我对编程比较陌生，我自己做了一个简单的聊天应用程序;从今天开始思考AIM。这更像是一个代码审查请求，而不是一个问题列表。在大多数情况下，该应用程序使用一些小错误，我将在下面重点介绍。请参阅项目中的代码：https://github.com/N8STROMO/Basic-Chat-Tcp以及下面列出的代码。问题随之而来。感谢您提供的任何帮助！
这是服务器代码：Server.cs
namespace Server
{
public class Server
{
// This is the port that the server will be listening on
const int PORT = 500;
// This is where the usernames and their connections will be held
readonly Dictionary<string, ServerUserConnection> userToConnections = new Dictionary<string, ServerUserConnection>();
readonly TcpListener listener;
public static void Main()
{
// Constructor for the ChatServer
Server server = new Server();
while(true)
{
Thread.Sleep(1); // Temp to keep alive
}
}
/// <summary>
/// Listens for data from clients
/// </summary>
public Server()
{
listener = TcpListener.Create(PORT);
listener.Start();
WaitForConnections();
}
/// <summary>
/// Begins an asynchronous operation to accept an incoming connection attempt
/// </summary>
private void WaitForConnections()
{
listener.BeginAcceptTcpClient(OnConnect, null);
}
/// <summary>
/// This method is executed asynchronously
/// Connects the client to the server
/// Broadcasts the user to client to be displayed on the chatform
/// Then waits for another connection to be established
/// </summary>
/// <param name="ar"></param>
void OnConnect(IAsyncResult ar)
{
//Asynchronously accepts an incoming connection attempt and creates a new TcpClient to handle remote host communication.
TcpClient client = listener.EndAcceptTcpClient(ar);
Console.WriteLine("Connected");
ReceiveUser(client);
BroadcastUserList();
WaitForConnections();
}
/// <summary>
/// Connects a user to the server and adds them to the dictionary userToConnections
/// </summary>
/// <param name="client"></param>
public void ReceiveUser(TcpClient client)
{
ServerUserConnection connection = new ServerUserConnection(this, client); // Constructor
userToConnections.Add(connection.userName, connection);
}
/// <summary>
/// For each user that is connected append the userList to include that user
/// TODO Do not need to keep a running list of users; send the user over then throw it away
/// </summary>
void BroadcastUserList()
{
string userList = "";
foreach(var connection in userToConnections)
{
userList += $"{connection.Value.userName},";
}
SendMsgToAll(MessageType.UserList, null, userList);
}
/// <summary>
/// Pushes out messages to the connected clients
/// </summary>
/// <param name="type"></param>
/// <param name="user"></param>
/// <param name="message"></param>
public void SendMsgToAll(MessageType type, ServerUserConnection user, string message)
{
Console.WriteLine($"{user?.userName}: {message}");
foreach(var connection in userToConnections)
{
Console.WriteLine($"Sending to {connection.Value.userName}");
Utils.SendInformation(type, connection.Value.stream, message);
}
}
}
}
这是ServerUserConnection.cs：我无法理解这里的继承是如何工作的以及base关键字的作用。
namespace Server
{
public class ServerUserConnection : UserConnection
{
readonly Server server;
/// <summary>
/// Facilitates connection
/// </summary>
/// <param name="server"></param>
/// <param name="client"></param>
public ServerUserConnection(Server server, TcpClient client) : base(client, GetUsername(client)) // Inherits from UserConnection()
{
this.server = server;
}
private static string GetUsername(TcpClient client)
{
NetworkStream stream = client.GetStream();
if(stream.CanRead)
{
// Receives infromation from the stream, determines MessageType, and returns username
string userName = Utils.ReceiveInformation(stream, client, out MessageType type);
Console.WriteLine(userName);
return userName;
}
return null;
}
/// <summary>
///
/// </summary>
/// <param name="type"></param>
/// <param name="message"></param>
protected override void OnRead(MessageType type, string message)
{
if(type != MessageType.ChatMessage)
{
return;
}
server.SendMsgToAll(MessageType.ChatMessage, this, $"{userName} {message}");
}
}
}
以下是客户端代码：Client.cs
namespace Client
{
public class ChatClient
{
private const int PORT = 500;
TcpClient client = new TcpClient();
public ChatForm chatForm;
public ClientUserConnection userConnection;
string data;
[STAThread]
public static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var client = new ChatClient();
var form = new ConnectForm(client);
Application.Run(form);
}
/// <summary>
/// This is called when the ConnectForm btnSubmit is pressed.
/// </summary>
/// <param name="ipAddress"></param>
/// <param name="userName"></param>
public void ConnectToServer(string ipAddress, string userName)
{
client.Connect(ipAddress, PORT);
SendUserName(userName);
}
/// <summary>
/// Sends user to the server
/// </summary>
public void SendUserName(string user)
{
userConnection = new ClientUserConnection(client, this, user);
Utils.SendInformation(MessageType.Connect, client.GetStream(), user);
}
/// <summary>
/// Sends a message to the server
/// </summary>
/// <param name="msg"></param>
public void SendMessage(string msg)
{
Utils.SendInformation(MessageType.ChatMessage, userConnection.stream, msg);
}
}
}
这是ClientUserConnection.cs：有没有办法重构或优化这个，以便不是保持一个正在运行的消息列表而是发送消息并将其丢弃？同样，关于继承的问题也是如此。
public class ClientUserConnection : UserConnection
{
public readonly Client.ChatClient chatClient;
public string message = "";
public string userListText;
/// <summary>
///
/// </summary>
/// <param name="client"></param>
/// <param name="chatClient"></param>
/// <param name="userName"></param>
public ClientUserConnection(TcpClient client, Client.ChatClient chatClient, string userName) : base(client, userName) // Inherits from UserConnection()
{
this.chatClient = chatClient;
}
/// <summary>
/// When the data is reads determine what kind of message it is
/// Parse/split out the message and user; display only relevant data
/// TODO Do not need to keep a running list of messages; send the message over then throw it away
/// </summary>
/// <param name="type"></param>
/// <param name="message"></param>
protected override void OnRead(MessageType type, string message)
{
if(type == MessageType.ChatMessage)
{
int iSpace = message.IndexOf(" ");
if(iSpace < 0)
{
// if error
return;
}
string from = message.Substring(0, iSpace);
string chatMessage = message.Substring(iSpace + 1, message.Length - iSpace - 1);
this.message += $"[{from}]: {chatMessage}{Environment.NewLine}";
}
else if(type == MessageType.UserList)
{
string[] userList = message.Split(',');
string userListText = "";
for(int i = 0; i < userList.Length; i++)
{
userListText += $"{userList[i]}{Environment.NewLine}";
}
this.userListText = userListText;
}
}
}
在此项目中，类库中还有三个文件：
这是MessageType.cs：
public enum MessageType
{
Connect, UserList, ChatMessage
}
这是UserConnection.cs：我仍然需要处理断开连接的用户。如果其中一个聊天表单已关闭，则会导致应用程序崩溃。
public abstract class UserConnection
{
public readonly TcpClient client;
public readonly NetworkStream stream;
public readonly string userName;
byte[] data;
/// <summary>
///
/// </summary>
/// <param name="client"></param>
/// <param name="userName"></param>
public UserConnection(TcpClient client, string userName)
{
this.client = client;
this.userName = userName;
stream = client.GetStream();
data = new byte[client.ReceiveBufferSize];
WaitForData();
}
/// <summary>
///
/// </summary>
private void WaitForData()
{
Console.WriteLine("Wait");
stream.BeginRead(data, 0, data.Length, OnReadData, null);
}
/// <summary>
/// SocketException: An existing connection was forcibly closed by the remote host
/// </summary>
/// <param name="ar"></param>
void OnReadData(IAsyncResult ar)
{
Console.WriteLine("Read");
int result = stream.EndRead(ar); // TODO disconnect & error handling
Console.WriteLine("Read done");
if(result <= 0)
{
Console.WriteLine("Error reading");
return;
}
string message = Utils.ReceiveInformation(data, result, out MessageType type);
OnRead(type, message);
WaitForData();
}
/// <summary>
///
/// </summary>
/// <param name="type"></param>
/// <param name="message"></param>
protected abstract void OnRead(MessageType type, string message);
}
这是Utils.cs：我无法理解有两种叫做ReceiveInformation（）的方法以及它们如何相互作用
public class Utils
{
/// <summary>
///
/// </summary>
/// <param name="stream"></param>
/// <param name="connection"></param>
/// <param name="type"></param>
/// <returns></returns>
public static string ReceiveInformation(NetworkStream stream, TcpClient connection, out MessageType type)
{
byte[] bytes = new byte[connection.ReceiveBufferSize];
int length = stream.Read(bytes, 0, bytes.Length);
return ReceiveInformation(bytes, length, out type);
}
/// <summary>
///
/// </summary>
/// <param name="bytes"></param>
/// <param name="length"></param>
/// <param name="type"></param>
/// <returns></returns>
public static string ReceiveInformation(byte[] bytes, int length, out MessageType type)
{
string data = Encoding.ASCII.GetString(bytes, 0, length);
int iSpace = data.IndexOf(' ');
if(iSpace < 0)
{
// TODO
}
string typeString = data.Substring(0, iSpace);
type = (MessageType)Enum.Parse(typeof(MessageType), typeString);
string message = data.Substring(iSpace + 1, data.Length - iSpace - 1);
return message;
}
/// <summary>
///
/// </summary>
/// <param name="type"></param>
/// <param name="stream"></param>
/// <param name="message"></param>
public static void SendInformation(MessageType type, NetworkStream stream, string message)
{
Byte[] sendBytes = Encoding.UTF8.GetBytes($"{type} {message}");
stream.Write(sendBytes, 0, sendBytes.Length);
}
}