Add the possibility to invite any external JID to a room

fix #3285

CHANGELOG.rst

@@ -13,6 +13,8 @@ Version 6.0
    being shutdown or the connection to the IRC server is cut unexpectedly.
  - Support for botan version 1.11.x has been dropped, only version 2.x is
    supported.
+ - Invitations can now be sent to any JID, not only JIDs served by the biboumi
+   instance itself.
 
 Version 5.0 - 2017-05-24
 ========================

doc/biboumi.1.rst

@@ -455,17 +455,22 @@ be replaced by a space, because the IRC server wouldn’t accept it.
 Invitations
 -----------
 
-Biboumi forwards the mediated invitations to the target nick.  If the user
-wishes to invite the user “FooBar” into a room, they can invite one of the
-following “JIDs” (one of them is not a JID, actually):
+If the invited JID is a user JID served by this biboumi instance, it will forward the
+invitation to the target nick, over IRC.
+Otherwise, the mediated instance will directly be sent to the invited JID, over XMPP.
 
-- foobar%anything@anything
-- anything@anything/FooBar
+Example: if the user wishes to invite the IRC user “FooBar” into a room, they can
+invite one of the following “JIDs” (one of them is not a JID, actually):
+
+- foobar%anything@biboumi.example.com
+- anything@biboumi.example.com/FooBar
 - FooBar
 
-Note that the “anything” part are simply ignored because they have no
-meaning for the IRC server: we already know which IRC server is targeted
-using the JID of the target channel.
+(Note that the “anything” parts are simply ignored because they carry no
+additional meaning for biboumi: we already know which IRC server is targeted
+using the JID of the target channel.)
+
+Otherwise, any valid JID can be used, to invite any XMPP user.
 
 Kicks and bans
 --------------

src/xmpp/biboumi_component.cpp

@@ -310,7 +310,11 @@ void BiboumiComponent::handle_message(const Stanza& stanza)
             const auto invite_to = invite->get_tag("to");
             if (!invite_to.empty())
               {
+                Jid invited_jid{invite_to};
+                if (invited_jid.domain == this->get_served_hostname() || invited_jid.local.empty())
                   bridge->send_irc_invitation(iid, invite_to);
+                else
+                  this->send_invitation_from_fulljid(std::to_string(iid), invite_to, from_str);
               }
           }
 
@@ -986,6 +990,16 @@ void BiboumiComponent::send_iq_room_list_result(const std::string& id, const std
 void BiboumiComponent::send_invitation(const std::string& room_target,
                                        const std::string& jid_to,
                                        const std::string& author_nick)
+{
+  if (author_nick.empty())
+    this->send_invitation_from_fulljid(room_target, jid_to, room_target + "@" + this->served_hostname);
+  else
+    this->send_invitation_from_fulljid(room_target, jid_to, room_target + "@" + this->served_hostname + "/" + author_nick);
+}
+
+void BiboumiComponent::send_invitation_from_fulljid(const std::string& room_target,
+                                       const std::string& jid_to,
+                                       const std::string& from)
 {
   Stanza message("message");
   {
@@ -994,10 +1008,7 @@ void BiboumiComponent::send_invitation(const std::string& room_target,
     XmlSubNode x(message, "x");
     x["xmlns"] = MUC_USER_NS;
     XmlSubNode invite(x, "invite");
-    if (author_nick.empty())
-      invite["from"] = room_target + "@" + this->served_hostname;
-    else
-      invite["from"] = room_target + "@" + this->served_hostname + "/" + author_nick;
+    invite["from"] = from;
   }
   this->send_stanza(message);
 }

src/xmpp/biboumi_component.hpp

@@ -87,6 +87,9 @@ public:
                                 const ChannelList& channel_list, std::vector<ListElement>::const_iterator begin,
                                 std::vector<ListElement>::const_iterator end, const ResultSetInfo& rs_info);
   void send_invitation(const std::string& room_target, const std::string& jid_to, const std::string& author_nick);
+private:
+  void send_invitation_from_fulljid(const std::string& room_target, const std::string& jid_to, const std::string& from);
+public:
   void accept_subscription(const std::string& from, const std::string& to);
   void ask_subscription(const std::string& from, const std::string& to);
   void send_presence_to_contact(const std::string& from, const std::string& to, const std::string& type, const std::string& id="");

tests/end_to_end/__main__.py

@@ -2406,6 +2406,9 @@ if __name__ == '__main__':
                      partial(send_stanza, "<message from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}'><x xmlns='http://jabber.org/protocol/muc#user'><invite to='{nick_two}'/></x></message>"),
                      partial(expect_stanza, "/message/body[text()='{nick_two} has been invited to #foo']"),
                      partial(expect_stanza, "/message[@to='{jid_two}/{resource_two}'][@from='#foo%{irc_server_one}']/muc_user:x/muc_user:invite[@from='#foo%{irc_server_one}/{nick_one}']"),
+
+                     partial(send_stanza, "<message from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}'><x xmlns='http://jabber.org/protocol/muc#user'><invite to='bertrand@example.com'/></x></message>"),
+                     partial(expect_stanza, "/message[@to='bertrand@example.com'][@from='#foo%{irc_server_one}']/muc_user:x/muc_user:invite[@from='{jid_one}/{resource_one}']"),
                 ]),
                 Scenario("virtual_channel_multisession",
                  [