1 files changed, 80 insertions, 17 deletions

diff --git a/rest_framework/exceptions.py b/rest_framework/exceptions.py
index 06b5e8a2..906de3b0 100644
--- a/rest_framework/exceptions.py
+++ b/rest_framework/exceptions.py
@@ -5,80 +5,143 @@ In addition Django's built in 403 and 404 exceptions are handled.
 (`django.http.Http404` and `django.core.exceptions.PermissionDenied`)
 """
 from __future__ import unicode_literals
+
+from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import ungettext_lazy
 from rest_framework import status
+from rest_framework.compat import force_text
 import math
 
 
+def _force_text_recursive(data):
+    """
+    Descend into a nested data structure, forcing any
+    lazy translation strings into plain text.
+    """
+    if isinstance(data, list):
+        return [
+            _force_text_recursive(item) for item in data
+        ]
+    elif isinstance(data, dict):
+        return dict([
+            (key, _force_text_recursive(value))
+            for key, value in data.items()
+        ])
+    return force_text(data)
+
+
 class APIException(Exception):
     """
     Base class for REST framework exceptions.
     Subclasses should provide `.status_code` and `.default_detail` properties.
     """
     status_code = status.HTTP_500_INTERNAL_SERVER_ERROR
-    default_detail = 'A server error occured'
+    default_detail = _('A server error occured')
 
     def __init__(self, detail=None):
-        self.detail = detail or self.default_detail
+        if detail is not None:
+            self.detail = force_text(detail)
+        else:
+            self.detail = force_text(self.default_detail)
 
     def __str__(self):
         return self.detail
 
 
+# The recommended style for using `ValidationError` is to keep it namespaced
+# under `serializers`, in order to minimize potential confusion with Django's
+# built in `ValidationError`. For example:
+#
+# from rest_framework import serializers
+# raise serializers.ValidationError('Value was invalid')
+
+class ValidationError(APIException):
+    status_code = status.HTTP_400_BAD_REQUEST
+
+    def __init__(self, detail):
+        # For validation errors the 'detail' key is always required.
+        # The details should always be coerced to a list if not already.
+        if not isinstance(detail, dict) and not isinstance(detail, list):
+            detail = [detail]
+        self.detail = _force_text_recursive(detail)
+
+    def __str__(self):
+        return str(self.detail)
+
+
 class ParseError(APIException):
     status_code = status.HTTP_400_BAD_REQUEST
-    default_detail = 'Malformed request.'
+    default_detail = _('Malformed request.')
 
 
 class AuthenticationFailed(APIException):
     status_code = status.HTTP_401_UNAUTHORIZED
-    default_detail = 'Incorrect authentication credentials.'
+    default_detail = _('Incorrect authentication credentials.')
 
 
 class NotAuthenticated(APIException):
     status_code = status.HTTP_401_UNAUTHORIZED
-    default_detail = 'Authentication credentials were not provided.'
+    default_detail = _('Authentication credentials were not provided.')
 
 
 class PermissionDenied(APIException):
     status_code = status.HTTP_403_FORBIDDEN
-    default_detail = 'You do not have permission to perform this action.'
+    default_detail = _('You do not have permission to perform this action.')
 
 
 class MethodNotAllowed(APIException):
     status_code = status.HTTP_405_METHOD_NOT_ALLOWED
-    default_detail = "Method '%s' not allowed."
+    default_detail = _("Method '%s' not allowed.")
 
     def __init__(self, method, detail=None):
-        self.detail = (detail or self.default_detail) % method
+        if detail is not None:
+            self.detail = force_text(detail)
+        else:
+            self.detail = force_text(self.default_detail) % method
 
 
 class NotAcceptable(APIException):
     status_code = status.HTTP_406_NOT_ACCEPTABLE
-    default_detail = "Could not satisfy the request Accept header"
+    default_detail = _('Could not satisfy the request Accept header')
 
     def __init__(self, detail=None, available_renderers=None):
-        self.detail = detail or self.default_detail
+        if detail is not None:
+            self.detail = force_text(detail)
+        else:
+            self.detail = force_text(self.default_detail)
         self.available_renderers = available_renderers
 
 
 class UnsupportedMediaType(APIException):
     status_code = status.HTTP_415_UNSUPPORTED_MEDIA_TYPE
-    default_detail = "Unsupported media type '%s' in request."
+    default_detail = _("Unsupported media type '%s' in request.")
 
     def __init__(self, media_type, detail=None):
-        self.detail = (detail or self.default_detail) % media_type
+        if detail is not None:
+            self.detail = force_text(detail)
+        else:
+            self.detail = force_text(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."
+    default_detail = _('Request was throttled.')
+    extra_detail = ungettext_lazy(
+        'Expected available in %(wait)d second.',
+        'Expected available in %(wait)d seconds.',
+        'wait'
+    )
 
     def __init__(self, wait=None, detail=None):
+        if detail is not None:
+            self.detail = force_text(detail)
+        else:
+            self.detail = force_text(self.default_detail)
+
         if wait is None:
-            self.detail = detail or self.default_detail
             self.wait = None
         else:
-            format = (detail or self.default_detail) + self.extra_detail
-            self.detail = format % (wait, wait != 1 and 's' or '')
             self.wait = math.ceil(wait)
+            self.detail += ' ' + force_text(
+                self.extra_detail % {'wait': self.wait}
+            )