1 files changed, 107 insertions, 0 deletions
diff --git a/src/leap/bitmask/mail/walk.py b/src/leap/bitmask/mail/walk.py
new file mode 100644
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+++ b/src/leap/bitmask/mail/walk.py
@@ -0,0 +1,107 @@
+# -*- coding: utf-8 -*-
+# walk.py
+# Copyright (C) 2013-2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Walk a message tree and generate documents that can be inserted in the backend
+store.
+"""
+from email.parser import Parser
+
+from cryptography.hazmat.backends.multibackend import MultiBackend
+from cryptography.hazmat.backends.openssl.backend import (
+    Backend as OpenSSLBackend)
+from cryptography.hazmat.primitives import hashes
+
+from leap.mail.utils import first
+
+crypto_backend = MultiBackend([OpenSSLBackend()])
+
+_parser = Parser()
+
+
+def get_tree(msg):
+    p = {}
+    p['ctype'] = msg.get_content_type()
+    p['headers'] = msg.items()
+
+    payload = msg.get_payload()
+    is_multi = msg.is_multipart()
+    if is_multi:
+        p['part_map'] = dict(
+            [(idx, get_tree(part)) for idx, part in enumerate(payload, 1)])
+        p['parts'] = len(payload)
+        p['phash'] = None
+    else:
+        p['parts'] = 0
+        p['size'] = len(payload)
+        p['phash'] = get_hash(payload)
+        p['part_map'] = {}
+    p['multi'] = is_multi
+    return p
+
+
+def get_tree_from_string(messagestr):
+    return get_tree(_parser.parsestr(messagestr))
+
+
+def get_body_phash(msg):
+    """
+    Find the body payload-hash for this message.
+    """
+    for part in msg.walk():
+        # XXX what other ctypes should be considered body?
+        if part.get_content_type() in ("text/plain", "text/html"):
+            # XXX avoid hashing again
+            return get_hash(part.get_payload())
+
+
+def get_raw_docs(msg):
+    """
+    We get also some of the headers to be able to
+    index the content. Here we remove any mutable part, as the the filename
+    in the content disposition.
+    """
+    return (
+        {'type': 'cnt',
+         'raw': part.get_payload(),
+         'phash': get_hash(part.get_payload()),
+         'content-type': part.get_content_type(),
+         'content-disposition': first(part.get(
+             'content-disposition', '').split(';')),
+         'content-transfer-encoding': part.get(
+             'content-transfer-encoding', '')
+         } for part in msg.walk() if not isinstance(part.get_payload(), list))
+
+
+def get_hash(s):
+    digest = hashes.Hash(hashes.SHA256(), crypto_backend)
+    digest.update(s)
+    return digest.finalize().encode("hex").upper()
+
+
+"""
+Groucho Marx: Now pay particular attention to this first clause, because it's
+              most important. There's the party of the first part shall be
+              known in this contract as the party of the first part. How do you
+              like that, that's pretty neat eh?
+
+Chico Marx: No, that's no good.
+Groucho Marx: What's the matter with it?
+
+Chico Marx: I don't know, let's hear it again.
+Groucho Marx: So the party of the first part shall be known in this contract as
+              the party of the first part.
+"""