CommunicationsFramework - Java (Netty) Socket Communication made easy

Recently I had the need to be able to talk to multiple game servers whilst players were not connected to the server. We originally used the plugin message api (to which my library PluginMessageAPI+ was born) however that didn't quite do it, we needed to add functionality that required communication between the Lobby & the game servers regardless of whether players are online or not.

The project started off simply using normal Java sockets (non NIO, with Object Input & Output streams) however I intended to use Netty at some future point. I quickly learnt the basics of Netty (NIO) and updated the framework to use it. The framework very quickly expanded to features I needed and it became what it is.

GitHub: here
JavaDocs: here

Requirements:

• Java 7 or higher (Java 8 is recommended for simpler/shorter code with lambdas)
• Any ports used be forwarded on the server-side (if you need to have access to them externally)

Features (up to date list here) :

• Easy persistent Client <-> Server connections.
• Secure connections with a key.
• Create your own packets with ease.
• Listen for connection events (such as connected, lost connection, reconnect and more to be added).
• Automatic handling of reconnects.
• Packet queue system which allows packets to be queued for sending when the connection currently isn't available (waiting for connection or reconnecting).
• Graceful disconnecting, no more exception spams when one side disconnects for whatever reason.
• Heartbeats which allow us to determine if the other side has disconnected quickly.
• Fully documented frontend, no need to deal with confusing internals (just make sure you only use classes within the "api" package).
• Community support (hopefully), the efforts of the community will usually always be better than what someone can achieve on their own and if one person adds a new feature, everyone benefits.

Usage:

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Unfortunately I do not currently own a dedicated server to which I can host a Maven repo for the project, you will have to clone the repo & build it locally to add the project to your local Maven repo. If that is not an option for you, you can always simply download the files from the repo and copy them into your project directly, however this is not recommended. I will update this thread as soon as I acquire a means of hosting CommunicationsFramework on a Maven repo.​

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The best way to learn is by example, I have included in the source code, 2 examples with lots of comments to explain what everything does. These examples will be updated as the framework evolves.​

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Standard (un-secure, simpler): https://github.com/iKeirNez/Communi...nez/communicationsframework/examples/standard​

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Authenticated (more secure, slightly less simple): https://github.com/iKeirNez/Communi...mmunicationsframework/examples/authentication​

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I highly recommend using the Authenticated client to prevent anyone from simply connecting to your server (unless that's what is intended).​

Future:

One of the highest on my list is to implement a way of sending very short messages in a much better matter (currently it involves creating an empty class which implements Packet).​

Pull requests would be awesome and much appreciated! See the GitHub README for more details.​

Feedback is greatly appreciated and helps motivate me. Let me know where you use this, how it benefits you or what you think needs improved upon.

 

iKeirNez
Any javadocs for this? It would take great advantage of gh-pages branch as I have done (not self advertising or anything, but I use as an example here. The javadocs are here).

 

Thanks for the advice, here are the JavaDocs http://ikeirnez.github.io/CommunicationsFramework/javadocs/

 

iKeirNez what's the delay between sending and receiving packets?

 

chasechocolate Depends on the latency between the servers, if its on the same machine it should be pretty much instant. Any idea on a good way to get timings, or do I just need manually calculate it?

 

iKeirNez Well I guess you could just send System.currentTimeMillis() in the data, and then compare it to the current time on the receiving server.

 

Alright, I'll try get some timings soon.

I spent some time writing a nice small project to test the timings of CommunicationsFramework. I sent 5000 packets with an average of 0.34 milliseconds (this includes processing and distributing to listeners) for the packet to be sent and received by the other side (locally, so latency doesn't affect the timings).

I will post the source for the application I used to determine the speed.

Edit: Here it is https://github.com/iKeirNez/Communi...rNez/CommunicationsFramework/examples/timings

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

iKeirNez
How do you use this in a plugin?

 

Are you asking how I personally use it or are you looking for code examples?

 

iKeirNez
If I want to send something between servers, how do I implement this in my plugin

Do I have to add a dependency, or add the code to my project

iKeirNez
I cloned it to eclipse but I get many errors

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Normally you'd add it in via a Maven repo, however I currently don't have one to host it on. You have to clone it into Eclipse as you have done but you also need to add Maven support to the project so that Maven will download needed dependencies. And then build it using Maven which will add the library to your local Maven repo.

 

iKeirNez
I am still getting errors

For example, in StandaredInitializer:
connection.getConnectionManager() gives an error:"The method getConnectionManager is undefined for the type IConnection"

Code:java

public static void addObjectHandlers(IConnection connection, ChannelPipeline channelPipeline){
        channelPipeline.addLast(
                new ObjectEncoder(),
                new ObjectDecoder(ClassResolvers.weakCachingResolver(connection.getConnectionManager().classLoader)),
                new BasicHandler(connection));
    }

 

Looks like lombok maybe isn't enabled? Make sure your compiling with Maven and not Eclipse.

 

iKeirNez
How do you do that?

 

If your compiling with Maven, lombok should work. As for the Maven in Eclipse, what Eclipse version are you using? Eclipse support for Maven isn't great, I'd recommend switching to IntelliJ IDEA which has this functionality built-in.

 

@iKeirNez
Switching to intellij worked, Thanks

 

Awesome. you'll never regret it.

 

Just thought I'd let you guys know that I'm planning a major update for this soon however its taking me longer due to school, private projects and life. However it will be very powerful when its done

 

Is this for an MC Server only or could it be used for non-mc server?

 

Can be used for anything as long as it's Java

 

Thanks, that'll be good for my new project.

 

Awesome, if its open to the public, keep me updated? Maybe via PM? Just interested to see how people use the framework. We'll have it up on the sonatype nexus maven repo soon (hopefully) and JavaDocs will be hosted by GitHub pages. Planning some very big changes for 3.0.

 

Yeah, sadly I'll need to change a lot of my code, but luckily I'm not far in xD. I'll PM you too.

 

Shouldn't be too hard to update it, 3.0 update could be awhile though. If its too much work you could always stay on a lower version.

 

JavaDocs are led to a 404.

 

Fixed

 

io.netty.channel.ChannelPipelineException: net.theemeraldisle.libs.netty.handlers.PacketHandler is not a @Sharable handler, so can't be added or removed multiple times.

Error at StandardInitializer.java:39

I think you need to add @Sharable to your packet handler.

Also, your ConnectionManagerFactory returns a null instance.
I used the deprecated ConcreteConnectionManager constructor in there for now.
But you may want to change that

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

lenis0012 Okay, the issue currently is that I'm working on version 3 and it's kinda tricky to go back to previous versions and add fixes. I believe in a more recent version I fixed the ConnectionManagerFactory returning null. I wasn't aware of the first issue but will look into it.

 

Ok.
But id id clone the latest code from github this morning

What about multi server support?

Right now you can only connect one client to a server.

Other then that, i like it a lot.

 

Currently you have to use different ports however we're working on allowing multiple server connections to share a port.