Shading the CommandAPI in your plugins

"Shading" is the process of including the CommandAPI inside your plugin, rather than requiring the CommandAPI as an external plugin. In other words, if you shade the CommandAPI into your plugin, you don't need to include the CommandAPI.jar in your server's plugins folder.


Shading vs CommandAPI plugin

The CommandAPI plugin has a few slight differences with the shaded CommandAPI jar file. The CommandAPI plugin has the following extra features that are not present in the shaded version:

  • Command conversion via a config.yml file

Shading requirements

For the CommandAPI to function as normal, you must call the CommandAPI's initializers in the onLoad() and onEnable() methods of your plugin:

CommandAPI.onLoad(CommandAPIConfig config);
CommandAPI.onEnable();

If you want to handle reloading, the CommandAPI has minimal support for it with the onDisable() method, which can go in your plugin. This is optional and is not required if you don't plan on reloading the server.

Loading

The onLoad(CommandAPIConfig) method initializes the CommandAPI's loading sequence. This must be called before you start to access the CommandAPI and must be placed in your plugin's onLoad() method. The argument CommandAPIConfig is used to configure how the CommandAPI works. The CommandAPIConfig class has the following parameters which let you set how the CommandAPI works similar to the config.yml, which is described here.

public class CommandAPIConfig {
    CommandAPIConfig verboseOutput(boolean value); // Enables verbose logging
    CommandAPIConfig silentLogs(boolean value);    // Disables ALL logging (except errors)
    CommandAPIConfig useLatestNMSVersion(boolean value); // Whether the latest NMS implementation should be used or not
    CommandAPIConfig missingExecutorImplementationMessage(String value); // Set message to display when executor implementation is missing
    CommandAPIConfig dispatcherFile(File file); // If not null, the CommandAPI will create a JSON file with Brigadier's command tree
    CommandAPIConfig setNamespace(String namespace); // The namespace to use when the CommandAPI registers a command
    CommandAPIConfig usePluginNamespace(); // Whether the CommandAPI should use the name of the plugin passed into the CommandAPIConfig implementation as the default namespace for commands

    <T> CommandAPIConfig initializeNBTAPI(Class<T> nbtContainerClass, Function<Object, T> nbtContainerConstructor); // Initializes hooks with an NBT API. See NBT arguments documentation page for more info
}

The CommandAPIConfig class follows a typical builder pattern (without you having to run .build() at the end), which lets you easily construct configuration instances.

However, the CommandAPIConfig class is abstract and cannot be used to configure the CommandAPI directly. Instead, you must use a subclass of CommandAPIConfig that corresponds to the platform you are developing for. For example, when developing for Bukkit, you should use the CommandAPIBukkiConfig class.

public class CommandAPIBukkitConfig extends CommandAPIConfig {
    CommandAPIBukkitConfig(JavaPlugin plugin);

    CommandAPIBukkitConfig shouldHookPaperReload(boolean hooked); // Whether the CommandAPI should hook into the Paper-exclusive ServerResourcesReloadedEvent
}

In order to create a CommandAPIBukkitConfig object, you must give it a reference to your JavaPlugin instance. The CommandAPI always uses this to registers events, so it is required when loading the CommandAPI on Bukkit. There are also Bukkit-specific features, such as the hook-paper-reload configuration option, which may be configured using a CommandAPIBukkitConfig instance.

For example, to load the CommandAPI on Bukkit with all logging disabled, you can use the following:

CommandAPI.onLoad(new CommandAPIBukkitConfig(plugin).silentLogs(true));
CommandAPI.onLoad(CommandAPIBukkitConfig(plugin).silentLogs(true))

Enabling & Disabling

The onEnable() method initializes the CommandAPI's enabling sequence. Similar to the onLoad(CommandAPIConfig) method, this must be placed in your plugin's onEnable() method. This isn't as strict as the onLoad(CommandAPIConfig) method, and can be placed anywhere in your onEnable() method.

The onDisable() method disables the CommandAPI gracefully. This should be placed in your plugin's onDisable() method. This doesn't unregister commands, so commands may persist during reloads - this can be mitigated using the CommandAPI.unregister() method.

Example - Setting up the CommandAPI in your plugin

public class MyPlugin extends JavaPlugin {

    @Override
    public void onLoad() {
        CommandAPI.onLoad(new CommandAPIBukkitConfig(this).verboseOutput(true)); // Load with verbose output
        
        new CommandAPICommand("ping")
            .executes((sender, args) -> {
                sender.sendMessage("pong!");
            })
            .register();
    }
    
    @Override
    public void onEnable() {
        CommandAPI.onEnable();
        
        // Register commands, listeners etc.
    }
    
    @Override
    public void onDisable() {
        CommandAPI.onDisable();
    }

}
class MyPlugin : JavaPlugin() {

    override fun onLoad() {
        CommandAPI.onLoad(CommandAPIBukkitConfig(this).verboseOutput(true)) // Load with verbose output

        CommandAPICommand("ping")
            .executes(CommandExecutor { sender, _ ->
                sender.sendMessage("pong!")
            })
            .register()
    }

    override fun onEnable() {
        CommandAPI.onEnable()

        // Register commands, listeners etc.
    }

    override fun onDisable() {
        CommandAPI.onDisable()
    }

}

A note about relocating

By default, the CommandAPI is written in the dev.jorel.commandapi package. It is highly recommended to "relocate" the shaded copy of the CommandAPI to your own package instead to prevent package clashes with other projects that shade the CommandAPI:

\begin{align} &\qquad\texttt{dev.jorel.commandapi} \rightarrow \texttt{my.custom.package.commandapi} \\ \end{align}


Shading with Maven

To shade the CommandAPI into a maven project, you'll need to use the commandapi-bukkit-shade dependency, which is optimized for shading and doesn't include plugin-specific files (such as plugin.yml). You do not need to use commandapi-bukkit-core if you are shading:

Add the CommandAPI shade dependency:

<dependencies>
    <dependency>
        <groupId>dev.jorel</groupId>
        <artifactId>commandapi-bukkit-shade</artifactId>
        <version>9.4.0-SNAPSHOT</version>
    </dependency>
</dependencies>

You can shade the CommandAPI easily by adding the maven-shade-plugin to your build sequence using version 3.3.0 (compatible with Java 16):

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>3.3.0</version>
            <executions>
                <execution>
                    <id>shade</id>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <minimizeJar>true</minimizeJar>
                <relocations>
                    <relocation>
                        <pattern>dev.jorel.commandapi</pattern>
                        <!-- TODO: Change this to my own package name -->
                        <shadedPattern>my.custom.package.commandapi</shadedPattern>
                    </relocation>
                </relocations>
            </configuration>
        </plugin>
    </plugins>
</build>

As we're shading the CommandAPI into your plugin, you don't need to add depend: [CommandAPI] to your plugin.yml file.


Shading with Gradle

To shade the CommandAPI into a Gradle project, we'll use the Gradle Shadow Plugin. Add this to your list of plugins:

plugins {
    id 'java'
    id 'com.github.johnrengelman.shadow' version '7.1.2'
}
plugins {
    java
    id("com.github.johnrengelman.shadow") version "7.1.2"
}

Add our repositories:

repositories {
    mavenCentral()

    // If you want to shade the NBT API as well
    maven { url = "https://repo.codemc.org/repository/maven-public/" }
}
repositories {
    mavenCentral()

    // If you want to shade the NBT API as well
    maven(url = "https://repo.codemc.org/repository/maven-public/")
}

Next, we declare our dependencies:

dependencies {
    implementation "dev.jorel:commandapi-bukkit-shade:9.4.0-SNAPSHOT"
}
dependencies {
    implementation("dev.jorel:commandapi-bukkit-shade:9.4.0-SNAPSHOT")
}

Then we add it to the shadowJar task configuration and relocate the CommandAPI to your desired location:

shadowJar {
    dependencies {
        include dependency("dev.jorel:commandapi-bukkit-shade:9.4.0-SNAPSHOT")
    }

    // TODO: Change this to my own package name
    relocate("dev.jorel.commandapi", "my.custom.package.commandapi")
}
shadowJar {
    dependencies {
        include(dependency("dev.jorel:commandapi-bukkit-shade:9.4.0-SNAPSHOT"))
    }

    // TODO: Change this to my own package name
    relocate("dev.jorel.commandapi", "my.custom.package.commandapi")
}

Finally, we can build the shaded jar using the following command:

gradlew build shadowJar

As we're shading the CommandAPI into your plugin, we don't need to add depend: [CommandAPI] to your plugin.yml file.