Lib/urllib/error.py

   1 """Exception classes raised by urllib.
   2
   3 The base exception class is URLError, which inherits from IOError.  It
   4 doesn't define any behavior of its own, but is the base class for all
   5 exceptions defined in this package.
   6
   7 HTTPError is an exception class that is also a valid HTTP response
   8 instance.  It behaves this way because HTTP protocol errors are valid
   9 responses, with a status code, headers, and a body.  In some contexts,
  10 an application may want to handle an exception like a regular
  11 response.
  12 """
  13
  14 import urllib.response
  15
  16 # do these error classes make sense?
  17 # make sure all of the IOError stuff is overridden.  we just want to be
  18 # subtypes.
  19
  20 class URLError(IOError):
  21     # URLError is a sub-type of IOError, but it doesn't share any of
  22     # the implementation.  need to override __init__ and __str__.
  23     # It sets self.args for compatibility with other EnvironmentError
  24     # subclasses, but args doesn't have the typical format with errno in
  25     # slot 0 and strerror in slot 1.  This may be better than nothing.
  26     def __init__(self, reason, filename=None):
  27         self.args = reason,
  28         self.reason = reason
  29         if filename is not None:
  30             self.filename = filename
  31
  32     def __str__(self):
  33         return '<urlopen error %s>' % self.reason
  34
  35 class HTTPError(URLError, urllib.response.addinfourl):
  36     """Raised when HTTP error occurs, but also acts like non-error return"""
  37     __super_init = urllib.response.addinfourl.__init__
  38
  39     def __init__(self, url, code, msg, hdrs, fp):
  40         self.code = code
  41         self.msg = msg
  42         self.hdrs = hdrs
  43         self.fp = fp
  44         self.filename = url
  45         # The addinfourl classes depend on fp being a valid file
  46         # object.  In some cases, the HTTPError may not have a valid
  47         # file object.  If this happens, the simplest workaround is to
  48         # not initialize the base classes.
  49         if fp is not None:
  50             self.__super_init(fp, hdrs, url, code)
  51
  52     def __str__(self):
  53         return 'HTTP Error %s: %s' % (self.code, self.msg)
  54
  55 # exception raised when downloaded size does not match content-length
  56 class ContentTooShortError(URLError):
  57     def __init__(self, message, content):
  58         URLError.__init__(self, message)
  59         self.content = content