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Diffstat (limited to 'urllib3/connectionpool.py')
| -rw-r--r-- | urllib3/connectionpool.py | 774 |
1 files changed, 774 insertions, 0 deletions
diff --git a/urllib3/connectionpool.py b/urllib3/connectionpool.py new file mode 100644 index 0000000..8bdf228 --- /dev/null +++ b/urllib3/connectionpool.py @@ -0,0 +1,774 @@ +import errno +import logging +import sys +import warnings + +from socket import error as SocketError, timeout as SocketTimeout +import socket + +try: # Python 3 + from queue import LifoQueue, Empty, Full +except ImportError: + from Queue import LifoQueue, Empty, Full + import Queue as _ # Platform-specific: Windows + + +from .exceptions import ( + ClosedPoolError, + ProtocolError, + EmptyPoolError, + HostChangedError, + LocationValueError, + MaxRetryError, + ProxyError, + ReadTimeoutError, + SSLError, + TimeoutError, + InsecureRequestWarning, +) +from .packages.ssl_match_hostname import CertificateError +from .packages import six +from .connection import ( + port_by_scheme, + DummyConnection, + HTTPConnection, HTTPSConnection, VerifiedHTTPSConnection, + HTTPException, BaseSSLError, ConnectionError +) +from .request import RequestMethods +from .response import HTTPResponse + +from .util.connection import is_connection_dropped +from .util.retry import Retry +from .util.timeout import Timeout +from .util.url import get_host + + +xrange = six.moves.xrange + +log = logging.getLogger(__name__) + +_Default = object() + + +## Pool objects +class ConnectionPool(object): + """ + Base class for all connection pools, such as + :class:`.HTTPConnectionPool` and :class:`.HTTPSConnectionPool`. + """ + + scheme = None + QueueCls = LifoQueue + + def __init__(self, host, port=None): + if not host: + raise LocationValueError("No host specified.") + + # httplib doesn't like it when we include brackets in ipv6 addresses + self.host = host.strip('[]') + self.port = port + + def __str__(self): + return '%s(host=%r, port=%r)' % (type(self).__name__, + self.host, self.port) + +# This is taken from http://hg.python.org/cpython/file/7aaba721ebc0/Lib/socket.py#l252 +_blocking_errnos = set([errno.EAGAIN, errno.EWOULDBLOCK]) + + +class HTTPConnectionPool(ConnectionPool, RequestMethods): + """ + Thread-safe connection pool for one host. + + :param host: + Host used for this HTTP Connection (e.g. "localhost"), passed into + :class:`httplib.HTTPConnection`. + + :param port: + Port used for this HTTP Connection (None is equivalent to 80), passed + into :class:`httplib.HTTPConnection`. + + :param strict: + Causes BadStatusLine to be raised if the status line can't be parsed + as a valid HTTP/1.0 or 1.1 status line, passed into + :class:`httplib.HTTPConnection`. + + .. note:: + Only works in Python 2. This parameter is ignored in Python 3. + + :param timeout: + Socket timeout in seconds for each individual connection. This can + be a float or integer, which sets the timeout for the HTTP request, + or an instance of :class:`urllib3.util.Timeout` which gives you more + fine-grained control over request timeouts. After the constructor has + been parsed, this is always a `urllib3.util.Timeout` object. + + :param maxsize: + Number of connections to save that can be reused. More than 1 is useful + in multithreaded situations. If ``block`` is set to false, more + connections will be created but they will not be saved once they've + been used. + + :param block: + If set to True, no more than ``maxsize`` connections will be used at + a time. When no free connections are available, the call will block + until a connection has been released. This is a useful side effect for + particular multithreaded situations where one does not want to use more + than maxsize connections per host to prevent flooding. + + :param headers: + Headers to include with all requests, unless other headers are given + explicitly. + + :param retries: + Retry configuration to use by default with requests in this pool. + + :param _proxy: + Parsed proxy URL, should not be used directly, instead, see + :class:`urllib3.connectionpool.ProxyManager`" + + :param _proxy_headers: + A dictionary with proxy headers, should not be used directly, + instead, see :class:`urllib3.connectionpool.ProxyManager`" + + :param \**conn_kw: + Additional parameters are used to create fresh :class:`urllib3.connection.HTTPConnection`, + :class:`urllib3.connection.HTTPSConnection` instances. + """ + + scheme = 'http' + ConnectionCls = HTTPConnection + + def __init__(self, host, port=None, strict=False, + timeout=Timeout.DEFAULT_TIMEOUT, maxsize=1, block=False, + headers=None, retries=None, + _proxy=None, _proxy_headers=None, + **conn_kw): + ConnectionPool.__init__(self, host, port) + RequestMethods.__init__(self, headers) + + self.strict = strict + + if not isinstance(timeout, Timeout): + timeout = Timeout.from_float(timeout) + + if retries is None: + retries = Retry.DEFAULT + + self.timeout = timeout + self.retries = retries + + self.pool = self.QueueCls(maxsize) + self.block = block + + self.proxy = _proxy + self.proxy_headers = _proxy_headers or {} + + # Fill the queue up so that doing get() on it will block properly + for _ in xrange(maxsize): + self.pool.put(None) + + # These are mostly for testing and debugging purposes. + self.num_connections = 0 + self.num_requests = 0 + self.conn_kw = conn_kw + + if self.proxy: + # Enable Nagle's algorithm for proxies, to avoid packet fragmentation. + # We cannot know if the user has added default socket options, so we cannot replace the + # list. + self.conn_kw.setdefault('socket_options', []) + + def _new_conn(self): + """ + Return a fresh :class:`HTTPConnection`. + """ + self.num_connections += 1 + log.info("Starting new HTTP connection (%d): %s" % + (self.num_connections, self.host)) + + conn = self.ConnectionCls(host=self.host, port=self.port, + timeout=self.timeout.connect_timeout, + strict=self.strict, **self.conn_kw) + return conn + + def _get_conn(self, timeout=None): + """ + Get a connection. Will return a pooled connection if one is available. + + If no connections are available and :prop:`.block` is ``False``, then a + fresh connection is returned. + + :param timeout: + Seconds to wait before giving up and raising + :class:`urllib3.exceptions.EmptyPoolError` if the pool is empty and + :prop:`.block` is ``True``. + """ + conn = None + try: + conn = self.pool.get(block=self.block, timeout=timeout) + + except AttributeError: # self.pool is None + raise ClosedPoolError(self, "Pool is closed.") + + except Empty: + if self.block: + raise EmptyPoolError(self, + "Pool reached maximum size and no more " + "connections are allowed.") + pass # Oh well, we'll create a new connection then + + # If this is a persistent connection, check if it got disconnected + if conn and is_connection_dropped(conn): + log.info("Resetting dropped connection: %s" % self.host) + conn.close() + if getattr(conn, 'auto_open', 1) == 0: + # This is a proxied connection that has been mutated by + # httplib._tunnel() and cannot be reused (since it would + # attempt to bypass the proxy) + conn = None + + return conn or self._new_conn() + + def _put_conn(self, conn): + """ + Put a connection back into the pool. + + :param conn: + Connection object for the current host and port as returned by + :meth:`._new_conn` or :meth:`._get_conn`. + + If the pool is already full, the connection is closed and discarded + because we exceeded maxsize. If connections are discarded frequently, + then maxsize should be increased. + + If the pool is closed, then the connection will be closed and discarded. + """ + try: + self.pool.put(conn, block=False) + return # Everything is dandy, done. + except AttributeError: + # self.pool is None. + pass + except Full: + # This should never happen if self.block == True + log.warning( + "Connection pool is full, discarding connection: %s" % + self.host) + + # Connection never got put back into the pool, close it. + if conn: + conn.close() + + def _validate_conn(self, conn): + """ + Called right before a request is made, after the socket is created. + """ + pass + + def _prepare_proxy(self, conn): + # Nothing to do for HTTP connections. + pass + + def _get_timeout(self, timeout): + """ Helper that always returns a :class:`urllib3.util.Timeout` """ + if timeout is _Default: + return self.timeout.clone() + + if isinstance(timeout, Timeout): + return timeout.clone() + else: + # User passed us an int/float. This is for backwards compatibility, + # can be removed later + return Timeout.from_float(timeout) + + def _raise_timeout(self, err, url, timeout_value): + """Is the error actually a timeout? Will raise a ReadTimeout or pass""" + + if isinstance(err, SocketTimeout): + raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value) + + # See the above comment about EAGAIN in Python 3. In Python 2 we have + # to specifically catch it and throw the timeout error + if hasattr(err, 'errno') and err.errno in _blocking_errnos: + raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value) + + # Catch possible read timeouts thrown as SSL errors. If not the + # case, rethrow the original. We need to do this because of: + # http://bugs.python.org/issue10272 + if 'timed out' in str(err) or 'did not complete (read)' in str(err): # Python 2.6 + raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value) + + def _make_request(self, conn, method, url, timeout=_Default, + **httplib_request_kw): + """ + Perform a request on a given urllib connection object taken from our + pool. + + :param conn: + a connection from one of our connection pools + + :param timeout: + Socket timeout in seconds for the request. This can be a + float or integer, which will set the same timeout value for + the socket connect and the socket read, or an instance of + :class:`urllib3.util.Timeout`, which gives you more fine-grained + control over your timeouts. + """ + self.num_requests += 1 + + timeout_obj = self._get_timeout(timeout) + timeout_obj.start_connect() + conn.timeout = timeout_obj.connect_timeout + + # Trigger any extra validation we need to do. + try: + self._validate_conn(conn) + except (SocketTimeout, BaseSSLError) as e: + # Py2 raises this as a BaseSSLError, Py3 raises it as socket timeout. + self._raise_timeout(err=e, url=url, timeout_value=conn.timeout) + raise + + # conn.request() calls httplib.*.request, not the method in + # urllib3.request. It also calls makefile (recv) on the socket. + conn.request(method, url, **httplib_request_kw) + + # Reset the timeout for the recv() on the socket + read_timeout = timeout_obj.read_timeout + + # App Engine doesn't have a sock attr + if getattr(conn, 'sock', None): + # In Python 3 socket.py will catch EAGAIN and return None when you + # try and read into the file pointer created by http.client, which + # instead raises a BadStatusLine exception. Instead of catching + # the exception and assuming all BadStatusLine exceptions are read + # timeouts, check for a zero timeout before making the request. + if read_timeout == 0: + raise ReadTimeoutError( + self, url, "Read timed out. (read timeout=%s)" % read_timeout) + if read_timeout is Timeout.DEFAULT_TIMEOUT: + conn.sock.settimeout(socket.getdefaulttimeout()) + else: # None or a value + conn.sock.settimeout(read_timeout) + + # Receive the response from the server + try: + try: # Python 2.7+, use buffering of HTTP responses + httplib_response = conn.getresponse(buffering=True) + except TypeError: # Python 2.6 and older + httplib_response = conn.getresponse() + except (SocketTimeout, BaseSSLError, SocketError) as e: + self._raise_timeout(err=e, url=url, timeout_value=read_timeout) + raise + + # AppEngine doesn't have a version attr. + http_version = getattr(conn, '_http_vsn_str', 'HTTP/?') + log.debug("\"%s %s %s\" %s %s" % (method, url, http_version, + httplib_response.status, + httplib_response.length)) + return httplib_response + + def close(self): + """ + Close all pooled connections and disable the pool. + """ + # Disable access to the pool + old_pool, self.pool = self.pool, None + + try: + while True: + conn = old_pool.get(block=False) + if conn: + conn.close() + + except Empty: + pass # Done. + + def is_same_host(self, url): + """ + Check if the given ``url`` is a member of the same host as this + connection pool. + """ + if url.startswith('/'): + return True + + # TODO: Add optional support for socket.gethostbyname checking. + scheme, host, port = get_host(url) + + # Use explicit default port for comparison when none is given + if self.port and not port: + port = port_by_scheme.get(scheme) + elif not self.port and port == port_by_scheme.get(scheme): + port = None + + return (scheme, host, port) == (self.scheme, self.host, self.port) + + def urlopen(self, method, url, body=None, headers=None, retries=None, + redirect=True, assert_same_host=True, timeout=_Default, + pool_timeout=None, release_conn=None, **response_kw): + """ + Get a connection from the pool and perform an HTTP request. This is the + lowest level call for making a request, so you'll need to specify all + the raw details. + + .. note:: + + More commonly, it's appropriate to use a convenience method provided + by :class:`.RequestMethods`, such as :meth:`request`. + + .. note:: + + `release_conn` will only behave as expected if + `preload_content=False` because we want to make + `preload_content=False` the default behaviour someday soon without + breaking backwards compatibility. + + :param method: + HTTP request method (such as GET, POST, PUT, etc.) + + :param body: + Data to send in the request body (useful for creating + POST requests, see HTTPConnectionPool.post_url for + more convenience). + + :param headers: + Dictionary of custom headers to send, such as User-Agent, + If-None-Match, etc. If None, pool headers are used. If provided, + these headers completely replace any pool-specific headers. + + :param retries: + Configure the number of retries to allow before raising a + :class:`~urllib3.exceptions.MaxRetryError` exception. + + Pass ``None`` to retry until you receive a response. Pass a + :class:`~urllib3.util.retry.Retry` object for fine-grained control + over different types of retries. + Pass an integer number to retry connection errors that many times, + but no other types of errors. Pass zero to never retry. + + If ``False``, then retries are disabled and any exception is raised + immediately. Also, instead of raising a MaxRetryError on redirects, + the redirect response will be returned. + + :type retries: :class:`~urllib3.util.retry.Retry`, False, or an int. + + :param redirect: + If True, automatically handle redirects (status codes 301, 302, + 303, 307, 308). Each redirect counts as a retry. Disabling retries + will disable redirect, too. + + :param assert_same_host: + If ``True``, will make sure that the host of the pool requests is + consistent else will raise HostChangedError. When False, you can + use the pool on an HTTP proxy and request foreign hosts. + + :param timeout: + If specified, overrides the default timeout for this one + request. It may be a float (in seconds) or an instance of + :class:`urllib3.util.Timeout`. + + :param pool_timeout: + If set and the pool is set to block=True, then this method will + block for ``pool_timeout`` seconds and raise EmptyPoolError if no + connection is available within the time period. + + :param release_conn: + If False, then the urlopen call will not release the connection + back into the pool once a response is received (but will release if + you read the entire contents of the response such as when + `preload_content=True`). This is useful if you're not preloading + the response's content immediately. You will need to call + ``r.release_conn()`` on the response ``r`` to return the connection + back into the pool. If None, it takes the value of + ``response_kw.get('preload_content', True)``. + + :param \**response_kw: + Additional parameters are passed to + :meth:`urllib3.response.HTTPResponse.from_httplib` + """ + if headers is None: + headers = self.headers + + if not isinstance(retries, Retry): + retries = Retry.from_int(retries, redirect=redirect, default=self.retries) + + if release_conn is None: + release_conn = response_kw.get('preload_content', True) + + # Check host + if assert_same_host and not self.is_same_host(url): + raise HostChangedError(self, url, retries) + + conn = None + + # Merge the proxy headers. Only do this in HTTP. We have to copy the + # headers dict so we can safely change it without those changes being + # reflected in anyone else's copy. + if self.scheme == 'http': + headers = headers.copy() + headers.update(self.proxy_headers) + + # Must keep the exception bound to a separate variable or else Python 3 + # complains about UnboundLocalError. + err = None + + try: + # Request a connection from the queue. + timeout_obj = self._get_timeout(timeout) + conn = self._get_conn(timeout=pool_timeout) + + conn.timeout = timeout_obj.connect_timeout + + is_new_proxy_conn = self.proxy is not None and not getattr(conn, 'sock', None) + if is_new_proxy_conn: + self._prepare_proxy(conn) + + # Make the request on the httplib connection object. + httplib_response = self._make_request(conn, method, url, + timeout=timeout_obj, + body=body, headers=headers) + + # If we're going to release the connection in ``finally:``, then + # the request doesn't need to know about the connection. Otherwise + # it will also try to release it and we'll have a double-release + # mess. + response_conn = not release_conn and conn + + # Import httplib's response into our own wrapper object + response = HTTPResponse.from_httplib(httplib_response, + pool=self, + connection=response_conn, + **response_kw) + + # else: + # The connection will be put back into the pool when + # ``response.release_conn()`` is called (implicitly by + # ``response.read()``) + + except Empty: + # Timed out by queue. + raise EmptyPoolError(self, "No pool connections are available.") + + except (BaseSSLError, CertificateError) as e: + # Close the connection. If a connection is reused on which there + # was a Certificate error, the next request will certainly raise + # another Certificate error. + if conn: + conn.close() + conn = None + raise SSLError(e) + + except (TimeoutError, HTTPException, SocketError, ConnectionError) as e: + if conn: + # Discard the connection for these exceptions. It will be + # be replaced during the next _get_conn() call. + conn.close() + conn = None + + stacktrace = sys.exc_info()[2] + if isinstance(e, SocketError) and self.proxy: + e = ProxyError('Cannot connect to proxy.', e) + elif isinstance(e, (SocketError, HTTPException)): + e = ProtocolError('Connection aborted.', e) + + retries = retries.increment(method, url, error=e, + _pool=self, _stacktrace=stacktrace) + retries.sleep() + + # Keep track of the error for the retry warning. + err = e + + finally: + if release_conn: + # Put the connection back to be reused. If the connection is + # expired then it will be None, which will get replaced with a + # fresh connection during _get_conn. + self._put_conn(conn) + + if not conn: + # Try again + log.warning("Retrying (%r) after connection " + "broken by '%r': %s" % (retries, err, url)) + return self.urlopen(method, url, body, headers, retries, + redirect, assert_same_host, + timeout=timeout, pool_timeout=pool_timeout, + release_conn=release_conn, **response_kw) + + # Handle redirect? + redirect_location = redirect and response.get_redirect_location() + if redirect_location: + if response.status == 303: + method = 'GET' + + try: + retries = retries.increment(method, url, response=response, _pool=self) + except MaxRetryError: + if retries.raise_on_redirect: + raise + return response + + log.info("Redirecting %s -> %s" % (url, redirect_location)) + return self.urlopen(method, redirect_location, body, headers, + retries=retries, redirect=redirect, + assert_same_host=assert_same_host, + timeout=timeout, pool_timeout=pool_timeout, + release_conn=release_conn, **response_kw) + + # Check if we should retry the HTTP response. + if retries.is_forced_retry(method, status_code=response.status): + retries = retries.increment(method, url, response=response, _pool=self) + retries.sleep() + log.info("Forced retry: %s" % url) + return self.urlopen(method, url, body, headers, + retries=retries, redirect=redirect, + assert_same_host=assert_same_host, + timeout=timeout, pool_timeout=pool_timeout, + release_conn=release_conn, **response_kw) + + return response + + +class HTTPSConnectionPool(HTTPConnectionPool): + """ + Same as :class:`.HTTPConnectionPool`, but HTTPS. + + When Python is compiled with the :mod:`ssl` module, then + :class:`.VerifiedHTTPSConnection` is used, which *can* verify certificates, + instead of :class:`.HTTPSConnection`. + + :class:`.VerifiedHTTPSConnection` uses one of ``assert_fingerprint``, + ``assert_hostname`` and ``host`` in this order to verify connections. + If ``assert_hostname`` is False, no verification is done. + + The ``key_file``, ``cert_file``, ``cert_reqs``, ``ca_certs`` and + ``ssl_version`` are only used if :mod:`ssl` is available and are fed into + :meth:`urllib3.util.ssl_wrap_socket` to upgrade the connection socket + into an SSL socket. + """ + + scheme = 'https' + ConnectionCls = HTTPSConnection + + def __init__(self, host, port=None, + strict=False, timeout=Timeout.DEFAULT_TIMEOUT, maxsize=1, + block=False, headers=None, retries=None, + _proxy=None, _proxy_headers=None, + key_file=None, cert_file=None, cert_reqs=None, + ca_certs=None, ssl_version=None, + assert_hostname=None, assert_fingerprint=None, + **conn_kw): + + HTTPConnectionPool.__init__(self, host, port, strict, timeout, maxsize, + block, headers, retries, _proxy, _proxy_headers, + **conn_kw) + self.key_file = key_file + self.cert_file = cert_file + self.cert_reqs = cert_reqs + self.ca_certs = ca_certs + self.ssl_version = ssl_version + self.assert_hostname = assert_hostname + self.assert_fingerprint = assert_fingerprint + + def _prepare_conn(self, conn): + """ + Prepare the ``connection`` for :meth:`urllib3.util.ssl_wrap_socket` + and establish the tunnel if proxy is used. + """ + + if isinstance(conn, VerifiedHTTPSConnection): + conn.set_cert(key_file=self.key_file, + cert_file=self.cert_file, + cert_reqs=self.cert_reqs, + ca_certs=self.ca_certs, + assert_hostname=self.assert_hostname, + assert_fingerprint=self.assert_fingerprint) + conn.ssl_version = self.ssl_version + + return conn + + def _prepare_proxy(self, conn): + """ + Establish tunnel connection early, because otherwise httplib + would improperly set Host: header to proxy's IP:port. + """ + # Python 2.7+ + try: + set_tunnel = conn.set_tunnel + except AttributeError: # Platform-specific: Python 2.6 + set_tunnel = conn._set_tunnel + + if sys.version_info <= (2, 6, 4) and not self.proxy_headers: # Python 2.6.4 and older + set_tunnel(self.host, self.port) + else: + set_tunnel(self.host, self.port, self.proxy_headers) + + conn.connect() + + def _new_conn(self): + """ + Return a fresh :class:`httplib.HTTPSConnection`. + """ + self.num_connections += 1 + log.info("Starting new HTTPS connection (%d): %s" + % (self.num_connections, self.host)) + + if not self.ConnectionCls or self.ConnectionCls is DummyConnection: + # Platform-specific: Python without ssl + raise SSLError("Can't connect to HTTPS URL because the SSL " + "module is not available.") + + actual_host = self.host + actual_port = self.port + if self.proxy is not None: + actual_host = self.proxy.host + actual_port = self.proxy.port + + conn = self.ConnectionCls(host=actual_host, port=actual_port, + timeout=self.timeout.connect_timeout, + strict=self.strict, **self.conn_kw) + + return self._prepare_conn(conn) + + def _validate_conn(self, conn): + """ + Called right before a request is made, after the socket is created. + """ + super(HTTPSConnectionPool, self)._validate_conn(conn) + + # Force connect early to allow us to validate the connection. + if not getattr(conn, 'sock', None): # AppEngine might not have `.sock` + conn.connect() + + if not conn.is_verified: + warnings.warn(( + 'Unverified HTTPS request is being made. ' + 'Adding certificate verification is strongly advised. See: ' + 'https://urllib3.readthedocs.org/en/latest/security.html'), + InsecureRequestWarning) + + +def connection_from_url(url, **kw): + """ + Given a url, return an :class:`.ConnectionPool` instance of its host. + + This is a shortcut for not having to parse out the scheme, host, and port + of the url before creating an :class:`.ConnectionPool` instance. + + :param url: + Absolute URL string that must include the scheme. Port is optional. + + :param \**kw: + Passes additional parameters to the constructor of the appropriate + :class:`.ConnectionPool`. Useful for specifying things like + timeout, maxsize, headers, etc. + + Example:: + + >>> conn = connection_from_url('http://google.com/') + >>> r = conn.request('GET', '/') + """ + scheme, host, port = get_host(url) + if scheme == 'https': + return HTTPSConnectionPool(host, port=port, **kw) + else: + return HTTPConnectionPool(host, port=port, **kw) |