Thread: Limit Playername Character Amount

Description: This tutorial will allow you to stop players logging onto your server with a name which is deemed by the server owner too long, if they try to logon with a name which is higher than the specified limit this is logged and the account is banned, if they attempt to do this more than a specified amount of times then their IP will be banned.

Difficulty: 2/10

Assumed Knowledge: Not much Java knowledge needed, just need to read.

Tested Server: Haven't actually tested it, but it should work.

Files/Classes Modified: client class

Procedure
Step 1: Open your client class and declare the following

Code:

	public static int longNameAttempts;
	public java.util.HashMap<String, Integer> longAttempts = new java.util.HashMap<String, Integer>();
	public static final int MAX_CHARACTERS = 15;
	public static final int MAX_ATTEMPTS = 5;

I will explain each part of this.

Code:

	public static int longNameAttempts;

The amount of times the user has tried to logon with a name which is too long

Code:

	public java.util.HashMap<String, Integer> longAttempts = new java.util.HashMap<String, Integer>();

Declare the HashMap which will contain the users IP and also how many times they have tried to connect with a name which is too long.

Code:

	public static final int MAX_CHARACTERS = 15;

The max amount of characters that is allowed on your server.

Code:

	public static final int MAX_ATTEMPTS = 5;

The max times a user can "try" and logon with a name which is too long before they are IP banned.


Step 2: Add the block which will check if the playername is too long.

Im not going to tell you where exactly to put it but its in the client class and in the initialize method.

Code:

                 if(playerName.length() > MAX_CHARACTERS-1) {
                	 appendToBanned(playerName);
                	 disconnected = true;
                	 misc.println(new StringBuilder(playerName).append(" was disconnected and banned - " +
                	 		"name longer than 14 characters ! (").append(connectedFrom).append(")").toString());
                	 longAttempts.put(connectedFrom, longNameAttempts++);
                	 
                	 if(longAttempts.get(connectedFrom) > MAX_ATTEMPTS-1) {
                		 appendToBannedIP(playerName);
                		 misc.println(new StringBuilder(playerName).append(" was IP banned, used characters " +
                		 		"longer that the allowed limit (").append(MAX_CHARACTERS).append(") " +
                		 				"more than ").append(MAX_ATTEMPTS).append(" times.").toString());
                		 longNameAttempts = 0;
                	 }
                 }

This code is pretty self explanitory but I will explain some parts.

Code:

 if(longAttempts.get(connectedFrom) > MAX_ATTEMPTS-1) {

If the attempts that they have made is higher than the max attempts execute this block of code.

Code:

 longAttempts.put(connectedFrom, longNameAttempts++);

Put the connected from and also the attempts number in the HashMap while also incrementing it.


Credits: Me, hopefully this can be used to stop people who like to logon to the server with long names thinking that they wont be able to get banned or somthing like that, normally most clients have name length limited that way but some people edit the clients to bypass this..

Enjoy. - Cascade/Nathanroys2008