1 files changed, 234 insertions, 0 deletions
diff --git a/urllib3/util/timeout.py b/urllib3/util/timeout.py
new file mode 100644
index 0000000..4f947cb
--- /dev/null
+++ b/urllib3/util/timeout.py
@@ -0,0 +1,234 @@
+from socket import _GLOBAL_DEFAULT_TIMEOUT
+import time
+
+from ..exceptions import TimeoutStateError
+
+
+def current_time():
+    """
+    Retrieve the current time, this function is mocked out in unit testing.
+    """
+    return time.time()
+
+
+_Default = object()
+# The default timeout to use for socket connections. This is the attribute used
+# by httplib to define the default timeout
+
+
+class Timeout(object):
+    """
+    Utility object for storing timeout values.
+
+    Example usage:
+
+    .. code-block:: python
+
+        timeout = urllib3.util.Timeout(connect=2.0, read=7.0)
+        pool = HTTPConnectionPool('www.google.com', 80, timeout=timeout)
+        pool.request(...) # Etc, etc
+
+    :param connect:
+        The maximum amount of time to wait for a connection attempt to a server
+        to succeed. Omitting the parameter will default the connect timeout to
+        the system default, probably `the global default timeout in socket.py
+        <http://hg.python.org/cpython/file/603b4d593758/Lib/socket.py#l535>`_.
+        None will set an infinite timeout for connection attempts.
+
+    :type connect: integer, float, or None
+
+    :param read:
+        The maximum amount of time to wait between consecutive
+        read operations for a response from the server. Omitting
+        the parameter will default the read timeout to the system
+        default, probably `the global default timeout in socket.py
+        <http://hg.python.org/cpython/file/603b4d593758/Lib/socket.py#l535>`_.
+        None will set an infinite timeout.
+
+    :type read: integer, float, or None
+
+    :param total:
+        This combines the connect and read timeouts into one; the read timeout
+        will be set to the time leftover from the connect attempt. In the
+        event that both a connect timeout and a total are specified, or a read
+        timeout and a total are specified, the shorter timeout will be applied.
+
+        Defaults to None.
+
+    :type total: integer, float, or None
+
+    .. note::
+
+        Many factors can affect the total amount of time for urllib3 to return
+        an HTTP response. Specifically, Python's DNS resolver does not obey the
+        timeout specified on the socket. Other factors that can affect total
+        request time include high CPU load, high swap, the program running at a
+        low priority level, or other behaviors. The observed running time for
+        urllib3 to return a response may be greater than the value passed to
+        `total`.
+
+        In addition, the read and total timeouts only measure the time between
+        read operations on the socket connecting the client and the server,
+        not the total amount of time for the request to return a complete
+        response. For most requests, the timeout is raised because the server
+        has not sent the first byte in the specified time. This is not always
+        the case; if a server streams one byte every fifteen seconds, a timeout
+        of 20 seconds will not ever trigger, even though the request will
+        take several minutes to complete.
+
+        If your goal is to cut off any request after a set amount of wall clock
+        time, consider having a second "watcher" thread to cut off a slow
+        request.
+    """
+
+    #: A sentinel object representing the default timeout value
+    DEFAULT_TIMEOUT = _GLOBAL_DEFAULT_TIMEOUT
+
+    def __init__(self, total=None, connect=_Default, read=_Default):
+        self._connect = self._validate_timeout(connect, 'connect')
+        self._read = self._validate_timeout(read, 'read')
+        self.total = self._validate_timeout(total, 'total')
+        self._start_connect = None
+
+    def __str__(self):
+        return '%s(connect=%r, read=%r, total=%r)' % (
+            type(self).__name__, self._connect, self._read, self.total)
+
+
+    @classmethod
+    def _validate_timeout(cls, value, name):
+        """ Check that a timeout attribute is valid
+
+        :param value: The timeout value to validate
+        :param name: The name of the timeout attribute to validate. This is used
+            for clear error messages
+        :return: the value
+        :raises ValueError: if the type is not an integer or a float, or if it
+            is a numeric value less than zero
+        """
+        if value is _Default:
+            return cls.DEFAULT_TIMEOUT
+
+        if value is None or value is cls.DEFAULT_TIMEOUT:
+            return value
+
+        try:
+            float(value)
+        except (TypeError, ValueError):
+            raise ValueError("Timeout value %s was %s, but it must be an "
+                             "int or float." % (name, value))
+
+        try:
+            if value < 0:
+                raise ValueError("Attempted to set %s timeout to %s, but the "
+                                 "timeout cannot be set to a value less "
+                                 "than 0." % (name, value))
+        except TypeError: # Python 3
+            raise ValueError("Timeout value %s was %s, but it must be an "
+                             "int or float." % (name, value))
+
+        return value
+
+    @classmethod
+    def from_float(cls, timeout):
+        """ Create a new Timeout from a legacy timeout value.
+
+        The timeout value used by httplib.py sets the same timeout on the
+        connect(), and recv() socket requests. This creates a :class:`Timeout`
+        object that sets the individual timeouts to the ``timeout`` value passed
+        to this function.
+
+        :param timeout: The legacy timeout value
+        :type timeout: integer, float, sentinel default object, or None
+        :return: a Timeout object
+        :rtype: :class:`Timeout`
+        """
+        return Timeout(read=timeout, connect=timeout)
+
+    def clone(self):
+        """ Create a copy of the timeout object
+
+        Timeout properties are stored per-pool but each request needs a fresh
+        Timeout object to ensure each one has its own start/stop configured.
+
+        :return: a copy of the timeout object
+        :rtype: :class:`Timeout`
+        """
+        # We can't use copy.deepcopy because that will also create a new object
+        # for _GLOBAL_DEFAULT_TIMEOUT, which socket.py uses as a sentinel to
+        # detect the user default.
+        return Timeout(connect=self._connect, read=self._read,
+                       total=self.total)
+
+    def start_connect(self):
+        """ Start the timeout clock, used during a connect() attempt
+
+        :raises urllib3.exceptions.TimeoutStateError: if you attempt
+            to start a timer that has been started already.
+        """
+        if self._start_connect is not None:
+            raise TimeoutStateError("Timeout timer has already been started.")
+        self._start_connect = current_time()
+        return self._start_connect
+
+    def get_connect_duration(self):
+        """ Gets the time elapsed since the call to :meth:`start_connect`.
+
+        :return: the elapsed time
+        :rtype: float
+        :raises urllib3.exceptions.TimeoutStateError: if you attempt
+            to get duration for a timer that hasn't been started.
+        """
+        if self._start_connect is None:
+            raise TimeoutStateError("Can't get connect duration for timer "
+                                    "that has not started.")
+        return current_time() - self._start_connect
+
+    @property
+    def connect_timeout(self):
+        """ Get the value to use when setting a connection timeout.
+
+        This will be a positive float or integer, the value None
+        (never timeout), or the default system timeout.
+
+        :return: the connect timeout
+        :rtype: int, float, :attr:`Timeout.DEFAULT_TIMEOUT` or None
+        """
+        if self.total is None:
+            return self._connect
+
+        if self._connect is None or self._connect is self.DEFAULT_TIMEOUT:
+            return self.total
+
+        return min(self._connect, self.total)
+
+    @property
+    def read_timeout(self):
+        """ Get the value for the read timeout.
+
+        This assumes some time has elapsed in the connection timeout and
+        computes the read timeout appropriately.
+
+        If self.total is set, the read timeout is dependent on the amount of
+        time taken by the connect timeout. If the connection time has not been
+        established, a :exc:`~urllib3.exceptions.TimeoutStateError` will be
+        raised.
+
+        :return: the value to use for the read timeout
+        :rtype: int, float, :attr:`Timeout.DEFAULT_TIMEOUT` or None
+        :raises urllib3.exceptions.TimeoutStateError: If :meth:`start_connect`
+            has not yet been called on this object.
+        """
+        if (self.total is not None and
+            self.total is not self.DEFAULT_TIMEOUT and
+            self._read is not None and
+            self._read is not self.DEFAULT_TIMEOUT):
+            # in case the connect timeout has not yet been established.
+            if self._start_connect is None:
+                return self._read
+            return max(0, min(self.total - self.get_connect_duration(),
+                              self._read))
+        elif self.total is not None and self.total is not self.DEFAULT_TIMEOUT:
+            return max(0, self.total - self.get_connect_duration())
+        else:
+            return self._read