Squashed 'core/' content from commit 4957443

git-subtree-dir: core
git-subtree-split: 4957443184ae0eb6323635a90a19acffb3e01d07

artdag/activitypub/actor.py

@@ -0,0 +1,206 @@
+# primitive/activitypub/actor.py
+"""
+ActivityPub Actor management.
+
+An Actor is an identity with:
+- Username and display name
+- RSA key pair for signing
+- ActivityPub-compliant JSON-LD representation
+"""
+
+import json
+import time
+from dataclasses import dataclass, field
+from pathlib import Path
+from typing import Any, Dict, Optional
+from cryptography.hazmat.primitives import hashes, serialization
+from cryptography.hazmat.primitives.asymmetric import rsa, padding
+
+DOMAIN = "artdag.rose-ash.com"
+
+
+def _generate_keypair() -> tuple[bytes, bytes]:
+    """Generate RSA key pair for signing."""
+    private_key = rsa.generate_private_key(
+        public_exponent=65537,
+        key_size=2048,
+    )
+    private_pem = private_key.private_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PrivateFormat.PKCS8,
+        encryption_algorithm=serialization.NoEncryption(),
+    )
+    public_pem = private_key.public_key().public_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PublicFormat.SubjectPublicKeyInfo,
+    )
+    return private_pem, public_pem
+
+
+@dataclass
+class Actor:
+    """
+    An ActivityPub Actor (identity).
+
+    Attributes:
+        username: Unique username (e.g., "giles")
+        display_name: Human-readable name
+        public_key: PEM-encoded public key
+        private_key: PEM-encoded private key (kept secret)
+        created_at: Timestamp of creation
+    """
+    username: str
+    display_name: str
+    public_key: bytes
+    private_key: bytes
+    created_at: float = field(default_factory=time.time)
+    domain: str = DOMAIN
+
+    @property
+    def id(self) -> str:
+        """ActivityPub actor ID (URL)."""
+        return f"https://{self.domain}/users/{self.username}"
+
+    @property
+    def handle(self) -> str:
+        """Fediverse handle."""
+        return f"@{self.username}@{self.domain}"
+
+    @property
+    def inbox(self) -> str:
+        """ActivityPub inbox URL."""
+        return f"{self.id}/inbox"
+
+    @property
+    def outbox(self) -> str:
+        """ActivityPub outbox URL."""
+        return f"{self.id}/outbox"
+
+    @property
+    def key_id(self) -> str:
+        """Key ID for HTTP Signatures."""
+        return f"{self.id}#main-key"
+
+    def to_activitypub(self) -> Dict[str, Any]:
+        """Return ActivityPub JSON-LD representation."""
+        return {
+            "@context": [
+                "https://www.w3.org/ns/activitystreams",
+                "https://w3id.org/security/v1",
+            ],
+            "type": "Person",
+            "id": self.id,
+            "preferredUsername": self.username,
+            "name": self.display_name,
+            "inbox": self.inbox,
+            "outbox": self.outbox,
+            "publicKey": {
+                "id": self.key_id,
+                "owner": self.id,
+                "publicKeyPem": self.public_key.decode("utf-8"),
+            },
+        }
+
+    def to_dict(self) -> Dict[str, Any]:
+        """Serialize for storage."""
+        return {
+            "username": self.username,
+            "display_name": self.display_name,
+            "public_key": self.public_key.decode("utf-8"),
+            "private_key": self.private_key.decode("utf-8"),
+            "created_at": self.created_at,
+            "domain": self.domain,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "Actor":
+        """Deserialize from storage."""
+        return cls(
+            username=data["username"],
+            display_name=data["display_name"],
+            public_key=data["public_key"].encode("utf-8"),
+            private_key=data["private_key"].encode("utf-8"),
+            created_at=data.get("created_at", time.time()),
+            domain=data.get("domain", DOMAIN),
+        )
+
+    @classmethod
+    def create(cls, username: str, display_name: str = None) -> "Actor":
+        """Create a new actor with generated keys."""
+        private_pem, public_pem = _generate_keypair()
+        return cls(
+            username=username,
+            display_name=display_name or username,
+            public_key=public_pem,
+            private_key=private_pem,
+        )
+
+
+class ActorStore:
+    """
+    Persistent storage for actors.
+
+    Structure:
+        store_dir/
+            actors.json       # Index of all actors
+            keys/
+                <username>.private.pem
+                <username>.public.pem
+    """
+
+    def __init__(self, store_dir: Path | str):
+        self.store_dir = Path(store_dir)
+        self.store_dir.mkdir(parents=True, exist_ok=True)
+        self._actors: Dict[str, Actor] = {}
+        self._load()
+
+    def _index_path(self) -> Path:
+        return self.store_dir / "actors.json"
+
+    def _load(self):
+        """Load actors from disk."""
+        index_path = self._index_path()
+        if index_path.exists():
+            with open(index_path) as f:
+                data = json.load(f)
+            self._actors = {
+                username: Actor.from_dict(actor_data)
+                for username, actor_data in data.get("actors", {}).items()
+            }
+
+    def _save(self):
+        """Save actors to disk."""
+        data = {
+            "version": "1.0",
+            "domain": DOMAIN,
+            "actors": {
+                username: actor.to_dict()
+                for username, actor in self._actors.items()
+            },
+        }
+        with open(self._index_path(), "w") as f:
+            json.dump(data, f, indent=2)
+
+    def create(self, username: str, display_name: str = None) -> Actor:
+        """Create and store a new actor."""
+        if username in self._actors:
+            raise ValueError(f"Actor {username} already exists")
+
+        actor = Actor.create(username, display_name)
+        self._actors[username] = actor
+        self._save()
+        return actor
+
+    def get(self, username: str) -> Optional[Actor]:
+        """Get an actor by username."""
+        return self._actors.get(username)
+
+    def list(self) -> list[Actor]:
+        """List all actors."""
+        return list(self._actors.values())
+
+    def __contains__(self, username: str) -> bool:
+        return username in self._actors
+
+    def __len__(self) -> int:
+        return len(self._actors)