aboutsummaryrefslogtreecommitdiff
path: root/urllib3/poolmanager.py
blob: b8d1e745d14997f084d44edf0c17fc646ca8d7bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
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']


pool_classes_by_scheme = {
    'http': HTTPConnectionPool,
    'https': HTTPSConnectionPool,
}

log = logging.getLogger(__name__)

SSL_KEYWORDS = ('key_file', 'cert_file', 'cert_reqs', 'ca_certs',
                'ssl_version')


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())

    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.")

        scheme = scheme or 'http'
        port = port or port_by_scheme.get(scheme, 80)
        pool_key = (scheme, host, port)

        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(scheme, host, 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)

        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)