Use cache for authentication backends

The commit introduces the following API incompatibilities:

In ejabberd_auth.erl:
* dirty_get_registered_users/0 is renamed to get_users/0
* get_vh_registered_users/1 is renamed to get_users/1
* get_vh_registered_users/2 is renamed to get_users/2
* get_vh_registered_users_number/1 is renamed to count_users/1
* get_vh_registered_users_number/2 is renamed to count_users/2

In ejabberd_auth callbacks
* plain_password_required/0 is replaced by plain_password_required/1
  where the argument is a virtual host
* store_type/0 is replaced by store_type/1 where the argument is
  a virtual host
* set_password/3 is now an optional callback
* remove_user/3 callback is no longer needed
* remove_user/2 now should return `ok | {error, atom()}`
* is_user_exists/2 now must only be implemented for backends
  with `external` store type
* check_password/6 is no longer needed
* check_password/4 now must only be implemented for backends
  with `external` store type
* try_register/3 is now an optional callback and should return
  `ok | {error, atom()}`
* dirty_get_registered_users/0 is no longer needed
* get_vh_registered_users/1 is no longer needed
* get_vh_registered_users/2 is renamed to get_users/2
* get_vh_registered_users_number/1 is no longer needed
* get_vh_registered_users_number/2 is renamed to count_users/2
* get_password_s/2 is no longer needed
* get_password/2 now must only be implemented for backends with
  `plain` or `scram` store type

Additionally, the commit introduces two new callbacks:
* use_cache/1 where the argument is a virtual host
* cache_nodes/1 where the argument is a virtual host

New options are also introduced: `auth_use_cache`, `auth_cache_missed`,
`auth_cache_life_time` and `auth_cache_size`.

1 files changed, 12 insertions, 74 deletions

diff --git a/src/ejabberd_auth_anonymous.erl b/src/ejabberd_auth_anonymous.erl
index 5bb2daed7..b3ae1f6dd 100644
--- a/src/ejabberd_auth_anonymous.erl
+++ b/src/ejabberd_auth_anonymous.erl
@@ -40,15 +40,9 @@
 	 unregister_connection/3
 	]).
 
--export([login/2, set_password/3, check_password/4,
-	 check_password/6, try_register/3,
-	 dirty_get_registered_users/0, get_vh_registered_users/1,
-	 get_vh_registered_users/2,
-	 get_vh_registered_users_number/1,
-	 get_vh_registered_users_number/2, get_password_s/2,
-	 get_password/2, get_password/3, is_user_exists/2,
-	 remove_user/2, remove_user/3, store_type/0,
-	 plain_password_required/0, opt_type/1]).
+-export([login/2, check_password/4, is_user_exists/2,
+	 get_users/2, count_users/2, store_type/1,
+	 plain_password_required/1, opt_type/1]).
 
 -include("ejabberd.hrl").
 -include("logger.hrl").
@@ -139,15 +133,7 @@ unregister_connection(_SID,
 %% ---------------------------------
 %% Specific anonymous auth functions
 %% ---------------------------------
-
-%% When anonymous login is enabled, check the password for permenant users
-%% before allowing access
-check_password(User, AuthzId, Server, Password) ->
-    check_password(User, AuthzId, Server, Password, undefined,
-		   undefined).
-
-check_password(User, _AuthzId, Server, _Password, _Digest,
-	       _DigestGen) ->
+check_password(User, _AuthzId, Server, _Password) ->
     case
       ejabberd_auth:is_user_exists_in_other_modules(?MODULE,
 						    User, Server)
@@ -173,68 +159,20 @@ login(User, Server) ->
 	  end
     end.
 
-%% When anonymous login is enabled, check that the user is permanent before
-%% changing its password
-set_password(User, Server, _Password) ->
-    case anonymous_user_exist(User, Server) of
-      true -> ok;
-      false -> {error, not_allowed}
-    end.
-
-%% When anonymous login is enabled, check if permanent users are allowed on
-%% the server:
-try_register(_User, _Server, _Password) ->
-    {error, not_allowed}.
-
-dirty_get_registered_users() -> [].
-
-get_vh_registered_users(Server) ->
-    [{U, S}
-     || {U, S, _R}
-	    <- ejabberd_sm:get_vh_session_list(Server)].
-
-get_vh_registered_users(Server, _) ->
-    get_vh_registered_users(Server).
-
-get_vh_registered_users_number(Server) ->
-    length(get_vh_registered_users(Server)).
+get_users(Server, _) ->
+    [{U, S} || {U, S, _R} <- ejabberd_sm:get_vh_session_list(Server)].
 
-get_vh_registered_users_number(Server, _) ->
-    get_vh_registered_users_number(Server).
-
-%% Return password of permanent user or false for anonymous users
-get_password(User, Server) ->
-    get_password(User, Server, <<"">>).
-
-get_password(User, Server, DefaultValue) ->
-    case anonymous_user_exist(User, Server) or
-	   login(User, Server)
-	of
-      %% We return the default value if the user is anonymous
-      true -> DefaultValue;
-      %% We return the permanent user password otherwise
-      false -> false
-    end.
-
-get_password_s(User, Server) ->
-    case get_password(User, Server) of
-        false ->
-            <<"">>;
-        Password ->
-            Password
-    end.
+count_users(Server, Opts) ->
+    length(get_users(Server, Opts)).
 
 is_user_exists(User, Server) ->
     anonymous_user_exist(User, Server).
 
-remove_user(_User, _Server) -> {error, not_allowed}.
-
-remove_user(_User, _Server, _Password) -> not_allowed.
-
-plain_password_required() -> false.
+plain_password_required(_) ->
+    false.
 
-store_type() ->
-	plain.
+store_type(_) ->
+    external.
 
 -spec opt_type(allow_multiple_connection) -> fun((boolean()) -> boolean());
 	      (anonymous_protocol) -> fun((sasl_anon | login_anon | both) ->