ProtocolLib
ProtocolLib
ProtocolLib has, for the most part, moved over to Spigot! If you need support, head over there!
Certain tasks are impossible to perform with the standard Bukkit API, and may require working with and even modify Minecraft directly. A common technique is to modify incoming and outgoing packets, or inject custom packets into the stream. This is quite cumbersome to do, however, and most implementations will break as soon as a new version of Minecraft has been released, mostly due to obfuscation.
Critically, different plugins that use this approach may hook into the same classes, with unpredictable outcomes. More than often this causes plugins to crash, but it may also lead to more subtle bugs.
Links
Development builds of ProtocolLib can be found here: https://ci.dmulloy2.net/job/ProtocolLib/
These builds have not been approved by the BukkitDev staff. Use them at your own risk.
Support
Please create a issue with as much information as possible if you experience a problem that has not already been reported. Comments with a huge stack trace will be deleted.
If you need help with the API, please use the issue tracker. If your question cannot be made public for whatever reason (including security bugs), send me a personal message instead.
For server operators
Just download ProtocolLib from the link above. It doesn't do anything on its own, it simply allows other plugins to function.
FAQ
- Why do I get FieldAccessExceptions when I try to read or write from packets?
Quote:The reason for these exceptions is because ProtocolLib is not using the packet format as described on the Wiki, it's using the in-memory representation of these packets. Often, the in-memory representation will use integers instead of shorts and bytes, and store more complex objects (like ItemStacks) directly.
You can figure out the in-memory representation from the Minecraft source code, or just use PacketWrapper where I've done all that work for you.
Examples
Source code for a bunch of example programs that use ProtocolLib can be found at this thread on the main support forum.
You may also be interested in PacketWrapper, a library that makes it possible to modify a packet without having to decompile the Minecraft source code.
Finally, for the more advanced users who want to use ProtocolLib if present, but still fall back on their own packet listening system, I recommend taking a look at this thread. I explain where and how to inject code into CraftBukkit in order to intercept sent and received packets yourself.
Maven repository
If you're using Maven, you'll be able to automatically download the JAR, JavaDoc and associated sources from the following repository:
<repositories> <repository> <id>dmulloy2-repo</id> <url>https://repo.dmulloy2.net/content/groups/public/</url> </repository> <!-- And so on --> </repositories>
You can add it as a dependency like so:
<dependencies> <dependency> <groupId>com.comphenix.protocol</groupId> <artifactId>ProtocolLib</artifactId> <version>4.5.0</version> </dependency> <!-- And so on --> </dependencies>
Commands
Protocol
Main administrative command. Supports the following sub-commands:
- config: Reload the configuration file.
- check: Check for new versions on BukkitDev.
- update: Check for new versions and automatically download the JAR. The server must be restarted for this to take effect.
- timings: Toggle measuring the amount of CPU time spent by each plugin. See here for more information.
- listeners: Display what plugins are using ProtocolLib, and the packet types they are intercepting.
All of these commands require the permission protocol.admin.
Example:
/protocol update
Packet
Add or remove a debug packet listener. This is useful for plugin authors who just wants to see when a packet is sent, and with what content.
Sub commands:
- add: Add a packet listener with a given packet ID.
- remove: Remove one or every packet listener with the given packet IDs.
- names: Print the name of every given packet ID.
Parameters (in order):
- Connection side: Either client or server.
- Multiple ID ranges: Can be a single packet ID like 14, or a range like 10 - 15. Defaults to 0 - 255 if not specified.
- Detailed: If TRUE, prints the full packet content.
Example:
/packet add client 10-13 true
For 3.0.0 and above, you should specify the protocol, sender and name instead:
/packet add play server chat true
In 3.4.0-SNAPSHOT and above, you can also display the packet before its modified by any packet listeners:
/packet add play server chat compare
Remove all listeners:
/packet remove client /packet remove server
Note that this command should rarely be used on a production server. Listening to too many packets may crash the server.
Filter
The filter system (introduced in 2.4.1) uses the built in JavaScript interpreter in JVM 6 (Rhino) to extend the packet command with filtering capabilities - it is now possible to, say, only print entity metadata packet events (packet add server 40) for a given entity ID:
> packet add server 40 true Added listener ListeningWhitelist{priority=MONITOR, packets=[40]} > filter add entity_filter 40 Enter filter program ('}' to complete or CANCEL): function(event, packet) { > return packet.a == 1000; >} Added filter entity_filter.
This should be much more convenient than having to compile a test plugin and reload the whole server. Note that this feature is disabled by default for security reasons. To enable it, add "debug: true" to config.yml.
Configuration
A small set of configuration options are available:
Global section
Option | Default |
Description |
---|---|---|
auto updater.notify | true | Inform any player with the permission protocol.info when a new version of ProtocolLib is out. |
auto updater.download | true | Automatically download and install the newest version of ProtocolLib. The installation will take effect when the server restarts. |
auto updater.delay | 43200 | The number of seconds between each check for a new update. |
auto updater.last | 0 | This simply records the last time (in seconds since 01.01.1970) an update check was performed. Set it to 0 to force a new update check. |
metrics | true | If TRUE, ProtocolLib will publish anonymous usage data to mcstats.org. Set it to FALSE to opt-out. |
background compiler | true | If TRUE, ProtocolLib will try and improve performance by replacing reflection with compiled code on-the-fly. |
ignore version check | None | Force ProtocolLib to start for a specified Minecraft version, even if it is incompatible. |
suppressed reports | None | If any error or warning report is present in this list, they will not appear in the console or the log. |
For more information, take a look at the default configuration file.
Tutorial for developers
See this page for more information.
Compatibility
One of the main goals of this project was to achieve maximum compatibility with Minecraft. And the end result is quite good, it should be resilient against future changes. It's likely that I won't have to update ProtocolLib for anything but bug and performance fixes.
How is this possible? It all comes down to reflection in the end. Essentially, no name is hard coded - every field, method and class is deduced by looking at field types, package names or parameter types. It's remarkably consistent across different versions.
(note that the below list hasn't been updated in ages and ymmv)
Plugins that appear to be compatible
Plugins known to be compatible
- SpoutPlugin
Plugins using ProtocolLib
- Orebfuscator
- TagAPI
- DisguiseCraft
- VanishNoPacket (v3.18.5 and earlier)
- BkCommonLib
- CraftBook
- ChairsReloaded (3.0.2 and earlier)
- Scavenger
- TabAPI
- Individual-Signs
- ItemRenamer
- RandomCoords
- AntiCommandTab
- Sneaky
- Spy
- Statues
- Seasons
- Safe Command Block
- PlayerHider
- Phantasma Chat Filter
- Ghost Hunt
- ReMap
- AttributeHider
- uCars
- uPlanes
- PropHunt
- Portable-Horses
- ClickEdit
- RageBan
- ReChat
- PlayEffect
- FakePlayers
- PlayerCountMessage
- Vampire
- Murder
- NoSpy
- PingNachricht
- NoCheatPlus
- ScoreboardStats
Inactive projects
Please let me know if you want me to add your plugin to this list. :)
Privacy
This plugin uses BStats to generate and publish anonymous aggregate usage statistics, but you can easily opt-out by setting metrics in config.yml to false.
If enabled, the following is sent every ten minutes:
- Metrics revision version (currently 6).
- Server's GUID
- Players currently online (not max player count)
- Server version string (the same version string you see in /version)
- Current version of ProtocolLib
- The name of every plugin that registers a packet listener in ProtocolLib.
Donating
If ProtocolLib has made your life significantly easier or you're feeling particularly generous, consider donating! It's a great way to support the many hours I've spent maintaining this plugin and keeps me motivated. Don't donate if you can't afford it.
I would like to thank everyone who has donated to ProtocoLib on BukkitDev. I really appreciate it. :)
Note: Create an issue if you're having problems. I generally don't check the BukkitDev comments.
I'm having a hard time understanding what this does for a plugin developer. So you can do certain actions based on packets sent and received?
@libraryaddict
Oh. :(
Do you know why?
You may as well remove Lib's Disguises from the list.
BukkitDev staff took it down.
@Andre424971
I assume you would like it to be added to the list then? :)
@McServerExpertDe
Sure. :)
Hello, please add my Plugin NoSpy (http://dev.bukkit.org/bukkit-plugins/nospy/) to your pluginlist.
Thank you
@JackzMc
I managed to find the culprit. :)
It's because EasyJetpack contains duplicate classes of "com.comphenix.executors", which conflicts with "com.comphenix.executors" in ProtocolLib. You're not supposed to use other people's name spaces in your own plugin, so this is clearly a mistake (likely an oversight due to Maven shading).
I've notified the developer of EasyJetpack on GitHub, though you could contact him or her yourself.
In the meantime, you can actually fix this yourself. Just open EasyJetpack-1.2.jar in a ZIP-program like 7-zip or WinRar (depending on your operating system) and remove the "com" folder. Save, and restart the server. The problem should be gone.
@aadnk
That was the startup log for protocol lib, the error after it enabled, that's what I meant.
Here's my FULL startup log, I just did "restart" in mcprohosting's console.
http://pastebin.com/PRnY3e8m - It expires in 1 day
Also this is for my testing server only. Both servers have the same spigot version, and the main server has more plugins and it loads 100% fine, but my testing server has way less and it will not load. Both have sexymotd plugin, but only the testing server has mcore (and it's not loading files correct)
EDIT: I uninstalled mcore, now sexymotd is causing it too.
@JackzMc
Startup thing? Do you mean some kind of control panel or plugin that can disable and re-enable plugins? Unfortunately, that is not supported by ProtocolLib - you have to completely reload the server each time.
And again, that stack trace doesn't contain any useful information, I'm afraid. It only tells me MCore failed, which is not surprising if ProtocolLib failed to load.
See if you can't find any other stack traces that may be related.
@aadnk
That was my startup thing, it just enabled it.
@JackzMc
That must be because ProtocolLib itself failed to load. Could you please post the stack trace (error message) you get right when ProtocolLib is loading. Just look for the text "ProtocolLib".
Or - just send me your entire server log on PM, if you can't find it.
@aadnk
Great! Thank you very much! :)
Protocollib 3.3.1 won't work for my server (red, instead of green). Using Spigot build #1487. So I tried 3.4.0, it won't load at all.
Using 3.3.1 and I restarted and got this:
http://pastebin.com/kzdCzbiA
@Ozelo
You need to update TagAPI to the latest version on BukkitDev.
Please, help. I dont't know what this could be:
@libraryaddict
There's already a constructor that takes an UUID. Though I suppose that static method was hiding it a bit. :P
Unfortunately, both UUID and name can be NULL in GameProfile (just not both at once), so if I return NULL instead of throwing an exception it would be impossible to separate the legitimate case of a NULL UUID and an invalid ID.
A possible alternative is using Optional (in Guava, not Java 8), but I don't feel that such a wrapper truly captures the fact that an invalid ID (anything that can't remotely be construed as an UUID) is an exceptional and incorrect state. It's also a bit unconventional given the current state of the API.
@aadnk
Cheers.
Also. Er. You need to provide a UUID constructor >.>
Personally I'd recommend just returning a null UUID if the ID can't be parsed. Sometimes plugins do stupid things with UUID's when modifying gameprofiles. Though that shouldn't be a issue as UUID's are no longer stored as strings.
@Snowbrz
I don't override or change the help command in ProtocolLib, no. It must be due to a different plugin. But are you sure you're not just using the standard "help" command in Bukkit?
@libraryaddict
@Stevenpcc
No problem. :)
@Minecraft4dummis
Timer? Do you mean a countdown clock? You don't need ProtocolLib for that - just use the Bukkit scheduler. Could you be a bit more specific?
am i able to make a timer with this plugin?
@aadnk
Thanks. Will watch it for a few days and report back if the leak still happens.