P2P(Peer to Peer)协议是一种节点对等的网络协议。它的主要作用是:
- 资源共享:P2P网络中的节点可以直接共享资源,如文件、计算资源等,实现去中心化的资源共享。
- 提高扩展性:P2P网络可以实现节点的动态加入和退出,网络规模可以很容易扩展到成千上万的节点。
- 增强鲁棒性:P2P网络的去中心化特性,使其不依赖于个别节点,可以抵抗部分节点的失效和攻击,网络性能不易受到影响。
- 分布式计算:P2P网络拥有大量节点资源,可以用于分布式计算、区块链等场景。
P2P工作原理:
- 建立连接:P2P节点需要先与网络中的其它节点建立连接,以加入P2P网络。
- 资源注册:节点将自己拥有的资源在网络中注册,包括资源信息、节点地址等。
- 资源查询:节点可以广播查询请求,查找所需要的资源所在节点。或通过资源索引节点查找。
- 直接传输:节点与资源所有节点建立直接连接,进行数据或者计算资源的传输与交互。
- 资源下线:节点可以选择将不再共享的资源从网络中注销。
namespace P2PRelease
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
CheckForIllegalCrossThreadCalls = false;
}
int Count = 0;
PeerNameRegistration[] PeerNameRegister = new PeerNameRegistration[50];
List<string> filePathList = new List<string>();
[Obsolete]
private void Form1_Load(object sender, EventArgs e)
{
IPAddress myip = new System.Net.IPAddress(Dns.GetHostByName(Dns.GetHostName()).AddressList[0].Address);
TexBoxLocalIp.Text = myip.ToString();
TexBoxLocalPort.Text = new Random().Next(10000, 15000).ToString();
Thread threadSendFile = new Thread(new ThreadStart(FileSend));
threadSendFile.Start();
}
private void FileSend()
{
while (true)
{
Socket socket = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
socket.Bind(new IPEndPoint(IPAddress.Any, 8000));
socket.Listen(1);
Socket client=socket.Accept();
byte[] fileNameBuffer = new byte[1024];
int pathLength=client.Receive(fileNameBuffer);
string fileName = Encoding.UTF8.GetString(fileNameBuffer, 0, pathLength);
string path="";
foreach(string name in filePathList)
{
if(fileName==name.Substring(name.LastIndexOf('\\')+1))
{
path = name;
break;
}
}
if (path == "")
{
client.Send(Encoding.UTF8.GetBytes("File not found!"));
client.Shutdown(SocketShutdown.Both);
client.Close();
socket.Close();
}
else
{
FileStream fs = File.OpenRead(path);
byte[] sendSize = Encoding.UTF8.GetBytes(fs.Length.ToString());
client.Send(sendSize);
int sendLength = 0;
byte[] sendData = new byte[1024];
while ((sendLength = fs.Read(sendData,0,sendData.Length)) > 0)
{
client.Send(sendData);
}
client.Shutdown(SocketShutdown.Both);
client.Close();
socket.Close();
}
}
}
private void ButtRegister_Click(object sender, EventArgs e)
{
//if (TexBoxResName.Text == "")
//{
// MessageBox.Show("请填写资源名");
// return;
//}
OpenFileDialog dialog = new OpenFileDialog();
dialog.InitialDirectory = @"d:\";
if (DialogResult.No == dialog.ShowDialog())
{
return;
}
string filePath = dialog.FileName;
filePathList.Add(filePath);
TexBoxResName.Text = filePath.Substring(filePath.LastIndexOf('\\')+1);
PeerName peerName = new PeerName(TexBoxResName.Text, PeerNameType.Unsecured);
PeerNameRegister[Count] = new PeerNameRegistration(peerName, Convert.ToInt32(TexBoxLocalPort.Text));
PeerNameRegister[Count].Comment = peerName.ToString();
PeerNameRegister[Count].Data = Encoding.UTF8.GetBytes(String.Format("{0}", DateTime.Now.ToString()));
PeerNameRegister[Count].Start();
Count++;
ShareList.Items.Add(peerName.ToString());
}
private void ButtRevoke_Click(object sender, EventArgs e)
{
if (Count == 0)
{
MessageBox.Show("没有要撤销的资源。");
return;
}
int index = ShareList.SelectedIndex;
if (index == -1)
{
MessageBox.Show("请选择要撤销的资源！");
return;
}
for(int i = 0; i < Count; i++)
{
if (PeerNameRegister[i].Comment == ShareList.Text.ToString())
{
PeerNameRegister[i].Stop();
ShareList.Items.RemoveAt(index);
break;
}
}
}
private void ButtSearch_Click(object sender, EventArgs e)
{
if (TexBoxSearchName.Text == "")
{
MessageBox.Show("请输入要搜索的资源名字");
return;
}
ViewResultlist.Items.Clear();
PeerName SearchName = new PeerName(TexBoxSearchName.Text, PeerNameType.Unsecured);
PeerNameResolver Resolver = new PeerNameResolver();
PeerNameRecordCollection collection = Resolver.Resolve(SearchName);
foreach(PeerNameRecord record in collection)
{
foreach(IPEndPoint iep in record.EndPointCollection)
{
if (iep.AddressFamily.Equals(AddressFamily.InterNetwork))
{
ListViewItem item = new ListViewItem();
item.SubItems.Add(TexBoxSearchName.Text);
item.SubItems.Add(iep.ToString());
item.SubItems.Add(Encoding.UTF8.GetString(record.Data));
ViewResultlist.Items.Add(item);
}
}
}
}
IPEndPoint remotePoint; string filename; FileStream downFile; SaveFileDialog saveFile;
private void ButtDown_Click(object sender, EventArgs e)
{
if (ViewResultlist.Items.Count == 0)
{
MessageBox.Show("Resource is not found!");
return;
}
ProgressFileDown.Value = 0;
Socket client = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
ListViewItem item = ViewResultlist.Items[0];
filename = item.SubItems[1].Text.ToString();
string location = item.SubItems[2].Text.ToString();
saveFile = new SaveFileDialog();
saveFile.FileName = filename;
if (DialogResult.No == saveFile.ShowDialog())
{
return;
}
downFile = File.Open(saveFile.FileName, FileMode.OpenOrCreate, FileAccess.Write);
try
{
string ip = location.Substring(0, location.LastIndexOf(':'));
remotePoint = new IPEndPoint(IPAddress.Parse(ip), 8000);
Thread connectThread = new Thread(new ParameterizedThreadStart(ConneceServer));
connectThread.Start(client);
}catch{
MessageBox.Show("*载下**服务器暂时未开启！");
}
}
private void ConneceServer(object obj)
{
Socket client = (Socket)obj;
try { client.Connect(remotePoint); }
catch
{
client.Close();
downFile.Close();
File.Delete(saveFile.FileName);
return;
}
client.Send(Encoding.UTF8.GetBytes(filename));
byte[] sizeData = new byte[1024];
int sizeLeng = client.Receive(sizeData);
string fileSzieStr = Encoding.UTF8.GetString(sizeData, 0, sizeLeng);
long fileSize = Convert.ToInt64(fileSzieStr);
int length = 0;
long receiveLength = 0;
byte[] fileData = new byte[1024];
length = client.Receive(fileData);
while ( length> 0)
{
downFile.Write(fileData, 0, length);
receiveLength += length;
ProgressFileDown.Value = (int)(receiveLength * 1.0 / fileSize * 100);
fileData = new byte[1024];
length = client.Receive(fileData);
}
downFile.Close();
client.Shutdown(SocketShutdown.Both);
client.Close();
}
}
}