# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1676824744 -3600
# Node ID e00dc913d9658000ac5524fbccb3039c859c5c1d
# Parent  272a8e54f0c817c586610fbfaaa7144b91efeecf
mod_unsubscriber: Revoke roster subscriptions of unreachable hosts

Wrote a version of this long ago, but it was lost to time. Here it is
again, from scratch!

diff -r 272a8e54f0c8 -r e00dc913d965 mod_unsubscriber/README.md
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_unsubscriber/README.md	Sun Feb 19 17:39:04 2023 +0100
@@ -0,0 +1,9 @@
+Over the years, some servers stop working for various reasons, and leave
+behind broken roster subscriptions that trigger failing s2s connections.
+This module allows cleaning up such cases by unsubscribing local users
+from their contacts on those servers. Also works for typos and the like.
+Use with care.
+
+```lua
+Component "gmail.com" "unsubscriber"
+```
diff -r 272a8e54f0c8 -r e00dc913d965 mod_unsubscriber/mod_unsubscriber.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_unsubscriber/mod_unsubscriber.lua	Sun Feb 19 17:39:04 2023 +0100
@@ -0,0 +1,23 @@
+assert(module:get_host_type() == "component", "This module should be loaded as a Component");
+
+local st = require "util.stanza";
+
+module:hook("presence/bare", function(event)
+	local origin, stanza = event.origin, event.stanza;
+	if stanza.attr.type == "probe" then
+		-- they are subscribed and want our current presence
+		-- tell them we denied their subscription
+		local reply = st.reply(stanza)
+		reply.attr.type = "unsubcribed";
+		origin.send(reply);
+		return true;
+	elseif stanza.attr.type == nil then
+		-- they think we are subscribed and sent their current presence
+		-- tell them we unsubscribe
+		local reply = st.reply(stanza)
+		reply.attr.type = "unsubcribe";
+		origin.send(reply);
+		return true;
+	end
+	-- fall trough to default error
+end);