AddCommandHandler

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Revision as of 15:16, 28 June 2007 by TDHBoss (talk | contribs) (Example)

This template is no longer in use as it results in poor readability. This function will attach a scripting function (handler) to a console command, so that whenever a player or administrator uses the command the function is called.

Multiple command handlers can be attached to a single command, and they will be called in the order that the handlers were attached. Equally, multiple commands can be handled by a single function, and the commandName parameter used to decide the course of action.

Syntax

bool addCommandHandler ( string commandName, function handlerFunction )

Required Arguments

  • commandName: This is the name of the command you wish to attach a handler to. This is what must be typed into the console to trigger the function.
  • handlerFunction: This is the name of the function that you want the command to trigger. This function can take two parameters, playerSource and commandName, followed by as many parameters you expect after your command. These are all optional. Function name IS NOT a string, so you shouldn't use "".
player playerSource, string commandName, [string arg1, string arg2, ...] 
  • playerSource: The player who triggered the command. If not triggered by a player (e.g. by admin), this will be false.
  • commandName: The name of the command triggered. This is useful if multiple commands go through one function.
  • arg1, arg2, ...: Each word after command name in the original command is passed here in a seperate variable. If there is no value for an argument, its variable will contain nil. You can deal with a variable number of arguments using the vararg expression, as shown in Example 3 below.

Returns

Returns true if the command handler was added successfully, false otherwise.

Example

Example 1: This example defines a command handler for the command createmarker. This will create a red marker at the position of the player player who uses it.

-- Define our function that will handle this command
function consoleCreateMarker ( playerSource, commandName )
	-- If a player triggered it (rather than the admin) then
	if ( playerSource ) then
		-- Get that player's position
		local x, y, z = getElementPosition ( playerSource )
		-- Create a size 2, red checkpoint marker at their position
		createMarker ( x, y, z, "checkpoint", 2, 255, 0, 0, 255 )
		-- Output it in the chat box
		outputChatBox ( "You got a red marker", playerSource )
	end
end
-- Register the command and attach it to the 'consoleCreateMarker' function
-- You must add a handler ONLY after function definition.
addCommandHandler ( "createmarker", consoleCreateMarker )

Example 2: This example implements a set_vehicle_color command.

-- Define our function that will handle this command
function consoleSetVehicleColor ( playerSource, commandName, col1, col2, col3, col4 )
	-- If a player triggered this in-game
	if ( playerSource ) then
		-- Get the player's vehicle
		local playerVehicle = getPlayerOccupiedVehicle ( playerSource )
		-- If the player is in a vehicle and we've got at least 1 parameter
		if ( playerVehicle and col1 ) then
			-- Get the vehicle's existing color and use it if fewer than 4 arguments were passed
			local exCol1, exCol2, exCol3, exCol4 = getVehicleColor ( playerVehicle )

			if not col2 then col2 = exCol2 end
			if not col3 then col3 = exCol3 end
			if not col4 then col4 = exCol4 end

			-- Set the vehicle's color
			setVehicleColor ( playerVehicle, col1, col2, col3, col4 )
		else
			-- If we didn't get at least 1 parameter or the player doesn't have a vehicle, display some help text
			outputConsole ( "This function will set your current vehicle's colors. A vehicle can have up to 4 colors.", playerSource )
			outputConsole ( "Syntax: set_vehicle_color color1 [ color2 color3 color4 ]", playerSource )
			outputConsole ( "You must be in a vehicle to use this function.", playerSource )
		end
	end
end
-- Register the command and attach it to the 'consoleSetVehicleColor' function
-- You must add a handler ONLY after function definition.
addCommandHandler ( "set_vehicle_color", consoleSetVehicleColor )

Example 3: This example makes use of Lua's vararg expression to output the number of parameters passed, merge them all into a single string and output it.

-- Define our function that will handle this command (which can accept a variable number of arguments after commandName)
function consoleCheckParameters ( playerSource, commandName, ... )
	-- If a player, not an admin, triggered it,
	if playerSource then
		-- Pack all extra arguments passed in a table
		local parametersTable = {...}
		-- Get the number of arguments in that table
		local parameterCount = #parametersTable
		-- Output it to the player's chatbox
		outputChatBox ( "Number of parameters: " .. parameterCount, playerSource )
		-- Join them together in a single comma-separated string
		local stringWithAllParameters = table.concat( parametersTable, ", " )
		-- Output this parameter list to the player's chatbox
		outputChatBox ( "Parameters passed: " .. stringWithAllParameter, playerSource )
	end
end
-- Register the command and attach it to the 'consoleCheckParameters' function
-- You must add a handler ONLY after function definition.
addCommandHandler ( "check_parameters", consoleCheckParamters )

See Also