Advanced commands

Let's talk about command a bit deeper.

Groups

You can make a "group" of command : it is an anonymous function where you register commands, and these commands will have common attributes. By example, you can define a prefix, that will apply to the commands inside the group :

commands.group().prefix("!").apply(() -> {
    commands.make("test", (context, args) -> context.sendMessage("Test")).register();
    commands.make("hello", (context, args) -> context.sendMessage("Hello !")).register();
});

In this example, the commands will not be test, and hello, but !test, and !hello, because they are registered in a group with the ! prefix. Obviously, commands registered outside this group will not have the prefix on them.

Middlewares

Command middlewares are functions that triggers before some command call. They can be used on multiple commands, and they can cancel a command call.

The command builder has two functions : middleware and middlewares, in this case, use middleware. We will use the other one later.

commands.make("test", (context, args) ->
    context.sendMessage("Test")
).middleware((command, context, args) ->
    LOGGER.info("The command is executed with args {}", args);
).register();

In this case, this is not really useful, but you can by example apply it to a group :

commands.group().prefix("!").middleware((command, context, args) ->
    LOGGER.info("A command is executed !")
).apply(() -> {
    commands.make("test", (context, args) -> context.sendMessage("Test")).register();
    commands.make("hello", (context, args) -> context.sendMessage("Hello !")).register();
});

With this code, everytime !test or !hello is called, "A command is executed !" should be printed on the console.

Sub commands

You can create sub commands, and even sub sub commands. What is a sub command ? By example, you have a command !test, and you want to create a sub command debug, the sub command will be triggered when a user will type !test debug.

Let's write an example :

commands.make("!test", (context, args) ->
    context.sendMessage("Test")
).register().sub("debug", (context, args) ->
    context.sendMessage("Debug")
).register();

This will make this :

Litarvan : !test
Bot      : Test

Litarvan : !test debug
Bot      : Debug

Obviously, you can create more complex commands, they also use the path syntax !

Important things to know when using sub commands :

• Groups modifiers (like the prefix or the middlewares) aren't applied on the sub commands, only on the parent one.
• Parent command middlewares are called when a sub command is triggered, and they can cancel the call, in this case, "args" parameter of the middleware is null.
• You need to call register() to then call the sub() function, so when dealing with multiple sub commands, put the parent command register() result in a Command variable, to then use the sub functions multiple times.