1 files changed, 55 insertions, 25 deletions

diff --git a/rest_framework/authentication.py b/rest_framework/authentication.py
index 30c78ebc..fc169189 100644
--- a/rest_framework/authentication.py
+++ b/rest_framework/authentication.py
@@ -21,32 +21,46 @@ class BaseAuthentication(object):
         """
         raise NotImplementedError(".authenticate() must be overridden.")
 
+    def authenticate_header(self, request):
+        """
+        Return a string to be used as the value of the `WWW-Authenticate`
+        header in a `401 Unauthenticated` response, or `None` if the
+        authentication scheme should return `403 Permission Denied` responses.
+        """
+        pass
+
 
 class BasicAuthentication(BaseAuthentication):
     """
     HTTP Basic authentication against username/password.
     """
+    www_authenticate_realm = 'api'
 
     def authenticate(self, request):
         """
         Returns a `User` if a correct username and password have been supplied
         using HTTP Basic authentication.  Otherwise returns `None`.
         """
-        if 'HTTP_AUTHORIZATION' in request.META:
-            auth = request.META['HTTP_AUTHORIZATION'].split()
-            if len(auth) == 2 and auth[0].lower() == "basic":
-                try:
-                    auth_parts = base64.b64decode(auth[1]).partition(':')
-                except TypeError:
-                    return None
-
-                try:
-                    userid = smart_unicode(auth_parts[0])
-                    password = smart_unicode(auth_parts[2])
-                except DjangoUnicodeDecodeError:
-                    return None
-
-                return self.authenticate_credentials(userid, password)
+        auth = request.META.get('HTTP_AUTHORIZATION', '').split()
+
+        if not auth or auth[0].lower() != "basic":
+            return None
+
+        if len(auth) != 2:
+            raise exceptions.AuthenticationFailed('Invalid basic header')
+
+        try:
+            auth_parts = base64.b64decode(auth[1]).partition(':')
+        except TypeError:
+            raise exceptions.AuthenticationFailed('Invalid basic header')
+
+        try:
+            userid = smart_unicode(auth_parts[0])
+            password = smart_unicode(auth_parts[2])
+        except DjangoUnicodeDecodeError:
+            raise exceptions.AuthenticationFailed('Invalid basic header')
+
+        return self.authenticate_credentials(userid, password)
 
     def authenticate_credentials(self, userid, password):
         """
@@ -55,6 +69,10 @@ class BasicAuthentication(BaseAuthentication):
         user = authenticate(username=userid, password=password)
         if user is not None and user.is_active:
             return (user, None)
+        raise exceptions.AuthenticationFailed('Invalid username/password')
+
+    def authenticate_header(self, request):
+        return 'Basic realm="%s"' % self.www_authenticate_realm
 
 
 class SessionAuthentication(BaseAuthentication):
@@ -74,7 +92,7 @@ class SessionAuthentication(BaseAuthentication):
 
         # Unauthenticated, CSRF validation not required
         if not user or not user.is_active:
-            return
+            return None
 
         # Enforce CSRF validation for session based authentication.
         class CSRFCheck(CsrfViewMiddleware):
@@ -85,7 +103,7 @@ class SessionAuthentication(BaseAuthentication):
         reason = CSRFCheck().process_view(http_request, None, (), {})
         if reason:
             # CSRF failed, bail with explicit error message
-            raise exceptions.PermissionDenied('CSRF Failed: %s' % reason)
+            raise exceptions.AuthenticationFailed('CSRF Failed: %s' % reason)
 
         # CSRF passed with authenticated user
         return (user, None)
@@ -112,14 +130,26 @@ class TokenAuthentication(BaseAuthentication):
     def authenticate(self, request):
         auth = request.META.get('HTTP_AUTHORIZATION', '').split()
 
-        if len(auth) == 2 and auth[0].lower() == "token":
-            key = auth[1]
-            try:
-                token = self.model.objects.get(key=key)
-            except self.model.DoesNotExist:
-                return None
+        if not auth or auth[0].lower() != "token":
+            return None
+
+        if len(auth) != 2:
+            raise exceptions.AuthenticationFailed('Invalid token header')
+
+        return self.authenticate_credentials(auth[1])
+
+    def authenticate_credentials(self, key):
+        try:
+            token = self.model.objects.get(key=key)
+        except self.model.DoesNotExist:
+            raise exceptions.AuthenticationFailed('Invalid token')
+
+        if token.user.is_active:
+            return (token.user, token)
+        raise exceptions.AuthenticationFailed('User inactive or deleted')
+
+    def authenticate_header(self, request):
+        return 'Token'
 
-            if token.user.is_active:
-                return (token.user, token)
 
 # TODO: OAuthAuthentication