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from __future__ import absolute_import
import collections
import functools
import logging
from ._collections import RecentlyUsedContainer
from .connectionpool import HTTPConnectionPool, HTTPSConnectionPool
from .connectionpool import port_by_scheme
from .exceptions import LocationValueError, MaxRetryError, ProxySchemeUnknown
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')
# 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_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
)
#: 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)):
for header 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:
raise
return response
kw['retries'] = retries
kw['redirect'] = redirect
log.info("Redirecting %s -> %s", url, redirect_location)
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 contaning 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 urlopen(self, method, url, redirect=True, **kw):
"Same as HTTP(S)ConnectionPool.urlopen, ``url`` must be absolute."
u = parse_url(url)
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)
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