Загрузить файлы в «venv/Lib/site-packages/pip/_vendor/urllib3»

venv/Lib/site-packages/pip/_vendor/urllib3/LICENSE.txt

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+MIT License
+
+Copyright (c) 2008-2020 Andrey Petrov and contributors (see CONTRIBUTORS.txt)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

venv/Lib/site-packages/pip/_vendor/urllib3/exceptions.py

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+from __future__ import absolute_import
+
+from .packages.six.moves.http_client import IncompleteRead as httplib_IncompleteRead
+
+# Base Exceptions
+
+
+class HTTPError(Exception):
+    """Base exception used by this module."""
+
+    pass
+
+
+class HTTPWarning(Warning):
+    """Base warning used by this module."""
+
+    pass
+
+
+class PoolError(HTTPError):
+    """Base exception for errors caused within a pool."""
+
+    def __init__(self, pool, message):
+        self.pool = pool
+        HTTPError.__init__(self, "%s: %s" % (pool, message))
+
+    def __reduce__(self):
+        # For pickling purposes.
+        return self.__class__, (None, None)
+
+
+class RequestError(PoolError):
+    """Base exception for PoolErrors that have associated URLs."""
+
+    def __init__(self, pool, url, message):
+        self.url = url
+        PoolError.__init__(self, pool, message)
+
+    def __reduce__(self):
+        # For pickling purposes.
+        return self.__class__, (None, self.url, None)
+
+
+class SSLError(HTTPError):
+    """Raised when SSL certificate fails in an HTTPS connection."""
+
+    pass
+
+
+class ProxyError(HTTPError):
+    """Raised when the connection to a proxy fails."""
+
+    def __init__(self, message, error, *args):
+        super(ProxyError, self).__init__(message, error, *args)
+        self.original_error = error
+
+
+class DecodeError(HTTPError):
+    """Raised when automatic decoding based on Content-Type fails."""
+
+    pass
+
+
+class ProtocolError(HTTPError):
+    """Raised when something unexpected happens mid-request/response."""
+
+    pass
+
+
+#: Renamed to ProtocolError but aliased for backwards compatibility.
+ConnectionError = ProtocolError
+
+
+# Leaf Exceptions
+
+
+class MaxRetryError(RequestError):
+    """Raised when the maximum number of retries is exceeded.
+
+    :param pool: The connection pool
+    :type pool: :class:`~urllib3.connectionpool.HTTPConnectionPool`
+    :param string url: The requested Url
+    :param exceptions.Exception reason: The underlying error
+
+    """
+
+    def __init__(self, pool, url, reason=None):
+        self.reason = reason
+
+        message = "Max retries exceeded with url: %s (Caused by %r)" % (url, reason)
+
+        RequestError.__init__(self, pool, url, message)
+
+
+class HostChangedError(RequestError):
+    """Raised when an existing pool gets a request for a foreign host."""
+
+    def __init__(self, pool, url, retries=3):
+        message = "Tried to open a foreign host with url: %s" % url
+        RequestError.__init__(self, pool, url, message)
+        self.retries = retries
+
+
+class TimeoutStateError(HTTPError):
+    """Raised when passing an invalid state to a timeout"""
+
+    pass
+
+
+class TimeoutError(HTTPError):
+    """Raised when a socket timeout error occurs.
+
+    Catching this error will catch both :exc:`ReadTimeoutErrors
+    <ReadTimeoutError>` and :exc:`ConnectTimeoutErrors <ConnectTimeoutError>`.
+    """
+
+    pass
+
+
+class ReadTimeoutError(TimeoutError, RequestError):
+    """Raised when a socket timeout occurs while receiving data from a server"""
+
+    pass
+
+
+# This timeout error does not have a URL attached and needs to inherit from the
+# base HTTPError
+class ConnectTimeoutError(TimeoutError):
+    """Raised when a socket timeout occurs while connecting to a server"""
+
+    pass
+
+
+class NewConnectionError(ConnectTimeoutError, PoolError):
+    """Raised when we fail to establish a new connection. Usually ECONNREFUSED."""
+
+    pass
+
+
+class EmptyPoolError(PoolError):
+    """Raised when a pool runs out of connections and no more are allowed."""
+
+    pass
+
+
+class ClosedPoolError(PoolError):
+    """Raised when a request enters a pool after the pool has been closed."""
+
+    pass
+
+
+class LocationValueError(ValueError, HTTPError):
+    """Raised when there is something wrong with a given URL input."""
+
+    pass
+
+
+class LocationParseError(LocationValueError):
+    """Raised when get_host or similar fails to parse the URL input."""
+
+    def __init__(self, location):
+        message = "Failed to parse: %s" % location
+        HTTPError.__init__(self, message)
+
+        self.location = location
+
+
+class URLSchemeUnknown(LocationValueError):
+    """Raised when a URL input has an unsupported scheme."""
+
+    def __init__(self, scheme):
+        message = "Not supported URL scheme %s" % scheme
+        super(URLSchemeUnknown, self).__init__(message)
+
+        self.scheme = scheme
+
+
+class ResponseError(HTTPError):
+    """Used as a container for an error reason supplied in a MaxRetryError."""
+
+    GENERIC_ERROR = "too many error responses"
+    SPECIFIC_ERROR = "too many {status_code} error responses"
+
+
+class SecurityWarning(HTTPWarning):
+    """Warned when performing security reducing actions"""
+
+    pass
+
+
+class SubjectAltNameWarning(SecurityWarning):
+    """Warned when connecting to a host with a certificate missing a SAN."""
+
+    pass
+
+
+class InsecureRequestWarning(SecurityWarning):
+    """Warned when making an unverified HTTPS request."""
+
+    pass
+
+
+class SystemTimeWarning(SecurityWarning):
+    """Warned when system time is suspected to be wrong"""
+
+    pass
+
+
+class InsecurePlatformWarning(SecurityWarning):
+    """Warned when certain TLS/SSL configuration is not available on a platform."""
+
+    pass
+
+
+class SNIMissingWarning(HTTPWarning):
+    """Warned when making a HTTPS request without SNI available."""
+
+    pass
+
+
+class DependencyWarning(HTTPWarning):
+    """
+    Warned when an attempt is made to import a module with missing optional
+    dependencies.
+    """
+
+    pass
+
+
+class ResponseNotChunked(ProtocolError, ValueError):
+    """Response needs to be chunked in order to read it as chunks."""
+
+    pass
+
+
+class BodyNotHttplibCompatible(HTTPError):
+    """
+    Body should be :class:`http.client.HTTPResponse` like
+    (have an fp attribute which returns raw chunks) for read_chunked().
+    """
+
+    pass
+
+
+class IncompleteRead(HTTPError, httplib_IncompleteRead):
+    """
+    Response length doesn't match expected Content-Length
+
+    Subclass of :class:`http.client.IncompleteRead` to allow int value
+    for ``partial`` to avoid creating large objects on streamed reads.
+    """
+
+    def __init__(self, partial, expected):
+        super(IncompleteRead, self).__init__(partial, expected)
+
+    def __repr__(self):
+        return "IncompleteRead(%i bytes read, %i more expected)" % (
+            self.partial,
+            self.expected,
+        )
+
+
+class InvalidChunkLength(HTTPError, httplib_IncompleteRead):
+    """Invalid chunk length in a chunked response."""
+
+    def __init__(self, response, length):
+        super(InvalidChunkLength, self).__init__(
+            response.tell(), response.length_remaining
+        )
+        self.response = response
+        self.length = length
+
+    def __repr__(self):
+        return "InvalidChunkLength(got length %r, %i bytes read)" % (
+            self.length,
+            self.partial,
+        )
+
+
+class InvalidHeader(HTTPError):
+    """The header provided was somehow invalid."""
+
+    pass
+
+
+class ProxySchemeUnknown(AssertionError, URLSchemeUnknown):
+    """ProxyManager does not support the supplied scheme"""
+
+    # TODO(t-8ch): Stop inheriting from AssertionError in v2.0.
+
+    def __init__(self, scheme):
+        # 'localhost' is here because our URL parser parses
+        # localhost:8080 -> scheme=localhost, remove if we fix this.
+        if scheme == "localhost":
+            scheme = None
+        if scheme is None:
+            message = "Proxy URL had no scheme, should start with http:// or https://"
+        else:
+            message = (
+                "Proxy URL had unsupported scheme %s, should use http:// or https://"
+                % scheme
+            )
+        super(ProxySchemeUnknown, self).__init__(message)
+
+
+class ProxySchemeUnsupported(ValueError):
+    """Fetching HTTPS resources through HTTPS proxies is unsupported"""
+
+    pass
+
+
+class HeaderParsingError(HTTPError):
+    """Raised by assert_header_parsing, but we convert it to a log.warning statement."""
+
+    def __init__(self, defects, unparsed_data):
+        message = "%s, unparsed data: %r" % (defects or "Unknown", unparsed_data)
+        super(HeaderParsingError, self).__init__(message)
+
+
+class UnrewindableBodyError(HTTPError):
+    """urllib3 encountered an error when trying to rewind a body"""
+
+    pass

venv/Lib/site-packages/pip/_vendor/urllib3/fields.py

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+from __future__ import absolute_import
+
+import email.utils
+import mimetypes
+import re
+
+from .packages import six
+
+
+def guess_content_type(filename, default="application/octet-stream"):
+    """
+    Guess the "Content-Type" of a file.
+
+    :param filename:
+        The filename to guess the "Content-Type" of using :mod:`mimetypes`.
+    :param default:
+        If no "Content-Type" can be guessed, default to `default`.
+    """
+    if filename:
+        return mimetypes.guess_type(filename)[0] or default
+    return default
+
+
+def format_header_param_rfc2231(name, value):
+    """
+    Helper function to format and quote a single header parameter using the
+    strategy defined in RFC 2231.
+
+    Particularly useful for header parameters which might contain
+    non-ASCII values, like file names. This follows
+    `RFC 2388 Section 4.4 <https://tools.ietf.org/html/rfc2388#section-4.4>`_.
+
+    :param name:
+        The name of the parameter, a string expected to be ASCII only.
+    :param value:
+        The value of the parameter, provided as ``bytes`` or `str``.
+    :ret:
+        An RFC-2231-formatted unicode string.
+    """
+    if isinstance(value, six.binary_type):
+        value = value.decode("utf-8")
+
+    if not any(ch in value for ch in '"\\\r\n'):
+        result = u'%s="%s"' % (name, value)
+        try:
+            result.encode("ascii")
+        except (UnicodeEncodeError, UnicodeDecodeError):
+            pass
+        else:
+            return result
+
+    if six.PY2:  # Python 2:
+        value = value.encode("utf-8")
+
+    # encode_rfc2231 accepts an encoded string and returns an ascii-encoded
+    # string in Python 2 but accepts and returns unicode strings in Python 3
+    value = email.utils.encode_rfc2231(value, "utf-8")
+    value = "%s*=%s" % (name, value)
+
+    if six.PY2:  # Python 2:
+        value = value.decode("utf-8")
+
+    return value
+
+
+_HTML5_REPLACEMENTS = {
+    u"\u0022": u"%22",
+    # Replace "\" with "\\".
+    u"\u005C": u"\u005C\u005C",
+}
+
+# All control characters from 0x00 to 0x1F *except* 0x1B.
+_HTML5_REPLACEMENTS.update(
+    {
+        six.unichr(cc): u"%{:02X}".format(cc)
+        for cc in range(0x00, 0x1F + 1)
+        if cc not in (0x1B,)
+    }
+)
+
+
+def _replace_multiple(value, needles_and_replacements):
+    def replacer(match):
+        return needles_and_replacements[match.group(0)]
+
+    pattern = re.compile(
+        r"|".join([re.escape(needle) for needle in needles_and_replacements.keys()])
+    )
+
+    result = pattern.sub(replacer, value)
+
+    return result
+
+
+def format_header_param_html5(name, value):
+    """
+    Helper function to format and quote a single header parameter using the
+    HTML5 strategy.
+
+    Particularly useful for header parameters which might contain
+    non-ASCII values, like file names. This follows the `HTML5 Working Draft
+    Section 4.10.22.7`_ and matches the behavior of curl and modern browsers.
+
+    .. _HTML5 Working Draft Section 4.10.22.7:
+        https://w3c.github.io/html/sec-forms.html#multipart-form-data
+
+    :param name:
+        The name of the parameter, a string expected to be ASCII only.
+    :param value:
+        The value of the parameter, provided as ``bytes`` or `str``.
+    :ret:
+        A unicode string, stripped of troublesome characters.
+    """
+    if isinstance(value, six.binary_type):
+        value = value.decode("utf-8")
+
+    value = _replace_multiple(value, _HTML5_REPLACEMENTS)
+
+    return u'%s="%s"' % (name, value)
+
+
+# For backwards-compatibility.
+format_header_param = format_header_param_html5
+
+
+class RequestField(object):
+    """
+    A data container for request body parameters.
+
+    :param name:
+        The name of this request field. Must be unicode.
+    :param data:
+        The data/value body.
+    :param filename:
+        An optional filename of the request field. Must be unicode.
+    :param headers:
+        An optional dict-like object of headers to initially use for the field.
+    :param header_formatter:
+        An optional callable that is used to encode and format the headers. By
+        default, this is :func:`format_header_param_html5`.
+    """
+
+    def __init__(
+        self,
+        name,
+        data,
+        filename=None,
+        headers=None,
+        header_formatter=format_header_param_html5,
+    ):
+        self._name = name
+        self._filename = filename
+        self.data = data
+        self.headers = {}
+        if headers:
+            self.headers = dict(headers)
+        self.header_formatter = header_formatter
+
+    @classmethod
+    def from_tuples(cls, fieldname, value, header_formatter=format_header_param_html5):
+        """
+        A :class:`~urllib3.fields.RequestField` factory from old-style tuple parameters.
+
+        Supports constructing :class:`~urllib3.fields.RequestField` from
+        parameter of key/value strings AND key/filetuple. A filetuple is a
+        (filename, data, MIME type) tuple where the MIME type is optional.
+        For example::
+
+            'foo': 'bar',
+            'fakefile': ('foofile.txt', 'contents of foofile'),
+            'realfile': ('barfile.txt', open('realfile').read()),
+            'typedfile': ('bazfile.bin', open('bazfile').read(), 'image/jpeg'),
+            'nonamefile': 'contents of nonamefile field',
+
+        Field names and filenames must be unicode.
+        """
+        if isinstance(value, tuple):
+            if len(value) == 3:
+                filename, data, content_type = value
+            else:
+                filename, data = value
+                content_type = guess_content_type(filename)
+        else:
+            filename = None
+            content_type = None
+            data = value
+
+        request_param = cls(
+            fieldname, data, filename=filename, header_formatter=header_formatter
+        )
+        request_param.make_multipart(content_type=content_type)
+
+        return request_param
+
+    def _render_part(self, name, value):
+        """
+        Overridable helper function to format a single header parameter. By
+        default, this calls ``self.header_formatter``.
+
+        :param name:
+            The name of the parameter, a string expected to be ASCII only.
+        :param value:
+            The value of the parameter, provided as a unicode string.
+        """
+
+        return self.header_formatter(name, value)
+
+    def _render_parts(self, header_parts):
+        """
+        Helper function to format and quote a single header.
+
+        Useful for single headers that are composed of multiple items. E.g.,
+        'Content-Disposition' fields.
+
+        :param header_parts:
+            A sequence of (k, v) tuples or a :class:`dict` of (k, v) to format
+            as `k1="v1"; k2="v2"; ...`.
+        """
+        parts = []
+        iterable = header_parts
+        if isinstance(header_parts, dict):
+            iterable = header_parts.items()
+
+        for name, value in iterable:
+            if value is not None:
+                parts.append(self._render_part(name, value))
+
+        return u"; ".join(parts)
+
+    def render_headers(self):
+        """
+        Renders the headers for this request field.
+        """
+        lines = []
+
+        sort_keys = ["Content-Disposition", "Content-Type", "Content-Location"]
+        for sort_key in sort_keys:
+            if self.headers.get(sort_key, False):
+                lines.append(u"%s: %s" % (sort_key, self.headers[sort_key]))
+
+        for header_name, header_value in self.headers.items():
+            if header_name not in sort_keys:
+                if header_value:
+                    lines.append(u"%s: %s" % (header_name, header_value))
+
+        lines.append(u"\r\n")
+        return u"\r\n".join(lines)
+
+    def make_multipart(
+        self, content_disposition=None, content_type=None, content_location=None
+    ):
+        """
+        Makes this request field into a multipart request field.
+
+        This method overrides "Content-Disposition", "Content-Type" and
+        "Content-Location" headers to the request parameter.
+
+        :param content_type:
+            The 'Content-Type' of the request body.
+        :param content_location:
+            The 'Content-Location' of the request body.
+
+        """
+        self.headers["Content-Disposition"] = content_disposition or u"form-data"
+        self.headers["Content-Disposition"] += u"; ".join(
+            [
+                u"",
+                self._render_parts(
+                    ((u"name", self._name), (u"filename", self._filename))
+                ),
+            ]
+        )
+        self.headers["Content-Type"] = content_type
+        self.headers["Content-Location"] = content_location

venv/Lib/site-packages/pip/_vendor/urllib3/filepost.py

@@ -0,0 +1,98 @@
+from __future__ import absolute_import
+
+import binascii
+import codecs
+import os
+from io import BytesIO
+
+from .fields import RequestField
+from .packages import six
+from .packages.six import b
+
+writer = codecs.lookup("utf-8")[3]
+
+
+def choose_boundary():
+    """
+    Our embarrassingly-simple replacement for mimetools.choose_boundary.
+    """
+    boundary = binascii.hexlify(os.urandom(16))
+    if not six.PY2:
+        boundary = boundary.decode("ascii")
+    return boundary
+
+
+def iter_field_objects(fields):
+    """
+    Iterate over fields.
+
+    Supports list of (k, v) tuples and dicts, and lists of
+    :class:`~urllib3.fields.RequestField`.
+
+    """
+    if isinstance(fields, dict):
+        i = six.iteritems(fields)
+    else:
+        i = iter(fields)
+
+    for field in i:
+        if isinstance(field, RequestField):
+            yield field
+        else:
+            yield RequestField.from_tuples(*field)
+
+
+def iter_fields(fields):
+    """
+    .. deprecated:: 1.6
+
+    Iterate over fields.
+
+    The addition of :class:`~urllib3.fields.RequestField` makes this function
+    obsolete. Instead, use :func:`iter_field_objects`, which returns
+    :class:`~urllib3.fields.RequestField` objects.
+
+    Supports list of (k, v) tuples and dicts.
+    """
+    if isinstance(fields, dict):
+        return ((k, v) for k, v in six.iteritems(fields))
+
+    return ((k, v) for k, v in fields)
+
+
+def encode_multipart_formdata(fields, boundary=None):
+    """
+    Encode a dictionary of ``fields`` using the multipart/form-data MIME format.
+
+    :param fields:
+        Dictionary of fields or list of (key, :class:`~urllib3.fields.RequestField`).
+
+    :param boundary:
+        If not specified, then a random boundary will be generated using
+        :func:`urllib3.filepost.choose_boundary`.
+    """
+    body = BytesIO()
+    if boundary is None:
+        boundary = choose_boundary()
+
+    for field in iter_field_objects(fields):
+        body.write(b("--%s\r\n" % (boundary)))
+
+        writer(body).write(field.render_headers())
+        data = field.data
+
+        if isinstance(data, int):
+            data = str(data)  # Backwards compatibility
+
+        if isinstance(data, six.text_type):
+            writer(body).write(data)
+        else:
+            body.write(data)
+
+        body.write(b"\r\n")
+
+    body.write(b("--%s--\r\n" % (boundary)))
+
+    content_type = str("multipart/form-data; boundary=%s" % boundary)
+
+    return body.getvalue(), content_type

venv/Lib/site-packages/pip/_vendor/urllib3/poolmanager.py

@@ -0,0 +1,540 @@
+from __future__ import absolute_import
+
+import collections
+import functools
+import logging
+
+from ._collections import HTTPHeaderDict, RecentlyUsedContainer
+from .connectionpool import HTTPConnectionPool, HTTPSConnectionPool, port_by_scheme
+from .exceptions import (
+    LocationValueError,
+    MaxRetryError,
+    ProxySchemeUnknown,
+    ProxySchemeUnsupported,
+    URLSchemeUnknown,
+)
+from .packages import six
+from .packages.six.moves.urllib.parse import urljoin
+from .request import RequestMethods
+from .util.proxy import connection_requires_http_tunnel
+from .util.retry import Retry
+from .util.url import parse_url
+
+__all__ = ["PoolManager", "ProxyManager", "proxy_from_url"]
+
+
+log = logging.getLogger(__name__)
+
+SSL_KEYWORDS = (
+    "key_file",
+    "cert_file",
+    "cert_reqs",
+    "ca_certs",
+    "ssl_version",
+    "ca_cert_dir",
+    "ssl_context",
+    "key_password",
+    "server_hostname",
+)
+
+# All known keyword arguments that could be provided to the pool manager, its
+# pools, or the underlying connections. This is used to construct a pool key.
+_key_fields = (
+    "key_scheme",  # str
+    "key_host",  # str
+    "key_port",  # int
+    "key_timeout",  # int or float or Timeout
+    "key_retries",  # int or Retry
+    "key_strict",  # bool
+    "key_block",  # bool
+    "key_source_address",  # str
+    "key_key_file",  # str
+    "key_key_password",  # str
+    "key_cert_file",  # str
+    "key_cert_reqs",  # str
+    "key_ca_certs",  # str
+    "key_ssl_version",  # str
+    "key_ca_cert_dir",  # str
+    "key_ssl_context",  # instance of ssl.SSLContext or urllib3.util.ssl_.SSLContext
+    "key_maxsize",  # int
+    "key_headers",  # dict
+    "key__proxy",  # parsed proxy url
+    "key__proxy_headers",  # dict
+    "key__proxy_config",  # class
+    "key_socket_options",  # list of (level (int), optname (int), value (int or str)) tuples
+    "key__socks_options",  # dict
+    "key_assert_hostname",  # bool or string
+    "key_assert_fingerprint",  # str
+    "key_server_hostname",  # str
+)
+
+#: The namedtuple class used to construct keys for the connection pool.
+#: All custom key schemes should include the fields in this key at a minimum.
+PoolKey = collections.namedtuple("PoolKey", _key_fields)
+
+_proxy_config_fields = ("ssl_context", "use_forwarding_for_https")
+ProxyConfig = collections.namedtuple("ProxyConfig", _proxy_config_fields)
+
+
+def _default_key_normalizer(key_class, request_context):
+    """
+    Create a pool key out of a request context dictionary.
+
+    According to RFC 3986, both the scheme and host are case-insensitive.
+    Therefore, this function normalizes both before constructing the pool
+    key for an HTTPS request. If you wish to change this behaviour, provide
+    alternate callables to ``key_fn_by_scheme``.
+
+    :param key_class:
+        The class to use when constructing the key. This should be a namedtuple
+        with the ``scheme`` and ``host`` keys at a minimum.
+    :type  key_class: namedtuple
+    :param request_context:
+        A dictionary-like object that contain the context for a request.
+    :type  request_context: dict
+
+    :return: A namedtuple that can be used as a connection pool key.
+    :rtype:  PoolKey
+    """
+    # Since we mutate the dictionary, make a copy first
+    context = request_context.copy()
+    context["scheme"] = context["scheme"].lower()
+    context["host"] = context["host"].lower()
+
+    # These are both dictionaries and need to be transformed into frozensets
+    for key in ("headers", "_proxy_headers", "_socks_options"):
+        if key in context and context[key] is not None:
+            context[key] = frozenset(context[key].items())
+
+    # The socket_options key may be a list and needs to be transformed into a
+    # tuple.
+    socket_opts = context.get("socket_options")
+    if socket_opts is not None:
+        context["socket_options"] = tuple(socket_opts)
+
+    # Map the kwargs to the names in the namedtuple - this is necessary since
+    # namedtuples can't have fields starting with '_'.
+    for key in list(context.keys()):
+        context["key_" + key] = context.pop(key)
+
+    # Default to ``None`` for keys missing from the context
+    for field in key_class._fields:
+        if field not in context:
+            context[field] = None
+
+    return key_class(**context)
+
+
+#: A dictionary that maps a scheme to a callable that creates a pool key.
+#: This can be used to alter the way pool keys are constructed, if desired.
+#: Each PoolManager makes a copy of this dictionary so they can be configured
+#: globally here, or individually on the instance.
+key_fn_by_scheme = {
+    "http": functools.partial(_default_key_normalizer, PoolKey),
+    "https": functools.partial(_default_key_normalizer, PoolKey),
+}
+
+pool_classes_by_scheme = {"http": HTTPConnectionPool, "https": HTTPSConnectionPool}
+
+
+class PoolManager(RequestMethods):
+    """
+    Allows for arbitrary requests while transparently keeping track of
+    necessary connection pools for you.
+
+    :param num_pools:
+        Number of connection pools to cache before discarding the least
+        recently used pool.
+
+    :param headers:
+        Headers to include with all requests, unless other headers are given
+        explicitly.
+
+    :param \\**connection_pool_kw:
+        Additional parameters are used to create fresh
+        :class:`urllib3.connectionpool.ConnectionPool` instances.
+
+    Example::
+
+        >>> manager = PoolManager(num_pools=2)
+        >>> r = manager.request('GET', 'http://google.com/')
+        >>> r = manager.request('GET', 'http://google.com/mail')
+        >>> r = manager.request('GET', 'http://yahoo.com/')
+        >>> len(manager.pools)
+        2
+
+    """
+
+    proxy = None
+    proxy_config = None
+
+    def __init__(self, num_pools=10, headers=None, **connection_pool_kw):
+        RequestMethods.__init__(self, headers)
+        self.connection_pool_kw = connection_pool_kw
+        self.pools = RecentlyUsedContainer(num_pools)
+
+        # Locally set the pool classes and keys so other PoolManagers can
+        # override them.
+        self.pool_classes_by_scheme = pool_classes_by_scheme
+        self.key_fn_by_scheme = key_fn_by_scheme.copy()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.clear()
+        # Return False to re-raise any potential exceptions
+        return False
+
+    def _new_pool(self, scheme, host, port, request_context=None):
+        """
+        Create a new :class:`urllib3.connectionpool.ConnectionPool` based on host, port, scheme, and
+        any additional pool keyword arguments.
+
+        If ``request_context`` is provided, it is provided as keyword arguments
+        to the pool class used. This method is used to actually create the
+        connection pools handed out by :meth:`connection_from_url` and
+        companion methods. It is intended to be overridden for customization.
+        """
+        pool_cls = self.pool_classes_by_scheme[scheme]
+        if request_context is None:
+            request_context = self.connection_pool_kw.copy()
+
+        # Although the context has everything necessary to create the pool,
+        # this function has historically only used the scheme, host, and port
+        # in the positional args. When an API change is acceptable these can
+        # be removed.
+        for key in ("scheme", "host", "port"):
+            request_context.pop(key, None)
+
+        if scheme == "http":
+            for kw in SSL_KEYWORDS:
+                request_context.pop(kw, None)
+
+        return pool_cls(host, port, **request_context)
+
+    def clear(self):
+        """
+        Empty our store of pools and direct them all to close.
+
+        This will not affect in-flight connections, but they will not be
+        re-used after completion.
+        """
+        self.pools.clear()
+
+    def connection_from_host(self, host, port=None, scheme="http", pool_kwargs=None):
+        """
+        Get a :class:`urllib3.connectionpool.ConnectionPool` based on the host, port, and scheme.
+
+        If ``port`` isn't given, it will be derived from the ``scheme`` using
+        ``urllib3.connectionpool.port_by_scheme``. If ``pool_kwargs`` is
+        provided, it is merged with the instance's ``connection_pool_kw``
+        variable and used to create the new connection pool, if one is
+        needed.
+        """
+
+        if not host:
+            raise LocationValueError("No host specified.")
+
+        request_context = self._merge_pool_kwargs(pool_kwargs)
+        request_context["scheme"] = scheme or "http"
+        if not port:
+            port = port_by_scheme.get(request_context["scheme"].lower(), 80)
+        request_context["port"] = port
+        request_context["host"] = host
+
+        return self.connection_from_context(request_context)
+
+    def connection_from_context(self, request_context):
+        """
+        Get a :class:`urllib3.connectionpool.ConnectionPool` based on the request context.
+
+        ``request_context`` must at least contain the ``scheme`` key and its
+        value must be a key in ``key_fn_by_scheme`` instance variable.
+        """
+        scheme = request_context["scheme"].lower()
+        pool_key_constructor = self.key_fn_by_scheme.get(scheme)
+        if not pool_key_constructor:
+            raise URLSchemeUnknown(scheme)
+        pool_key = pool_key_constructor(request_context)
+
+        return self.connection_from_pool_key(pool_key, request_context=request_context)
+
+    def connection_from_pool_key(self, pool_key, request_context=None):
+        """
+        Get a :class:`urllib3.connectionpool.ConnectionPool` based on the provided pool key.
+
+        ``pool_key`` should be a namedtuple that only contains immutable
+        objects. At a minimum it must have the ``scheme``, ``host``, and
+        ``port`` fields.
+        """
+        with self.pools.lock:
+            # If the scheme, host, or port doesn't match existing open
+            # connections, open a new ConnectionPool.
+            pool = self.pools.get(pool_key)
+            if pool:
+                return pool
+
+            # Make a fresh ConnectionPool of the desired type
+            scheme = request_context["scheme"]
+            host = request_context["host"]
+            port = request_context["port"]
+            pool = self._new_pool(scheme, host, port, request_context=request_context)
+            self.pools[pool_key] = pool
+
+        return pool
+
+    def connection_from_url(self, url, pool_kwargs=None):
+        """
+        Similar to :func:`urllib3.connectionpool.connection_from_url`.
+
+        If ``pool_kwargs`` is not provided and a new pool needs to be
+        constructed, ``self.connection_pool_kw`` is used to initialize
+        the :class:`urllib3.connectionpool.ConnectionPool`. If ``pool_kwargs``
+        is provided, it is used instead. Note that if a new pool does not
+        need to be created for the request, the provided ``pool_kwargs`` are
+        not used.
+        """
+        u = parse_url(url)
+        return self.connection_from_host(
+            u.host, port=u.port, scheme=u.scheme, pool_kwargs=pool_kwargs
+        )
+
+    def _merge_pool_kwargs(self, override):
+        """
+        Merge a dictionary of override values for self.connection_pool_kw.
+
+        This does not modify self.connection_pool_kw and returns a new dict.
+        Any keys in the override dictionary with a value of ``None`` are
+        removed from the merged dictionary.
+        """
+        base_pool_kwargs = self.connection_pool_kw.copy()
+        if override:
+            for key, value in override.items():
+                if value is None:
+                    try:
+                        del base_pool_kwargs[key]
+                    except KeyError:
+                        pass
+                else:
+                    base_pool_kwargs[key] = value
+        return base_pool_kwargs
+
+    def _proxy_requires_url_absolute_form(self, parsed_url):
+        """
+        Indicates if the proxy requires the complete destination URL in the
+        request.  Normally this is only needed when not using an HTTP CONNECT
+        tunnel.
+        """
+        if self.proxy is None:
+            return False
+
+        return not connection_requires_http_tunnel(
+            self.proxy, self.proxy_config, parsed_url.scheme
+        )
+
+    def _validate_proxy_scheme_url_selection(self, url_scheme):
+        """
+        Validates that were not attempting to do TLS in TLS connections on
+        Python2 or with unsupported SSL implementations.
+        """
+        if self.proxy is None or url_scheme != "https":
+            return
+
+        if self.proxy.scheme != "https":
+            return
+
+        if six.PY2 and not self.proxy_config.use_forwarding_for_https:
+            raise ProxySchemeUnsupported(
+                "Contacting HTTPS destinations through HTTPS proxies "
+                "'via CONNECT tunnels' is not supported in Python 2"
+            )
+
+    def urlopen(self, method, url, redirect=True, **kw):
+        """
+        Same as :meth:`urllib3.HTTPConnectionPool.urlopen`
+        with custom cross-host redirect logic and only sends the request-uri
+        portion of the ``url``.
+
+        The given ``url`` parameter must be absolute, such that an appropriate
+        :class:`urllib3.connectionpool.ConnectionPool` can be chosen for it.
+        """
+        u = parse_url(url)
+        self._validate_proxy_scheme_url_selection(u.scheme)
+
+        conn = self.connection_from_host(u.host, port=u.port, scheme=u.scheme)
+
+        kw["assert_same_host"] = False
+        kw["redirect"] = False
+
+        if "headers" not in kw:
+            kw["headers"] = self.headers.copy()
+
+        if self._proxy_requires_url_absolute_form(u):
+            response = conn.urlopen(method, url, **kw)
+        else:
+            response = conn.urlopen(method, u.request_uri, **kw)
+
+        redirect_location = redirect and response.get_redirect_location()
+        if not redirect_location:
+            return response
+
+        # Support relative URLs for redirecting.
+        redirect_location = urljoin(url, redirect_location)
+
+        if response.status == 303:
+            # Change the method according to RFC 9110, Section 15.4.4.
+            method = "GET"
+            # And lose the body not to transfer anything sensitive.
+            kw["body"] = None
+            kw["headers"] = HTTPHeaderDict(kw["headers"])._prepare_for_method_change()
+
+        retries = kw.get("retries")
+        if not isinstance(retries, Retry):
+            retries = Retry.from_int(retries, redirect=redirect)
+
+        # Strip headers marked as unsafe to forward to the redirected location.
+        # Check remove_headers_on_redirect to avoid a potential network call within
+        # conn.is_same_host() which may use socket.gethostbyname() in the future.
+        if retries.remove_headers_on_redirect and not conn.is_same_host(
+            redirect_location
+        ):
+            headers = list(six.iterkeys(kw["headers"]))
+            for header in headers:
+                if header.lower() in retries.remove_headers_on_redirect:
+                    kw["headers"].pop(header, None)
+
+        try:
+            retries = retries.increment(method, url, response=response, _pool=conn)
+        except MaxRetryError:
+            if retries.raise_on_redirect:
+                response.drain_conn()
+                raise
+            return response
+
+        kw["retries"] = retries
+        kw["redirect"] = redirect
+
+        log.info("Redirecting %s -> %s", url, redirect_location)
+
+        response.drain_conn()
+        return self.urlopen(method, redirect_location, **kw)
+
+
+class ProxyManager(PoolManager):
+    """
+    Behaves just like :class:`PoolManager`, but sends all requests through
+    the defined proxy, using the CONNECT method for HTTPS URLs.
+
+    :param proxy_url:
+        The URL of the proxy to be used.
+
+    :param proxy_headers:
+        A dictionary containing headers that will be sent to the proxy. In case
+        of HTTP they are being sent with each request, while in the
+        HTTPS/CONNECT case they are sent only once. Could be used for proxy
+        authentication.
+
+    :param proxy_ssl_context:
+        The proxy SSL context is used to establish the TLS connection to the
+        proxy when using HTTPS proxies.
+
+    :param use_forwarding_for_https:
+        (Defaults to False) If set to True will forward requests to the HTTPS
+        proxy to be made on behalf of the client instead of creating a TLS
+        tunnel via the CONNECT method. **Enabling this flag means that request
+        and response headers and content will be visible from the HTTPS proxy**
+        whereas tunneling keeps request and response headers and content
+        private.  IP address, target hostname, SNI, and port are always visible
+        to an HTTPS proxy even when this flag is disabled.
+
+    Example:
+        >>> proxy = urllib3.ProxyManager('http://localhost:3128/')
+        >>> r1 = proxy.request('GET', 'http://google.com/')
+        >>> r2 = proxy.request('GET', 'http://httpbin.org/')
+        >>> len(proxy.pools)
+        1
+        >>> r3 = proxy.request('GET', 'https://httpbin.org/')
+        >>> r4 = proxy.request('GET', 'https://twitter.com/')
+        >>> len(proxy.pools)
+        3
+
+    """
+
+    def __init__(
+        self,
+        proxy_url,
+        num_pools=10,
+        headers=None,
+        proxy_headers=None,
+        proxy_ssl_context=None,
+        use_forwarding_for_https=False,
+        **connection_pool_kw
+    ):
+
+        if isinstance(proxy_url, HTTPConnectionPool):
+            proxy_url = "%s://%s:%i" % (
+                proxy_url.scheme,
+                proxy_url.host,
+                proxy_url.port,
+            )
+        proxy = parse_url(proxy_url)
+
+        if proxy.scheme not in ("http", "https"):
+            raise ProxySchemeUnknown(proxy.scheme)
+
+        if not proxy.port:
+            port = port_by_scheme.get(proxy.scheme, 80)
+            proxy = proxy._replace(port=port)
+
+        self.proxy = proxy
+        self.proxy_headers = proxy_headers or {}
+        self.proxy_ssl_context = proxy_ssl_context
+        self.proxy_config = ProxyConfig(proxy_ssl_context, use_forwarding_for_https)
+
+        connection_pool_kw["_proxy"] = self.proxy
+        connection_pool_kw["_proxy_headers"] = self.proxy_headers
+        connection_pool_kw["_proxy_config"] = self.proxy_config
+
+        super(ProxyManager, self).__init__(num_pools, headers, **connection_pool_kw)
+
+    def connection_from_host(self, host, port=None, scheme="http", pool_kwargs=None):
+        if scheme == "https":
+            return super(ProxyManager, self).connection_from_host(
+                host, port, scheme, pool_kwargs=pool_kwargs
+            )
+
+        return super(ProxyManager, self).connection_from_host(
+            self.proxy.host, self.proxy.port, self.proxy.scheme, pool_kwargs=pool_kwargs
+        )
+
+    def _set_proxy_headers(self, url, headers=None):
+        """
+        Sets headers needed by proxies: specifically, the Accept and Host
+        headers. Only sets headers not provided by the user.
+        """
+        headers_ = {"Accept": "*/*"}
+
+        netloc = parse_url(url).netloc
+        if netloc:
+            headers_["Host"] = netloc
+
+        if headers:
+            headers_.update(headers)
+        return headers_
+
+    def urlopen(self, method, url, redirect=True, **kw):
+        "Same as HTTP(S)ConnectionPool.urlopen, ``url`` must be absolute."
+        u = parse_url(url)
+        if not connection_requires_http_tunnel(self.proxy, self.proxy_config, u.scheme):
+            # For connections using HTTP CONNECT, httplib sets the necessary
+            # headers on the CONNECT to the proxy. If we're not using CONNECT,
+            # we'll definitely need to set 'Host' at the very least.
+            headers = kw.get("headers", self.headers)
+            kw["headers"] = self._set_proxy_headers(url, headers)
+
+        return super(ProxyManager, self).urlopen(method, url, redirect=redirect, **kw)
+
+
+def proxy_from_url(url, **kw):
+    return ProxyManager(proxy_url=url, **kw)