django-rest-framework/djangorestframework/exceptions.py

"""
Handled exceptions raised by REST framework.

In addition Django's built in 403 and 404 exceptions are handled.
(`django.http.Http404` and `django.core.exceptions.PermissionDenied`)
"""
from djangorestframework import status


class APIException(Exception):
    """
    Base class for REST framework exceptions.
    Subclasses should provide `.status_code` and `.detail` properties.
    """
    pass


class ParseError(APIException):
    status_code = status.HTTP_400_BAD_REQUEST
    default_detail = 'Malformed request.'

    def __init__(self, detail=None):
        self.detail = detail or self.default_detail


class PermissionDenied(APIException):
    status_code = status.HTTP_403_FORBIDDEN
    default_detail = 'You do not have permission to perform this action.'

    def __init__(self, detail=None):
        self.detail = detail or self.default_detail


class MethodNotAllowed(APIException):
    status_code = status.HTTP_405_METHOD_NOT_ALLOWED
    default_detail = "Method '%s' not allowed."

    def __init__(self, method, detail=None):
        self.detail = (detail or self.default_detail) % method


class UnsupportedMediaType(APIException):
    status_code = status.HTTP_415_UNSUPPORTED_MEDIA_TYPE
    default_detail = "Unsupported media type '%s' in request."

    def __init__(self, media_type, detail=None):
        self.detail = (detail or self.default_detail) % media_type


class Throttled(APIException):
    status_code = status.HTTP_429_TOO_MANY_REQUESTS
    default_detail = "Request was throttled."
    extra_detail = "Expected available in %d second%s."

    def __init__(self, wait=None, detail=None):
        import math
        self.wait = wait and math.ceil(wait) or None
        if wait is not None:
            format = detail or self.default_detail + self.extra_detail
            self.detail = format % (self.wait, self.wait != 1 and 's' or '')
        else:
            self.detail = detail or self.default_detail