Check for valid clan ID

scripts/server/clan.js

@@ -979,6 +979,10 @@ function createClan(name) {
 function deleteClan(clanId, whoDeleted = 0) {
 	//saveAllClansToDatabase();
 
+	if (getClanData(clanId) == false) {
+		return false;
+	}
+
 	let dbConnection = connectToDatabase();
 	if (dbConnection) {
 		let dbQuery = queryDatabase(dbConnection, `UPDATE clan_main SET clan_deleted = 1, clan_when_deleted = UNIX_TIMESTAMP, clan_who_deleted = ${whoDeleted} WHERE clan_id = ${clanId}`);
@@ -999,9 +1003,14 @@ function deleteClan(clanId, whoDeleted = 0) {
  * @return {ClanData} The clan's data (class instance)
  */
 function getClanData(clanId) {
+	if (clanId == -1) {
+		return false;
+	}
+
 	if (typeof getServerData().clans[clanId] != null) {
 		return getServerData().clans[clanId];
 	}
+
 	return false;
 }
 
@@ -1238,11 +1247,17 @@ function getPlayerClan(client) {
 // ===========================================================================
 
 function getClanIdFromDatabaseId(databaseId) {
+	if (databaseId <= 0) {
+		return -1;
+	}
+
 	for (let i in getServerData().clans) {
 		if (getServerData().clans[i].databaseId == databaseId) {
 			return i;
 		}
 	}
+
+	return -1;
 }
 
 // ===========================================================================
@@ -1263,6 +1278,14 @@ function getClanRankIdFromDatabaseId(clanId, databaseId) {
  * @return {ClanRankData} The clan rank's data (class instance)
  */
 function getClanRankData(clanId, rankId) {
+	if (clanId == -1) {
+		return false;
+	}
+
+	if (rankId == -1) {
+		return false;
+	}
+
 	return getServerData().clans[clanId].ranks[rankId];
 }