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from __future__ import absolute_import 

import collections 

import functools 

import logging 

import warnings 

 

from ._collections import RecentlyUsedContainer 

from .connectionpool import HTTPConnectionPool, HTTPSConnectionPool 

from .connectionpool import port_by_scheme 

from .exceptions import ( 

LocationValueError, 

MaxRetryError, 

ProxySchemeUnknown, 

InvalidProxyConfigurationWarning, 

) 

from .packages import six 

from .packages.six.moves.urllib.parse import urljoin 

from .request import RequestMethods 

from .util.url import parse_url 

from .util.retry import Retry 

 

 

__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", 

) 

 

# 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_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) 

 

 

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 

 

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, dispose_func=lambda p: p.close()) 

 

# 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:`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:`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:`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[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:`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 urlopen(self, method, url, redirect=True, **kw): 

""" 

Same as :meth:`urllib3.connectionpool.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) 

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 is not None and u.scheme == "http": 

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) 

 

# RFC 7231, Section 6.4.4 

if response.status == 303: 

method = "GET" 

 

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. 

 

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, 

**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 not proxy.port: 

port = port_by_scheme.get(proxy.scheme, 80) 

proxy = proxy._replace(port=port) 

 

if proxy.scheme not in ("http", "https"): 

raise ProxySchemeUnknown(proxy.scheme) 

 

self.proxy = proxy 

self.proxy_headers = proxy_headers or {} 

 

connection_pool_kw["_proxy"] = self.proxy 

connection_pool_kw["_proxy_headers"] = self.proxy_headers 

 

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 _validate_proxy_scheme_url_selection(self, url_scheme): 

if url_scheme == "https" and self.proxy.scheme == "https": 

warnings.warn( 

"Your proxy configuration specified an HTTPS scheme for the proxy. " 

"Are you sure you want to use HTTPS to contact the proxy? " 

"This most likely indicates an error in your configuration. " 

"Read this issue for more info: " 

"https://github.com/urllib3/urllib3/issues/1850", 

InvalidProxyConfigurationWarning, 

stacklevel=3, 

) 

 

def urlopen(self, method, url, redirect=True, **kw): 

"Same as HTTP(S)ConnectionPool.urlopen, ``url`` must be absolute." 

u = parse_url(url) 

self._validate_proxy_scheme_url_selection(u.scheme) 

 

if u.scheme == "http": 

# For proxied HTTPS requests, httplib sets the necessary headers 

# on the CONNECT to the proxy. For HTTP, 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)