Commands (SourceMod Scripting)

SourceMod allows you to create console commands similar to AMX Mod X. There are two main types of console commands:

• Server Commands, which are fired from one of the following input methods:
  • the server console itself;
  • the remove console (RCON);
  • the ServerCommand() function, either from SourceMod or the Half-Life 2 engine.
• Console Commands, which are fired from one of the following input methods:
  • a client's console
  • any of the server command input methods

For server commands, there is no client index. For console/client commands, there is a client index, but it may be 0 to indicate that the command is from the server.

Note that button "commands," such as +attach and +duck, are not actually console commands. They are a separate command stream sent over the network, as they need to be tied to a specific frame.

Server Commands

As noted above, server commands are fired through the server console, whether remote, local, or through the Source engine. There is no client index associated with a server command.

Server commands are registered through the RegServerCmd() function, listed in console.inc. When registering a server command, you may be hooking an already existing command, and thus whether you return Plugin_Handled or Plugin_Continue is important.

• Plugin_Continue: The original server command will be processed, if there was one. If the server command was created by a plugin, this has no effect.
• Plugin_Handled: The original server command will not be processed, if there was one. If the server command was created by a plugin, this has no effect.
• Plugin_Stop: This original server command will not be processed, if there was one. Additionally, no further hooks will be called for this command until it is fired again.

Adding Server Commands

Let's say we want to add a test command to show how Half-Life 2 breaks down command arguments. A possible implementation might be:

public OnPluginStart()
{
	RegServerCmd("test_command", Command_Test)
}
 
public Action:Command_Test(args)
{
	new String:arg[128]
	new String:full[256]
 
	GetCmdArgString(full, sizeof(full))
 
	PrintToServer("Argument string: %s", full)
	PrintToServer("Argument count: %d", args)
	for (new i=1; i<=args; i++)
	{
		GetCmdArg(i, arg, sizeof(arg))
		PrintToServer("Argument %d: %s", i, arg)
	}
}

Blocking Server Commands

Let's say we wanted to disable the "kickid" command on the server. There's no real good reason to do this, but for example's sake:

public OnPluginStart()
{
	RegServerCmd("kickid", Command_KickId)
}
 
public Action:Command_Kickid(args)
{
	return Plugin_Handled
}

Console Commands

Unlike server commands, console commands can be triggered by either the server or the client, so the callback function receives a client index as well as the argument count. If the server fired the command, the client index will be 0.

When returning the Action from the callback, the following effects will happen:

• Plugin_Continue: The original functionality of the command (if any) will still be processed. If there was no original functionality, the client will receive "Unknown command" in their console.
• Plugin_Handled: The original functionality of the command (if any) will be blocked. If there was no functionality originally, this prevents clients from seeing "Unknown command" in their console.
• Plugin_Stop: Same as Plugin_Handled, except that this will be the last hook called.

Note that, unlike AMX Mod X, SourceMod does not allow you to register command filters. I.e., there is no equivalent to this notation:

register_clcmd("say /ff", "Command_SayFF");

This notation was removed to make our internal code simpler and faster. Writing the same functionality is easy, and demonstrated below.

Adding Commands

Adding client commands is very simple. Let's port our earlier testing command to display information about the client as well.

public OnPluginStart()
{
	RegConsoleCmd("test_command", Command_Test)
}
 
public Action:Command_Test(client, args)
{
	new String:arg[128]
	new String:full[256]
 
	GetCmdArgString(full, sizeof(full))
 
	if (client)
	{
		new String:name[32]
		GetClientName(client, name, sizeof(name))
		PrintToServer("Command from client: %s", name);
	} else {
		PrintToServer("Command from server.");
	}
 
	PrintToServer("Argument string: %s", full)
	PrintToServer("Argument count: %d", args)
	for (new i=1; i<=args; i++)
	{
		GetCmdArg(i, arg, sizeof(arg))
		PrintToServer("Argument %d: %s", i, arg)
	}
}

Hooking Commands

A common example is hooking the say command. Let's say we want to tell players whether FF is enabled when they say '/ff' in game.

Before we implement this, a common point of confusion with the 'say' command is that Half-Life 2 (and Half-Life 1), by default, send it with the text in one big quoted string. This means if you say "I like hot dogs," your command will be broken down as such:

• Argument string: "I like hot dogs"
• Argument count: 1
• Argument #1: I like hot dogs

However, if a player types this in their console: say I like yams, it will be broken up as:

• Argument string: I like yams
• Argument count: 4
• Argument #1: I
• Argument #2: like
• Argument #3: yams

Thus, to take into account both of these situations, we are going to use GetCmdArgString and manually parse the input.

public OnPluginStart()
{
	RegConsoleCmd("say", Command_Say)
}
 
public Action:Command_Say(client, args)
{
	new String:text[192]
	GetCmdArgString(text, sizeof(text))
 
	new startidx = 0
	if (text[0] == '"')
	{
		startidx = 1
		/* Strip the ending quote, if there is one */
		new len = strlen(text);
		if (text[len-1] == '"')
		{
			text[len-1] = '\0'
		}
	}
 
	if (StrEqual(text[startidx], "/ff"))
	{
		new Handle:ff = FindConVar("mp_friendlyfire")
		if (GetConVarInt(ff))
		{
			PrintToConsole(client, "Friendly fire is enabled.")
		} else {
			PrintToConsole(client, "Friendly fire is disabled.")
		}
		/* Block the client's messsage from broadcasting */
		return Plugin_Handled
	}
 
	/* Let say continue normally */
	return Plugin_Continue
}

Creating Admin Commands

Let's create a simple admin command which kicks another player by their full name.

public OnPluginStart()
{
	RegAdminCmd("admin_kick",
		Command_Kick,
		ADMFLAG_KICK,
		"Kicks a player by name")
}
 
public Action:Command_Kick(client, args)
{
	if (args < 1)
	{
		PrintToConsole(client, "Usage: admin_kick <name>")
		return Plugin_Handled
	}
 
	new String:name[32], maxplayers, target = -1
	GetCmdArg(1, name, sizeof(name))
 
	maxplayers = GetMaxClients()
	for (new i=1; i<=maxplayers; i++)
	{
		if (!IsClientConnected(i))
		{
			continue
		}
		decl String:other[32]
		GetClientName(i, other, sizeof(other))
		if (StrEqual(name, other))
		{
			target = i
		}
	}
 
	if (target == -1)
	{
		PrintToConsole(client, "Could not find any player with the name: \"%s\"", name)
		return Plugin_Handled
	}
 
	ServerCommand("kickid %d", GetClientUserId(target));
 
	return Plugin_Handled
}

Immunity

In our previous example, we did not take immunity into account. Immunity is a much more complex system in SourceMod than it was in AMX Mod X, and there is no simple flag to denote its permissions. Instead, two functions are provided:

• CanAdminTarget: Tests raw AdminId values for immunity.
• CanUserTarget: Tests in-game clients for immunity.

While immunity is generally tested player versus player, it is possible you might want to check for immunity and not have a targetting client. While there is no convenience function for this yet, a good idea might be to check for either default or global immunity on the player's groups (these can be user-defined for non-player targeted scenarios).

When checking for immunity, the following heuristics are performed in this exact order:

1. If the targeting AdminId is INVALID_ADMIN_ID, targeting fails.
2. If the targetted AdminId is INVALID_ADMIN_ID, targeting succeeds.
3. If the targeting admin has Admin_Root (ADMFLAG_ROOT), targeting succeeds.
4. If the targetted admin has global immunity, targeting fails.
5. If the targetted admin has default immunity, and the targeting admin belongs to no groups, targeting fails.
6. If the targetted admin has specific immunity from the targeting admin via group immunities, targeting fails.
7. If no conclusion is reached via the previous steps, targeting succeeds.

So, how can we adapt our function about to use immunity?

public Action:Command_Kick(client, args)
{
	if (args < 1)
	{
		PrintToConsole(client, "Usage: admin_kick <name>")
		return Plugin_Handled
	}
 
	new String:name[32], maxplayers, target = -1
	GetCmdArg(1, name, sizeof(name))
 
	maxplayers = GetMaxClients()
	for (new i=1; i<=maxplayers; i++)
	{
		if (!IsClientConnected(i))
		{
			continue
		}
		decl String:other[32]
		GetClientName(i, other, sizeof(other))
		if (StrEqual(name, other))
		{
			target = i
		}
	}
 
	if (target == -1)
	{
		PrintToConsole(client, "Could not find any player with the name: \"%s\"", name)
		return Plugin_Handled
	}
 
	if (!CanUserTarget(client, target))
	{
		PrintToConsole(client, "You cannot target this client.")
		return Plugin_Handled
	}
 
	ServerCommand("kickid %d", GetClientUserId(target))
 
	return Plugin_Handled
}

Client-Only Commands

SourceMod exposes a forward that is called whenever a client executes any command string in their console, called OnClientCommand. An example of this looks like:

public Action:OnClientCommand(client, args)
{
	new String:cmd[16]
	GetCmdArg(0, cmd, sizeof(cmd));	/* Get command name */
 
	if (StrEqual(cmd, "test_command"))
	{
		/* Got the client command! Block it... */
		return Plugin_Handled
	}
 
	return Plugin_Continue
}

It is worth noting that not everything a client sends will be available through this command. Command registered via external sources in C++ may not be available, especially if they are created via CON_COMMAND in the game mod itself. For example, "say" is usually implemented this way, because it can be used by both clients and the server, and thus it does not channel through this forward.