C#使用TCP实现HTTP客户端请求

事例实现一个网页的下载

namespace ConsoleApplication12
{
    class Program
    {
        private const int readBufferSize = 1024;
        static void Main(string[] args)
        {
            if (args.Length != 1)
            {
                Console.WriteLine("参数错误");
            }
            string ip = args[0];
            //创建任务
            Task<String> task = RequestHttpAsync(ip);
            //阻塞线程
            Console.WriteLine(task.Result);
            Console.ReadKey();
        }

        private static async Task<String> RequestHttpAsync(string ip)
        {
            using (var client = new TcpClient())
            {
                try
                {
                    //连接指定的地址 默认端口80
                    await client.ConnectAsync(ip, 80);
                    //支持读写
                    NetworkStream networkStream = client.GetStream();
                    //请求头
                    string header = "GET / HTTP/1.1\r\n" + $"Host: {ip}:80\r\n"
                        + "Connection: colse\r\n" + "\r\n";
                    byte[] buffer = Encoding.UTF8.GetBytes(header);
                    await networkStream.WriteAsync(buffer, 0, buffer.Length);
                    await networkStream.FlushAsync();

                    var memoryStream = new MemoryStream();
                    buffer = new byte[readBufferSize];
                    int read = 0;
                    do
                    {
                        read = await networkStream.ReadAsync(buffer, 0, readBufferSize);
                        memoryStream.Write(buffer, 0, read);
                        Array.Clear(buffer, 0, buffer.Length);
                    }
                    while (read > 0);
                    memoryStream.Seek(0, SeekOrigin.Begin);
                    var reader = new StreamReader(memoryStream);
                    return reader.ReadToEnd();
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                    return null;
                }
            }
        }
    }
}