开发笔记 第24页

using System;
using System.Net.Http;
using System.Threading.Tasks;

public class HttpClientExample
{
    public static async Task Main()
    {
        using var client = new HttpClient();
        var response = await client.GetAsync("https://api.example.com/data");
        
        if (response.IsSuccessStatusCode)
        {
            var content = await response.Content.ReadAsStringAsync();
            Console.WriteLine(content);
        }
        else
        {
            Console.WriteLine($"Failed to retrieve data: {response.StatusCode}");
        }
    }
}

using System;
using System.IO;
using System.Net;

class WebClientExample
{
    public static void Main()
    {
        using (var client = new WebClient())
        {
            try
            {
                string result = client.DownloadString("https://api.example.com/info");
                Console.WriteLine(result);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error: {ex.Message}");
            }
        }
    }
}

using System;
using System.Net.Http;
using System.Threading.Tasks;

class HttpRequestMessageExample
{
    public static async Task Main()
    {
        using var client = new HttpClient();
        var request = new HttpRequestMessage(HttpMethod.Get, "https://api.example.com/info");
        request.Headers.Add("Authorization", "Bearer your-access-token");

        var response = await client.SendAsync(request);

        if (response.IsSuccessStatusCode)
        {
            var content = await response.Content.ReadAsStringAsync();
            Console.WriteLine(content);
        }
        else
        {
            Console.WriteLine($"Failed to retrieve data: {response.StatusCode}");
        }
    }
}

using System;
using System.IO.Pipelines;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

/// <summary>
/// WebSocket客户端类，用于与WebSocket服务器建立连接和通信。
/// </summary>
public class WebSocketClient
{
    /// <summary>
    /// 客户端WebSocket实例。
    /// </summary>
    private readonly ClientWebSocket _webSocket = new ClientWebSocket();
    
    /// <summary>
    /// 用于取消操作的CancellationTokenSource。
    /// </summary>
    private readonly CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();

    /// <summary>
    /// 连接到指定的WebSocket服务器。
    /// </summary>
    /// <param name="uri">WebSocket服务器的URI。</param>
    public async Task Connect(string uri)
    {
        // 使用提供的URI连接到WebSocket服务器
        await _webSocket.ConnectAsync(new Uri(uri), _cancellationTokenSource.Token);
    }

    /// <summary>
    /// 向WebSocket服务器发送消息。
    /// </summary>
    /// <param name="message">要发送的消息字符串。</param>
    public async Task SendMessage(string message)
    {
        // 将消息转换为UTF8编码的字节
        byte[] buffer = Encoding.UTF8.GetBytes(message);
        
        // 创建ArraySegment，封装要发送的字节缓冲区
        ArraySegment<byte> segment = new ArraySegment<byte>(buffer);
        
        // 发送消息到WebSocket服务器
        await _webSocket.SendAsync(segment, WebSocketMessageType.Text, true, _cancellationTokenSource.Token);
    }

    /// <summary>
    /// 接收WebSocket服务器发送的消息。
    /// </summary>
    /// <param name="onMessageReceived">接收到消息时调用的回调函数。</param>
    public async Task ReceiveMessage(Action<string> onMessageReceived)
    {
        // 当WebSocket连接处于打开状态时，持续接收消息
        while (_webSocket.State == WebSocketState.Open)
        {
            var buffer = new byte[1024];
            
            // 接收来自WebSocket服务器的数据
            var result = await _webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), _cancellationTokenSource.Token);
            
            // 如果接收到的类型为关闭，则关闭连接
            if (result.MessageType == WebSocketMessageType.Close)
            {
                await _webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing", CancellationToken.None);
                break;
            }
            
            // 将接收到的字节转换为字符串，并通过回调函数处理
            var receivedMessage = Encoding.UTF8.GetString(buffer, 0, result.Count);
            onMessageReceived(receivedMessage);
        }
    }

    /// <summary>
    /// 断开与WebSocket服务器的连接。
    /// </summary>
    public async Task Disconnect()
    {
        // 取消接收和发送操作
        _cancellationTokenSource.Cancel();
        
        // 关闭WebSocket连接
        await _webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing", CancellationToken.None);
    }
}

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Threading.Tasks;

public class Startup
{
    /// <summary>
    /// 配置服务容器。
    /// </summary>
    /// <param name="services">服务集合。</param>
    public void ConfigureServices(IServiceCollection services)
    {
        // 添加控制器服务
        services.AddControllers();
    }

    /// <summary>
    /// 配置应用管道。
    /// </summary>
    /// <param name="app">应用构建器。</param>
    /// <param name="env">主机环境。</param>
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        // 在开发环境中启用异常页面
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        // 启用路由
        app.UseRouting();

        // 启用WebSocket中间件
        app.UseWebSockets();

        // 配置端点处理器
        app.UseEndpoints(endpoints =>
        {
            // 映射默认的GET请求处理器
            endpoints.MapGet("/", async context =>
            {
                await context.Response.WriteAsync("Hello World!");
            });

            // 映射WebSocket请求处理器
            endpoints.Map("/ws", async context =>
            {
                // 检查当前请求是否为WebSocket请求
                if (context.WebSockets.IsWebSocketRequest)
                {
                    // 接受WebSocket连接
                    using var webSocket = await context.WebSockets.AcceptWebSocketAsync();

                    // 持续监听WebSocket消息
                    while (true)
                    {
                        // 准备接收缓冲区
                        var buffer = new byte[1024 * 4];
                        
                        // 接收WebSocket消息
                        var result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);

                        // 如果收到的类型为关闭消息，则关闭连接
                        if (result.MessageType == WebSocketMessageType.Close)
                        {
                            await webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing", CancellationToken.None);
                            break;
                        }

                        // 解码接收到的消息
                        var message = Encoding.UTF8.GetString(buffer, 0, result.Count);
                        Console.WriteLine($"Received: {message}");

                        // 回复消息给客户端
                        await webSocket.SendAsync(
                            new ArraySegment<byte>(Encoding.UTF8.GetBytes($"Echo: {message}")),
                            result.MessageType,
                            result.EndOfMessage,
                            CancellationToken.None);
                    }
                }
                else
                {
                    // 如果不是WebSocket请求，则返回400错误
                    context.Response.StatusCode = 400;
                }
            });
        });
    }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class TcpClientExample
{
    public static void Main()
    {
        try
        {
            // 创建一个新的Socket实例
            using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
            {
                // 连接到服务器
                IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
                IPEndPoint remoteEP = new IPEndPoint(ipAddress, 11000);
                socket.Connect(remoteEP);

                // 发送数据
                string message = "Hello Server!";
                byte[] data = Encoding.ASCII.GetBytes(message);
                socket.Send(data);

                // 接收服务器响应
                data = new byte[1024];
                int bytes = socket.Receive(data);
                Console.WriteLine("Received: {0}", Encoding.ASCII.GetString(data, 0, bytes));
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: {0}", e.ToString());
        }
    }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class TcpServerExample
{
    public static void Main()
    {
        try
        {
            // 创建一个新的Socket实例
            using (Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
            {
                // 绑定到本地端口
                IPAddress ipAddress = IPAddress.Any;
                IPEndPoint localEP = new IPEndPoint(ipAddress, 11000);
                listener.Bind(localEP);

                // 监听连接
                listener.Listen(10);

                // 接受客户端连接
                Console.WriteLine("Waiting for a connection...");
                Socket handler = listener.Accept();

                // 接收数据
                byte[] data = new byte[1024];
                int bytes = handler.Receive(data);
                Console.WriteLine("Text received: {0}", Encoding.ASCII.GetString(data, 0, bytes));

                // 发送响应
                string response = "Hello Client!";
                byte[] responseData = Encoding.ASCII.GetBytes(response);
                handler.Send(responseData);
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: {0}", e.ToString());
        }
    }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class UdpClientExample
{
    public static void Main()
    {
        try
        {
            // 创建一个新的Socket实例
            using (UdpClient client = new UdpClient())
            {
                // 发送数据
                string message = "Hello UDP Server!";
                byte[] data = Encoding.ASCII.GetBytes(message);
                IPEndPoint server = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 11000);
                client.Send(data, data.Length, server);

                // 接收服务器响应
                data = client.Receive(ref server);
                Console.WriteLine("Received: {0}", Encoding.ASCII.GetString(data));
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: {0}", e.ToString());
        }
    }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class UdpServerExample
{
    public static void Main()
    {
        try
        {
            // 创建一个新的Socket实例
            using (UdpClient listener = new UdpClient(11000))
            {
                // 接收数据
                IPEndPoint client = new IPEndPoint(IPAddress.Any, 0);
                byte[] data = listener.Receive(ref client);
                Console.WriteLine("Text received: {0}", Encoding.ASCII.GetString(data));

                // 发送响应
                string response = "Hello UDP Client!";
                byte[] responseData = Encoding.ASCII.GetBytes(response);
                listener.Send(responseData, responseData.Length, client);
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: {0}", e.ToString());
        }
    }
}

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Cryptography.X509Certificates;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        // 创建 HttpClientHandler 实例
        var handler = new HttpClientHandler();

        // 配置 SSL/TLS 设置
        // 设置检查服务器证书的委托
        handler.ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;

        // 设置是否自动重定向
        handler.AllowAutoRedirect = true;

        // 设置代理
        // handler.UseProxy = true;
        // handler.Proxy = new WebProxy("http://proxy.example.com:8080");

        // 创建 HttpClient 实例
        using var httpClient = new HttpClient(handler);

        // 设置请求头部
        httpClient.DefaultRequestHeaders.Accept.Clear();
        httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        // 发送 HTTPS 请求
        var response = await httpClient.GetAsync("https://api.example.com/data");

        // 检查响应状态
        if (response.IsSuccessStatusCode)
        {
            var content = await response.Content.ReadAsStringAsync();
            Console.WriteLine(content);
        }
        else
        {
            Console.WriteLine($"Failed to retrieve data: {response.StatusCode}");
        }
    }
}

using System;
using System.Security.Cryptography;
using System.Text;

public static class PasswordHasher
{
    public static string HashPassword(string password, byte[] salt)
    {
        using (var sha256 = SHA256.Create())
        {
            var passwordSalted = Encoding.UTF8.GetBytes(password + Encoding.UTF8.GetString(salt));
            var hash = sha256.ComputeHash(passwordSalted);
            return Convert.ToBase64String(hash);
        }
    }

    public static byte[] GenerateSalt()
    {
        using (var rng = new RNGCryptoServiceProvider())
        {
            var salt = new byte[32];
            rng.GetBytes(salt);
            return salt;
        }
    }
}

// 使用示例
byte[] salt = PasswordHasher.GenerateSalt();
string hashedPassword = PasswordHasher.HashPassword("password123", salt);

using System;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

public static class PasswordHasher
{
    public static string HashPasswordUsingBcrypt(string password)
    {
        using (var bcrypt = new Rfc2898DeriveBytes(password, 16, 10000)) // 16 bytes of salt, 10000 iterations
        {
            return Convert.ToBase64String(bcrypt.GetBytes(24)); // 24 bytes of hash
        }
    }
}

// 使用示例
string hashedPassword = PasswordHasher.HashPasswordUsingBcrypt("password123");

public static bool VerifyPassword(string inputPassword, string storedHash, byte[] storedSalt)
{
    string hashOfInput = PasswordHasher.HashPassword(inputPassword, storedSalt);
    return hashOfInput == storedHash;
}

string query = "SELECT * FROM SystemUser WHERE Username = @username";
SqlCommand command = new SqlCommand(query, connection);
command.Parameters.AddWithValue("@username", inputUsername);

string userContent = "<script>alert('XSS');</script>";
string encodedContent = HttpUtility.HtmlEncode(userContent);

@Html.AntiForgeryToken()

[Authorize]
public ActionResult SecureAction()
{
    // 安全操作
}

private bool IsFileSafeByExtension(string filePath)
{
    string[] allowedExtensions = { ".jpg", ".png", ".gif" };
    string extension = Path.GetExtension(filePath).ToLower();
    return allowedExtensions.Contains(extension);
}

private bool IsFileSafeByContent(string filePath)
{
    byte[] magicNumbers = File.ReadAllBytes(filePath);
    if (magicNumbers.Length >= 2 && magicNumbers[0] == 0xFF && magicNumbers[1] == 0xD8) // JPEG
    {
        return true;
    }
    // Add checks for other formats...
    return false;
}

using System;  
using System.Net.Http;  
using System.Threading.Tasks;  
using Newtonsoft.Json; // 需要安装Newtonsoft.Json NuGet包  
  
class Program  
{  
    static async Task Main(string[] args)  
    {  
        string apiKey = "API密钥";  
        string fileUrl = "文件ID";  
  
        string url = $"https://www.virustotal.com/vtapi/v3/files/{fileUrl}/report";  
        HttpClient client = new HttpClient();  
        client.DefaultRequestHeaders.Add("x-apikey", apiKey);  
  
        HttpResponseMessage response = await client.GetAsync(url);  
  
        if (response.IsSuccessStatusCode)  
        {  
            string responseBody = await response.Content.ReadAsStringAsync();  
            dynamic report = JsonConvert.DeserializeObject(responseBody);  
  
            if (report.positives > 0)  
            {  
                Console.WriteLine("文件含有病毒或恶意软件。");  
            }  
            else  
            {  
                Console.WriteLine("文件安全。");  
            }  
        }  
        else  
        {  
            Console.WriteLine("API请求失败。");  
        }  
    }  
}

private bool IsFileSafeByPermissions(string filePath)
{
    var fileInfo = new FileInfo(filePath);
    var security = fileInfo.GetAccessControl();
    // Check permissions here...
    return true; // Placeholder logic
}

private bool IsFileSafeBySize(string filePath, long maxSizeInBytes)
{
    var fileInfo = new FileInfo(filePath);
    return fileInfo.Length <= maxSizeInBytes;
}

private bool IsFileSafe(string filePath)
{
    return IsFileSafeByExtension(filePath) &&
           IsFileSafeByContent(filePath) &&
           IsFileSafeFromVirus(filePath) &&
           IsFileSafeByPermissions(filePath) &&
           IsFileSafeBySize(filePath, 1024 * 1024); // Limit to 1MB
}

using System;
using System.Web;

public class CookieHandler : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        // 创建一个新的Cookie对象
        HttpCookie cookie = new HttpCookie("UserSession");

        // 设置Cookie值
        cookie.Value = "123456"; // 假设这是用户的唯一标识符

        // 设置Cookie的过期时间
        cookie.Expires = DateTime.Now.AddDays(1); // 设置Cookie在一天后过期

        // 设置HttpOnly属性以增加安全性
        cookie.HttpOnly = true;

        // 如果你的网站支持HTTPS，设置Secure属性
        if (context.Request.IsSecureConnection)
            cookie.Secure = true;

        // 添加Cookie到响应中
        context.Response.AppendCookie(cookie);
    }

    public bool IsReusable
    {
        get { return false; }
    }
}

PM> Install-Package Fody
PM> Install-Package MethodTimer.Fody

using MethodTimer;

namespace DemoConsole
{
    internal class Program
    {
        /// <summary>
        /// 程序入口
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args)
        {
            // 调用示例方法
            new Program().DoSomething();

            Console.WriteLine("测试方法执行结束!！！");

            Console.ReadKey();
        }

        /// <summary>
        /// 示例方法
        /// </summary>
        [Time]
        public void DoSomething()
        {
            Console.WriteLine("测试方法执行时间！！！");
        }
    }
}

using MethodTimer;

namespace ConsoleApp3
{
    [Time]
    internal class Program
    {
        /// <summary>
        /// 程序入口
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args)
        {
            // 调用示例方法
            new Program().DoSomething();

            new Program().ToDoSomething();

            Console.WriteLine("方法执行结束!！！");

            Console.ReadKey();
        }

        /// <summary>
        /// 示例方法1
        /// </summary>
      
        public void DoSomething()
        {
            Console.WriteLine("001——测试执行时间方法！！！");
           
        }
        /// <summary>
        /// 示例方法2
        /// </summary>

        public void ToDoSomething()
        {
            Console.WriteLine("002——测试执行时间方法！！！");

        }
    }
}

 public class MyClass
 {
        [Time]
        public void DoSomething()
        {
            Stopwatch stopwatch = new Stopwatch();
            stopwatch.Start();

            // 原始方法体
            System.Threading.Thread.Sleep(1000); // 模拟工作

            stopwatch.Stop();

            // 输出或记录执行时间
            Console.WriteLine($"执行时间：{stopwatch.Elapsed.TotalMilliseconds} ms");
        }
 }

public static class MethodTimeLogger
{
    public static void Log(MethodBase methodBase, TimeSpan elapsed, string message)
    {
        //Do some logging here
    }
}

public class MyClass
{
    public void MyMethod()
    {
        var stopwatch = Stopwatch.StartNew();
        try
        {
            Console.WriteLine("Hello");
        }
        finally
        {
            stopwatch.Stop();
            MethodTimeLogger.Log(methodof(MyClass.MyMethod), stopwatch.Elapsed);
        }
    }
}