's not a multipart message
+        if not headers.is_multipart():
+            payload = get_payload()
+
+            if isinstance(payload, (bytes, str)):
+                unparsed_data = payload
+
+    if defects or unparsed_data:
+        raise HeaderParsingError(defects=defects, unparsed_data=unparsed_data)
+
+
+def is_response_to_head(response):
+    """
+    Checks whether the request of a response has been a HEAD-request.
+    Handles the quirks of AppEngine.
+
+    :param conn:
+    :type conn: :class:`httplib.HTTPResponse`
+    """
+    # FIXME: Can we do this somehow without accessing private httplib _method?
+    method = response._method
+    if isinstance(method, int):  # Platform-specific: Appengine
+        return method == 3
+    return method.upper() == 'HEAD'
diff --git a/python/urllib3/util/retry.py b/python/urllib3/util/retry.py
new file mode 100644
index 0000000..e7d0abd
--- /dev/null
+++ b/python/urllib3/util/retry.py
@@ -0,0 +1,411 @@
+from __future__ import absolute_import
+import time
+import logging
+from collections import namedtuple
+from itertools import takewhile
+import email
+import re
+
+from ..exceptions import (
+    ConnectTimeoutError,
+    MaxRetryError,
+    ProtocolError,
+    ReadTimeoutError,
+    ResponseError,
+    InvalidHeader,
+)
+from ..packages import six
+
+
+log = logging.getLogger(__name__)
+
+
+# Data structure for representing the metadata of requests that result in a retry.
+RequestHistory = namedtuple('RequestHistory', ["method", "url", "error",
+                                               "status", "redirect_location"])
+
+
+class Retry(object):
+    """ Retry configuration.
+
+    Each retry attempt will create a new Retry object with updated values, so
+    they can be safely reused.
+
+    Retries can be defined as a default for a pool::
+
+        retries = Retry(connect=5, read=2, redirect=5)
+        http = PoolManager(retries=retries)
+        response = http.request('GET', 'http://example.com/')
+
+    Or per-request (which overrides the default for the pool)::
+
+        response = http.request('GET', 'http://example.com/', retries=Retry(10))
+
+    Retries can be disabled by passing ``False``::
+
+        response = http.request('GET', 'http://example.com/', retries=False)
+
+    Errors will be wrapped in :class:`~urllib3.exceptions.MaxRetryError` unless
+    retries are disabled, in which case the causing exception will be raised.
+
+    :param int total:
+        Total number of retries to allow. Takes precedence over other counts.
+
+        Set to ``None`` to remove this constraint and fall back on other
+        counts. It's a good idea to set this to some sensibly-high value to
+        account for unexpected edge cases and avoid infinite retry loops.
+
+        Set to ``0`` to fail on the first retry.
+
+        Set to ``False`` to disable and imply ``raise_on_redirect=False``.
+
+    :param int connect:
+        How many connection-related errors to retry on.
+
+        These are errors raised before the request is sent to the remote server,
+        which we assume has not triggered the server to process the request.
+
+        Set to ``0`` to fail on the first retry of this type.
+
+    :param int read:
+        How many times to retry on read errors.
+
+        These errors are raised after the request was sent to the server, so the
+        request may have side-effects.
+
+        Set to ``0`` to fail on the first retry of this type.
+
+    :param int redirect:
+        How many redirects to perform. Limit this to avoid infinite redirect
+        loops.
+
+        A redirect is a HTTP response with a status code 301, 302, 303, 307 or
+        308.
+
+        Set to ``0`` to fail on the first retry of this type.
+
+        Set to ``False`` to disable and imply ``raise_on_redirect=False``.
+
+    :param int status:
+        How many times to retry on bad status codes.
+
+        These are retries made on responses, where status code matches
+        ``status_forcelist``.
+
+        Set to ``0`` to fail on the first retry of this type.
+
+    :param iterable method_whitelist:
+        Set of uppercased HTTP method verbs that we should retry on.
+
+        By default, we only retry on methods which are considered to be
+        idempotent (multiple requests with the same parameters end with the
+        same state). See :attr:`Retry.DEFAULT_METHOD_WHITELIST`.
+
+        Set to a ``False`` value to retry on any verb.
+
+    :param iterable status_forcelist:
+        A set of integer HTTP status codes that we should force a retry on.
+        A retry is initiated if the request method is in ``method_whitelist``
+        and the response status code is in ``status_forcelist``.
+
+        By default, this is disabled with ``None``.
+
+    :param float backoff_factor:
+        A backoff factor to apply between attempts after the second try
+        (most errors are resolved immediately by a second try without a
+        delay). urllib3 will sleep for::
+
+            {backoff factor} * (2 ** ({number of total retries} - 1))
+
+        seconds. If the backoff_factor is 0.1, then :func:`.sleep` will sleep
+        for [0.0s, 0.2s, 0.4s, ...] between retries. It will never be longer
+        than :attr:`Retry.BACKOFF_MAX`.
+
+        By default, backoff is disabled (set to 0).
+
+    :param bool raise_on_redirect: Whether, if the number of redirects is
+        exhausted, to raise a MaxRetryError, or to return a response with a
+        response code in the 3xx range.
+
+    :param bool raise_on_status: Similar meaning to ``raise_on_redirect``:
+        whether we should raise an exception, or return a response,
+        if status falls in ``status_forcelist`` range and retries have
+        been exhausted.
+
+    :param tuple history: The history of the request encountered during
+        each call to :meth:`~Retry.increment`. The list is in the order
+        the requests occurred. Each list item is of class :class:`RequestHistory`.
+
+    :param bool respect_retry_after_header:
+        Whether to respect Retry-After header on status codes defined as
+        :attr:`Retry.RETRY_AFTER_STATUS_CODES` or not.
+
+    :param iterable remove_headers_on_redirect:
+        Sequence of headers to remove from the request when a response
+        indicating a redirect is returned before firing off the redirected
+        request.
+    """
+
+    DEFAULT_METHOD_WHITELIST = frozenset([
+        'HEAD', 'GET', 'PUT', 'DELETE', 'OPTIONS', 'TRACE'])
+
+    RETRY_AFTER_STATUS_CODES = frozenset([413, 429, 503])
+
+    DEFAULT_REDIRECT_HEADERS_BLACKLIST = frozenset(['Authorization'])
+
+    #: Maximum backoff time.
+    BACKOFF_MAX = 120
+
+    def __init__(self, total=10, connect=None, read=None, redirect=None, status=None,
+                 method_whitelist=DEFAULT_METHOD_WHITELIST, status_forcelist=None,
+                 backoff_factor=0, raise_on_redirect=True, raise_on_status=True,
+                 history=None, respect_retry_after_header=True,
+                 remove_headers_on_redirect=DEFAULT_REDIRECT_HEADERS_BLACKLIST):
+
+        self.total = total
+        self.connect = connect
+        self.read = read
+        self.status = status
+
+        if redirect is False or total is False:
+            redirect = 0
+            raise_on_redirect = False
+
+        self.redirect = redirect
+        self.status_forcelist = status_forcelist or set()
+        self.method_whitelist = method_whitelist
+        self.backoff_factor = backoff_factor
+        self.raise_on_redirect = raise_on_redirect
+        self.raise_on_status = raise_on_status
+        self.history = history or tuple()
+        self.respect_retry_after_header = respect_retry_after_header
+        self.remove_headers_on_redirect = remove_headers_on_redirect
+
+    def new(self, **kw):
+        params = dict(
+            total=self.total,
+            connect=self.connect, read=self.read, redirect=self.redirect, status=self.status,
+            method_whitelist=self.method_whitelist,
+            status_forcelist=self.status_forcelist,
+            backoff_factor=self.backoff_factor,
+            raise_on_redirect=self.raise_on_redirect,
+            raise_on_status=self.raise_on_status,
+            history=self.history,
+            remove_headers_on_redirect=self.remove_headers_on_redirect
+        )
+        params.update(kw)
+        return type(self)(**params)
+
+    @classmethod
+    def from_int(cls, retries, redirect=True, default=None):
+        """ Backwards-compatibility for the old retries format."""
+        if retries is None:
+            retries = default if default is not None else cls.DEFAULT
+
+        if isinstance(retries, Retry):
+            return retries
+
+        redirect = bool(redirect) and None
+        new_retries = cls(retries, redirect=redirect)
+        log.debug("Converted retries value: %r -> %r", retries, new_retries)
+        return new_retries
+
+    def get_backoff_time(self):
+        """ Formula for computing the current backoff
+
+        :rtype: float
+        """
+        # We want to consider only the last consecutive errors sequence (Ignore redirects).
+        consecutive_errors_len = len(list(takewhile(lambda x: x.redirect_location is None,
+                                                    reversed(self.history))))
+        if consecutive_errors_len <= 1:
+            return 0
+
+        backoff_value = self.backoff_factor * (2 ** (consecutive_errors_len - 1))
+        return min(self.BACKOFF_MAX, backoff_value)
+
+    def parse_retry_after(self, retry_after):
+        # Whitespace: https://tools.ietf.org/html/rfc7230#section-3.2.4
+        if re.match(r"^\s*[0-9]+\s*$", retry_after):
+            seconds = int(retry_after)
+        else:
+            retry_date_tuple = email.utils.parsedate(retry_after)
+            if retry_date_tuple is None:
+                raise InvalidHeader("Invalid Retry-After header: %s" % retry_after)
+            retry_date = time.mktime(retry_date_tuple)
+            seconds = retry_date - time.time()
+
+        if seconds < 0:
+            seconds = 0
+
+        return seconds
+
+    def get_retry_after(self, response):
+        """ Get the value of Retry-After in seconds. """
+
+        retry_after = response.getheader("Retry-After")
+
+        if retry_after is None:
+            return None
+
+        return self.parse_retry_after(retry_after)
+
+    def sleep_for_retry(self, response=None):
+        retry_after = self.get_retry_after(response)
+        if retry_after:
+            time.sleep(retry_after)
+            return True
+
+        return False
+
+    def _sleep_backoff(self):
+        backoff = self.get_backoff_time()
+        if backoff <= 0:
+            return
+        time.sleep(backoff)
+
+    def sleep(self, response=None):
+        """ Sleep between retry attempts.
+
+        This method will respect a server's ``Retry-After`` response header
+        and sleep the duration of the time requested. If that is not present, it
+        will use an exponential backoff. By default, the backoff factor is 0 and
+        this method will return immediately.
+        """
+
+        if response:
+            slept = self.sleep_for_retry(response)
+            if slept:
+                return
+
+        self._sleep_backoff()
+
+    def _is_connection_error(self, err):
+        """ Errors when we're fairly sure that the server did not receive the
+        request, so it should be safe to retry.
+        """
+        return isinstance(err, ConnectTimeoutError)
+
+    def _is_read_error(self, err):
+        """ Errors that occur after the request has been started, so we should
+        assume that the server began processing it.
+        """
+        return isinstance(err, (ReadTimeoutError, ProtocolError))
+
+    def _is_method_retryable(self, method):
+        """ Checks if a given HTTP method should be retried upon, depending if
+        it is included on the method whitelist.
+        """
+        if self.method_whitelist and method.upper() not in self.method_whitelist:
+            return False
+
+        return True
+
+    def is_retry(self, method, status_code, has_retry_after=False):
+        """ Is this method/status code retryable? (Based on whitelists and control
+        variables such as the number of total retries to allow, whether to
+        respect the Retry-After header, whether this header is present, and
+        whether the returned status code is on the list of status codes to
+        be retried upon on the presence of the aforementioned header)
+        """
+        if not self._is_method_retryable(method):
+            return False
+
+        if self.status_forcelist and status_code in self.status_forcelist:
+            return True
+
+        return (self.total and self.respect_retry_after_header and
+                has_retry_after and (status_code in self.RETRY_AFTER_STATUS_CODES))
+
+    def is_exhausted(self):
+        """ Are we out of retries? """
+        retry_counts = (self.total, self.connect, self.read, self.redirect, self.status)
+        retry_counts = list(filter(None, retry_counts))
+        if not retry_counts:
+            return False
+
+        return min(retry_counts) < 0
+
+    def increment(self, method=None, url=None, response=None, error=None,
+                  _pool=None, _stacktrace=None):
+        """ Return a new Retry object with incremented retry counters.
+
+        :param response: A response object, or None, if the server did not
+            return a response.
+        :type response: :class:`~urllib3.response.HTTPResponse`
+        :param Exception error: An error encountered during the request, or
+            None if the response was received successfully.
+
+        :return: A new ``Retry`` object.
+        """
+        if self.total is False and error:
+            # Disabled, indicate to re-raise the error.
+            raise six.reraise(type(error), error, _stacktrace)
+
+        total = self.total
+        if total is not None:
+            total -= 1
+
+        connect = self.connect
+        read = self.read
+        redirect = self.redirect
+        status_count = self.status
+        cause = 'unknown'
+        status = None
+        redirect_location = None
+
+        if error and self._is_connection_error(error):
+            # Connect retry?
+            if connect is False:
+                raise six.reraise(type(error), error, _stacktrace)
+            elif connect is not None:
+                connect -= 1
+
+        elif error and self._is_read_error(error):
+            # Read retry?
+            if read is False or not self._is_method_retryable(method):
+                raise six.reraise(type(error), error, _stacktrace)
+            elif read is not None:
+                read -= 1
+
+        elif response and response.get_redirect_location():
+            # Redirect retry?
+            if redirect is not None:
+                redirect -= 1
+            cause = 'too many redirects'
+            redirect_location = response.get_redirect_location()
+            status = response.status
+
+        else:
+            # Incrementing because of a server error like a 500 in
+            # status_forcelist and a the given method is in the whitelist
+            cause = ResponseError.GENERIC_ERROR
+            if response and response.status:
+                if status_count is not None:
+                    status_count -= 1
+                cause = ResponseError.SPECIFIC_ERROR.format(
+                    status_code=response.status)
+                status = response.status
+
+        history = self.history + (RequestHistory(method, url, error, status, redirect_location),)
+
+        new_retry = self.new(
+            total=total,
+            connect=connect, read=read, redirect=redirect, status=status_count,
+            history=history)
+
+        if new_retry.is_exhausted():
+            raise MaxRetryError(_pool, url, error or ResponseError(cause))
+
+        log.debug("Incremented Retry for (url='%s'): %r", url, new_retry)
+
+        return new_retry
+
+    def __repr__(self):
+        return ('{cls.__name__}(total={self.total}, connect={self.connect}, '
+                'read={self.read}, redirect={self.redirect}, status={self.status})').format(
+                    cls=type(self), self=self)
+
+
+# For backwards compatibility (equivalent to pre-v1.9):
+Retry.DEFAULT = Retry(3)
diff --git a/python/urllib3/util/ssl_.py b/python/urllib3/util/ssl_.py
new file mode 100644
index 0000000..64ea192
--- /dev/null
+++ b/python/urllib3/util/ssl_.py
@@ -0,0 +1,381 @@
+from __future__ import absolute_import
+import errno
+import warnings
+import hmac
+import socket
+
+from binascii import hexlify, unhexlify
+from hashlib import md5, sha1, sha256
+
+from ..exceptions import SSLError, InsecurePlatformWarning, SNIMissingWarning
+from ..packages import six
+
+
+SSLContext = None
+HAS_SNI = False
+IS_PYOPENSSL = False
+IS_SECURETRANSPORT = False
+
+# Maps the length of a digest to a possible hash function producing this digest
+HASHFUNC_MAP = {
+    32: md5,
+    40: sha1,
+    64: sha256,
+}
+
+
+def _const_compare_digest_backport(a, b):
+    """
+    Compare two digests of equal length in constant time.
+
+    The digests must be of type str/bytes.
+    Returns True if the digests match, and False otherwise.
+    """
+    result = abs(len(a) - len(b))
+    for l, r in zip(bytearray(a), bytearray(b)):
+        result |= l ^ r
+    return result == 0
+
+
+_const_compare_digest = getattr(hmac, 'compare_digest',
+                                _const_compare_digest_backport)
+
+
+try:  # Test for SSL features
+    import ssl
+    from ssl import wrap_socket, CERT_NONE, PROTOCOL_SSLv23
+    from ssl import HAS_SNI  # Has SNI?
+except ImportError:
+    pass
+
+
+try:
+    from ssl import OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION
+except ImportError:
+    OP_NO_SSLv2, OP_NO_SSLv3 = 0x1000000, 0x2000000
+    OP_NO_COMPRESSION = 0x20000
+
+
+# Python 2.7 doesn't have inet_pton on non-Linux so we fallback on inet_aton in
+# those cases. This means that we can only detect IPv4 addresses in this case.
+if hasattr(socket, 'inet_pton'):
+    inet_pton = socket.inet_pton
+else:
+    # Maybe we can use ipaddress if the user has urllib3[secure]?
+    try:
+        import ipaddress
+
+        def inet_pton(_, host):
+            if isinstance(host, bytes):
+                host = host.decode('ascii')
+            return ipaddress.ip_address(host)
+
+    except ImportError:  # Platform-specific: Non-Linux
+        def inet_pton(_, host):
+            return socket.inet_aton(host)
+
+
+# A secure default.
+# Sources for more information on TLS ciphers:
+#
+# - https://wiki.mozilla.org/Security/Server_Side_TLS
+# - https://www.ssllabs.com/projects/best-practices/index.html
+# - https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/
+#
+# The general intent is:
+# - Prefer TLS 1.3 cipher suites
+# - prefer cipher suites that offer perfect forward secrecy (DHE/ECDHE),
+# - prefer ECDHE over DHE for better performance,
+# - prefer any AES-GCM and ChaCha20 over any AES-CBC for better performance and
+#   security,
+# - prefer AES-GCM over ChaCha20 because hardware-accelerated AES is common,
+# - disable NULL authentication, MD5 MACs and DSS for security reasons.
+DEFAULT_CIPHERS = ':'.join([
+    'TLS13-AES-256-GCM-SHA384',
+    'TLS13-CHACHA20-POLY1305-SHA256',
+    'TLS13-AES-128-GCM-SHA256',
+    'ECDH+AESGCM',
+    'ECDH+CHACHA20',
+    'DH+AESGCM',
+    'DH+CHACHA20',
+    'ECDH+AES256',
+    'DH+AES256',
+    'ECDH+AES128',
+    'DH+AES',
+    'RSA+AESGCM',
+    'RSA+AES',
+    '!aNULL',
+    '!eNULL',
+    '!MD5',
+])
+
+try:
+    from ssl import SSLContext  # Modern SSL?
+except ImportError:
+    import sys
+
+    class SSLContext(object):  # Platform-specific: Python 2
+        def __init__(self, protocol_version):
+            self.protocol = protocol_version
+            # Use default values from a real SSLContext
+            self.check_hostname = False
+            self.verify_mode = ssl.CERT_NONE
+            self.ca_certs = None
+            self.options = 0
+            self.certfile = None
+            self.keyfile = None
+            self.ciphers = None
+
+        def load_cert_chain(self, certfile, keyfile):
+            self.certfile = certfile
+            self.keyfile = keyfile
+
+        def load_verify_locations(self, cafile=None, capath=None):
+            self.ca_certs = cafile
+
+            if capath is not None:
+                raise SSLError("CA directories not supported in older Pythons")
+
+        def set_ciphers(self, cipher_suite):
+            self.ciphers = cipher_suite
+
+        def wrap_socket(self, socket, server_hostname=None, server_side=False):
+            warnings.warn(
+                'A true SSLContext object is not available. This prevents '
+                'urllib3 from configuring SSL appropriately and may cause '
+                'certain SSL connections to fail. You can upgrade to a newer '
+                'version of Python to solve this. For more information, see '
+                'https://urllib3.readthedocs.io/en/latest/advanced-usage.html'
+                '#ssl-warnings',
+                InsecurePlatformWarning
+            )
+            kwargs = {
+                'keyfile': self.keyfile,
+                'certfile': self.certfile,
+                'ca_certs': self.ca_certs,
+                'cert_reqs': self.verify_mode,
+                'ssl_version': self.protocol,
+                'server_side': server_side,
+            }
+            return wrap_socket(socket, ciphers=self.ciphers, **kwargs)
+
+
+def assert_fingerprint(cert, fingerprint):
+    """
+    Checks if given fingerprint matches the supplied certificate.
+
+    :param cert:
+        Certificate as bytes object.
+    :param fingerprint:
+        Fingerprint as string of hexdigits, can be interspersed by colons.
+    """
+
+    fingerprint = fingerprint.replace(':', '').lower()
+    digest_length = len(fingerprint)
+    hashfunc = HASHFUNC_MAP.get(digest_length)
+    if not hashfunc:
+        raise SSLError(
+            'Fingerprint of invalid length: {0}'.format(fingerprint))
+
+    # We need encode() here for py32; works on py2 and p33.
+    fingerprint_bytes = unhexlify(fingerprint.encode())
+
+    cert_digest = hashfunc(cert).digest()
+
+    if not _const_compare_digest(cert_digest, fingerprint_bytes):
+        raise SSLError('Fingerprints did not match. Expected "{0}", got "{1}".'
+                       .format(fingerprint, hexlify(cert_digest)))
+
+
+def resolve_cert_reqs(candidate):
+    """
+    Resolves the argument to a numeric constant, which can be passed to
+    the wrap_socket function/method from the ssl module.
+    Defaults to :data:`ssl.CERT_NONE`.
+    If given a string it is assumed to be the name of the constant in the
+    :mod:`ssl` module or its abbreviation.
+    (So you can specify `REQUIRED` instead of `CERT_REQUIRED`.
+    If it's neither `None` nor a string we assume it is already the numeric
+    constant which can directly be passed to wrap_socket.
+    """
+    if candidate is None:
+        return CERT_NONE
+
+    if isinstance(candidate, str):
+        res = getattr(ssl, candidate, None)
+        if res is None:
+            res = getattr(ssl, 'CERT_' + candidate)
+        return res
+
+    return candidate
+
+
+def resolve_ssl_version(candidate):
+    """
+    like resolve_cert_reqs
+    """
+    if candidate is None:
+        return PROTOCOL_SSLv23
+
+    if isinstance(candidate, str):
+        res = getattr(ssl, candidate, None)
+        if res is None:
+            res = getattr(ssl, 'PROTOCOL_' + candidate)
+        return res
+
+    return candidate
+
+
+def create_urllib3_context(ssl_version=None, cert_reqs=None,
+                           options=None, ciphers=None):
+    """All arguments have the same meaning as ``ssl_wrap_socket``.
+
+    By default, this function does a lot of the same work that
+    ``ssl.create_default_context`` does on Python 3.4+. It:
+
+    - Disables SSLv2, SSLv3, and compression
+    - Sets a restricted set of server ciphers
+
+    If you wish to enable SSLv3, you can do::
+
+        from urllib3.util import ssl_
+        context = ssl_.create_urllib3_context()
+        context.options &= ~ssl_.OP_NO_SSLv3
+
+    You can do the same to enable compression (substituting ``COMPRESSION``
+    for ``SSLv3`` in the last line above).
+
+    :param ssl_version:
+        The desired protocol version to use. This will default to
+        PROTOCOL_SSLv23 which will negotiate the highest protocol that both
+        the server and your installation of OpenSSL support.
+    :param cert_reqs:
+        Whether to require the certificate verification. This defaults to
+        ``ssl.CERT_REQUIRED``.
+    :param options:
+        Specific OpenSSL options. These default to ``ssl.OP_NO_SSLv2``,
+        ``ssl.OP_NO_SSLv3``, ``ssl.OP_NO_COMPRESSION``.
+    :param ciphers:
+        Which cipher suites to allow the server to select.
+    :returns:
+        Constructed SSLContext object with specified options
+    :rtype: SSLContext
+    """
+    context = SSLContext(ssl_version or ssl.PROTOCOL_SSLv23)
+
+    context.set_ciphers(ciphers or DEFAULT_CIPHERS)
+
+    # Setting the default here, as we may have no ssl module on import
+    cert_reqs = ssl.CERT_REQUIRED if cert_reqs is None else cert_reqs
+
+    if options is None:
+        options = 0
+        # SSLv2 is easily broken and is considered harmful and dangerous
+        options |= OP_NO_SSLv2
+        # SSLv3 has several problems and is now dangerous
+        options |= OP_NO_SSLv3
+        # Disable compression to prevent CRIME attacks for OpenSSL 1.0+
+        # (issue #309)
+        options |= OP_NO_COMPRESSION
+
+    context.options |= options
+
+    context.verify_mode = cert_reqs
+    if getattr(context, 'check_hostname', None) is not None:  # Platform-specific: Python 3.2
+        # We do our own verification, including fingerprints and alternative
+        # hostnames. So disable it here
+        context.check_hostname = False
+    return context
+
+
+def ssl_wrap_socket(sock, keyfile=None, certfile=None, cert_reqs=None,
+                    ca_certs=None, server_hostname=None,
+                    ssl_version=None, ciphers=None, ssl_context=None,
+                    ca_cert_dir=None):
+    """
+    All arguments except for server_hostname, ssl_context, and ca_cert_dir have
+    the same meaning as they do when using :func:`ssl.wrap_socket`.
+
+    :param server_hostname:
+        When SNI is supported, the expected hostname of the certificate
+    :param ssl_context:
+        A pre-made :class:`SSLContext` object. If none is provided, one will
+        be created using :func:`create_urllib3_context`.
+    :param ciphers:
+        A string of ciphers we wish the client to support.
+    :param ca_cert_dir:
+        A directory containing CA certificates in multiple separate files, as
+        supported by OpenSSL's -CApath flag or the capath argument to
+        SSLContext.load_verify_locations().
+    """
+    context = ssl_context
+    if context is None:
+        # Note: This branch of code and all the variables in it are no longer
+        # used by urllib3 itself. We should consider deprecating and removing
+        # this code.
+        context = create_urllib3_context(ssl_version, cert_reqs,
+                                         ciphers=ciphers)
+
+    if ca_certs or ca_cert_dir:
+        try:
+            context.load_verify_locations(ca_certs, ca_cert_dir)
+        except IOError as e:  # Platform-specific: Python 2.7
+            raise SSLError(e)
+        # Py33 raises FileNotFoundError which subclasses OSError
+        # These are not equivalent unless we check the errno attribute
+        except OSError as e:  # Platform-specific: Python 3.3 and beyond
+            if e.errno == errno.ENOENT:
+                raise SSLError(e)
+            raise
+    elif getattr(context, 'load_default_certs', None) is not None:
+        # try to load OS default certs; works well on Windows (require Python3.4+)
+        context.load_default_certs()
+
+    if certfile:
+        context.load_cert_chain(certfile, keyfile)
+
+    # If we detect server_hostname is an IP address then the SNI
+    # extension should not be used according to RFC3546 Section 3.1
+    # We shouldn't warn the user if SNI isn't available but we would
+    # not be using SNI anyways due to IP address for server_hostname.
+    if ((server_hostname is not None and not is_ipaddress(server_hostname))
+            or IS_SECURETRANSPORT):
+        if HAS_SNI and server_hostname is not None:
+            return context.wrap_socket(sock, server_hostname=server_hostname)
+
+        warnings.warn(
+            'An HTTPS request has been made, but the SNI (Server Name '
+            'Indication) extension to TLS is not available on this platform. '
+            'This may cause the server to present an incorrect TLS '
+            'certificate, which can cause validation failures. You can upgrade to '
+            'a newer version of Python to solve this. For more information, see '
+            'https://urllib3.readthedocs.io/en/latest/advanced-usage.html'
+            '#ssl-warnings',
+            SNIMissingWarning
+        )
+
+    return context.wrap_socket(sock)
+
+
+def is_ipaddress(hostname):
+    """Detects whether the hostname given is an IP address.
+
+    :param str hostname: Hostname to examine.
+    :return: True if the hostname is an IP address, False otherwise.
+    """
+    if six.PY3 and isinstance(hostname, bytes):
+        # IDN A-label bytes are ASCII compatible.
+        hostname = hostname.decode('ascii')
+
+    families = [socket.AF_INET]
+    if hasattr(socket, 'AF_INET6'):
+        families.append(socket.AF_INET6)
+
+    for af in families:
+        try:
+            inet_pton(af, hostname)
+        except (socket.error, ValueError, OSError):
+            pass
+        else:
+            return True
+    return False
diff --git a/python/urllib3/util/timeout.py b/python/urllib3/util/timeout.py
new file mode 100644
index 0000000..cec817e
--- /dev/null
+++ b/python/urllib3/util/timeout.py
@@ -0,0 +1,242 @@
+from __future__ import absolute_import
+# The default socket timeout, used by httplib to indicate that no timeout was
+# specified by the user
+from socket import _GLOBAL_DEFAULT_TIMEOUT
+import time
+
+from ..exceptions import TimeoutStateError
+
+# A sentinel value to indicate that no timeout was specified by the user in
+# urllib3
+_Default = object()
+
+
+# Use time.monotonic if available.
+current_time = getattr(time, "monotonic", time.time)
+
+
+class Timeout(object):
+    """ Timeout configuration.
+
+    Timeouts can be defined as a default for a pool::
+
+        timeout = Timeout(connect=2.0, read=7.0)
+        http = PoolManager(timeout=timeout)
+        response = http.request('GET', 'http://example.com/')
+
+    Or per-request (which overrides the default for the pool)::
+
+        response = http.request('GET', 'http://example.com/', timeout=Timeout(10))
+
+    Timeouts can be disabled by setting all the parameters to ``None``::
+
+        no_timeout = Timeout(connect=None, read=None)
+        response = http.request('GET', 'http://example.com/, timeout=no_timeout)
+
+
+    :param total:
+        This combines the connect and read timeouts into one; the read timeout
+        will be set to the time leftover from the connect attempt. In the
+        event that both a connect timeout and a total are specified, or a read
+        timeout and a total are specified, the shorter timeout will be applied.
+
+        Defaults to None.
+
+    :type total: integer, float, or None
+
+    :param connect:
+        The maximum amount of time to wait for a connection attempt to a server
+        to succeed. Omitting the parameter will default the connect timeout to
+        the system default, probably `the global default timeout in socket.py
+        <http://hg.python.org/cpython/file/603b4d593758/Lib/socket.py#l535>`_.
+        None will set an infinite timeout for connection attempts.
+
+    :type connect: integer, float, or None
+
+    :param read:
+        The maximum amount of time to wait between consecutive
+        read operations for a response from the server. Omitting
+        the parameter will default the read timeout to the system
+        default, probably `the global default timeout in socket.py
+        <http://hg.python.org/cpython/file/603b4d593758/Lib/socket.py#l535>`_.
+        None will set an infinite timeout.
+
+    :type read: integer, float, or None
+
+    .. note::
+
+        Many factors can affect the total amount of time for urllib3 to return
+        an HTTP response.
+
+        For example, Python's DNS resolver does not obey the timeout specified
+        on the socket. Other factors that can affect total request time include
+        high CPU load, high swap, the program running at a low priority level,
+        or other behaviors.
+
+        In addition, the read and total timeouts only measure the time between
+        read operations on the socket connecting the client and the server,
+        not the total amount of time for the request to return a complete
+        response. For most requests, the timeout is raised because the server
+        has not sent the first byte in the specified time. This is not always
+        the case; if a server streams one byte every fifteen seconds, a timeout
+        of 20 seconds will not trigger, even though the request will take
+        several minutes to complete.
+
+        If your goal is to cut off any request after a set amount of wall clock
+        time, consider having a second "watcher" thread to cut off a slow
+        request.
+    """
+
+    #: A sentinel object representing the default timeout value
+    DEFAULT_TIMEOUT = _GLOBAL_DEFAULT_TIMEOUT
+
+    def __init__(self, total=None, connect=_Default, read=_Default):
+        self._connect = self._validate_timeout(connect, 'connect')
+        self._read = self._validate_timeout(read, 'read')
+        self.total = self._validate_timeout(total, 'total')
+        self._start_connect = None
+
+    def __str__(self):
+        return '%s(connect=%r, read=%r, total=%r)' % (
+            type(self).__name__, self._connect, self._read, self.total)
+
+    @classmethod
+    def _validate_timeout(cls, value, name):
+        """ Check that a timeout attribute is valid.
+
+        :param value: The timeout value to validate
+        :param name: The name of the timeout attribute to validate. This is
+            used to specify in error messages.
+        :return: The validated and casted version of the given value.
+        :raises ValueError: If it is a numeric value less than or equal to
+            zero, or the type is not an integer, float, or None.
+        """
+        if value is _Default:
+            return cls.DEFAULT_TIMEOUT
+
+        if value is None or value is cls.DEFAULT_TIMEOUT:
+            return value
+
+        if isinstance(value, bool):
+            raise ValueError("Timeout cannot be a boolean value. It must "
+                             "be an int, float or None.")
+        try:
+            float(value)
+        except (TypeError, ValueError):
+            raise ValueError("Timeout value %s was %s, but it must be an "
+                             "int, float or None." % (name, value))
+
+        try:
+            if value <= 0:
+                raise ValueError("Attempted to set %s timeout to %s, but the "
+                                 "timeout cannot be set to a value less "
+                                 "than or equal to 0." % (name, value))
+        except TypeError:  # Python 3
+            raise ValueError("Timeout value %s was %s, but it must be an "
+                             "int, float or None." % (name, value))
+
+        return value
+
+    @classmethod
+    def from_float(cls, timeout):
+        """ Create a new Timeout from a legacy timeout value.
+
+        The timeout value used by httplib.py sets the same timeout on the
+        connect(), and recv() socket requests. This creates a :class:`Timeout`
+        object that sets the individual timeouts to the ``timeout`` value
+        passed to this function.
+
+        :param timeout: The legacy timeout value.
+        :type timeout: integer, float, sentinel default object, or None
+        :return: Timeout object
+        :rtype: :class:`Timeout`
+        """
+        return Timeout(read=timeout, connect=timeout)
+
+    def clone(self):
+        """ Create a copy of the timeout object
+
+        Timeout properties are stored per-pool but each request needs a fresh
+        Timeout object to ensure each one has its own start/stop configured.
+
+        :return: a copy of the timeout object
+        :rtype: :class:`Timeout`
+        """
+        # We can't use copy.deepcopy because that will also create a new object
+        # for _GLOBAL_DEFAULT_TIMEOUT, which socket.py uses as a sentinel to
+        # detect the user default.
+        return Timeout(connect=self._connect, read=self._read,
+                       total=self.total)
+
+    def start_connect(self):
+        """ Start the timeout clock, used during a connect() attempt
+
+        :raises urllib3.exceptions.TimeoutStateError: if you attempt
+            to start a timer that has been started already.
+        """
+        if self._start_connect is not None:
+            raise TimeoutStateError("Timeout timer has already been started.")
+        self._start_connect = current_time()
+        return self._start_connect
+
+    def get_connect_duration(self):
+        """ Gets the time elapsed since the call to :meth:`start_connect`.
+
+        :return: Elapsed time.
+        :rtype: float
+        :raises urllib3.exceptions.TimeoutStateError: if you attempt
+            to get duration for a timer that hasn't been started.
+        """
+        if self._start_connect is None:
+            raise TimeoutStateError("Can't get connect duration for timer "
+                                    "that has not started.")
+        return current_time() - self._start_connect
+
+    @property
+    def connect_timeout(self):
+        """ Get the value to use when setting a connection timeout.
+
+        This will be a positive float or integer, the value None
+        (never timeout), or the default system timeout.
+
+        :return: Connect timeout.
+        :rtype: int, float, :attr:`Timeout.DEFAULT_TIMEOUT` or None
+        """
+        if self.total is None:
+            return self._connect
+
+        if self._connect is None or self._connect is self.DEFAULT_TIMEOUT:
+            return self.total
+
+        return min(self._connect, self.total)
+
+    @property
+    def read_timeout(self):
+        """ Get the value for the read timeout.
+
+        This assumes some time has elapsed in the connection timeout and
+        computes the read timeout appropriately.
+
+        If self.total is set, the read timeout is dependent on the amount of
+        time taken by the connect timeout. If the connection time has not been
+        established, a :exc:`~urllib3.exceptions.TimeoutStateError` will be
+        raised.
+
+        :return: Value to use for the read timeout.
+        :rtype: int, float, :attr:`Timeout.DEFAULT_TIMEOUT` or None
+        :raises urllib3.exceptions.TimeoutStateError: If :meth:`start_connect`
+            has not yet been called on this object.
+        """
+        if (self.total is not None and
+                self.total is not self.DEFAULT_TIMEOUT and
+                self._read is not None and
+                self._read is not self.DEFAULT_TIMEOUT):
+            # In case the connect timeout has not yet been established.
+            if self._start_connect is None:
+                return self._read
+            return max(0, min(self.total - self.get_connect_duration(),
+                              self._read))
+        elif self.total is not None and self.total is not self.DEFAULT_TIMEOUT:
+            return max(0, self.total - self.get_connect_duration())
+        else:
+            return self._read
diff --git a/python/urllib3/util/url.py b/python/urllib3/util/url.py
new file mode 100644
index 0000000..6b6f996
--- /dev/null
+++ b/python/urllib3/util/url.py
@@ -0,0 +1,230 @@
+from __future__ import absolute_import
+from collections import namedtuple
+
+from ..exceptions import LocationParseError
+
+
+url_attrs = ['scheme', 'auth', 'host', 'port', 'path', 'query', 'fragment']
+
+# We only want to normalize urls with an HTTP(S) scheme.
+# urllib3 infers URLs without a scheme (None) to be http.
+NORMALIZABLE_SCHEMES = ('http', 'https', None)
+
+
+class Url(namedtuple('Url', url_attrs)):
+    """
+    Datastructure for representing an HTTP URL. Used as a return value for
+    :func:`parse_url`. Both the scheme and host are normalized as they are
+    both case-insensitive according to RFC 3986.
+    """
+    __slots__ = ()
+
+    def __new__(cls, scheme=None, auth=None, host=None, port=None, path=None,
+                query=None, fragment=None):
+        if path and not path.startswith('/'):
+            path = '/' + path
+        if scheme:
+            scheme = scheme.lower()
+        if host and scheme in NORMALIZABLE_SCHEMES:
+            host = host.lower()
+        return super(Url, cls).__new__(cls, scheme, auth, host, port, path,
+                                       query, fragment)
+
+    @property
+    def hostname(self):
+        """For backwards-compatibility with urlparse. We're nice like that."""
+        return self.host
+
+    @property
+    def request_uri(self):
+        """Absolute path including the query string."""
+        uri = self.path or '/'
+
+        if self.query is not None:
+            uri += '?' + self.query
+
+        return uri
+
+    @property
+    def netloc(self):
+        """Network location including host and port"""
+        if self.port:
+            return '%s:%d' % (self.host, self.port)
+        return self.host
+
+    @property
+    def url(self):
+        """
+        Convert self into a url
+
+        This function should more or less round-trip with :func:`.parse_url`. The
+        returned url may not be exactly the same as the url inputted to
+        :func:`.parse_url`, but it should be equivalent by the RFC (e.g., urls
+        with a blank port will have : removed).
+
+        Example: ::
+
+            >>> U = parse_url('http://google.com/mail/')
+            >>> U.url
+            'http://google.com/mail/'
+            >>> Url('http', 'username:password', 'host.com', 80,
+            ... '/path', 'query', 'fragment').url
+            'http://username:password@host.com:80/path?query#fragment'
+        """
+        scheme, auth, host, port, path, query, fragment = self
+        url = ''
+
+        # We use "is not None" we want things to happen with empty strings (or 0 port)
+        if scheme is not None:
+            url += scheme + '://'
+        if auth is not None:
+            url += auth + '@'
+        if host is not None:
+            url += host
+        if port is not None:
+            url += ':' + str(port)
+        if path is not None:
+            url += path
+        if query is not None:
+            url += '?' + query
+        if fragment is not None:
+            url += '#' + fragment
+
+        return url
+
+    def __str__(self):
+        return self.url
+
+
+def split_first(s, delims):
+    """
+    Given a string and an iterable of delimiters, split on the first found
+    delimiter. Return two split parts and the matched delimiter.
+
+    If not found, then the first part is the full input string.
+
+    Example::
+
+        >>> split_first('foo/bar?baz', '?/=')
+        ('foo', 'bar?baz', '/')
+        >>> split_first('foo/bar?baz', '123')
+        ('foo/bar?baz', '', None)
+
+    Scales linearly with number of delims. Not ideal for large number of delims.
+    """
+    min_idx = None
+    min_delim = None
+    for d in delims:
+        idx = s.find(d)
+        if idx < 0:
+            continue
+
+        if min_idx is None or idx < min_idx:
+            min_idx = idx
+            min_delim = d
+
+    if min_idx is None or min_idx < 0:
+        return s, '', None
+
+    return s[:min_idx], s[min_idx + 1:], min_delim
+
+
+def parse_url(url):
+    """
+    Given a url, return a parsed :class:`.Url` namedtuple. Best-effort is
+    performed to parse incomplete urls. Fields not provided will be None.
+
+    Partly backwards-compatible with :mod:`urlparse`.
+
+    Example::
+
+        >>> parse_url('http://google.com/mail/')
+        Url(scheme='http', host='google.com', port=None, path='/mail/', ...)
+        >>> parse_url('google.com:80')
+        Url(scheme=None, host='google.com', port=80, path=None, ...)
+        >>> parse_url('/foo?bar')
+        Url(scheme=None, host=None, port=None, path='/foo', query='bar', ...)
+    """
+
+    # While this code has overlap with stdlib's urlparse, it is much
+    # simplified for our needs and less annoying.
+    # Additionally, this implementations does silly things to be optimal
+    # on CPython.
+
+    if not url:
+        # Empty
+        return Url()
+
+    scheme = None
+    auth = None
+    host = None
+    port = None
+    path = None
+    fragment = None
+    query = None
+
+    # Scheme
+    if '://' in url:
+        scheme, url = url.split('://', 1)
+
+    # Find the earliest Authority Terminator
+    # (http://tools.ietf.org/html/rfc3986#section-3.2)
+    url, path_, delim = split_first(url, ['/', '?', '#'])
+
+    if delim:
+        # Reassemble the path
+        path = delim + path_
+
+    # Auth
+    if '@' in url:
+        # Last '@' denotes end of auth part
+        auth, url = url.rsplit('@', 1)
+
+    # IPv6
+    if url and url[0] == '[':
+        host, url = url.split(']', 1)
+        host += ']'
+
+    # Port
+    if ':' in url:
+        _host, port = url.split(':', 1)
+
+        if not host:
+            host = _host
+
+        if port:
+            # If given, ports must be integers. No whitespace, no plus or
+            # minus prefixes, no non-integer digits such as ^2 (superscript).
+            if not port.isdigit():
+                raise LocationParseError(url)
+            try:
+                port = int(port)
+            except ValueError:
+                raise LocationParseError(url)
+        else:
+            # Blank ports are cool, too. (rfc3986#section-3.2.3)
+            port = None
+
+    elif not host and url:
+        host = url
+
+    if not path:
+        return Url(scheme, auth, host, port, path, query, fragment)
+
+    # Fragment
+    if '#' in path:
+        path, fragment = path.split('#', 1)
+
+    # Query
+    if '?' in path:
+        path, query = path.split('?', 1)
+
+    return Url(scheme, auth, host, port, path, query, fragment)
+
+
+def get_host(url):
+    """
+    Deprecated. Use :func:`parse_url` instead.
+    """
+    p = parse_url(url)
+    return p.scheme or 'http', p.hostname, p.port
diff --git a/python/urllib3/util/wait.py b/python/urllib3/util/wait.py
new file mode 100644
index 0000000..4db71ba
--- /dev/null
+++ b/python/urllib3/util/wait.py
@@ -0,0 +1,150 @@
+import errno
+from functools import partial
+import select
+import sys
+try:
+    from time import monotonic
+except ImportError:
+    from time import time as monotonic
+
+__all__ = ["NoWayToWaitForSocketError", "wait_for_read", "wait_for_write"]
+
+
+class NoWayToWaitForSocketError(Exception):
+    pass
+
+
+# How should we wait on sockets?
+#
+# There are two types of APIs you can use for waiting on sockets: the fancy
+# modern stateful APIs like epoll/kqueue, and the older stateless APIs like
+# select/poll. The stateful APIs are more efficient when you have a lots of
+# sockets to keep track of, because you can set them up once and then use them
+# lots of times. But we only ever want to wait on a single socket at a time
+# and don't want to keep track of state, so the stateless APIs are actually
+# more efficient. So we want to use select() or poll().
+#
+# Now, how do we choose between select() and poll()? On traditional Unixes,
+# select() has a strange calling convention that makes it slow, or fail
+# altogether, for high-numbered file descriptors. The point of poll() is to fix
+# that, so on Unixes, we prefer poll().
+#
+# On Windows, there is no poll() (or at least Python doesn't provide a wrapper
+# for it), but that's OK, because on Windows, select() doesn't have this
+# strange calling convention; plain select() works fine.
+#
+# So: on Windows we use select(), and everywhere else we use poll(). We also
+# fall back to select() in case poll() is somehow broken or missing.
+
+if sys.version_info >= (3, 5):
+    # Modern Python, that retries syscalls by default
+    def _retry_on_intr(fn, timeout):
+        return fn(timeout)
+else:
+    # Old and broken Pythons.
+    def _retry_on_intr(fn, timeout):
+        if timeout is None:
+            deadline = float("inf")
+        else:
+            deadline = monotonic() + timeout
+
+        while True:
+            try:
+                return fn(timeout)
+            # OSError for 3 <= pyver < 3.5, select.error for pyver <= 2.7
+            except (OSError, select.error) as e:
+                # 'e.args[0]' incantation works for both OSError and select.error
+                if e.args[0] != errno.EINTR:
+                    raise
+                else:
+                    timeout = deadline - monotonic()
+                    if timeout < 0:
+                        timeout = 0
+                    if timeout == float("inf"):
+                        timeout = None
+                    continue
+
+
+def select_wait_for_socket(sock, read=False, write=False, timeout=None):
+    if not read and not write:
+        raise RuntimeError("must specify at least one of read=True, write=True")
+    rcheck = []
+    wcheck = []
+    if read:
+        rcheck.append(sock)
+    if write:
+        wcheck.append(sock)
+    # When doing a non-blocking connect, most systems signal success by
+    # marking the socket writable. Windows, though, signals success by marked
+    # it as "exceptional". We paper over the difference by checking the write
+    # sockets for both conditions. (The stdlib selectors module does the same
+    # thing.)
+    fn = partial(select.select, rcheck, wcheck, wcheck)
+    rready, wready, xready = _retry_on_intr(fn, timeout)
+    return bool(rready or wready or xready)
+
+
+def poll_wait_for_socket(sock, read=False, write=False, timeout=None):
+    if not read and not write:
+        raise RuntimeError("must specify at least one of read=True, write=True")
+    mask = 0
+    if read:
+        mask |= select.POLLIN
+    if write:
+        mask |= select.POLLOUT
+    poll_obj = select.poll()
+    poll_obj.register(sock, mask)
+
+    # For some reason, poll() takes timeout in milliseconds
+    def do_poll(t):
+        if t is not None:
+            t *= 1000
+        return poll_obj.poll(t)
+
+    return bool(_retry_on_intr(do_poll, timeout))
+
+
+def null_wait_for_socket(*args, **kwargs):
+    raise NoWayToWaitForSocketError("no select-equivalent available")
+
+
+def _have_working_poll():
+    # Apparently some systems have a select.poll that fails as soon as you try
+    # to use it, either due to strange configuration or broken monkeypatching
+    # from libraries like eventlet/greenlet.
+    try:
+        poll_obj = select.poll()
+        _retry_on_intr(poll_obj.poll, 0)
+    except (AttributeError, OSError):
+        return False
+    else:
+        return True
+
+
+def wait_for_socket(*args, **kwargs):
+    # We delay choosing which implementation to use until the first time we're
+    # called. We could do it at import time, but then we might make the wrong
+    # decision if someone goes wild with monkeypatching select.poll after
+    # we're imported.
+    global wait_for_socket
+    if _have_working_poll():
+        wait_for_socket = poll_wait_for_socket
+    elif hasattr(select, "select"):
+        wait_for_socket = select_wait_for_socket
+    else:  # Platform-specific: Appengine.
+        wait_for_socket = null_wait_for_socket
+    return wait_for_socket(*args, **kwargs)
+
+
+def wait_for_read(sock, timeout=None):
+    """ Waits for reading to be available on a given socket.
+    Returns True if the socket is readable, or False if the timeout expired.
+    """
+    return wait_for_socket(sock, read=True, timeout=timeout)
+
+
+def wait_for_write(sock, timeout=None):
+    """ Waits for writing to be available on a given socket.
+    Returns True if the socket is readable, or False if the timeout expired.
+    """
+    return wait_for_socket(sock, write=True, timeout=timeout)