import collections
import functools
import logging
try: # Python 3
from urllib.parse import urljoin
except ImportError:
from urlparse import urljoin
from ._collections import RecentlyUsedContainer
from .connectionpool import HTTPConnectionPool, HTTPSConnectionPool
from .connectionpool import port_by_scheme
from .exceptions import LocationValueError, MaxRetryError
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')
# The base fields to use when determining what pool to get a connection from;
# these do not rely on the ``connection_pool_kw`` and can be determined by the
# URL and potentially the ``urllib3.connection.port_by_scheme`` dictionary.
#
# All custom key schemes should include the fields in this key at a minimum.
BasePoolKey = collections.namedtuple('BasePoolKey', ('scheme', 'host', 'port'))
# The fields to use when determining what pool to get a HTTP and HTTPS
# connection from. All additional fields must be present in the PoolManager's
# ``connection_pool_kw`` instance variable.
HTTPPoolKey = collections.namedtuple(
'HTTPPoolKey', BasePoolKey._fields + ('timeout', 'retries', 'strict',
'block', 'source_address')
)
HTTPSPoolKey = collections.namedtuple(
'HTTPSPoolKey', HTTPPoolKey._fields + SSL_KEYWORDS
)
def _default_key_normalizer(key_class, request_context):
"""
Create a pool key of type ``key_class`` for a request.
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.
:param request_context:
A dictionary-like object that contain the context for a request.
It should contain a key for each field in the :class:`HTTPPoolKey`
"""
context = {}
for key in key_class._fields:
context[key] = request_context.get(key)
context['scheme'] = context['scheme'].lower()
context['host'] = context['host'].lower()
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, HTTPPoolKey),
'https': functools.partial(_default_key_normalizer, HTTPSPoolKey),
}
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):
"""
Create a new :class:`ConnectionPool` based on host, port and scheme.
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 = pool_classes_by_scheme[scheme]
kwargs = self.connection_pool_kw
if scheme == 'http':
kwargs = self.connection_pool_kw.copy()
for kw in SSL_KEYWORDS:
kwargs.pop(kw, None)
return pool_cls(host, port, **kwargs)
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'):
"""
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 not host:
raise LocationValueError("No host specified.")
request_context = self.connection_pool_kw.copy()
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)
def connection_from_pool_key(self, pool_key):
"""
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
pool = self._new_pool(pool_key.scheme, pool_key.host, pool_key.port)
self.pools[pool_key] = pool
return pool
def connection_from_url(self, url):
"""
Similar to :func:`urllib3.connectionpool.connection_from_url` but
doesn't pass any additional parameters to the
:class:`urllib3.connectionpool.ConnectionPool` constructor.
Additional parameters are taken from the :class:`.PoolManager`
constructor.
"""
u = parse_url(url)
return self.connection_from_host(u.host, port=u.port, scheme=u.scheme)
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)
assert proxy.scheme in ("http", "https"), \
'Not supported proxy scheme %s' % 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'):
if scheme == "https":
return super(ProxyManager, self).connection_from_host(
host, port, scheme)
return super(ProxyManager, self).connection_from_host(
self.proxy.host, self.proxy.port, self.proxy.scheme)
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)