Failed to get reserved channel on sponge minecraft server

Question

I'm looking for using MC|Brand channel on a sponge minecraft server.

When i'm trying to use :

Sponge.getChannelRegistrar().getOrCreateRaw(plugin, channel).addListener((data, connection, side) -> {
    if(side == Type.CLIENT) {
        // do something
    }
});

I'm getting this issue:

org.spongepowered.api.network.ChannelRegistrationException: Reserved channels cannot be registered by plugins
        at org.spongepowered.server.network.VanillaChannelRegistrar.validateChannel(VanillaChannelRegistrar.java:71) ~[VanillaChannelRegistrar.class:1.12.2-7.3.0]
        at org.spongepowered.server.network.VanillaChannelRegistrar.createRawChannel(VanillaChannelRegistrar.java:104) ~[VanillaChannelRegistrar.class:1.12.2-7.3.0]
        at org.spongepowered.api.network.ChannelRegistrar.getOrCreateRaw(ChannelRegistrar.java:122) ~[ChannelRegistrar.class:1.12.2-7.3.0]

How can I fix it, just by using channel ? Is there an event for reserved MC channel message ?

score 0 · Accepted Answer · answered Oct 08 '21 at 23:16

I tried to register the channel exactly as Sponge does, but without the check that create the issue.

To do it, I use Java Reflection like that :

RawDataChannel spongeChannel = null; // declare channel
try {
    // firstly, try default channel registration to go faster
    spongeChannel = Sponge.getChannelRegistrar().getOrCreateRaw(plugin, channel);
} catch (ChannelRegistrationException e) { // error -> can't register
    try {
        // load class
        Class<?> vanillaRawChannelClass = Class.forName("org.spongepowered.server.network.VanillaRawDataChannel");
        Class<?> vanillaChannelRegistrarClass = Class.forName("org.spongepowered.server.network.VanillaChannelRegistrar");
        Class<?> vanillaBindingClass = Class.forName("org.spongepowered.server.network.VanillaChannelBinding");
        // get constructor of raw channel
        Constructor<?> rawChannelConstructor = vanillaRawChannelClass.getConstructor(ChannelRegistrar.class, String.class, PluginContainer.class);
        spongeChannel = (RawDataChannel) rawChannelConstructor.newInstance(Sponge.getChannelRegistrar(), channel, plugin.getContainer()); // new channel instance
        // now register channel
        Method registerChannel = vanillaChannelRegistrarClass.getDeclaredMethod("registerChannel", vanillaBindingClass); // get the method to register
        registerChannel.setAccessible(true); // it's a private method, so set as accessible
        registerChannel.invoke(Sponge.getChannelRegistrar(), spongeChannel); // run channel registration
    } catch (Exception exc) {
        exc.printStackTrace(); // reflection failed
    }
}
if(spongeChannel == null) // channel not registered
    return;
// my channel is now registered, by one of both available method. That's perfect
spongeChannel.addListener((data, connection, side) -> { // my listener
    if(side == Type.CLIENT) {
        // do something
    }
});;

If there already have an error, specially when the reflection failed, I suggest you to check for new version, maybe method have change her parameter or class have been moved.

You can find Sponge code on their github.

Failed to get reserved channel on sponge minecraft server

1 Answers1