Merge branch 'local-signing' into 'master'

Make sure AP post requests are signed by a local user when forwarding.

See merge request jaywink/federation!172

CHANGELOG.md

@@ -55,6 +55,8 @@
 
 * Signatures are not verified and the corresponding payload is dropped if no public key is found.
 
+* Sign forwarded AP replies and shares with the target content author's private key. 
+
 ### Internal changes
 
 * Dropped python 3.6 support.

federation/outbound.py

@@ -132,7 +132,10 @@ def handle_send(
                      ]
     :arg parent_user: (Optional) User object of the parent object, if there is one. This must be given for the
                       Diaspora protocol if a parent object exists, so that a proper ``parent_author_signature`` can
-                      be generated. If given, the payload will be sent as this user.
+                      be generated. If given, the payload will be sent as this user. For Activitypub, the
+                      parent_user's private key will be used to generate the http signature if the author_user
+                      is not a local user.
+
     :arg payload_logger: (Optional) Function to log the payloads with.
     """
     payloads = []
@@ -221,8 +224,10 @@ def handle_send(
                     }
                 )
                 continue
+            # The parent_user MUST be local
+            local_user = author_user if author_user.rsa_private_key else parent_user
             payloads.append({
-                "auth": get_http_authentication(author_user.rsa_private_key, f"{author_user.id}#main-key"),
+                "auth": get_http_authentication(local_user.rsa_private_key, f"{local_user.id}#main-key"),
                 "headers": {
                     "Content-Type": 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"',
                 },

federation/utils/django.py

@@ -23,7 +23,7 @@ def get_configuration():
     }
     try:
         configuration.update(settings.FEDERATION)
-    except ImproperlyConfigured:
+    except (ModuleNotFoundError, ImproperlyConfigured):
         # Django is not properly configured, return defaults
         return configuration
     if not all([