mirror of
https://github.com/dmulloy2/ProtocolLib.git
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140 lines
5.0 KiB
Markdown
140 lines
5.0 KiB
Markdown
ProtocolLib
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===========
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Certain tasks are impossible to perform with the standard Bukkit API, and may require
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working with and even modify Minecraft directly. A common technique is to modify incoming
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and outgoing [packets](http://www.wiki.vg/Protocol), or inject custom packets into the
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stream. This is quite cumbersome to do, however, and most implementations will break
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as soon as a new version of Minecraft has been released, mostly due to obfuscation.
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Critically, different plugins that use this approach may _hook_ into the same classes,
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with unpredictable outcomes. More than often this causes plugins to crash, but it may also
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lead to more subtle bugs.
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### Resources
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* [JavaDoc](http://aadnk.github.com/ProtocolLib/Javadoc/)
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Building
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--------
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You can compile this project yourself by using the latest version of Maven.
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A new API
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---------
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__ProtocolLib__ attempts to solve this problem by providing a event API, much like Bukkit,
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that allow plugins to monitor, modify or cancel packets sent and received. But more importantly,
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the API also hides all the gritty, obfuscated classes with a simple index based read/write system.
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You no longer have to reference CraftBukkit!
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### Using ProtocolLib
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To use the library, first add ProtocolLib.jar to your Java build path. Then, add ProtocolLib
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as a dependency (or soft-dependency, if you can live without it) to your plugin.yml file:
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depends: [ProtocolLib]
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Future versions will be available in a public Maven repository, possibly on Maven central. But it
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will always be possible to reference ProtocolLib manually.
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Then get a reference to ProtocolManager in onLoad() and you're good to go.
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private ProtocolManager protocolManager;
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public void onLoad() {
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protocolManager = ProtocolLibrary.getProtocolManager();
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}
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To listen for packets sent by the server to a client, add a server-side listener:
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// Disable all sound effects
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protocolManager.addPacketListener(
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new PacketAdapter(this, ConnectionSide.SERVER_SIDE, ListenerPriority.NORMAL, 0x3E) {
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@Override
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public void onPacketSending(PacketEvent event) {
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// Item packets
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switch (event.getPacketID()) {
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case 0x3E: // Sound effect
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event.setCancelled(true);
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break;
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}
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}
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});
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It's also possible to read and modify the content of these packets. For instance, you can create a global
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censor by listening for Packet3Chat events:
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// Censor
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protocolManager.addPacketListener(
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new PacketAdapter(this, ConnectionSide.CLIENT_SIDE, ListenerPriority.NORMAL, 0x03) {
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@Override
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public void onPacketReceiving(PacketEvent event) {
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if (event.getPacketID() == 0x03) {
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try {
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PacketContainer packet = event.getPacket();
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String message = packet.getSpecificModifier(String.class).read(0);
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if (message.contains("shit") || message.contains("damn")) {
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event.setCancelled(true);
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event.getPlayer().sendMessage("Bad manners!");
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}
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} catch (FieldAccessException e) {
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getLogger().log(Level.SEVERE, "Couldn't access field.", e);
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}
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}
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}
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});
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### Sending packets
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Normally, you might have to do something ugly like the following:
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Packet60Explosion fakeExplosion = new Packet60Explosion();
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fakeExplosion.a = player.getLocation().getX();
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fakeExplosion.b = player.getLocation().getY();
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fakeExplosion.c = player.getLocation().getZ();
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fakeExplosion.d = 3.0F;
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fakeExplosion.e = new ArrayList<Object>();
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((CraftPlayer) player).getHandle().netServerHandler.sendPacket(fakeExplosion);
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But with ProtocolLib, you can turn that into something more manageable. Notice that
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you don't have to create an ArrayList this version:
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PacketContainer fakeExplosion = protocolManager.createPacket(60);
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fakeExplosion.getSpecificModifier(double.class).
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write(0, player.getLocation().getX()).
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write(1, player.getLocation().getY()).
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write(2, player.getLocation().getZ());
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fakeExplosion.getSpecificModifier(float.class).
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write(0, 3.0F);
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protocolManager.sendServerPacket(player, fakeExplosion);
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Compatiblity
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------------
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One of the main goals of this project was to achieve maximum compatibility with CraftBukkit. And the end
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result is quite flexible - in tests I successfully ran an unmodified ProtocolLib on CraftBukkit 1.8.0, and
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it should be resiliant against future changes. It's likely that I won't have to update ProtocolLib for
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anything but bug and performance fixes.
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How is this possible? It all comes down to reflection in the end. Essentially, no name is hard coded -
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every field, method and class is deduced by looking at field types, package names or parameter
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types. It's remarkably consistent across different versions.
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### Incompatiblity
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The following plugins (to be expanded) are not compatible with ProtocolLib:
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