Writing a Cuberite plugin
++ This article will explain how to write a basic plugin. It details basic requirements + for a plugin, explains how to register a hook and bind a command, and gives plugin + standards details. +
++ Let us begin. In order to begin development, we must firstly obtain a compiled copy + of Cuberite, and make sure that the Core plugin is within the Plugins folder, and activated. + Core handles much of the Cuberite end-user experience and gameplay will be very bland without it. +
+Creating the basic template
++ Plugins are written in Lua. Therefore, create a new Lua file. You can create as many files as you wish, with + any filename - Cuberite bungs them all together at runtime, however, let us create a file called main.lua for now. + Format it like so: +
+
+PLUGIN = nil
+
+function Initialize(Plugin)
+ Plugin:SetName("NewPlugin")
+ Plugin:SetVersion(1)
+
+ -- Hooks
+
+ PLUGIN = Plugin -- NOTE: only needed if you want OnDisable() to use GetName() or something like that
+
+ -- Command Bindings
+
+ LOG("Initialised " .. Plugin:GetName() .. " v." .. Plugin:GetVersion())
+ return true
+end
+
+function OnDisable()
+ LOG(PLUGIN:GetName() .. " is shutting down...")
+end
+
+ + Now for an explanation of the basics. +
-
+
- function Initialize is called on plugin startup. It is the place where the plugin is set up. +
- Plugin:SetName sets the name of the plugin. +
- Plugin:SetVersion sets the revision number of the plugin. This must be an integer. +
- LOG logs to console a message, in this case, it prints that the plugin was initialised. +
- The PLUGIN variable just stores this plugin's object, so GetName() can be called in OnDisable (as no Plugin parameter is passed there, contrary to Initialize). + This global variable is only needed if you want to know the plugin details (name, etc.) when shutting down. +
- function OnDisable is called when the plugin is disabled, commonly when the server is shutting down. Perform cleanup and logging here. +
Registering hooks
++ Hooks are things that Cuberite calls when an internal event occurs. For example, a hook is fired when a player places a block, moves, + logs on, eats, and many other things. For a full list, see the API documentation. +
++ A hook can be either informative or overridable. In any case, returning false will not trigger a response, but returning true will cancel + the hook and prevent it from being propagated further to other plugins. An overridable hook simply means that there is visible behaviour + to a hook's cancellation, such as a chest being prevented from being opened. There are some exceptions to this where only changing the value the + hook passes has an effect, and not the actual return value, an example being the HOOK_KILLING hook. See the API docs for details. +
++ To register a hook, insert the following code template into the "-- Hooks" area in the previous code example. +
++cPluginManager.AddHook(cPluginManager.HOOK_NAME_HERE, FunctionNameToBeCalled) ++
+ What does this code do? +
-
+
- cPluginManager.AddHook registers the hook. The hook name is the second parameter. See the previous API documentation link for a list of all hooks. +
+ So in total, this is a working representation of what we have so far covered. +
+
+function Initialize(Plugin)
+ Plugin:SetName("DerpyPlugin")
+ Plugin:SetVersion(1)
+
+ cPluginManager.AddHook(cPluginManager.HOOK_PLAYER_MOVING, OnPlayerMoving)
+
+ LOG("Initialised " .. Plugin:GetName() .. " v." .. Plugin:GetVersion())
+ return true
+end
+
+function OnPlayerMoving(Player) -- See API docs for parameters of all hooks
+ return true -- Prohibit player movement, see docs for whether a hook is cancellable
+end
+
+ + So, that code stops the player from moving. Not particularly helpful, but yes :P. Note that ALL documentation is available + on the main API docs page, so if ever in doubt, go there. +
+Binding a command
+Format
++ So now we know how to hook into Cuberite, how do we bind a command, such as /explode, for a player to type? That is more complicated. + We firstly add this template to the "-- Command bindings" section of the initial example: +
+
+-- ADD THIS IF COMMAND DOES NOT REQUIRE A PARAMETER (/explode)
+cPluginManager.BindCommand("/commandname", "permissionnode", FunctionToCall, " - Description of command")
+
+-- ADD THIS IF COMMAND DOES REQUIRE A PARAMETER (/explode Notch)
+cPluginManager.BindCommand("/commandname", "permissionnode", FunctionToCall, " ~ Description of command and parameter(s)")
+
+ + What does it do, and why are there two? +
-
+
- PluginManager:BindCommand binds a command. It takes the command name (with a slash), the permission a player needs to execute the command, the function + to call when the command is executed, and a description of the command. +
+ So why are there two? Standards. A plugin that accepts a parameter MUST use a format for the description of " ~ Description of command and parms" + whereas a command that doesn't accept parameters MUST use " - Description of command" instead. Be sure to put a space before the tildes or dashes. + Additionally, try to keep the description brief and on one line on the client. +
+Parameters
++ What parameters are in the function Cuberite calls when the command is executed? A 'Split' array and a 'Player' object. +
+The Split Array
+
+ The Split array is an array of all text submitted to the server, including the actual command. Cuberite automatically splits the text into the array,
+ so plugin authors do not need to worry about that. An example of a Split array passed for the command, "/derp zubby explode" would be:
+ /derp (Split[1])
+ zubby (Split[2])
+ explode (Split[3])
+
+ The total amount of parameters passed were: 3 (#Split)
+
The Player Object and sending them messages
++ The Player object is basically a pointer to the player that has executed the command. You can do things with them, but most common is sending + a message. Again, see the API documentation for fuller details. But, you ask, how do we send a message to the client? +
++ There are dedicated functions used for sending a player formatted messages. By format, I refer to coloured prefixes/coloured text (depending on configuration) + that clearly categorise what type of message a player is being sent. For example, an informational message has a yellow coloured [INFO] prefix, and a warning message + has a rose coloured [WARNING] prefix. A few of the most used functions are listed here, but see the API docs for more details. Look in the cRoot, cWorld, and cPlayer sections + for functions that broadcast to the entire server, the whole world, and a single player, respectively. +
+
+-- Format: §yellow[INFO] §white%text% (yellow [INFO], white text following it)
+-- Use: Informational message, such as instructions for usage of a command
+Player:SendMessageInfo("Usage: /explode [player]")
+
+-- Format: §green[INFO] §white%text% (green [INFO] etc.)
+-- Use: Success message, like when a command executes successfully
+Player:SendMessageSuccess("Notch was blown up!")
+
+-- Format: §rose[INFO] §white%text% (rose coloured [INFO] etc.)
+-- Use: Failure message, like when a command was entered correctly but failed to run, such as when the destination player wasn't found in a /tp command
+Player:SendMessageFailure("Player Salted was not found")
+
+ + Those are the basics. If you want to output text to the player for a reason other than the three listed above, and you want to colour the text, simply concatenate + "cChatColor.*colorhere*" with your desired text, concatenate being "..". See the API docs for more details of all colours, as well as details on logging to console with + LOG("Text"). +
+Final example and conclusion
++ So, a working example that checks the validity of a command, and blows up a player, and also refuses pickup collection to players with >100ms ping. +
+
+function Initialize(Plugin)
+ Plugin:SetName("DerpyPluginThatBlowsPeopleUp")
+ Plugin:SetVersion(9001)
+
+ cPluginManager.BindCommand("/explode", "derpyplugin.explode", Explode, " ~ Explode a player");
+
+ cPluginManager:AddHook(cPluginManager.HOOK_COLLECTING_PICKUP, OnCollectingPickup)
+
+ LOG("Initialised " .. Plugin:GetName() .. " v." .. Plugin:GetVersion())
+ return true
+end
+
+function Explode(Split, Player)
+ if (#Split ~= 2) then
+ -- There was more or less than one argument (excluding the "/explode" bit)
+ -- Send the proper usage to the player and exit
+ Player:SendMessage("Usage: /explode [playername]")
+ return true
+ end
+
+ -- Create a callback ExplodePlayer with parameter Explodee, which Cuberite calls for every player on the server
+ local HasExploded = false
+ local ExplodePlayer = function(Explodee)
+ -- If the player we are currently at is the one we specified as the parameter
+ if (Explodee:GetName() == Split[2]) then
+ -- Create an explosion at the same position as they are; see API docs for further details of this function
+ Player:GetWorld():DoExplosionAt(Explodee:GetPosX(), Explodee:GetPosY(), Explodee:GetPosZ(), false, esPlugin)
+ Player:SendMessageSuccess(Split[2] .. " was successfully exploded")
+ HasExploded = true;
+ return true -- Signalize to Cuberite that we do not need to call this callback for any more players
+ end
+ end
+
+ -- Tell Cuberite to loop through all players and call the callback above with the Player object it has found
+ cRoot:Get():FindAndDoWithPlayer(Split[2], ExplodePlayer)
+
+ if not(HasExploded) then
+ -- We have not broken out so far, therefore, the player must not exist, send failure
+ Player:SendMessageFailure(Split[2] .. " was not found")
+ end
+
+ return true
+end
+
+function OnCollectingPickup(Player, Pickup) -- Again, see the API docs for parameters of all hooks. In this case, it is a Player and Pickup object
+ if (Player:GetClientHandle():GetPing() > 100) then -- Get ping of player, in milliseconds
+ return true -- Discriminate against high latency - you don't get drops :D
+ else
+ return false -- You do get the drops! Yay~
+ end
+end
+
+ + Make sure to read the comments for a description of what everything does. Also be sure to return true for all command handlers, unless you want Cuberite to print out an "Unknown command" message + when the command gets executed :P. Make sure to follow standards - use CoreMessaging.lua functions for messaging, dashes for no parameter commands and tildes for vice versa, + and finally, the API documentation is your friend! +
++ Happy coding ;) +
+ + +