Add google-endpoints to third_party/.

third_party/google-endpoints/urllib3/poolmanager.py

Index: third_party/google-endpoints/urllib3/poolmanager.py
diff --git a/third_party/google-endpoints/urllib3/poolmanager.py b/third_party/google-endpoints/urllib3/poolmanager.py
new file mode 100644
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+++ b/third_party/google-endpoints/urllib3/poolmanager.py
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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')
+
+# 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 = self.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
+
+        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)
+
+        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'):
+        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)