Use proper timestamp instead of OS-dependent

ssb/feed/models.py

@@ -0,0 +1,125 @@
+import datetime
+from base64 import b64encode
+from collections import namedtuple, OrderedDict
+from hashlib import sha256
+
+from simplejson import dumps, loads
+
+from ssb.util import tag
+
+
+OrderedMsg = namedtuple('OrderedMsg', ('previous', 'author', 'sequence', 'timestamp', 'hash', 'content'))
+
+
+class NoPrivateKeyException(Exception):
+    pass
+
+
+def to_ordered(data):
+    smsg = OrderedMsg(**data)
+    return OrderedDict((k, getattr(smsg, k)) for k in smsg._fields)
+
+
+def get_millis_1970():
+    return int(datetime.datetime.utcnow().timestamp() * 1000)
+
+
+class Feed(object):
+    def __init__(self, public_key):
+        self.public_key = public_key
+
+    @property
+    def id(self):
+        return tag(self.public_key).decode('ascii')
+
+    def sign(self, msg):
+        raise NoPrivateKeyException('Cannot use remote identity to sign (no private key!)')
+
+
+class LocalFeed(Feed):
+    def __init__(self, private_key):
+        self.private_key = private_key
+
+    @property
+    def public_key(self):
+        return self.private_key.verify_key
+
+    def sign(self, msg):
+        return self.private_key.sign(msg).signature
+
+
+class Message(object):
+    def __init__(self, feed, content, signature, sequence=1, timestamp=None, previous=None):
+        self.feed = feed
+        self.content = content
+
+        if signature is None:
+            raise ValueError("signature can't be None")
+        self.signature = signature
+
+        self.previous = previous
+        if self.previous:
+            self.sequence = self.previous.sequence + 1
+        else:
+            self.sequence = sequence
+
+        self.timestamp = get_millis_1970() if timestamp is None else timestamp
+
+    @classmethod
+    def parse(cls, data, feed):
+        obj = loads(data, object_pairs_hook=OrderedDict)
+        msg = cls(feed, obj['content'], timestamp=obj['timestamp'])
+        return msg
+
+    def serialize(self, add_signature=True):
+        return dumps(self.to_dict(add_signature=add_signature), indent=2).encode('utf-8')
+
+    def to_dict(self, add_signature=True):
+        obj = to_ordered({
+            'previous': self.previous.key if self.previous else None,
+            'author': self.feed.id,
+            'sequence': self.sequence,
+            'timestamp': self.timestamp,
+            'hash': 'sha256',
+            'content': self.content
+        })
+
+        if add_signature:
+            obj['signature'] = self.signature
+        return obj
+
+    def verify(self, signature):
+        return self.signature == signature
+
+    @property
+    def hash(self):
+        hash = sha256(self.serialize()).digest()
+        return b64encode(hash).decode('ascii') + '.sha256'
+
+    @property
+    def key(self):
+        return '%' + self.hash
+
+
+class LocalMessage(Message):
+    def __init__(self, feed, content, signature=None, sequence=1, timestamp=None, previous=None):
+        self.feed = feed
+        self.content = content
+
+        self.previous = previous
+        if self.previous:
+            self.sequence = self.previous.sequence + 1
+        else:
+            self.sequence = sequence
+
+        self.timestamp = get_millis_1970() if timestamp is None else timestamp
+
+        if signature is None:
+            self.signature = self._sign()
+        else:
+            self.signature = signature
+
+    def _sign(self):
+        # ensure ordering of keys and indentation of 2 characters, like ssb-keys
+        data = self.serialize(add_signature=False)
+        return (b64encode(bytes(self.feed.sign(data))) + b'.sig.ed25519').decode('ascii')