From eacf7addb2ebf33bb783e018d41a959785474279 Mon Sep 17 00:00:00 2001
From: damencho <damencho@jitsi.org>
Date: Fri, 11 Jul 2025 15:55:17 +0300
Subject: [PATCH] feat: Adds a room option to hide display name.

Options to hide it for non-moderators and for all.
---
 .../prosody-plugins/mod_muc_allowners.lua     |  2 +-
 .../prosody-plugins/mod_muc_displayname.lua   | 74 +++++++++++++++++++
 2 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 resources/prosody-plugins/mod_muc_displayname.lua

diff --git a/resources/prosody-plugins/mod_muc_allowners.lua b/resources/prosody-plugins/mod_muc_allowners.lua
index dbb4572ac5..03e35bd0a9 100644
--- a/resources/prosody-plugins/mod_muc_allowners.lua
+++ b/resources/prosody-plugins/mod_muc_allowners.lua
@@ -23,7 +23,7 @@ load_config();
 -- List of the bare_jids of all occupants that are currently joining (went through pre-join) and will be promoted
 -- as moderators. As pre-join (where added) and joined event (where removed) happen one after another this list should
 -- have length of 1
-local joining_moderator_participants = {};
+local joining_moderator_participants = module:shared('moderators/joining_moderator_participants');
 
 module:hook("muc-room-created", function(event)
     local room = event.room;
diff --git a/resources/prosody-plugins/mod_muc_displayname.lua b/resources/prosody-plugins/mod_muc_displayname.lua
new file mode 100644
index 0000000000..c15f6433d2
--- /dev/null
+++ b/resources/prosody-plugins/mod_muc_displayname.lua
@@ -0,0 +1,74 @@
+--- To be enabled under the main muc component
+local filters = require 'util.filters';
+local st = require 'util.stanza';
+
+local util = module:require 'util';
+local get_room_by_name_and_subdomain = util.get_room_by_name_and_subdomain;
+local is_admin = util.is_admin;
+local ends_with = util.ends_with;
+local internal_room_jid_match_rewrite = util.internal_room_jid_match_rewrite;
+
+local NICK_NS = 'http://jabber.org/protocol/nick';
+
+-- we need to get the shared resource for joining moderators, as participants are marked as moderators
+-- after joining which is after the filter for stanza/out, but we need to know will this participant be a moderator
+local joining_moderator_participants = module:shared('moderators/joining_moderator_participants');
+
+function filter_stanza_out(stanza, session)
+    if stanza.name ~= 'presence' or stanza.attr.type == 'error'
+        or stanza.attr.type == 'unavailable' or ends_with(stanza.attr.from, '/focus') then
+        return stanza;
+    end
+
+    local room = get_room_by_name_and_subdomain(session.jitsi_web_query_room, session.jitsi_web_query_prefix);
+
+    if not room or room._data.hideDisplayNameForGuests ~= true then
+        return stanza;
+    end
+
+    local occupant = room:get_occupant_by_real_jid(stanza.attr.to);
+    if occupant then
+        if stanza.attr.from == internal_room_jid_match_rewrite(occupant.nick) then
+            -- we ignore self-presences, in this case and role will not be correct
+            return stanza;
+        end
+
+        if occupant.role ~= 'moderator' and not joining_moderator_participants[occupant.bare_jid] then
+            local st_clone = st.clone(stanza);
+            st_clone:remove_children('nick', NICK_NS);
+            return st_clone;
+        end
+    end
+
+    return stanza;
+end
+
+function filter_stanza_in(stanza, session)
+    if stanza.name ~= 'presence' or stanza.attr.type == 'error' or stanza.attr.type == 'unavailable' then
+        return stanza;
+    end
+
+    local room = get_room_by_name_and_subdomain(session.jitsi_web_query_room, session.jitsi_web_query_prefix);
+
+    -- if hideDisplayNameForAll we want to drop any display name from the presence stanza
+    if not room or room._data.hideDisplayNameForAll ~= true then
+        return stanza;
+    end
+
+    stanza:remove_children('nick', NICK_NS);
+
+    return stanza;
+end
+
+function filter_session(session)
+    filters.add_filter(session, 'stanzas/out', filter_stanza_out, -100);
+    filters.add_filter(session, 'stanzas/in', filter_stanza_in, -100);
+end
+
+function module.load()
+    filters.add_filter_hook(filter_session);
+end
+
+function module.unload()
+    filters.remove_filter_hook(filter_session);
+end