from UserDict import UserDict
class Error(UserDict):
"""Universal error class.
An error is a dictionary-like object, containing a specific
user-readable error message and an object associated with it.
Since Error inherits UserDict, other informative values can be arbitrarily
attached to errors. For this reason, subclassing Error is rare.
Example:
err = Error(user, 'Invalid password.')
err['time'] = time.time()
err['attempts'] = attempts
The object and message can be accessed via methods:
print err.object()
print err.message()
When creating errors, you can pass None for both the object and the message.
You can also pass additional values, which are then included in the error:
>>> err = Error(None, 'Too bad.', timestamp=time.time())
>>> err.keys()
['timestamp']
Or include the values as a dictionary, instead of keyword arguments:
>>> info = {'timestamp': time.time()}
>>> err = Error(None, 'Too bad.', info)
Or you could even do both if you needed to.
"""
def __init__(self, object, message, valueDict={}, **valueArgs):
"""Initialize the error.
Takes the object the error occurred for, and the user-readable
error message. The message should be self sufficient such that
if printed by itself, the user would understand it.
"""
UserDict.__init__(self)
self._object = object
self._message = message
self.update(valueDict)
self.update(valueArgs)
def object(self):
return self._object
def message(self):
return self._message
def __repr__(self):
return 'ERROR(object=%s; message=%s; data=%s)' % (
repr(self._object), repr(self._message), repr(self.data))
def __str__(self):
return 'ERROR: %s' % self._message
def __nonzero__(self):
return 1
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