Move activitypub serialization into a module

fedireads/activitypub/create.py

@@ -0,0 +1,33 @@
+''' format Create activities and sign them '''
+from base64 import b64encode
+from Crypto.PublicKey import RSA
+from Crypto.Signature import pkcs1_15
+from Crypto.Hash import SHA256
+
+def get_create(user, status_json):
+    ''' create activitypub json for a Create activity '''
+    signer = pkcs1_15.new(RSA.import_key(user.private_key))
+    content = status_json['content']
+    signed_message = signer.sign(SHA256.new(content.encode('utf8')))
+    return {
+        '@context': 'https://www.w3.org/ns/activitystreams',
+
+        'id': '%s/activity' % status_json['id'],
+        'type': 'Create',
+        'actor': user.actor,
+        'published': status_json['published'],
+
+        'to': ['%s/followers' % user.actor],
+        'cc': ['https://www.w3.org/ns/activitystreams#Public'],
+
+        'object': status_json,
+        'signature': {
+            'type': 'RsaSignature2017',
+            'creator': '%s#main-key' % user.absolute_id,
+            'created': status_json['published'],
+            'signatureValue': b64encode(signed_message).decode('utf8'),
+        }
+    }
+
+
+