GotoPS

Enet bindings in Go for Growtopia Private Server using cgo. Based on codecat/go-enet

Tip

Want to see an example of a server that uses this library? Look at gotops.

Installation

First, you might need to build enet from enet/ directory and install it as library:

Windows: Build the enet dynamic library (.dll) with Code::Blocks. (Tested with: TDM-GCC 10.3.0 installed, Windows 11 Intel Core I7-6700HQ).

git clone --recurse-submodules https://github.com/eikarna/gotops
cd gotops/enet
"C:\Program Files\CodeBlocks\codeblocks.exe" /na /nd enet_dll.cbp

If you got error message: 'IP_TTL' undeclared (first use in this function), just add #include <Ws2tcpip.h> to the top of win32.c.

REMEMBER TO BUILD TARGET "Release" ONLY.

Got Any Error again? just try to fix it by yourself.

After successfully build, you must copy build output files (include: libenet.a, libenet.dll, libenet.def) to your root project. And then you can use this go module without any problem.

Linux: Install the enet library with make.

git clone --recurse-submodules https://github.com/eikarna/gotops
cd gotops/enet
autoreconf -vfi
./configure && make && sudo make install

Termux: Same as Linux, but after run autoreconf -vfi:

./configure
make
make prefix=/data/data/com.termux/files/usr libdir=/data/data/com.termux/files/usr/lib install

If you got warning message: libtool: warning: remember to run 'libtool --finish /usr/local/lib', just run:

libtool --finish /data/data/com.termux/files/usr/lib

MacOS: Install the enet package with brew: brew install enet

$ go get github.com/eikarna/gotops

Usage

import "github.com/eikarna/gotops"

The API is mostly the same as the C API, except it's more object-oriented.

Server example

This is a basic server example that responds to packets "ping" and "bye".

package main

import (
	"github.com/eikarna/gotops"
	"github.com/codecat/go-libs/log"
)

func main() {
	// Initialize enet
	enet.Initialize()

	// Create a host listening on 0.0.0.0:17091
	host, err := enet.NewHost(enet.NewListenAddress(17091), 1024, 1, 0, 0)
	if err != nil {
		log.Error("Couldn't create host: %s", err.Error())
		return
	}

	// The event loop
	for true {
		// Wait until the next event
		ev := host.Service(1000)

		// Do nothing if we didn't get any event
		if ev.GetType() == enet.EventNone {
			continue
		}

		switch ev.GetType() {
		case enet.EventConnect: // A new peer has connected
			log.Info("New peer connected: %s", ev.GetPeer().GetAddress())

		case enet.EventDisconnect: // A connected peer has disconnected
			log.Info("Peer disconnected: %s", ev.GetPeer().GetAddress())

		case enet.EventReceive: // A peer sent us some data
			// Get the packet
			packet := ev.GetPacket()

			// We must destroy the packet when we're done with it
			defer packet.Destroy()

			// Get the bytes in the packet
			packetBytes := packet.GetData()

			// Respond "pong" to "ping"
			if string(packetBytes) == "ping" {
				ev.GetPeer().SendString("pong", ev.GetChannelID(), enet.PacketFlagReliable)
				continue
			}

			// Disconnect the peer if they say "bye"
			if string(packetBytes) == "bye" {
				log.Info("Bye!")
				ev.GetPeer().Disconnect(0)
				continue
			}
		}
	}

	// Destroy the host when we're done with it
	host.Destroy()

	// Uninitialize enet
	enet.Deinitialize()
}

Client example

This is a basic client example that sends a ping to the server every second that there is no event.

package main

import (
	"github.com/eikarna/gotops"
	"github.com/codecat/go-libs/log"
)

func main() {
	// Initialize enet
	enet.Initialize()

	// Create a client host
	client, err := enet.NewHost(nil, 1, 1, 0, 0)
	if err != nil {
		log.Error("Couldn't create host: %s", err.Error())
		return
	}

	// Connect the client host to the server
	peer, err := client.Connect(enet.NewAddress("127.0.0.1", 17091), 1, 0)
	if err != nil {
		log.Error("Couldn't connect: %s", err.Error())
		return
	}

	// The event loop
	for true {
		// Wait until the next event
		ev := client.Service(1000)

		// Send a ping if we didn't get any event
		if ev.GetType() == enet.EventNone {
			peer.SendString("ping", 0, enet.PacketFlagReliable)
			continue
		}

		switch ev.GetType() {
		case enet.EventConnect: // We connected to the server
			log.Info("Connected to the server!")

		case enet.EventDisconnect: // We disconnected from the server
			log.Info("Lost connection to the server!")

		case enet.EventReceive: // The server sent us data
			packet := ev.GetPacket()
			log.Info("Received %d bytes from server", len(packet.GetData()))
			packet.Destroy()
		}
	}

	// Destroy the host when we're done with it
	client.Destroy()

	// Uninitialize enet
	enet.Deinitialize()
}