Make fetching a remote public key easier

little_boxes/activitypub.py

@@ -10,6 +10,7 @@ from typing import Optional
 from typing import Type
 from typing import Union
 
+from .key import Key
 from .backend import Backend
 from .errors import ActivityGoneError
 from .errors import ActivityNotFoundError
@@ -553,6 +554,9 @@ class Person(BaseActivity):
     OBJECT_REQUIRED = False
     ACTOR_REQUIRED = False
 
+    def get_key(self) -> Key:
+        return Key.from_dict(self.publicKey)
+
 
 class Service(Person):
     ACTIVITY_TYPE = ActivityType.SERVICE

little_boxes/key.py

@@ -10,12 +10,13 @@ from Crypto.Util import number
 class Key(object):
     DEFAULT_KEY_SIZE = 2048
 
-    def __init__(self, owner: str) -> None:
+    def __init__(self, owner: str, id_: Optional[str] = None) -> None:
         self.owner = owner
         self.privkey_pem: Optional[str] = None
         self.pubkey_pem: Optional[str] = None
         self.privkey: Optional[Any] = None
         self.pubkey: Optional[Any] = None
+        self.id_ = id_
 
     def load_pub(self, pubkey_pem: str) -> None:
         self.pubkey_pem = pubkey_pem
@@ -42,6 +43,15 @@ class Key(object):
             "publicKeyPem": self.pubkey_pem,
         }
 
+    @classmethod
+    def from_dict(cls, data):
+        try:
+            k = cls(data["owner"], data["id"])
+            k.load_pub(data["publicKeyPem"])
+        except KeyError:
+            raise ValueError(f"bad key data {data!r}")
+        return k
+
     def to_magic_key(self) -> str:
         mod = base64.urlsafe_b64encode(
             number.long_to_bytes(self.privkey.n)  # type: ignore