1 files changed, 68 insertions, 0 deletions
diff --git a/u1db/remote/basic_auth_middleware.py b/u1db/remote/basic_auth_middleware.py
new file mode 100644
index 00000000..a2cbff62
--- /dev/null
+++ b/u1db/remote/basic_auth_middleware.py
@@ -0,0 +1,68 @@
+# Copyright 2012 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db.  If not, see <http://www.gnu.org/licenses/>.
+"""U1DB Basic Auth authorisation WSGI middleware."""
+import httplib
+try:
+    import simplejson as json
+except ImportError:
+    import json  # noqa
+from wsgiref.util import shift_path_info
+
+
+class Unauthorized(Exception):
+    """User authorization failed."""
+
+
+class BasicAuthMiddleware(object):
+    """U1DB Basic Auth Authorisation WSGI middleware."""
+
+    def __init__(self, app, prefix):
+        self.app = app
+        self.prefix = prefix
+
+    def _error(self, start_response, status, description, message=None):
+        start_response("%d %s" % (status, httplib.responses[status]),
+                       [('content-type', 'application/json')])
+        err = {"error": description}
+        if message:
+            err['message'] = message
+        return [json.dumps(err)]
+
+    def __call__(self, environ, start_response):
+        if self.prefix and not environ['PATH_INFO'].startswith(self.prefix):
+            return self._error(start_response, 400, "bad request")
+        auth = environ.get('HTTP_AUTHORIZATION')
+        if not auth:
+            return self._error(start_response, 401, "unauthorized",
+                               "Missing Basic Authentication.")
+        scheme, encoded = auth.split(None, 1)
+        if scheme.lower() != 'basic':
+            return self._error(
+                start_response, 401, "unauthorized",
+                "Missing Basic Authentication")
+        user, password = encoded.decode('base64').split(':', 1)
+        try:
+            self.verify_user(environ, user, password)
+        except Unauthorized:
+            return self._error(
+                start_response, 401, "unauthorized",
+                "Incorrect password or login.")
+        del environ['HTTP_AUTHORIZATION']
+        shift_path_info(environ)
+        return self.app(environ, start_response)
+
+    def verify_user(self, environ, username, password):
+        raise NotImplementedError(self.verify_user)