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Diffstat (limited to 'urllib3/poolmanager.py')
| -rw-r--r-- | urllib3/poolmanager.py | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/urllib3/poolmanager.py b/urllib3/poolmanager.py new file mode 100644 index 0000000..76b6a12 --- /dev/null +++ b/urllib3/poolmanager.py @@ -0,0 +1,280 @@ +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, ProxySchemeUnknown +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) + + 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) |