NIO UDP echo server.swift

readme.md

Unable to run in macOS target

Apparently the problem is caused by not having clang modules enabled for the C targets. To enable them go to your Xcode project and in all the C targets (the NIO ones start with a C like CAtomics), change the Enable Modules (C and Objective-C) to YES.

And add the following import paths: -Xcc -fmodule-map-file=$(SRCROOT)/Protocol/Atem.xcodeproj/GeneratedModuleMap/CNIOAtomics/module.modulemap -Xcc -fmodule-map-file=$(SRCROOT)/Protocol/Atem.xcodeproj/GeneratedModuleMap/CNIOLinux/module.modulemap -Xcc  -fmodule-map-file=$(SRCROOT)/Protocol/Atem.xcodeproj/GeneratedModuleMap/CNIODarwin/module.modulemap

You probably want to use an .xcconfig file to do that automatically. swift package generate-xcodeproj --xcconfig-overrides path/to/your/.xcconfig

NioUDP.swift

import Foundation
import NIO

final class Echo: ChannelInboundHandler {
	typealias   InboundIn = AddressedEnvelope<ByteBuffer>
	typealias OutboundOut = AddressedEnvelope<ByteBuffer>
	
	static let response = "You sent: ".data(using: .utf8)!
	
	func channelRead(ctx: ChannelHandlerContext, data: NIOAny) {
		var incomingEnvelope = unwrapInboundIn(data)
		var buffer = ctx.channel.allocator.buffer(capacity: Echo.response.count + incomingEnvelope.data.readableBytes)
		buffer.write(bytes: Echo.response)
		buffer.write(buffer: &incomingEnvelope.data)
		
		let envelope = AddressedEnvelope(remoteAddress: incomingEnvelope.remoteAddress, data: buffer)
		ctx.write(wrapOutboundOut(envelope), promise: nil)
	}
	
	func channelReadComplete(ctx: ChannelHandlerContext) {
		ctx.flush()
	}
}

let 🔂 = MultiThreadedEventLoopGroup(numThreads: 1)
let bootstrap = DatagramBootstrap(group: 🔂)
	.channelOption(ChannelOptions.socket(SocketOptionLevel(SOL_SOCKET), SO_REUSEADDR), value: 1)
	.channelInitializer { $0.pipeline.add(handler: Echo()) }
defer {
	try! 🔂.syncShutdownGracefully()
}


try bootstrap
	.bind(host: "127.0.0.1", port: 4065)
	.wait()
	.closeFuture
	.wait()

package.swift

import PackageDescription

let package = Package(
  name: "NIO UDP Echo server",

  dependencies: [
    .package(url: "https://github.com/apple/swift-nio.git", 
             from: "1.1.0"),
  ],

  targets: [
    .target(name: "NIO UDP Echo server", 
      dependencies: [
        "NIO"
      ]
    )
  ]
)