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//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2017-2018 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
import NIO
import Dispatch
private let newLine = "\n".utf8.first!
/// Very simple example codec which will buffer inbound data until a `\n` was found.
final class LineDelimiterCodec: ByteToMessageDecoder {
public typealias InboundIn = ByteBuffer
public typealias InboundOut = ByteBuffer
public var cumulationBuffer: ByteBuffer?
public func decode(context: ChannelHandlerContext, buffer: inout ByteBuffer) throws -> DecodingState {
let readable = buffer.withUnsafeReadableBytes { $0.firstIndex(of: newLine) }
if let r = readable {
context.fireChannelRead(self.wrapInboundOut(buffer.readSlice(length: r + 1)!))
return .continue
}
return .needMoreData
}
}
/// This `ChannelInboundHandler` demonstrates a few things:
/// * Synchronisation between `EventLoop`s.
/// * Mixing `Dispatch` and SwiftNIO.
/// * `Channel`s are thread-safe, `ChannelHandlerContext`s are not.
///
/// As we are using an `MultiThreadedEventLoopGroup` that uses more then 1 thread we need to ensure proper
/// synchronization on the shared state in the `ChatHandler` (as the same instance is shared across
/// child `Channel`s). For this a serial `DispatchQueue` is used when we modify the shared state (the `Dictionary`).
/// As `ChannelHandlerContext` is not thread-safe we need to ensure we only operate on the `Channel` itself while
/// `Dispatch` executed the submitted block.
final class ChatHandler: ChannelInboundHandler {
public typealias InboundIn = ByteBuffer
public typealias OutboundOut = ByteBuffer
// All access to channels is guarded by channelsSyncQueue.
private let channelsSyncQueue = DispatchQueue(label: "channelsQueue")
private var channels: [ObjectIdentifier: Channel] = [:]
public func channelActive(context: ChannelHandlerContext) {
let remoteAddress = context.remoteAddress!
let channel = context.channel
self.channelsSyncQueue.async {
// broadcast the message to all the connected clients except the one that just became active.
self.writeToAll(channels: self.channels, allocator: channel.allocator, message: "(ChatServer) - New client connected with address: \(remoteAddress)\n")
self.channels[ObjectIdentifier(channel)] = channel
}
var buffer = channel.allocator.buffer(capacity: 64)
buffer.writeString("(ChatServer) - Welcome to: \(context.localAddress!)\n")
context.writeAndFlush(self.wrapOutboundOut(buffer), promise: nil)
}
public func channelInactive(context: ChannelHandlerContext) {
let channel = context.channel
self.channelsSyncQueue.async {
if self.channels.removeValue(forKey: ObjectIdentifier(channel)) != nil {
// Broadcast the message to all the connected clients except the one that just was disconnected.
self.writeToAll(channels: self.channels, allocator: channel.allocator, message: "(ChatServer) - Client disconnected\n")
}
}
}
public func channelRead(context: ChannelHandlerContext, data: NIOAny) {
let id = ObjectIdentifier(context.channel)
var read = self.unwrapInboundIn(data)
// 64 should be good enough for the ipaddress
var buffer = context.channel.allocator.buffer(capacity: read.readableBytes + 64)
buffer.writeString("(\(context.remoteAddress!)) - ")
buffer.writeBuffer(&read)
self.channelsSyncQueue.async {
// broadcast the message to all the connected clients except the one that wrote it.
self.writeToAll(channels: self.channels.filter { id != $0.key }, buffer: buffer)
}
}
public func errorCaught(context: ChannelHandlerContext, error: Error) {
print("error: ", error)
// As we are not really interested getting notified on success or failure we just pass nil as promise to
// reduce allocations.
context.close(promise: nil)
}
private func writeToAll(channels: [ObjectIdentifier: Channel], allocator: ByteBufferAllocator, message: String) {
let buffer = allocator.buffer(string: message)
self.writeToAll(channels: channels, buffer: buffer)
}
private func writeToAll(channels: [ObjectIdentifier: Channel], buffer: ByteBuffer) {
channels.forEach { $0.value.writeAndFlush(buffer, promise: nil) }
}
}
// We need to share the same ChatHandler for all as it keeps track of all
// connected clients. For this ChatHandler MUST be thread-safe!
let chatHandler = ChatHandler()
let group = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
let bootstrap = ServerBootstrap(group: group)
// Specify backlog and enable SO_REUSEADDR for the server itself
.serverChannelOption(ChannelOptions.backlog, value: 256)
.serverChannelOption(ChannelOptions.socketOption(.so_reuseaddr), value: 1)
// Set the handlers that are applied to the accepted Channels
.childChannelInitializer { channel in
// Add handler that will buffer data until a \n is received
channel.pipeline.addHandler(ByteToMessageHandler(LineDelimiterCodec())).flatMap { v in
// It's important we use the same handler for all accepted channels. The ChatHandler is thread-safe!
channel.pipeline.addHandler(chatHandler)
}
}
// Enable SO_REUSEADDR for the accepted Channels
.childChannelOption(ChannelOptions.socketOption(.so_reuseaddr), value: 1)
.childChannelOption(ChannelOptions.maxMessagesPerRead, value: 16)
.childChannelOption(ChannelOptions.recvAllocator, value: AdaptiveRecvByteBufferAllocator())
defer {
try! group.syncShutdownGracefully()
}
// First argument is the program path
let arguments = CommandLine.arguments
let arg1 = arguments.dropFirst().first
let arg2 = arguments.dropFirst(2).first
let defaultHost = "::1"
let defaultPort = 9999
enum BindTo {
case ip(host: String, port: Int)
case unixDomainSocket(path: String)
}
let bindTarget: BindTo
switch (arg1, arg1.flatMap(Int.init), arg2.flatMap(Int.init)) {
case (.some(let h), _ , .some(let p)):
/* we got two arguments, let's interpret that as host and port */
bindTarget = .ip(host: h, port: p)
case (let portString?, .none, _):
// Couldn't parse as number, expecting unix domain socket path.
bindTarget = .unixDomainSocket(path: portString)
case (_, let p?, _):
// Only one argument --> port.
bindTarget = .ip(host: defaultHost, port: p)
default:
bindTarget = .ip(host: defaultHost, port: defaultPort)
}
let channel = try { () -> Channel in
switch bindTarget {
case .ip(let host, let port):
return try bootstrap.bind(host: host, port: port).wait()
case .unixDomainSocket(let path):
return try bootstrap.bind(unixDomainSocketPath: path).wait()
}
}()
guard let localAddress = channel.localAddress else {
fatalError("Address was unable to bind. Please check that the socket was not closed or that the address family was understood.")
}
print("Server started and listening on \(localAddress)")
// This will never unblock as we don't close the ServerChannel.
try channel.closeFuture.wait()
print("ChatServer closed")
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