Add salmon support (WIP)

[friends.git] / friends / salmoning / __init__.py

diff --git a/friends/salmoning/__init__.py b/friends/salmoning/__init__.py
new file mode 100644 (file)
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+++ b/friends/salmoning/__init__.py
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+#!/usr/bin/python2.4
+#
+# Copyright 2010 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""Support library for the Salmon Protocol.
+
+See Salmon I-D for specification.  This module
+implements a support library for Salmon on top of the
+Magic Envelope library and other bits.
+"""
+
+__author__ = 'jpanzer@google.com (John Panzer)'
+
+
+#import base64
+#import xml.dom.minidom as dom
+
+import magicsig
+
+
+class SalmonProtocol(object):
+  """Implementation of Salmon Protocol."""
+
+  magicenv = magicsig.MagicEnvelopeProtocol()
+
+  def _GetKeypair(self, signer_uri):
+    return self.key_retriever.LookupPublicKey(signer_uri)
+
+  def SignSalmon(self, text, mimetype, requestor_id):
+    """Signs a Salmon on behalfo the the current_user.
+
+    Input text must be in a recognized format so authorship can be
+    verified.
+
+    Args:
+      text: Text of message to be signed.
+      mimetype: The MIME type of the message to sign.
+      requestor_id: The id of the requestor (usually current logged in user).
+    Returns:
+      The Magic Envelope parameters from section 3.1 of the
+      Magic Signatures spec, as a dict.
+    """
+    
+    assert mimetype == 'application/atom+xml'
+
+    requestor_id = magicsig.NormalizeUserIdToUri(requestor_id)
+
+    if not self.magicenv.IsAllowedSigner(text, 
+        magicsig.NormalizeUserIdToUri(requestor_id)):
+        # TODO: Fix authorship if missing author, raise
+        # exception otherwise.
+        return
+
+    env = magicsig.Envelope(
+        self.magicenv,
+        raw_data_to_sign=text,
+        signer_uri=requestor_id,
+        signer_key=self._GetKeypair(requestor_id),
+        data_type='application/atom+xml',
+        encoding='base64url',
+        alg='RSA-SHA256')
+
+
+    return env.ToXML()
+
+  def ParseSalmon(self, text, mimetype):
+    """Parses a salmon from text with given mimetype.
+
+    Returns:
+      The salmon data as a dict, with fields:
+    """
+
+    self.magicenv.key_retriever = self.key_retriever
+
+    return magicsig.Envelope(
+       self.magicenv,
+       mime_type=mimetype,
+       document=text).ToAtom()