add compute_id method to event class

Author: jeffthibault

nostr/event.py

@@ -25,7 +25,7 @@ def __init__(
         if not isinstance(content, str):
             raise TypeError("Argument 'content' must be of type str")
 
-        self.id = id if id != None else sha256(Event.serialize(public_key, created_at, kind, tags, content)).hexdigest()
+        self.id = id if not id is None else Event.compute_id(public_key, created_at, kind, tags, content)
         self.public_key = public_key
         self.content = content
         self.created_at = created_at
@@ -39,14 +39,19 @@ def serialize(public_key: str, created_at: int, kind: int, tags: "list[list[str]
         data_str = json.dumps(data, separators=(',', ':'))
         return data_str.encode()
 
-    def sign(self, sk: str) -> None:
-        private_key = PrivateKey(bytes.fromhex(sk))
-        sig = private_key.schnorr_sign(bytes.fromhex(self.id), None, raw=True)
+    @staticmethod
+    def compute_id(public_key: str, created_at: int, kind: int, tags: "list[list[str]]", content: str) -> str:
+        return sha256(Event.serialize(public_key, created_at, kind, tags, content)).hexdigest()
+
+    def sign(self, private_key_hex: str) -> None:
+        sk = PrivateKey(bytes.fromhex(private_key_hex))
+        sig = sk.schnorr_sign(bytes.fromhex(self.id), None, raw=True)
         self.signature = sig.hex()
 
     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)
+        event_id = Event.compute_id(self.public_key, self.created_at, self.kind, self.tags, self.content)
+        return pub_key.schnorr_verify(event_id, bytes.fromhex(self.signature), None, raw=True)
 
     def to_json_object(self) -> dict:
         return {