版本记录

版本号	时间
V1.0	2019.07.09 星期二

前言

实时通信在很多App上都有应用，包括我在上一家公司做的App也使用了实时通信技术，用于私聊和群聊，所以这里特意开一个专题一起学习一下实时通信技术。感兴趣的看下面几篇文章。
1. 实时通信技术研究（一） —— 基于Socket和TCP网络的实时聊天信息流的实现（一）

源码

1. Swift

首先看下工程组织结构

下面就是源码了

1. ChatRoomViewController.swift

import UIKit

class ChatRoomViewController: UIViewController {
  let tableView = UITableView()
  let messageInputBar = MessageInputView()
  let chatRoom = ChatRoom()
  
  var messages: [Message] = []
  
  var username = ""
  
  override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    chatRoom.delegate = self
    chatRoom.setupNetworkCommunication()
    chatRoom.joinChat(username: username)
  }
  
  override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    chatRoom.stopChatSession()
  }
}

//MARK - Message Input Bar
extension ChatRoomViewController: MessageInputDelegate {
  func sendWasTapped(message: String) {
    chatRoom.send(message: message)
  }
}

extension ChatRoomViewController: ChatRoomDelegate {
  func received(message: Message) {
    insertNewMessageCell(message)
  }
}

2. ChatRoomViewController+Table.swift

import UIKit

extension ChatRoomViewController: UITableViewDataSource, UITableViewDelegate {
  func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = MessageTableViewCell(style: .default, reuseIdentifier: "MessageCell")
    cell.selectionStyle = .none
    
    let message = messages[indexPath.row]
    cell.apply(message: message)
    
    return cell
  }
  
  func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return messages.count
  }
  
  func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    let height = MessageTableViewCell.height(for: messages[indexPath.row])
    return height
  }
  
  func insertNewMessageCell(_ message: Message) {
    messages.append(message)
    let indexPath = IndexPath(row: messages.count - 1, section: 0)
    tableView.beginUpdates()
    tableView.insertRows(at: [indexPath], with: .bottom)
    tableView.endUpdates()
    tableView.scrollToRow(at: indexPath, at: .bottom, animated: true)
  }
}

3. JoinChatViewController.swift

import UIKit

class JoinChatViewController: UIViewController {
  let logoImageView = UIImageView()
  let shadowView = UIView()
  let nameTextField = TextField()
}

extension JoinChatViewController: UITextFieldDelegate {
  func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    let chatRoomVC = ChatRoomViewController()
    if let username = nameTextField.text {
      chatRoomVC.username = username
    }
    navigationController?.pushViewController(chatRoomVC, animated: true)
    return true
  }
}

class TextField: UITextField {
  let padding = UIEdgeInsets(top: 0, left: 16, bottom: 0, right: 8)
  
  override func textRect(forBounds bounds: CGRect) -> CGRect {
    return bounds.inset(by: padding)
  }
  
  override func placeholderRect(forBounds bounds: CGRect) -> CGRect {
    return bounds.inset(by: padding)
  }
  
  override func editingRect(forBounds bounds: CGRect) -> CGRect {
    return bounds.inset(by: padding)
  }
}

4. Label.swift

import UIKit

class Label: UILabel {
  override func drawText(in rect: CGRect) {
    let insets = UIEdgeInsets.init(top: 8, left: 16, bottom: 8, right: 16)
    super.drawText(in: rect.inset(by: insets))
  }
}

5. Layouts.swift

import UIKit

extension ChatRoomViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
    
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: UIResponder.keyboardWillChangeFrameNotification, object: nil)
    
    loadViews()
  }
  
  @objc func keyboardWillChange(notification: NSNotification) {
    if let userInfo = notification.userInfo {
      let endFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)!.cgRectValue
      let messageBarHeight = messageInputBar.bounds.size.height
      let point = CGPoint(x: messageInputBar.center.x, y: endFrame.origin.y - messageBarHeight/2.0)
      let inset = UIEdgeInsets(top: 0, left: 0, bottom: endFrame.size.height, right: 0)
      UIView.animate(withDuration: 0.25) {
        self.messageInputBar.center = point
        self.tableView.contentInset = inset
      }
    }
  }
  
  func loadViews() {
    navigationItem.title = "Let's Chat!"
    navigationItem.backBarButtonItem?.title = "Run!"
    
    view.backgroundColor = UIColor(red: 24 / 255, green: 180 / 255, blue: 128 / 255, alpha: 1.0)
    
    tableView.dataSource = self
    tableView.delegate = self
    tableView.separatorStyle = .none
    
    view.addSubview(tableView)
    view.addSubview(messageInputBar)
    
    messageInputBar.delegate = self
  }
  
  override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    let messageBarHeight:CGFloat = 60.0
    let size = view.bounds.size
    tableView.frame = CGRect(x: 0, y: 0, width: size.width, height: size.height - messageBarHeight - view.safeAreaInsets.bottom)
    messageInputBar.frame = CGRect(x: 0, y: size.height - messageBarHeight - view.safeAreaInsets.bottom, width: size.width, height: messageBarHeight)
  }
}

extension JoinChatViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
    
    loadViews()
    
    view.addSubview(shadowView)
    view.addSubview(logoImageView)
    view.addSubview(nameTextField)
  }

  func loadViews() {
    view.backgroundColor = UIColor(red: 24/255, green: 180/255, blue: 128/255, alpha: 1.0)
    navigationItem.title = "Doge Chat!"
    
    logoImageView.image = UIImage(named: "doge")
    logoImageView.layer.cornerRadius = 4
    logoImageView.clipsToBounds = true
    
    shadowView.layer.shadowColor = UIColor.black.cgColor
    shadowView.layer.shadowRadius = 5
    shadowView.layer.shadowOffset = CGSize(width: 0.0, height: 5.0)
    shadowView.layer.shadowOpacity = 0.5
    shadowView.backgroundColor = UIColor(red: 24 / 255, green: 180 / 255, blue: 128 / 255, alpha: 1.0)
    
    nameTextField.placeholder = "What's your username?"
    nameTextField.backgroundColor = .white
    nameTextField.layer.cornerRadius = 4
    nameTextField.delegate = self
    
    let backItem = UIBarButtonItem()
    backItem.title = "Run!"
    navigationItem.backBarButtonItem = backItem
  }
  
  override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    
    logoImageView.bounds = CGRect(x: 0, y: 0, width: 150, height: 150)
    logoImageView.center = CGPoint(x: view.bounds.size.width / 2.0, y: logoImageView.bounds.size.height / 2.0 + view.bounds.size.height/4)
    shadowView.frame = logoImageView.frame
    
    nameTextField.bounds = CGRect(x: 0, y: 0, width: view.bounds.size.width - 40, height: 44)
    nameTextField.center = CGPoint(x: view.bounds.size.width / 2.0, y: logoImageView.center.y + logoImageView.bounds.size.height / 2.0 + 20 + 22)
  }
}

extension MessageTableViewCell {
  override func layoutSubviews() {
    super.layoutSubviews()
    
    if isJoinMessage() {
      layoutForJoinMessage()
    } else {
      messageLabel.font = UIFont(name: "Helvetica", size: 17)
      messageLabel.textColor = .white
      
      let size = messageLabel.sizeThatFits(CGSize(width: 2 * (bounds.size.width / 3), height: .greatestFiniteMagnitude))
      messageLabel.frame = CGRect(x: 0, y: 0, width: size.width + 32, height: size.height + 16)
      
      if messageSender == .ourself {
        nameLabel.isHidden = true
        
        messageLabel.center = CGPoint(x: bounds.size.width - messageLabel.bounds.size.width/2.0 - 16, y: bounds.size.height/2.0)
        messageLabel.backgroundColor = UIColor(red: 24 / 255, green: 180 / 255, blue: 128 / 255, alpha: 1.0)
      } else {
        nameLabel.isHidden = false
        nameLabel.sizeToFit()
        nameLabel.center = CGPoint(x: nameLabel.bounds.size.width / 2.0 + 16 + 4, y: nameLabel.bounds.size.height/2.0 + 4)
        
        messageLabel.center = CGPoint(x: messageLabel.bounds.size.width / 2.0 + 16, y: messageLabel.bounds.size.height/2.0 + nameLabel.bounds.size.height + 8)
        messageLabel.backgroundColor = .lightGray
      }
    }
    
    messageLabel.layer.cornerRadius = min(messageLabel.bounds.size.height / 2.0, 20)
  }
  
  func layoutForJoinMessage() {
    messageLabel.font = UIFont.systemFont(ofSize: 10)
    messageLabel.textColor = .lightGray
    messageLabel.backgroundColor = UIColor(red: 247 / 255, green: 247 / 255, blue: 247 / 255, alpha: 1.0)
    
    let size = messageLabel.sizeThatFits(CGSize(width: 2 * (bounds.size.width / 3), height: .greatestFiniteMagnitude))
    messageLabel.frame = CGRect(x: 0, y: 0, width: size.width + 32, height: size.height + 16)
    messageLabel.center = CGPoint(x: bounds.size.width / 2, y: bounds.size.height / 2.0)
  }
  
  func isJoinMessage() -> Bool {
    if let words = messageLabel.text?.components(separatedBy: " ") {
      if words.count >= 2 && words[words.count - 2] == "has" && words[words.count - 1] == "joined" {
        return true
      }
    }
    
    return false
  }
}

6. Message.swift

import Foundation

struct Message {
  let message: String
  let senderUsername: String
  let messageSender: MessageSender
  
  init(message: String, messageSender: MessageSender, username: String) {
    self.message = message.withoutWhitespace()
    self.messageSender = messageSender
    self.senderUsername = username
  }
}

7. MessageInputView.swift

import UIKit

protocol MessageInputDelegate {
  func sendWasTapped(message: String)
}

class MessageInputView: UIView {
  var delegate: MessageInputDelegate?
  
  let textView = UITextView()
  let sendButton = UIButton()
  
  override init(frame: CGRect) {
    super.init(frame: frame)
    
    backgroundColor = UIColor(red: 247 / 255, green: 247 / 255, blue: 247 / 255, alpha: 1.0)
    textView.layer.cornerRadius = 4
    textView.layer.borderColor = UIColor(red: 200 / 255, green: 200 / 255, blue: 200 / 255, alpha: 0.6).cgColor
    textView.layer.borderWidth = 1
    
    sendButton.backgroundColor = UIColor(red: 8 / 255, green: 183 / 255, blue: 231 / 255, alpha: 1.0)
    sendButton.layer.cornerRadius = 4
    sendButton.setTitle("Send", for: .normal)
    sendButton.isEnabled = true
    
    sendButton.addTarget(self, action: #selector(MessageInputView.sendTapped), for: .touchUpInside)
    
    addSubview(textView)
    addSubview(sendButton)
  }
  
  @objc func sendTapped() {
    if let delegate = delegate, let message = textView.text {
      delegate.sendWasTapped(message:  message)
      textView.text = ""
    }
  }
  
  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
  
  override func layoutSubviews() {
    super.layoutSubviews()
    
    let size = bounds.size
    textView.bounds = CGRect(x: 0, y: 0, width: size.width - 32 - 8 - 60, height: 40)
    sendButton.bounds = CGRect(x: 0, y: 0, width: 60, height: 44)
    
    textView.center = CGPoint(x: textView.bounds.size.width/2.0 + 16, y: bounds.size.height / 2.0)
    sendButton.center = CGPoint(x: bounds.size.width - 30 - 16, y: bounds.size.height / 2.0)
  }
}

extension MessageInputView: UITextViewDelegate {
  func textViewShouldEndEditing(_ textView: UITextView) -> Bool {
    return true
  }
}

8. MessageTableViewCell.swift

import UIKit

enum MessageSender {
  case ourself
  case someoneElse
}

class MessageTableViewCell: UITableViewCell {
  var messageSender: MessageSender = .ourself
  let messageLabel = Label()
  let nameLabel = UILabel()
  
  func apply(message: Message) {
    nameLabel.text = message.senderUsername
    messageLabel.text = message.message
    messageSender = message.messageSender
    setNeedsLayout()
  }
  
  override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
    super.init(style: style, reuseIdentifier: reuseIdentifier)
    messageLabel.clipsToBounds = true
    messageLabel.textColor = .white
    messageLabel.numberOfLines = 0
    
    nameLabel.textColor = .lightGray
    nameLabel.font = UIFont(name: "Helvetica", size: 10)

    clipsToBounds = true
    
    addSubview(messageLabel)
    addSubview(nameLabel)
  }
  
  class func height(for message: Message) -> CGFloat {
    let maxSize = CGSize(width: 2*(UIScreen.main.bounds.size.width/3), height: CGFloat.greatestFiniteMagnitude)
    let nameHeight = message.messageSender == .ourself ? 0 : (height(forText: message.senderUsername, fontSize: 10, maxSize: maxSize) + 4 )
    let messageHeight = height(forText: message.message, fontSize: 17, maxSize: maxSize)
    
    return nameHeight + messageHeight + 32 + 16
  }
  
  private class func height(forText text: String, fontSize: CGFloat, maxSize: CGSize) -> CGFloat {
    let font = UIFont(name: "Helvetica", size: fontSize)!
    let attrString = NSAttributedString(string: text, attributes:[NSAttributedString.Key.font: font,
                                                                  NSAttributedString.Key.foregroundColor: UIColor.white])
    let textHeight = attrString.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, context: nil).size.height

    return textHeight
  }
  
  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}

9. StringExtension.swift

import Foundation

extension String {
  func withoutWhitespace() -> String {
    return self.replacingOccurrences(of: "\n", with: "")
      .replacingOccurrences(of: "\r", with: "")
      .replacingOccurrences(of: "\0", with: "")
  }
}

10. AppDelegate.swift

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
  var window: UIWindow?
  
  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    //UIApplication.shared.statusBarStyle = .default
    window = UIWindow(frame: UIScreen.main.bounds)
    window!.rootViewController = UINavigationController(rootViewController: JoinChatViewController())
    window!.makeKeyAndVisible()
    return true
  }
}

11. ChatRoom.swift

import UIKit

protocol ChatRoomDelegate: class {
  func received(message: Message)
}

class ChatRoom: NSObject {
  //1
  var inputStream: InputStream!
  var outputStream: OutputStream!
  
  weak var delegate: ChatRoomDelegate?
  
  //2
  var username = ""
  
  //3
  let maxReadLength = 4096
  
  func setupNetworkCommunication() {
    // 1
    var readStream: Unmanaged<CFReadStream>?
    var writeStream: Unmanaged<CFWriteStream>?
    
    // 2
    CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault,
                                       "localhost" as CFString,
                                       80,
                                       &readStream,
                                       &writeStream)
    
    inputStream = readStream!.takeRetainedValue()
    outputStream = writeStream!.takeRetainedValue()
    
    inputStream.delegate = self
    
    inputStream.schedule(in: .current, forMode: .common)
    outputStream.schedule(in: .current, forMode: .common)
    
    inputStream.open()
    outputStream.open()
  }
  
  func joinChat(username: String) {
    //1
    let data = "iam:\(username)".data(using: .utf8)!
    
    //2
    self.username = username
    
    //3
    _ = data.withUnsafeBytes {
      guard let pointer = $0.baseAddress?.assumingMemoryBound(to: UInt8.self) else {
        print("Error joining chat")
        return
      }
      //4
      outputStream.write(pointer, maxLength: data.count)
    }
  }
  
  func send(message: String) {
    let data = "msg:\(message)".data(using: .utf8)!
    
    _ = data.withUnsafeBytes {
      guard let pointer = $0.baseAddress?.assumingMemoryBound(to: UInt8.self) else {
        print("Error joining chat")
        return
      }
      outputStream.write(pointer, maxLength: data.count)
    }
  }
  
  func stopChatSession() {
    inputStream.close()
    outputStream.close()
  }

}

extension ChatRoom: StreamDelegate {
  func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
    switch eventCode {
    case .hasBytesAvailable:
      print("new message received")
      readAvailableBytes(stream: aStream as! InputStream)
    case .endEncountered:
      print("new message received")
      stopChatSession()
    case .errorOccurred:
      print("error occurred")
    case .hasSpaceAvailable:
      print("has space available")
    default:
      print("some other event...")
    }
  }
  
  private func readAvailableBytes(stream: InputStream) {
    let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: maxReadLength)
    while stream.hasBytesAvailable {
      let numberOfBytesRead = inputStream.read(buffer, maxLength: maxReadLength)
      
      if numberOfBytesRead < 0, let error = stream.streamError {
        print(error)
        break
      }
      
      // Construct the message object
      if let message = processedMessageString(buffer: buffer, length: numberOfBytesRead) {
        // Notify interested parties
        delegate?.received(message: message)
      }
    }
  }
  
  private func processedMessageString(buffer: UnsafeMutablePointer<UInt8>,
                                      length: Int) -> Message? {
    //1
    guard
      let stringArray = String(
        bytesNoCopy: buffer,
        length: length,
        encoding: .utf8,
        freeWhenDone: true)?.components(separatedBy: ":"),
      let name = stringArray.first,
      let message = stringArray.last
      else {
        return nil
    }
    //2
    let messageSender: MessageSender = (name == self.username) ? .ourself : .someoneElse
    //3
    return Message(message: message, messageSender: messageSender, username: name)
  }
}

后记

本篇主要讲述了基于Socket和TCP网络的实时聊天信息流的实现，感兴趣的给个赞或者关注~~~