Use the MP Moderators forum group to check for mod authority.

People who have MP mod authority for testing or other reasons can continue to use the existing user_is_moderator column check, but for people who are supposed to moderate the server, now the forum group will be used.

This will make it easier to add/remove people to/from the group, and also ensure that the list of actual moderators matches up with the list available to users.

New config attributes added for this are:
* db_group_table - should be, based on the phpbb documentation I found, phpbb_user_group
* mp_mod_group - should be set to Multiplayer Moderators group ID

Backport of 02ebcff06c

doc/man/wesnothd.6

@@ -247,6 +247,12 @@ section is present in the configuration the server will run without any nick reg
 .B db_game_modification_info_table
 (for user_handler=forum) The name of the table in which wesnothd will save its own data about the modifications used in a game.
 .TP
+.B db_group_table
+(for user_handler=forum) The name of the table in which your phpbb forums saves its user group data. Most likely this will be <table-prefix>_user_group  (e.g. phpbb3_user_group).
+.TP
+.B mp_mod_group
+(for user_handler=forum) The ID of the forum group to be considered as having moderation authority.
+.TP
 .B user_expiration
 (for user_handler=sample) The time after which a registered nick expires (in days).
 .RE

src/server/forum_user_handler.cpp

@@ -45,6 +45,8 @@ fuh::fuh(const config& c)
 	, db_game_info_table_(c["db_game_info_table"].str())
 	, db_game_player_info_table_(c["db_game_player_info_table"].str())
 	, db_game_modification_info_table_(c["db_game_modification_info_table"].str())
+	, db_group_table_(c["db_group_table"].str())
+	, mp_mod_group_(std::stoi(c["mp_mod_group"]))
 	, conn(mysql_init(nullptr))
 {
 	mysql_options(conn, MYSQL_SET_CHARSET_NAME, "utf8mb4");
@@ -157,9 +159,9 @@ bool fuh::user_is_moderator(const std::string& name) {
 	if(!user_exists(name)) return false;
 
 	try {
-		return get_writable_detail_for_user<int>(name, "user_is_moderator") == 1;
+		return get_writable_detail_for_user<int>(name, "user_is_moderator") == 1 || is_user_in_group(name, mp_mod_group_);
 	} catch (const sql_error& e) {
-		ERR_UH << "Could not query user_is_moderator for user '" << name << "' :" << e.message << std::endl;
+		ERR_UH << "Could not query user_is_moderator/MP Moderators group for user '" << name << "' :" << e.message << std::endl;
 		// If the database is down mark nobody as a mod
 		return false;
 	}
@@ -407,6 +409,15 @@ void fuh::write_detail(const std::string& name, const std::string& detail, T&& v
 	}
 }
 
+bool fuh::is_user_in_group(const std::string& name, unsigned int group_id) {
+	try {
+		return prepared_statement<bool>("SELECT 1 FROM `" + db_users_table_ + "` u, `" + db_group_table_ + "` ug WHERE UPPER(u.username)=UPPER(?) AND u.USER_ID = ug.USER_ID AND ug.GROUP_ID = ?", name, group_id);
+	} catch (const sql_error& e) {
+		ERR_UH << "Could not execute test query for user group '" << group_id << "' and username '" << name << "'" << e.message << std::endl;
+		return false;
+	}
+}
+
 bool fuh::extra_row_exists(const std::string& name) {
 
 	// Make a test query for this username

src/server/forum_user_handler.hpp

@@ -105,7 +105,8 @@ class fuh : public user_handler {
 		std::time_t retrieve_ban_duration_internal(const std::string& col, const std::string& detail);
 		std::time_t retrieve_ban_duration_internal(const std::string& col, unsigned int detail);
 
-		std::string db_name_, db_host_, db_user_, db_password_, db_users_table_, db_banlist_table_, db_extra_table_, db_game_info_table_, db_game_player_info_table_, db_game_modification_info_table_;
+		std::string db_name_, db_host_, db_user_, db_password_, db_users_table_, db_banlist_table_, db_extra_table_, db_game_info_table_, db_game_player_info_table_, db_game_modification_info_table_, db_group_table_;
+		unsigned int mp_mod_group_;
 
 		MYSQL *conn;
 
@@ -123,4 +124,6 @@ class fuh : public user_handler {
 
 		// Same as user_exists() but checks if we have a row for this user in the extra table
 		bool extra_row_exists(const std::string& name);
+
+		bool is_user_in_group(const std::string& name, unsigned int group_id);
 };

utils/mp-server/table_definitions.sql

@@ -10,6 +10,14 @@
 --     KEY user_type (user_type)
 -- ) ENGINE=InnoDB AUTO_INCREMENT=50 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
 
+-- a minimal groups table, if not using a phpbb3 installation
+-- CREATE TABLE user_groups
+-- (
+--     group_id mediumint(8) unsigned NOT NULL,
+--     user_id mediumint(8) unsigned NOT NULL,
+--     PRIMARY KEY (user_id, group_id)
+-- ) ENGINE=InnoDB;
+
 -- table which the forum inserts bans into, which wesnothd checks during login
 -- CREATE TABLE ban
 -- (