:mod:`urllib.error` --- Exception classes raised by urllib.request
==================================================================

.. module:: urllib.error
   :synopsis: Next generation URL opening library.
.. moduleauthor:: Jeremy Hylton <jhylton@users.sourceforge.net>
.. sectionauthor:: Senthil Kumaran <orsenthil@gmail.com>


The :mod:`urllib.error` module defines exception classes raise by
urllib.request. The base exception class is URLError, which inherits from
IOError.

The following exceptions are raised by :mod:`urllib.error` as appropriate:


.. exception:: URLError

   The handlers raise this exception (or derived exceptions) when they run into a
   problem.  It is a subclass of :exc:`IOError`.

   .. attribute:: reason

      The reason for this error.  It can be a message string or another exception
      instance (:exc:`socket.error` for remote URLs, :exc:`OSError` for local
      URLs).


.. exception:: HTTPError

   Though being an exception (a subclass of :exc:`URLError`), an :exc:`HTTPError`
   can also function as a non-exceptional file-like return value (the same thing
   that :func:`urlopen` returns).  This is useful when handling exotic HTTP
   errors, such as requests for authentication.

   .. attribute:: code

      An HTTP status code as defined in `RFC 2616 <http://www.faqs.org/rfcs/rfc2616.html>`_. 
      This numeric value corresponds to a value found in the dictionary of
      codes as found in :attr:`http.server.BaseHTTPRequestHandler.responses`.

.. exception:: ContentTooShortError(msg[, content])

   This exception is raised when the :func:`urlretrieve` function detects that the
   amount of the downloaded data is less than the  expected amount (given by the
   *Content-Length* header). The :attr:`content` attribute stores the downloaded
   (and supposedly truncated) data.