Admin sends a messagae on account creation

.gitignore

@@ -1,3 +1,4 @@
 **/__pycache__/*
 server/app/migrations
 server/database.sqlite
+*.pem

client/user_interface.py

@@ -95,9 +95,15 @@ class SubRosaUI:
 def main():
     from argparse import ArgumentParser
     parser = ArgumentParser()
-    parser.add_argument("username")
-    parser.add_argument("-k", "--key", default="subrosa_private_key.pem")
-    parser.add_argument("-s", "--server-url", default="http://127.0.0.1:5000")
+    parser.add_argument("username", help="Existing or new username.")
+    parser.add_argument("-k", "--key", 
+        default="subrosa_private_key.pem", 
+        help="Private key file. Will be created if it does not exist."
+    )
+    parser.add_argument("-s", "--server-url", 
+        default="http://subrosa.makingwithcode.org",
+        help='Server URL. Use "http://127.0.0.1:5000" for a local server.'
+    )
     args = parser.parse_args()
     ui = SubRosaUI(args.key, args.server_url)
     ui.run(args.username)

pyproject.toml

@@ -4,7 +4,6 @@ version = "0.1.0"
 description = ""
 authors = ["Chris Proctor <chris@chrisproctor.net>"]
 readme = "README.md"
-packages = [{include = "lab_subrosa"}]
 
 [tool.poetry.dependencies]
 python = "^3.10"
@@ -12,7 +11,6 @@ django-banjo = "^0.5.1"
 cryptography = "^42.0.7"
 requests = "^2.31.0"
 
-
 [build-system]
 requires = ["poetry-core"]
 build-backend = "poetry.core.masonry.api"

server/app/views.py

@@ -7,16 +7,32 @@ import sys
 sys.path.insert(0, "..")
 from encryption import PrivateKey, PublicKey
 
+def get_or_create_admin():
+    if not User.objects.filter(name='subrosa_admin').exists():
+        private_key = PrivateKey.generate()
+        public_key = private_key.get_public_key()
+        admin = User(name='subrosa_admin', public_key=str(public_key))
+        admin.save()
+    return User.objects.get(name='subrosa_admin')
+
 @route_post("users/new", args={'name': str, 'public_key': str})
 def create_user(params):
     "Creates a new user"
+    admin = get_or_create_admin()
     try:
-        PublicKey.load(params['public_key'])
+        public_key = PublicKey.load(params['public_key'])
     except (ValueError, FileNotFoundError):
         raise NotAllowed("Invalid public key")
     try:
         new_user = User.from_dict(params)
         new_user.save()
+        welcome = "Welcome to SubRosa! Please be a good community member."
+        message = Message(
+            sender=admin, 
+            recipient=new_user,
+            ciphertext=public_key.encrypt(welcome)
+        )
+        message.save()
         return new_user.to_dict()
     except:
         raise NotAllowed(f"Username {params['name']} is already in use.")