Refine nickname handling and implement PARTED message type

README.md

@@ -86,8 +86,12 @@ Wire-level extensions (backwards-compatible):
     link. Clients should treat `K_NICK` as optional and fall back to `K_SRC`
     when it is missing.
 
-    Nickname policy (current implementation): trimmed Unicode string, UTF-8
-    encodable on the wire, maximum 32 characters.
+    Nicknames are advisory only; clients should treat them as display hints.
+    The hub may ignore, sanitize, replace, or omit them.
+
+    Current hub sanitation policy: store/emit only trimmed nicknames that are
+    UTF-8 encodable, contain no newlines/NUL, and are at most `nick_max_chars`
+    characters (default: 32).
 
 Configure trusted operators and banned identities in the TOML config:
 

rrcd/cli.py

@@ -121,6 +121,10 @@ room_invite_timeout_s = 900.0
 # Optional behaviors.
 include_joined_member_list = false
 
+# Nickname policy.
+# Maximum accepted nickname length (Unicode characters). 0 disables length limiting.
+nick_max_chars = 32
+
 # Limits.
 max_rooms_per_session = 32
 max_room_name_len = 64

rrcd/config.py

@@ -26,6 +26,12 @@ class HubRuntimeConfig:
     # Invite timeout for keyed rooms (+k). Invites are removed on join or expiry.
     room_invite_timeout_s: float = 900.0
     include_joined_member_list: bool = False
+
+    # Optional policy controls.
+    # Maximum accepted/stored nickname length (Unicode characters). 0 disables
+    # length limiting.
+    nick_max_chars: int = 32
+
     max_rooms_per_session: int = 32
     max_room_name_len: int = 64
     rate_limit_msgs_per_minute: int = 240

rrcd/constants.py

@@ -11,7 +11,6 @@ K_SRC = 4
 K_ROOM = 5
 K_BODY = 6
 K_NICK = 7
-NICK_MAX_CHARS = 32
 
 # Message types
 T_HELLO = 1
@@ -20,6 +19,7 @@ T_WELCOME = 2
 T_JOIN = 10
 T_JOINED = 11
 T_PART = 12
+T_PARTED = 13
 
 T_MSG = 20
 T_NOTICE = 21

rrcd/envelope.py

@@ -3,18 +3,7 @@ from __future__ import annotations
 import os
 import time
 
-from .constants import (
-    K_BODY,
-    K_ID,
-    K_NICK,
-    K_ROOM,
-    K_SRC,
-    K_T,
-    K_TS,
-    K_V,
-    NICK_MAX_CHARS,
-    RRC_VERSION,
-)
+from .constants import K_BODY, K_ID, K_NICK, K_ROOM, K_SRC, K_T, K_TS, K_V, RRC_VERSION
 from .util import normalize_nick
 
 
@@ -103,17 +92,5 @@ def validate_envelope(env: dict) -> None:
         nick = env[K_NICK]
         if not isinstance(nick, str):
             raise TypeError("nickname must be a string")
-        if nick.strip() == "":
-            raise ValueError("nickname must not be empty")
-
-        # Require normalized form on the wire.
-        if nick != nick.strip():
-            raise ValueError("nickname must not have leading/trailing whitespace")
-        if len(nick) > int(NICK_MAX_CHARS):
-            raise ValueError("nickname too long")
-        if "\n" in nick or "\r" in nick or "\x00" in nick:
-            raise ValueError("nickname contains control characters")
-        try:
-            nick.encode("utf-8", "strict")
-        except UnicodeError as e:
-            raise ValueError(f"nickname is not valid UTF-8: {e}") from e
+        # Per spec, nicknames are advisory and may be empty or "ridiculous".
+        # Type-check only; implementations may sanitize/ignore for display.

rrcd/service.py

@@ -29,6 +29,7 @@ from .constants import (
     T_MSG,
     T_NOTICE,
     T_PART,
+    T_PARTED,
     T_PING,
     T_PONG,
     T_WELCOME,
@@ -671,6 +672,7 @@ class HubService:
             f"banned={len(old_banned)}->{len(new_banned)} "
             f"registered_rooms={len(old_registry)}->{len(new_registry)}"
         )
+        lines.append(f"policy: nick_max_chars={new_cfg.nick_max_chars}")
 
         if cfg_changes:
             lines.append("config_changes:")
@@ -1209,7 +1211,8 @@ class HubService:
         lines.append(
             f"limits: rate_limit_msgs_per_minute={self.config.rate_limit_msgs_per_minute} "
             f"max_rooms_per_session={self.config.max_rooms_per_session} "
-            f"max_room_name_len={self.config.max_room_name_len}"
+            f"max_room_name_len={self.config.max_room_name_len} "
+            f"nick_max_chars={self.config.nick_max_chars}"
         )
         lines.append(
             f"features: ping_interval_s={self.config.ping_interval_s} "
@@ -2151,7 +2154,7 @@ class HubService:
 
             if isinstance(body, dict):
                 nick = body.get(B_HELLO_NICK)
-                n = normalize_nick(nick)
+                n = normalize_nick(nick, max_chars=self.config.nick_max_chars)
                 if n is not None:
                     sess["nick"] = n
 
@@ -2296,6 +2299,21 @@ class HubService:
                             self._persist_room_state_to_registry(link, r)
                     if st is not None and not st.get("registered"):
                         self._room_state.pop(r, None)
+
+            # Per spec: acknowledge PART with PARTED.
+            parted_body = None
+            if self.config.include_joined_member_list:
+                members: list[bytes] = []
+                for member_link in self.rooms.get(r, set()):
+                    s = self.sessions.get(member_link)
+                    ph = s.get("peer") if s else None
+                    if isinstance(ph, (bytes, bytearray)):
+                        members.append(bytes(ph))
+                parted_body = members
+
+            if self.identity is not None:
+                parted = make_envelope(T_PARTED, src=self.identity.hash, room=r, body=parted_body)
+                self._queue_env(outgoing, link, parted)
             return
 
         if t in (T_MSG, T_NOTICE):
@@ -2352,8 +2370,9 @@ class HubService:
             # Backwards-compatible extension: hub can attach the nickname learned
             # from HELLO so clients can render a human-friendly name.
             nick = sess.get("nick")
-            if isinstance(nick, str) and nick.strip():
-                env[K_NICK] = nick.strip()
+            n = normalize_nick(nick, max_chars=self.config.nick_max_chars)
+            if n is not None:
+                env[K_NICK] = n
             else:
                 # Prevent client-supplied spoofed nicknames.
                 env.pop(K_NICK, None)

rrcd/util.py

@@ -2,14 +2,14 @@ from __future__ import annotations
 
 import os
 
-from .constants import NICK_MAX_CHARS
+_DEFAULT_NICK_MAX_CHARS = 32
 
 
 def expand_path(p: str) -> str:
     return os.path.expanduser(os.path.expandvars(p))
 
 
-def normalize_nick(value) -> str | None:
+def normalize_nick(value, *, max_chars: int = _DEFAULT_NICK_MAX_CHARS) -> str | None:
     if not isinstance(value, str):
         return None
 
@@ -17,7 +17,12 @@ def normalize_nick(value) -> str | None:
     if not s:
         return None
 
-    if len(s) > int(NICK_MAX_CHARS):
+    try:
+        limit = int(max_chars)
+    except Exception:
+        limit = int(_DEFAULT_NICK_MAX_CHARS)
+
+    if limit > 0 and len(s) > limit:
         return None
 
     # Keep this conservative: avoid embedded newlines or NUL, which frequently

tests/test_envelope.py

@@ -26,18 +26,14 @@ def test_validate_accepts_optional_nick_extension() -> None:
     validate_envelope(env)
 
 
-def test_validate_rejects_nick_too_long() -> None:
+def test_validate_allows_ridiculous_or_empty_nick() -> None:
     env = make_envelope(T_HELLO, src=b"peer", body=None)
-    env[K_NICK] = "a" * 33
-    with pytest.raises(ValueError):
-        validate_envelope(env)
+    env[K_NICK] = ""
+    validate_envelope(env)
 
-
-def test_validate_rejects_nick_with_whitespace() -> None:
     env = make_envelope(T_HELLO, src=b"peer", body=None)
-    env[K_NICK] = " alice "
-    with pytest.raises(ValueError):
-        validate_envelope(env)
+    env[K_NICK] = "   "
+    validate_envelope(env)
 
 
 def test_validate_rejects_missing_required_key() -> None: