mod_pubsub, mod_pep: Support per-node configurable inclusion of publisher

This matches ejabberd's behaviour, using the 'pubsub#itemreply' config option.

Although the current definition of this option in the specification is not
as clear as it could be, I think matching what existing deployments do is the
best option to resolve the ambiguity and reduce fragmentation.

We should update the spec to be clearer about how to use and interpret this
option.

The 'expose_publisher' option for mod_pubsub is now an override (always expose
or never expose). If unset, it will use the per-node config (which defaults to
not exposing).

Thanks to Link Mauve, edhelas and goffi for sparking this feature.

3 files changed, 36 insertions, 4 deletions

diff --git a/plugins/mod_pep.lua b/plugins/mod_pep.lua
index 71e45e7c..c7afde6f 100644
--- a/plugins/mod_pep.lua
+++ b/plugins/mod_pep.lua
@@ -136,10 +136,14 @@ end
 local function get_broadcaster(username)
 	local user_bare = jid_join(username, host);
 	local function simple_broadcast(kind, node, jids, item, _, node_obj)
+		local expose_publisher;
 		if node_obj then
 			if node_obj.config["notify_"..kind] == false then
 				return;
 			end
+			if node_obj.config.itemreply == "publisher" then
+				expose_publisher = true;
+			end
 		end
 		if kind == "retract" then
 			kind = "items"; -- XEP-0060 signals retraction in an <items> container
@@ -151,6 +155,9 @@ local function get_broadcaster(username)
 				if node_obj and node_obj.config.include_payload == false then
 					item:maptags(function () return nil; end);
 				end
+				if not expose_publisher then
+					item.attr.publisher = nil;
+				end
 			end
 		end
 
diff --git a/plugins/mod_pubsub/mod_pubsub.lua b/plugins/mod_pubsub/mod_pubsub.lua
index f51e8fe4..d66c31b7 100644
--- a/plugins/mod_pubsub/mod_pubsub.lua
+++ b/plugins/mod_pubsub/mod_pubsub.lua
@@ -12,7 +12,7 @@ local xmlns_pubsub_owner = "http://jabber.org/protocol/pubsub#owner";
 local autocreate_on_publish = module:get_option_boolean("autocreate_on_publish", false);
 local autocreate_on_subscribe = module:get_option_boolean("autocreate_on_subscribe", false);
 local pubsub_disco_name = module:get_option_string("name", "Prosody PubSub Service");
-local expose_publisher = module:get_option_boolean("expose_publisher", false)
+local service_expose_publisher = module:get_option_boolean("expose_publisher")
 
 local service;
 
@@ -81,7 +81,11 @@ function simple_broadcast(kind, node, jids, item, actor, node_obj, service) --lu
 			if node_obj and node_obj.config.include_payload == false then
 				item:maptags(function () return nil; end);
 			end
-			if not expose_publisher then
+			local node_expose_publisher = service_expose_publisher;
+			if node_expose_publisher == nil and node_obj and node_obj.config.itemreply == "publisher" then
+				node_expose_publisher = true;
+			end
+			if not node_expose_publisher then
 				item.attr.publisher = nil;
 			elseif not item.attr.publisher and actor ~= true then
 				item.attr.publisher = service.config.normalize_jid(actor);
@@ -192,7 +196,7 @@ function set_service(new_service)
 	service = new_service;
 	service.config.autocreate_on_publish = autocreate_on_publish;
 	service.config.autocreate_on_subscribe = autocreate_on_subscribe;
-	service.config.expose_publisher = expose_publisher;
+	service.config.expose_publisher = service_expose_publisher;
 
 	service.config.nodestore = node_store;
 	service.config.itemstore = create_simple_itemstore;
@@ -219,7 +223,7 @@ function module.load()
 	set_service(pubsub.new({
 		autocreate_on_publish = autocreate_on_publish;
 		autocreate_on_subscribe = autocreate_on_subscribe;
-		expose_publisher = expose_publisher;
+		expose_publisher = service_expose_publisher;
 
 		node_defaults = {
 			["persist_items"] = true;
diff --git a/plugins/mod_pubsub/pubsub.lib.lua b/plugins/mod_pubsub/pubsub.lib.lua
index cd3efb09..829e2b45 100644
--- a/plugins/mod_pubsub/pubsub.lib.lua
+++ b/plugins/mod_pubsub/pubsub.lib.lua
@@ -164,6 +164,17 @@ local node_config_form = dataform {
 		var = "pubsub#notify_retract";
 		value = true;
 	};
+	{
+		type = "list-single";
+		label = "Specify whose JID to include as the publisher of items";
+		name = "pubsub#itemreply";
+		var = "itemreply";
+		options = {
+			{ label = "Include the node owner's JID", value = "owner" };
+			{ label = "Include the item publisher's JID", value = "publisher" };
+			{ label = "Don't include any JID with items", value = "none", default = true };
+		};
+	};
 };
 _M.node_config_form = node_config_form;
 
@@ -347,6 +358,13 @@ function handlers.get_items(origin, stanza, items, service)
 		origin.send(pubsub_error_reply(stanza, "nodeid-required"));
 		return true;
 	end
+
+	local node_obj = service.nodes[node];
+	if not node_obj then
+		origin.send(pubsub_error_reply(stanza, "item-not-found"));
+		return true;
+	end
+
 	local resultspec; -- TODO rsm.get()
 	if items.attr.max_items then
 		resultspec = { max = tonumber(items.attr.max_items) };
@@ -358,6 +376,9 @@ function handlers.get_items(origin, stanza, items, service)
 	end
 
 	local expose_publisher = service.config.expose_publisher;
+	if expose_publisher == nil and node_obj.config.itemreply == "publisher" then
+		expose_publisher = true;
+	end
 
 	local data = st.stanza("items", { node = node });
 	local iter, v, i = ipairs(results);