from pyrs import schema
import six
from . import lib
from . import response
[docs]class Error(Exception):
"""
This is the base exception of this framework.
The response based on this exception will be a JSON data
"""
#: HTTP status code (default=500)
status = 500
#: HTTP Response headers, (default None processed as empty)
headers = None
#: Error code should be a string. If it's not specified the class fully
#: qualified name will be used
error = None
#: Description of error. Should give details about the error
#: In the message it will appearing as error_description
description = None
#: Reference for this error. You can pointing out a documentation which
#: gives more information about how could this error happen and how could
#: be possible to avoid
uri = None
#: None used as empty dict. Gives extra information about this error which
#: could be parsed by the consumer of API.
details = None
#: You can specify your schema class for validating your message
#: By default the application default error schema the `ErrorSchema` will
#: be used
schema = None
def __init__(self, *args, **details):
super(Error, self).__init__(*args)
if six.PY3:
self.traceback = lib.parse_traceback(self.__traceback__)
cause = self.__cause__ or self.__context__
else:
self.traceback = lib.get_traceback()
cause = None
self.cause = details.pop('cause', cause)
self.details = details
[docs] def get_status(self):
"""
This method gives back the status property by default which will be
threated as HTTP status code. You can override, then provide your own
status code based on the context.
"""
return self.status
[docs] def get_message(self, debug=False):
"""
Should give back a dictionary which will be threated the response body.
The message should be conform with the `ErrorSchema`.
"""
res = {
'error': self.error or lib.get_fqname(self)
}
if self.args:
res['message'] = self.args[0]
if self.description:
res['error_description'] = self.description
if self.uri:
res['error_uri'] = self.uri
details = self.get_details(debug)
if details:
res['details'] = details
return res
[docs] def get_details(self, debug=False):
"""
Gives back detailed information about the error and the context.
By default its an empty dictionary. The `debug` depends on the debug
parameter should give back traceback information and the positional
arguments of the exception.
As this is part of the message should conform with the `ErrorSchema`.
"""
details = {}
if self.details:
details = self.details.copy()
if debug:
details['traceback'] = self.traceback
details['args'] = self.args[1:]
return details
@classmethod
[docs] def wrap(cls, original):
"""
Wraps the exception gives back an `Error` instance. The created `Error`
instance `error` property will be updated by the fully qualified name
of the `original` exception.
You could use it for `Error` instances as well, though is not
recommended.
"""
ex = cls(*original.args, cause=original)
ex.error = lib.get_fqname(original)
return ex
[docs]class ClientError(Error):
"""
Generic Client Error. Normally the client errors have 4xx status codes.
"""
status = 400
[docs]class ValidationError(Error):
status = 500
error = 'validation_error'
[docs]class DetailsSchema(schema.Object):
"""
Details part of the error schema. Additional properties possible.
"""
traceback = schema.Array()
args = schema.Array()
class Attrs:
additional = True
[docs]class ErrorSchema(schema.Object):
"""
Describe how the error response should look like. Goal of this schema is
a minimalistic but usable error response.
"""
error = schema.String(required=True)
error_description = schema.String()
error_uri = schema.String()
message = schema.String()
details = DetailsSchema()
[docs] def dump(self, ex):
msg = ex.get_message(self['debug'])
return super(ErrorSchema, self).dump(msg)
[docs]class ErrorResponse(response.Response):
[docs] def setup(self):
if not isinstance(self.content, Error):
self.content = Error.wrap(self.content)
self.status = self.content.get_status()
self.headers = self.content.get_headers()
if self.content.schema:
self.processor = self.content.schema(debug=self.app['debug'])
else:
self.processor = ErrorSchema(debug=self.app['debug'])