1.tcp protocol
###Definition of tcp protocol:
1. TCP Protocol Transmission Control Protocol (TCP
) is a connection-oriented, reliable, byte stream-based transport layer communication protocol, defined by IETF's RFC 793.TCP is designed to accommodate a layered protocol hierarchy that supports multiple network applications.
TCP is relied upon to provide reliable communication services between pairs of processes in a host computer connected to different but interconnected computer communication networks. TCP assumes that it can obtain simple, possibly unreliable datagram services from lower-level protocols.
In principle, TCP should be able to operate on top of a variety of communications systems, from hardwired connections to packet-switched or circuit-switched networks.
Advantages of tcp protocol:
It has the characteristics of orderly, safe, reliable, not easy to lose packets, and high latency.
tcp: used for chatting and transferring files
2.Basic connection of TCP protocol
2.1TCP protocol server
private static void StartService()
{
//tcp :协议端
//实例化一个Tcp协议的socket对象
socketServer = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//给服务器绑定地址与端口
IPAddress ipaddress = IPAddress.Parse("192.168.218.12");
IPEndPoint iPEndPoint = new IPEndPoint(ipaddress, 7999);
//把ip与端口绑定在Socket里面
socketServer.Bind(iPEndPoint);
//侦听
socketServer.Listen(100);
Console.WriteLine("tcp启动");
Task.Run(() =>
{
while (true)//循环等待客户端连接
{
//会等待客户端的连接,会卡在这里,不往下运行,直到有下一个宽带连接才会继续往下运行
//当有客户端连接的时候,会返回客户端连接的对象
Socket socketkint = socketServer.Accept();
byte[] byteff = encoding.GetBytes("你今天吃饭了吗");
socketkint.Send(byteff);
Task.Run(() =>
{
try
{
while (true)//循环接收数据
{
//接受数据
byte[] buffer = new byte[1024];
//返回接收到的数据大小,接收数据也会卡住,只有接收到数据的时候才会继续往下进行
int longth = socketkint.Receive(buffer);
if (longth == 0)
{
Console.WriteLine("一个客户端断开连接");
return;
}
//把字符转成字符串
string str = encoding.GetString(buffer, 0, longth);
Console.WriteLine(str);
}
}
catch (Exception ex)
{
Console.WriteLine("出现异常" + ex.Message);
return;
}
finally
{
socketkint.Close();
}
});
}
});
}
2.2 Client of TCP protocol
private static void StartClient()
{
//实例化一个TCP协议的Socket对象
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//服务端的地址和端口
IPEndPoint iPEndPoint = new IPEndPoint(IPAddress.Parse("192.168.218.12"), 7999);
try
{
//连接远程的服务端
socket.Connect(iPEndPoint);
Console.WriteLine("连接服务端成功");
}
catch (Exception ex)
{
Console.WriteLine("连接异常：" + ex.ToString());
return;
}
//循环接收数据
Task.Run(() =>
{
try
{
while (true)
{
byte[] buffer = new byte[1024];
//等待接收对方发送的数据，返回对方发送数据的长度，数据会存放在buffer里面
int length = socket.Receive(buffer);
//把byte[]转成字符串
string str = encoding.GetString(buffer, 0, length);
Console.WriteLine(str);
}
}
catch (Exception ex)
{
Console.WriteLine("出现异常：" + ex.Message);
}
finally
{
//关闭连接，释放资源
socket.Close();
}
});
//循环发送数据
Task.Run(async () =>
{
try
{
int num = 1;
while (true)
{
byte[] buffer = encoding.GetBytes("我是客户端" + num);
//发送数据
socket.Send(buffer);
num++;
//等待1000毫秒
await Task.Delay(1000);
}
}
catch (Exception ex)
{
Console.WriteLine("出现异常：" + ex.Message);
}
});
}
3.TCP file transfer:
3.1 Server:
public static void StartFileServer()
{
socketServer = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socketServer.Bind(new IPEndPoint(IPAddress.Any, 8500));
socketServer.Listen(100);
Console.WriteLine("客户端启动");
ServerAccept();
}
//等待客户端连接
private static void ServerAccept()
{
Task.Run(() =>
{
while (true)
{
//等待客户端的连接
Socket socketClient = socketServer.Accept();
Console.WriteLine("客户端上线了");
//接收客户端的消息
byte[] buffer = new byte[1024];
int length = socketClient.Receive(buffer);
//接收文件信息的消息
string str = encoding.GetString(buffer, 0, length);
string[] strs = str.Split('-');
//文件大小
long fileSize = Convert.ToInt64(strs[0]);
string fileName = strs[1];
//给客户端回复"OK"
FileStream stream = System.IO.File.Create($"F:\\dfile\\{
fileName}");
socketClient.Send(encoding.GetBytes("OK"));
// 接收客户端的文件
long NowSize = 0;
Console.WriteLine("正在接收...");
while (true)
{
buffer = new byte[1024 * 10];
length = socketClient.Receive(buffer);
// 把读到的数据写入文件
stream.Write(buffer, 0, length);
NowSize += length;
//读取结束
if (NowSize == fileSize)
{
break;
}
}
stream.Close();
socketClient.Close();
}
});
}
3.2 Client:
//启动客户端
private static void ClientServer()
{
//连接服务端
socketClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socketClient.Connect(new IPEndPoint(IPAddress.Parse("192.168.218.12"), 8500));
string fullname = "F:\\df1\\a.txt";
//读取文件名及其后缀
string filename = Path.GetFileName(fullname);
FileStream fs = File.OpenRead(fullname);
socketClient.Send(encoding.GetBytes($"{
fs.Length}-{
filename}"));
//接收服务端消息"OK"
byte[] buffer = new byte[100];
int iength = socketClient.Receive(buffer);
string str = Encoding.UTF8.GetString(buffer, 0, iength);
if (str != "OK")//不是"OK"
{
fs.Close();
socketClient.Close();
return;
}
Console.WriteLine("努力加载中...");
//发送文件
Task.Factory.StartNew(() =>
{
buffer = new byte[1024 * 10];
while (true)
{
int length = fs.Read(buffer, 0, buffer.Length);
if (length == 0)//为0是发送结束
{
fs.Close() ;
socketClient.Close();
Console.WriteLine("发送结束");
break;
}
socketClient.Send(buffer, 0, length, SocketFlags.None);
}
});
}
4.TCP hexadecimal conversion
4.1 Server
private static void StartServer()
{
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.Bind(new IPEndPoint(IPAddress.Any, 8500));
socket.Listen(10);
Console.WriteLine("客户端启动");
Task.Run(() =>
{
Socket socketClient = socket.Accept();
Console.WriteLine("客户上线");
while (true)
{
//收到客户端消息
byte[] buffer = new byte[1024];
int length = socketClient.Receive(buffer);
/*byte[] data = new byte[length];
string str = string.Empty;
for (int i = 0; i < length; i++)
{
str += $"{buffer[i].ToString("x2")}";
data[i] = (byte)(buffer[i] + 1);
}
Console.WriteLine("收到的客户端消息"+str);
//收到客户端消息+1给客户端回复过去
socketClient.Send(data);*/
if (length == 1)
{
byte data = buffer[0];
if (data == 0x0A)
{
byte tem = (byte)(random.Next(0, 50));
socketClient.Send(new byte[] {
tem });
}
else if (data == 0x0B)
{
byte hum = (byte)(random.Next(0, 50));
socketClient.Send(new byte[] {
hum });
}
}
}
});
}
4.2 Client
private static void StartClient()
{
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.Connect(new IPEndPoint(IPAddress.Parse("192.168.218.12"), 8500));
Task.Run(async () =>
{
while (true)
{
//socket.Send(new byte[] { 0xAA, 0xAB, 0xAC });
/* byte[] buffer = new byte[1024];
int len = socket.Receive(buffer);
string str = string.Empty;
for (int i = 0; i < len; i++)
{
str += $"{buffer[i].ToString("x2")}";
}
Console.WriteLine("发送的消息" + str);*/
int num = random.Next(0, 100);
byte cmd = (byte)(num % 2 == 0 ? 0x0A : 0x0B);
socket.Send(new byte[] {
cmd });
byte[] buffer = new byte[1024];
int length = socket.Receive(buffer);
if (length == 1)
{
byte data = buffer[0];
if (cmd == 0x0A)
{
Console.WriteLine("a" + data);
}
else if (cmd == 0x0B)
{
Console.WriteLine("b" + data);
}
}
await Task.Delay(200);
}
});
}