Gergely Polonkai
b30aa39d6b
It results in mostly the same style, plus it’s configurable via pyproject.toml.
129 lines
3.5 KiB
Python
129 lines
3.5 KiB
Python
import datetime
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from base64 import b64encode
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from collections import namedtuple, OrderedDict
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from hashlib import sha256
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from simplejson import dumps, loads
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from ssb.util import tag
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OrderedMsg = namedtuple("OrderedMsg", ("previous", "author", "sequence", "timestamp", "hash", "content"))
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class NoPrivateKeyException(Exception):
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pass
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def to_ordered(data):
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smsg = OrderedMsg(**data)
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return OrderedDict((k, getattr(smsg, k)) for k in smsg._fields)
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def get_millis_1970():
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return int(datetime.datetime.utcnow().timestamp() * 1000)
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class Feed(object):
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def __init__(self, public_key):
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self.public_key = public_key
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@property
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def id(self):
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return tag(self.public_key).decode("ascii")
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def sign(self, msg):
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raise NoPrivateKeyException("Cannot use remote identity to sign (no private key!)")
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class LocalFeed(Feed):
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def __init__(self, private_key):
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self.private_key = private_key
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@property
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def public_key(self):
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return self.private_key.verify_key
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def sign(self, msg):
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return self.private_key.sign(msg).signature
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class Message(object):
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def __init__(self, feed, content, signature, sequence=1, timestamp=None, previous=None):
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self.feed = feed
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self.content = content
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if signature is None:
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raise ValueError("signature can't be None")
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self.signature = signature
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self.previous = previous
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if self.previous:
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self.sequence = self.previous.sequence + 1
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else:
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self.sequence = sequence
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self.timestamp = get_millis_1970() if timestamp is None else timestamp
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@classmethod
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def parse(cls, data, feed):
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obj = loads(data, object_pairs_hook=OrderedDict)
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msg = cls(feed, obj["content"], timestamp=obj["timestamp"])
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return msg
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def serialize(self, add_signature=True):
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return dumps(self.to_dict(add_signature=add_signature), indent=2).encode("utf-8")
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def to_dict(self, add_signature=True):
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obj = to_ordered(
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{
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"previous": self.previous.key if self.previous else None,
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"author": self.feed.id,
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"sequence": self.sequence,
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"timestamp": self.timestamp,
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"hash": "sha256",
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"content": self.content,
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}
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)
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if add_signature:
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obj["signature"] = self.signature
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return obj
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def verify(self, signature):
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return self.signature == signature
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@property
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def hash(self):
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hash = sha256(self.serialize()).digest()
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return b64encode(hash).decode("ascii") + ".sha256"
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@property
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def key(self):
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return "%" + self.hash
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class LocalMessage(Message):
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def __init__(self, feed, content, signature=None, sequence=1, timestamp=None, previous=None):
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self.feed = feed
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self.content = content
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self.previous = previous
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if self.previous:
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self.sequence = self.previous.sequence + 1
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else:
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self.sequence = sequence
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self.timestamp = get_millis_1970() if timestamp is None else timestamp
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if signature is None:
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self.signature = self._sign()
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else:
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self.signature = signature
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def _sign(self):
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# ensure ordering of keys and indentation of 2 characters, like ssb-keys
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data = self.serialize(add_signature=False)
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return (b64encode(bytes(self.feed.sign(data))) + b".sig.ed25519").decode("ascii")
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