我正在开发一个通过TCP传输文件的项目。它是用.NET 4.7编写的。该程序在客户端连接在同一台计算机上的服务器上时工作,但当我将其发送给朋友时,我尝试连接它时出现错误:
连接尝试失败,因为连接方在一段时间后没有正确响应,或者建立的连接失败,因为连接的主机无法响应
目前,程序只发送一些有关将被复制的文件的信息,并且没有任何加密,因为我甚至无法发送这些信息。
这是服务器的代码(使用Invoke是因为它在一个单独的线程上运行):
private void Server_Start()
{
try
{
// Set port on 13000
int port = 13000;
//Get the ip adress for the server
String localIp;
using (var client = new WebClient())
{
// Try connecting to Google public DNS and get the local endpoint as IP
// If failed to connect set IP as local IP
if (CheckForInternetConnection())
{
try
{
using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, 0))
{
socket.Connect("8.8.8.8", 65530);
IPEndPoint endPoint = socket.LocalEndPoint as IPEndPoint;
localIp = endPoint.Address.ToString();
}
}
catch (Exception e)
{
localIp = "127.0.0.1";
}
}
else
{
localIp = "127.0.0.1";
}
}
IPAddress IP = IPAddress.Parse(localIp);
// Create listener and start listening
server = new TcpListener(IP, port);
server.Start();
// Buffer for data
Byte[] bytes = new byte[256];
String data = string.Empty;
this.Invoke((MethodInvoker)(() => Log.Items.Add("Server started on ip: " + IP.ToString())));
while (true)
{
// Accepting requests
TcpClient client = server.AcceptTcpClient();
// Get the stream object
NetworkStream stream = client.GetStream();
// Read length of file name
byte[] nameLength = new byte[4];
stream.Read(nameLength, 0, 4);
int nameSize = BitConverter.ToInt32(nameLength, 0);
// Read the name of file
byte[] name = new byte[nameSize];
stream.Read(name, 0, nameSize);
String fileName = Encoding.UTF8.GetString(name);
// Read size of file
byte[] fileSizeB = new byte[4];
stream.Read(fileSizeB, 0, 4);
int fileSize = BitConverter.ToInt32(fileSizeB, 0);
// Read start signal
byte[] startB = new byte[9+1];
stream.Read(startB, 0, 9);
String start = Encoding.UTF8.GetString(startB);
this.Invoke((MethodInvoker)(() => Log.Items.Add("Size of name: " + nameSize.ToString())));
this.Invoke((MethodInvoker)(() => Log.Items.Add("Name of file: " + fileName)));
this.Invoke((MethodInvoker)(() => Log.Items.Add("File size: " + fileSize.ToString())));
this.Invoke((MethodInvoker)(() => Log.Items.Add("Start signal: " + start)));
// Response to client
byte[] message = Encoding.UTF8.GetBytes("Testmessage");
stream.Write(message, 0, message.Length);
}
server.Stop();
Log.Items.Add("Server started on ip: " + IP.ToString());
}
catch (Exception e)
{
this.Invoke((MethodInvoker)(() => Log.Items.Add(e)));
}
}
这是客户端的代码:
private void button1_Click(object sender, EventArgs e)
{
IPAddress iP = IPAddress.Parse(ConnectIp.Text);
int port = 13000;
int buffersize = 1024;
TcpClient client = new TcpClient();
NetworkStream netStream;
// Try to connect to server
try
{
client.Connect(new IPEndPoint(iP, port));
}
catch(Exception ex)
{
this.Invoke((MethodInvoker)(() => Log.Items.Add(ex.Message)));
return;
}
netStream = client.GetStream();
String path = "D:\\testingEnv\\test1\\testing\\Matematika\\2017\\Školsko\\2017-SS-skolsko-B-1234-zad.pdf";
String Filename = Path.GetFileName(path);
// We wish to send some data in advance:
// File name, file size, number of packets, send start and send end
byte[] data = File.ReadAllBytes(path);
// First packet contains: name size, file name, file size and "sendStart" signal
byte[] nameSize = BitConverter.GetBytes(Encoding.UTF8.GetByteCount(Filename)); // Int
byte[] nameB = Encoding.UTF8.GetBytes(Filename);
byte[] fileSize = BitConverter.GetBytes(data.Length);
byte[] start = Encoding.UTF8.GetBytes("sendStart");
// Last packet constains: "sendEnd" signal to stop reading netStream
byte[] end = Encoding.UTF8.GetBytes("sendEnd");
// Creating the first package: nameSize, fileName, fileSize and start signal
byte[] FirstPackage = new byte[4 + nameB.Length + 4 + 9];
nameSize.CopyTo(FirstPackage, 0);
nameB.CopyTo(FirstPackage, 4);
fileSize.CopyTo(FirstPackage, 4 + nameB.Length);
start.CopyTo(FirstPackage, 4 + nameB.Length + 4);
// Send the first pckage
netStream.Write(FirstPackage, 0, FirstPackage.Length);
byte[] buffer = new byte[30];
// Read the response
netStream.Read(buffer, 0, 11);
netStream.Close();
client.Close();
}
一位朋友试图移植13000端口,但它也没有用。我们甚至尝试过防火墙没什么问题。我在互联网上搜索但找不到任何问题的解决方案。
需要注意的是,两个函数都在同一个应用程序中。我不知道这是不是问题的原因。
有谁知道这里有什么问题?
提前致谢
您是否尝试使用telnet连接到服务器? “telnet localhost 13000”或来自其他计算机的正确IP和地址nbr?在调试服务器代码时尝试这样做。如果telnet工作,那么客户端代码有一些问题..