I am building an FTP server that will get images from a camera and store the photos in a local directory. I am having issues grabbing the file from the port given to me. Here is the conversation:
Server(me):"220 Ready!"
Client:"USER Guest"
Server: "331 Username ok, need password"
Client:"PASS "
Server: "230 user logged in"
Client: "PWD"
Server: "257 \"/\""
Client: "EPRT |1|172.22.22.103|58719|
Server:"500 IDK"
Client: "PORT 172,22,22,103,147,237"
Server:"200 Ready for Transport"
Client: "TYPE I"
Server:"200 I understand it is an image file"
Client: "STOR .TEST.RHPRYI"
I found the port by converting the last two numbers to hexadecimal (93,ED) appending them and then converting back to decimal. My final port is 37869.
I then create a new TcpClient to use as a download, but my TcpListener never picks up the camera. Also I am not sure my download method is correct.
I got lots of my code from here:
http://www.codeproject.com/Articles/380769/Creating-an-FTP-Server-in-Csharp-with-IPv-Support
Really my question comes down to: How do I get the file being sent by the client as an FTP server in C#?
Here is my code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Net;
using System.Threading;
using System.Net.Sockets;
using System.Drawing;
using Microsoft.VisualBasic;
//Creates a TcpServer that is used to transfer images from the Axis Camera to a directory on a computer
//ftpdmin was chosen as the name because it was supposed to be a replica of a program in c just made in csharp
//However, it was really hard to transfer from c because all of the struct names and functions were nonintuitive
//This program is completely made from internet sources, and there are definitely bugs. For instance it does not implement
// many FTP calls.
namespace ftpdmin
{
class Server
{
//TCPListener listens to a given IP and port to wait for a connection with the camera
//Download Listener listens to the port given by the camera in the PORT command, which is the
//port at which the files needed to be downloaded are stored.
//Listen thread implements tcpListener. We do not want to be stuck in an infinite loop, but
//we always want to be listening to the camera. That is why we use another thread.
//Downlaod thread implements the downloadlistener for the same reason as above
//File name is the download files name given by the camera in the STOR command.
//direct is the directory to save the files at on the local computer. It was given in the main
// method of the console program. See Program.cs
private TcpListener tcpListener;
private TcpListener downloadListener;
private Thread listenThread;
private Thread downloadThread;
private string fileName;
private string direct;
//Initialize Ip adress and threads
public Server(string dir)
{
direct = dir;
this.tcpListener = new TcpListener(IPAddress.Parse("172.22.22.104"), 3000);
this.listenThread = new Thread(new ThreadStart(ListenForClients));
this.listenThread.Start();
}
private void ListenForClients()
{
//Start listening
this.tcpListener.Start();
while (true)
{
//blocks until a client has connected to the server
TcpClient client = this.tcpListener.AcceptTcpClient();
//create a thread to handle communication
//with connected client
Thread clientThread = new Thread(new ParameterizedThreadStart(HandleClientComm));
clientThread.Start(client);
}
}
private void ListenForDownloads()
{
this.downloadThread.Start();
while(true)
{
TcpClient downloadClient = this.downloadListener.AcceptTcpClient();
Thread clientDownloadThread = new Thread(new ParameterizedThreadStart(HandleClientDownload));
clientDownloadThread.Start(downloadClient);
}
}
private void HandleClientDownload(object downloadClient)
{
Console.WriteLine("IM HERE");
TcpClient downloaderClient = (TcpClient) downloadClient;
NetworkStream downloadStream = downloaderClient.GetStream();
StreamWriter downloadWriter = new StreamWriter(downloadStream, Encoding.ASCII);
StreamReader downloadReader = new StreamReader(downloadStream);
try
{
//Sets up the path to store the file
string path = Path.Combine(direct, fileName);
FileStream file = File.Create(path);
//Implements the method to download a file
CopyStream(file, downloadStream);
file.Close();
}
catch (Exception e)
{
Console.WriteLine("a socket error has occured:" + e);
}
}
private void HandleClientComm(object client)
{
//A Server is TCP has to respond to a bunch of commands from the client. The first thing it
//does when it connects is send code 220 which says it is good to continue.
TcpClient tcpClient = (TcpClient)client;
NetworkStream clientStream = tcpClient.GetStream();
StreamWriter writer = new StreamWriter(clientStream, Encoding.ASCII);
StreamReader reader=new StreamReader(clientStream);
writer.WriteLine("220 Ready!");
writer.Flush();
string command=reader.ReadLine().ToUpperInvariant();
int downloadPort=0;
string ipOfDownload="";
Console.WriteLine(command);
while(!command.Equals("QUIT"))
{
//USER comes with the username given to the client. Here I do not check if the cameras username
//is the same as the username in the program. I just give the command 331 which means continue.
if(command.Contains("USER"))
{
writer.WriteLine("331 Username ok, need password");
writer.Flush();
}
//PASS is the same as username. I do not check the passwords, I just give 230 which continues the FTP.
else if(command.Contains("PASS"))
{
writer.WriteLine("230 User Logged In");
writer.Flush();
}
//PWD is Print working directory. I send 257 to say I have a PWD, and I send / because that is what is saved
// in the camera. I am not actually going to save files at this directory, I just want to continue.
else if(command.Contains("PWD"))
{
writer.WriteLine("257 \"/\"");
writer.Flush();
}
//This is an important command. The client is sending an IP where it wants to do file transfers. It comes in a
//Weird format so all this function is doing is allowing me store Ip as "172.22.22.103" instead of "PORT 172,22,22,103"
//Also there is a port listed at the end, but it is given in 2 numbers. The conversion to one port number is done by
//changing the two numbers to hexadecimal, appending them, and then transforming them back to decimal.
else if(command.Contains("PORT"))
{
string portPart1 = "";
string portPart2 = "";
Console.WriteLine(command);
int numberOfCommas=0;
int i=0;
bool notPort=true;
bool isNotPortPart2=true;
while(i<command.Length && notPort)
{
if(command[i].Equals(','))
{
if(numberOfCommas==3)
{
notPort=false;
}
else
{
ipOfDownload+=".";
numberOfCommas++;
}
}
else if(Information.IsNumeric(command[i]))
{
ipOfDownload+=command[i];
}
i++;
}
while(i<command.Length && isNotPortPart2)
{
if(Information.IsNumeric(command[i]))
{
portPart1+=command[i];
}
else
{
isNotPortPart2=false;
}
i++;
}
while(i<command.Length)
{
portPart2+=command[i];
i++;
}
Console.WriteLine("IP=" +ipOfDownload);
Console.WriteLine("PortPart1="+portPart1);
Console.WriteLine("PortPart2="+portPart2);
int portPart1int = int.Parse(portPart1);
int portPart2int = int.Parse(portPart2);
string portPart1Hex = portPart1int.ToString("X");
string portPart2Hex = portPart2int.ToString("X");
string downloadPortHex = portPart1Hex + portPart2Hex;
downloadPort = Convert.ToInt32(downloadPortHex, 16);
Console.WriteLine("PortPart1Hex=" + portPart1Hex);
Console.WriteLine("PortPart2Hex=" + portPart2Hex);
Console.WriteLine("FinalPort: " + downloadPort);
this.downloadListener = new TcpListener(IPAddress.Parse(ipOfDownload), downloadPort);
this.downloadThread = new Thread(new ThreadStart(ListenForDownloads));
writer.WriteLine("200 Ready for Transport");
writer.Flush();
}
//The client sends TYPE I for image. usually an ftp would switchto binary mode because that is the only way
//a file can be transferred cleanly.
else if(command.Contains("TYPE"))
{
writer.WriteLine("200 I understand it is an image file");
writer.Flush();
}
//This command gives the name of the file being transferred. I substring to get rid of
//The STOR . that comes before the file name
else if(command.Contains("STOR"))
{
fileName = command.Substring(6);
Console.WriteLine(fileName);
}
//For all other commands sent by the client, I send 500 which means I'm not implementing those commands.
else
{
writer.WriteLine("500 IDK");
writer.Flush();
}
command=reader.ReadLine().ToUpperInvariant();
Console.WriteLine(command);
}
writer.WriteLine("221 BYE");
writer.Flush();
tcpClient.Close();
}
private static long CopyStream(Stream input, Stream output, int bufferSize)
{
byte[] buffer = new byte[bufferSize];
int count = 0;
long total = 0;
while ((count = input.Read(buffer, 0, buffer.Length)) > 0)
{
output.Write(buffer, 0, count);
total += count;
}
return total;
}
private static long CopyStreamAscii(Stream input, Stream output, int bufferSize)
{
char[] buffer = new char[bufferSize];
int count = 0;
long total = 0;
using (StreamReader rdr = new StreamReader(input))
{
using (StreamWriter wtr = new StreamWriter(output, Encoding.ASCII))
{
while ((count = rdr.Read(buffer, 0, buffer.Length)) > 0)
{
wtr.Write(buffer, 0, count);
total += count;
}
}
}
return total;
}
private long CopyStream(Stream input, Stream output)
{
//if (_transferType == "I")
//{
return CopyStream(input, output, 4096);
//}
//else
//{
// return CopyStreamAscii(input, output, 4096);
//}
}
}
