nostrclient/nostr/event.py
2023-03-23 10:35:45 +02:00

127 lines
3.9 KiB
Python

import json
import time
from dataclasses import dataclass, field
from enum import IntEnum
from hashlib import sha256
from typing import List
from secp256k1 import PublicKey
from .message_type import ClientMessageType
class EventKind(IntEnum):
SET_METADATA = 0
TEXT_NOTE = 1
RECOMMEND_RELAY = 2
CONTACTS = 3
ENCRYPTED_DIRECT_MESSAGE = 4
DELETE = 5
@dataclass
class Event:
content: str = None
public_key: str = None
created_at: int = None
kind: int = EventKind.TEXT_NOTE
tags: List[List[str]] = field(
default_factory=list
) # Dataclasses require special handling when the default value is a mutable type
signature: str = None
def __post_init__(self):
if self.content is not None and not isinstance(self.content, str):
# DMs initialize content to None but all other kinds should pass in a str
raise TypeError("Argument 'content' must be of type str")
if self.created_at is None:
self.created_at = int(time.time())
@staticmethod
def serialize(
public_key: str, created_at: int, kind: int, tags: List[List[str]], content: str
) -> bytes:
data = [0, public_key, created_at, kind, tags, content]
data_str = json.dumps(data, separators=(",", ":"), ensure_ascii=False)
return data_str.encode()
@staticmethod
def compute_id(
public_key: str, created_at: int, kind: int, tags: List[List[str]], content: str
):
return sha256(
Event.serialize(public_key, created_at, kind, tags, content)
).hexdigest()
@property
def id(self) -> str:
# Always recompute the id to reflect the up-to-date state of the Event
return Event.compute_id(
self.public_key, self.created_at, self.kind, self.tags, self.content
)
def add_pubkey_ref(self, pubkey: str):
"""Adds a reference to a pubkey as a 'p' tag"""
self.tags.append(["p", pubkey])
def add_event_ref(self, event_id: str):
"""Adds a reference to an event_id as an 'e' tag"""
self.tags.append(["e", event_id])
def verify(self) -> bool:
pub_key = PublicKey(
bytes.fromhex("02" + self.public_key), True
) # add 02 for schnorr (bip340)
return pub_key.schnorr_verify(
bytes.fromhex(self.id), bytes.fromhex(self.signature), None, raw=True
)
def to_message(self) -> str:
return json.dumps(
[
ClientMessageType.EVENT,
{
"id": self.id,
"pubkey": self.public_key,
"created_at": self.created_at,
"kind": self.kind,
"tags": self.tags,
"content": self.content,
"sig": self.signature,
},
]
)
@dataclass
class EncryptedDirectMessage(Event):
recipient_pubkey: str = None
cleartext_content: str = None
reference_event_id: str = None
def __post_init__(self):
if self.content is not None:
self.cleartext_content = self.content
self.content = None
if self.recipient_pubkey is None:
raise Exception("Must specify a recipient_pubkey.")
self.kind = EventKind.ENCRYPTED_DIRECT_MESSAGE
super().__post_init__()
# Must specify the DM recipient's pubkey in a 'p' tag
self.add_pubkey_ref(self.recipient_pubkey)
# Optionally specify a reference event (DM) this is a reply to
if self.reference_event_id is not None:
self.add_event_ref(self.reference_event_id)
@property
def id(self) -> str:
if self.content is None:
raise Exception(
"EncryptedDirectMessage `id` is undefined until its message is encrypted and stored in the `content` field"
)
return super().id