Develop Reference

sr.ReadLine() isn't receiving data that is being sent

I am trying to implement an authentication method for my program. I have a server-side program that handles authentication:
class Program
{
static TcpListener listener = new TcpListener(9120);
public const string DECRYPT_KEY = "KObOBonONoinbOClHNKYJkgIKUFkjfKcvCYckcvBBCVKcbvHHCxthjcTJYBXJahjh";
static void Main(string[] args)
{
listener.Start();
while (true)
{
if (listener.Pending())
{
new Thread(TryAuthenticate).Start();
}
}
}
static void TryAuthenticate()
{
TcpClient needsAuth = listener.AcceptTcpClient();
StreamReader sr = new StreamReader(needsAuth.GetStream());
string line = sr.ReadLine();
if (!line.StartsWith("AUTH? ")) return;
StreamReader sr2 = new StreamReader("keys.pks");
string line2;
while ((line2 = sr2.ReadLine()) != null)
{
if (line == line2)
{
new StreamWriter(needsAuth.GetStream()).WriteLine("AFFIRMATIVE");
sr.Close();
}
}
sr2.Close();
needsAuth.Close();
}
}
And on the client-side I have this code:
class Authentication
{
public static bool Authenticate(string id)
{
if (id == "dEbUg2020") return true;
TcpClient client = new TcpClient("127.0.0.1", 9120);
StreamWriter sw = new StreamWriter(client.GetStream());
StreamReader sr = new StreamReader(client.GetStream());
sw.WriteLine("AUTH? " + id);
if (sr.ReadLine() == "AFFIRMATIVE")
{
sw.Close();
sr.Close();
client.Close();
return true;
}
else
{
sw.Close();
sr.Close();
client.Close();
return false;
}
}
}
I have tried debugging on both the client and the server side.
On the client-side, it starts hanging at if (sr.ReadLine() == "AFFIRMATIVE").
On the server-side, it starts hanging at string line = sr.ReadLine();.
I have done some research and it has told me that when sr.ReadLine() is expecting data but doesn't get any, it hangs until it does.
But I have sent data, and both the client/server hangs indefinitely until it crashes. I am stuck, does anyone know why this isn't working?

After writing a message with your sw StreamWriter, you need to flush it with sw.Flush(); for it to actually be sent to the other side.
So
sw.WriteLine("Some line");
sw.Flush();
Otherwise, you're not sending anything.

Named Pipe Input Output in C#

I am working with named pipes and very confused about how the interaction between the client and server is happening.
My server is a VM with a named pipe attached to it. I have created a client stream in C# this way:
NamedPipeClientStream client = new NamedPipeClientStream(".", "TestPipe", PipeDirection.InOut);
Let's say the VM prompt is like below:
Hello!
Do you accept (y/n): y
Text1 : 1.2.3.4
Text2 : 2.3.4.5
What I essentially need to do is, check if the line read by the stream is "Do you accept (y/n):", if it matches then write y to the stream.es with Text1, then write 1.2.3.4 in the stream
Problems I am facing:
The prompt doesn't display anything after Hello!. What I thought
is, it is maybe waiting for the next input. So, instead of doing
this:
if(line.contains("Do you accept (y/n):"))
writer.writeLine("y")
I did this:
if(line.contains("Hello!"))
writer.writeLine("y");
Is this the correct thing? If it is, then it means that the server
isn't pushing the text in the buffer on which it is awaiting input.
So, every time I'll have to do the check for the previous line and
write the output of the next expected line to the writer stream?
Also, as per above, for passing 1.2.3.4 for Text1, I did this:
if(line.contains("Do you accept (y/n):"))
writer.writeLine("1.2.3.4")
What appears in my execution prompt is: Text1 : 1111111 ie. it's
only repeating the first character of the input I have passed. Why
such? I have already set AutoFlush = true to my writer stream.
Any pointers here will be highly appreciated!
Edit: Including the snippet
using System;
using System.IO;
using System.IO.Pipes;
using System.Linq;
using System.Windows;
namespace App1 {
static void Main(string [] args) {
NamedPipeClientStream client = new NamedPipeClientStream(".", "TestPipe", PipeDirection.InOut);
while(!client.IsConnected);
Streamreader reader = new StreamReader(client);
StreamWriter writer = new StreamWriter(client);
string line = "";
writer.AutoFlush = true;
while((line = reader.readLine()) != null) {
if(line.Contains("Hello!") {
writer.writeLine("1.2.3.4"); // input for the next prompt
}
else if(line.Contains("Text1") {
writer.writeLine("2.3.4.5"); // input for next prompt of Text2
}
writer.Flush();
writer.WaitForPipeDrain();
}
}
}
Is above the right way?
Also, sometimes the pipe reader is missing data. Like it shows Tet1 instead of Text1. Why such?

You have this statement: while(!client.IsConnected); which causes the client to wait for the connection before proceeding. However, the client never attempts to connect (client.Connect();), so presumably you will be waiting forever. Replace that line with if (!client.IsConnected) {client.Connect();} to get this to work.
Beyond that, per the comments, without knowing what your server side code looks like it's hard to say what the client should be sending; as the two sides are having a scripted conversation.
Here's an example of some working server & client code to illustrate how you could perform this conversation:
Code to kick off both client & server:
static void Main()
{
var server = Task.Factory.StartNew(() => RunServer());
var client = Task.Factory.StartNew(() => RunClient());
Task.WaitAll(server, client);
Console.WriteLine("Done");
}
Client code:
static void RunClient()
{
using (var pipeClient = new NamedPipeClientStream(".", "TestPipe", PipeDirection.InOut))
{
Console.WriteLine("Client is waiting to connect");
if(!pipeClient.IsConnected){pipeClient.Connect();}
Console.WriteLine("Client is connected");
using (var reader = new StreamReader(pipeClient))
{
using (var writer = new StreamWriter(pipeClient))
{
var running = true;
while(running)
{
Console.WriteLine("Client is waiting for input");
var message = reader.ReadLine();
if (message != null)
{
Console.WriteLine("Client: Recieved from server {0}", message);
switch (message)
{
case "Do you accept (y/n):":
writer.WriteLine("y");
writer.WriteLine("quit");
writer.Flush();
break;
case "quit":
running = false;
break;
}
}
}
}
}
}
Console.WriteLine("Client Quits");
}
Server code:
static void RunServer()
{
using (var pipeServer = new NamedPipeServerStream("TestPipe", PipeDirection.InOut))
{
using (var reader = new StreamReader(pipeServer))
{
using (var writer = new StreamWriter(pipeServer))
{
var running = true;
Console.WriteLine("Server is waiting for a client");
pipeServer.WaitForConnection();
Console.WriteLine("Server has connection from client");
Console.WriteLine("Server: Saying Hi");
writer.WriteLine("Hello!");
Console.WriteLine("Server: Prompting for Input");
writer.WriteLine("Do you accept (y/n):");
writer.Flush();
while(running)
{
pipeServer.WaitForPipeDrain();
var message = reader.ReadLine();
Console.WriteLine("Server: Recieved from client {0}", message);
if (message.Equals("quit"))
{
writer.WriteLine("quit");
running = false;
}
}
}
}
}
Console.WriteLine("Server Quits");
}
Update
Amended code to read characters rather than lines; so we don't have to wait for a line break before seeing the server's messages.
//using System.Threading.Tasks;
//using System.IO.Pipes;
static void Main()
{
var server = Task.Factory.StartNew(() => RunServer());
var client = Task.Factory.StartNew(() => RunClient());
Task.WaitAll(server, client);
Console.WriteLine("Done");
}
static void RunClient()
{
using (var pipeClient = new NamedPipeClientStream(".", "TestPipe", PipeDirection.InOut))
{
Console.WriteLine("Client is waiting to connect");
if(!pipeClient.IsConnected){pipeClient.Connect();}
Console.WriteLine("Client is connected");
using (var reader = new StreamReader(pipeClient))
{
using (var writer = new StreamWriter(pipeClient))
{
var message = string.Empty;
var running = true;
while(running)
{
Console.WriteLine("Client is waiting for input");
var chr = reader.Read();
if (chr >= 32)
{
message = message + (char)chr;
Console.WriteLine("Client: Recieved from server {0}", message);
switch (message)
{
case "Do you accept (y/n):":
writer.WriteLine("y");
writer.WriteLine("quit");
writer.Flush();
break;
case "quit":
running = false;
break;
}
}
else {
message = string.Empty;
Console.WriteLine("Client: New Line Received from Server");
}
}
}
}
}
Console.WriteLine("Client Quits");
}
static void RunServer()
{
using (var pipeServer = new NamedPipeServerStream("TestPipe", PipeDirection.InOut))
{
using (var reader = new StreamReader(pipeServer))
{
using (var writer = new StreamWriter(pipeServer))
{
var running = true;
Console.WriteLine("Server is waiting for a client");
pipeServer.WaitForConnection();
Console.WriteLine("Server has connection from client");
Console.WriteLine("Server: Saying Hi");
writer.WriteLine("Hello!");
Console.WriteLine("Server: Prompting for Input");
writer.Write("Do you accept (y/n):"); //NB: This is a write, not a write line!
writer.Flush();
while(running)
{
pipeServer.WaitForPipeDrain();
var message = reader.ReadLine();
Console.WriteLine("Server: Recieved from client {0}", message);
switch (message)
{
case "quit":
writer.WriteLine("quit");
running = false;
break;
default:
writer.WriteLine("");
break;
}
}
}
}
}
Console.WriteLine("Server Quits");
}
So this is what your code should look like:
int charAsInt;
var line = string.Empty;
while(((charAsInt = reader.Read()) != -1)) {
if (charAsInt >= 32) { //is a displayable character
line = line + (char)charAsInt;
//your code to handle the lines
if(line.Contains("Hello!")) {
writer.WriteLine("1.2.3.4"); // input for the next prompt
} else if(line.Contains("Text1") {
writer.WriteLine("2.3.4.5"); // input for next prompt of Text2
}
writer.Flush();
//writer.WaitForPipeDrain();
} else { //is a control character
if (charAsInt == 10 || charAsInt == 13) { //carriage return or line feed; i.e. end of line
if (line.Length > 0) {
Debug.WriteLine("Last line read was {0}", line); //just so you can see info as it comes from the server
line = string.Empty;
}
}
}
}

How can I save http requests from applications in c#?

When I connect my phone to iTunes it sends a request to a certain server so I have managed to divert to my server which I think I don't have the file or files that iTunes asks for but I would like to know what iTunes is requesting.
Here is my code
using System.Net.Sockets;
using System.Net;
using System.Threading;
using System.Text;
using System.Collections.Generic;
using System.IO;
namespace SimpleWebServer
{
class Server
{
/************************************\
* Acrobyte Http Web Server *
* Alexio Puk2sefu *
* www.acrobytemob.com *
* Alexiopuk2sefu#acrobytemob.com *
\************************************/
public bool running = false; // Is it running?
private int timeout = 8; // Time limit for data transfers.
private Encoding charEncoder = Encoding.UTF8; // To encode string
private Socket serverSocket; // Our server socket
private string contentPath; // Root path of our contents
// Content types that are supported by our server
// You can add more...
// To see other types: http://www.webmaster-toolkit.com/mime-types.shtml
private Dictionary<string, string> extensions = new Dictionary<string, string>()
{
//{ "extension", "content type" }
{ "htm", "text/html" },
{ "html", "text/html" },
{ "xml", "text/xml" },
{ "txt", "text/plain" },
{ "css", "text/css" },
{ "png", "image/png" },
{ "gif", "image/gif" },
{ "jpg", "image/jpg" },
{ "jpeg", "image/jpeg" },
{ "zip", "application/zip"},
{ "plist", "application/plist"},
{ "app", "application/app"},
{ "file", "application/file"}
};
public bool start(IPAddress ipAddress, int port, int maxNOfCon, string contentPath)
{
if (running) return false; // If it is already running, exit.
try
{
// A tcp/ip socket (ipv4)
serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
serverSocket.Bind(new IPEndPoint(ipAddress, port));
serverSocket.Listen(maxNOfCon);
serverSocket.ReceiveTimeout = timeout;
serverSocket.SendTimeout = timeout;
running = true;
this.contentPath = contentPath;
}
catch { return false; }
// Our thread that will listen connection requests and create new threads to handle them.
Thread requestListenerT = new Thread(() =>
{
while (running)
{
Socket clientSocket;
try
{
clientSocket = serverSocket.Accept();
// Create new thread to handle the request and continue to listen the socket.
Thread requestHandler = new Thread(() =>
{
clientSocket.ReceiveTimeout = timeout;
clientSocket.SendTimeout = timeout;
try { handleTheRequest(clientSocket); }
catch
{
try { clientSocket.Close(); } catch { }
}
});
requestHandler.Start();
}
catch{}
}
});
requestListenerT.Start();
return true;
}
public void stop()
{
if (running)
{
running = false;
try { serverSocket.Close(); }
catch { }
serverSocket = null;
}
}
private void handleTheRequest(Socket clientSocket)
{
byte[] buffer = new byte[10240]; // 10 kb, just in case
int receivedBCount = clientSocket.Receive(buffer); // Receive the request
string strReceived = charEncoder.GetString(buffer, 0, receivedBCount);
// Parse the method of the request
string httpMethod = strReceived.Substring(0, strReceived.IndexOf(" "));
int start = strReceived.IndexOf(httpMethod) + httpMethod.Length + 1;
int length = strReceived.LastIndexOf("HTTP") - start - 1;
string requestedUrl = strReceived.Substring(start, length);
string requestedFile;
if (httpMethod.Equals("GET") || httpMethod.Equals("POST"))
requestedFile = requestedUrl.Split('?')[0];
else // You can implement other methods...
{
notImplemented(clientSocket);
return;
}
requestedFile = requestedFile.Replace("/", "\\").Replace("\\..", ""); // Not to go back
start = requestedFile.LastIndexOf('.') + 1;
if (start > 0)
{
length = requestedFile.Length - start;
string extension = requestedFile.Substring(start, length);
if (extensions.ContainsKey(extension)) // Do we support this extension?
if (File.Exists(contentPath + requestedFile)) // If yes check existence
// Everything is OK, send requested file with correct content type:
sendOkResponse(clientSocket, File.ReadAllBytes(contentPath + requestedFile), extensions[extension]);
else
notFound(clientSocket); // We don't support this extension. We are assuming that it doesn't exist.
}
else
{
// If file is not specified try to send index.htm or index.html
// You can add more (for example "default.html")
if (requestedFile.Substring(length - 1, 1) != "\\")
requestedFile += "\\";
if (File.Exists(contentPath + requestedFile + "index.htm"))
sendOkResponse(clientSocket, File.ReadAllBytes(contentPath + requestedFile + "\\index.htm"), "text/html");
else if (File.Exists(contentPath + requestedFile + "index.html"))
sendOkResponse(clientSocket, File.ReadAllBytes(contentPath + requestedFile + "\\index.html"), "text/html");
else
notFound(clientSocket);
}
}
private void notImplemented(Socket clientSocket)
{
sendResponse(clientSocket, "<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"></head><body><h2>Atasoy Simple Web Server</h2><div>501 - Method Not Implemented</div></body></html>", "501 Not Implemented", "text/html");
}
private void notFound(Socket clientSocket)
{
sendResponse(clientSocket, "<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"></head><body><h2>Atasoy Simple Web Server</h2><div>404 - Not Found</div></body></html>", "404 Not Found", "text/html");
}
private void sendOkResponse(Socket clientSocket, byte[] bContent, string contentType)
{
sendResponse(clientSocket, bContent, "200 OK", contentType);
}
// For strings
private void sendResponse(Socket clientSocket, string strContent, string responseCode, string contentType)
{
byte[] bContent = charEncoder.GetBytes(strContent);
sendResponse(clientSocket, bContent, responseCode, contentType);
}
// For byte arrays
private void sendResponse(Socket clientSocket, byte[] bContent, string responseCode, string contentType)
{
try
{
byte[] bHeader = charEncoder.GetBytes(
"HTTP/1.1 " + responseCode + "\r\n"
+ "Server: Acrobyte Web Server\r\n"
+ "Content-Length: " + bContent.Length.ToString() + "\r\n"
+ "Connection: close\r\n"
+ "Content-Type: " + contentType + "\r\n\r\n");
clientSocket.Send(bHeader);
clientSocket.Send(bContent);
clientSocket.Close();
}
catch { }
}
}
}
So the request is coming to this server but iTunes says error and I simply would like to save that request and view it later

C# IRC Bot Error: 'Cannot read from a closed text reader'

I used this code once before, and it worked. Now, every time it tries to connect to an IRC server, I get the error: 'Cannot read from a closed text reader'
I've changed the adresses for privacy
This is my code:
using System;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Threading;
namespace IRCBot
{
class Program
{
}
class IrcBot
{
// Irc server to connect
public static string SERVER = "irc.rizon.net";
// Irc server's port (6667 is default port)
private static int PORT = 6660;
// User information defined in RFC 2812 (Internet Relay Chat: Client Protocol) is sent to irc server
private static string USER = "irc_bot";
// Bot's nickname
private static string NICK = "BotNick";
// Channel to join
private static string CHANNEL = "#testing";
// StreamWriter is declared here so that PingSender can access it
public static StreamWriter writer;
static void Main(string[] args)
{
NetworkStream stream;
TcpClient irc;
string inputLine;
StreamReader reader;
string nickname;
try
{
irc = new TcpClient(SERVER, PORT);
stream = irc.GetStream();
reader = new StreamReader(stream);
writer = new StreamWriter(stream);
// Start PingSender thread
PingSender ping = new PingSender();
ping.Start();
writer.WriteLine(USER);
writer.Flush();
writer.WriteLine("NICK " + NICK);
writer.Flush();
writer.WriteLine("JOIN " + CHANNEL);
writer.Flush();
while (true)
{
while ((inputLine = reader.ReadLine()) != null)
{
if (inputLine.EndsWith("JOIN :" + CHANNEL))
{
// Parse nickname of person who joined the channel
nickname = inputLine.Substring(1, inputLine.IndexOf("!") - 1);
// Welcome the nickname to channel by sending a notice
writer.WriteLine("NOTICE " + nickname + " :Hi " + nickname +
" and welcome to " + CHANNEL + " channel!");
writer.Flush();
// Sleep to prevent excess flood
Thread.Sleep(2000);
}
}
// Close all streams
writer.Close();
reader.Close();
irc.Close();
}
}
catch (Exception e)
{
// Show the exception, sleep for a while and try to establish a new connection to irc server
Console.WriteLine(e.ToString());
Thread.Sleep(5000);
string[] argv = { };
Main(argv);
}
}
}
class PingSender
{
static string PING = "PING :";
private Thread pingSender;
// Empty constructor makes instance of Thread
public PingSender()
{
pingSender = new Thread(new ThreadStart(this.Run));
}
// Starts the thread
public void Start()
{
pingSender.Start();
}
// Send PING to irc server every 15 seconds
public void Run()
{
while (true)
{
IrcBot.writer.WriteLine(PING + IrcBot.SERVER);
IrcBot.writer.Flush();
Thread.Sleep(15000);
}
}
}
}

Close all streams must be outside while:
while (true)
{
while ((inputLine = reader.ReadLine()) != null)
{
....
}
}
// Close all streams
writer.Close();
reader.Close();
irc.Close();

Move all your stream closing lines to "finally" block:
try
{
...
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
Thread.Sleep(5000);
string[] argv = { };
Main(argv);
}
finally
{
//Close all streams
writer?.Close();
reader?.Close();
irc?.Close();
}
Note, I've used new C#6 null-propagation operator ?. here cause your streams can be null. If you're using C# ver<6 then write it like this:
if (writer!=null) writer.Close();

Image does not show in browser using Web Server in c#

For the following code, if I request a html page containing an image, I cannot see the image in the browser. What am I doing wrong?
HERE IS C# CODE:
namespace WebServer
{
class Program
{
static void Main(string[] args)
{
TcpListener listener = new TcpListener(8080);
listener.Start();
while (true) {
Console.WriteLine("Waiting for connection...");
TcpClient Client = listener.AcceptTcpClient();
StreamReader sr = new StreamReader(Client.GetStream());
StreamWriter sw = new StreamWriter(Client.GetStream());
try
{
string request = sr.ReadLine();
Console.WriteLine(request);
string[] tokens = request.Split(' ');
string page = tokens[1];
if (page == "/") {
page = "index.htm";
}
StreamReader file = new StreamReader("../../web/"+page);
sw.WriteLine("HTTP/1.0 200 ok\n");
//send the file
string data = file.ReadLine();
while (data != null)
{
sw.WriteLine(data);
sw.Flush();
data = file.ReadLine();
}
}
catch (Exception ex)
{
//error
sw.WriteLine("HTTP/1.0 404 ok\n");
sw.WriteLine("<h1>Sorry! We could not find your file!</h1>");
sw.Flush();
}
Client.Close();
}
}
}
}
Why does this problem occur, and how can I solve it?
How can i show image and video file use in browser ?