So, for a bit of background :
This class is created to accept and respond to calls made remotely in an HTTP format.
The problem is when the method of the request is POST, sometimes the request is processed correctly, but most of the times the class just ends up being irresponsive.
Also, the line "Debug1" and "Debug2" are never written to the console, even when the request is processed correctly.
The line "Debug3" appears only when the request is processed correctly.
I know this will probably look messy, C# is only a hobby for me, and I'm learning :)
Thanks for spending some time to go through this code!
Here is the code:
class WebServer
{
private TcpListener myListener;
public WebServer(int port)
{
//Threading the listener
try
{
myListener = new TcpListener(IPAddress.Any, port) ;
myListener.Start();
Thread th = new Thread(new ThreadStart(StartListen));
th.Start() ;
}
catch(Exception e)
{
Logs.Add("WebServer|An Exception Occurred while Listening :" +e.ToString());
}
}
private void StartListen()
{
int iStartPos = 0;
string sHttpVersion;
string sResponse = "";
string sCode = " 200 OK";
while(true)
{
//Accept a new connection
Socket mySocket = myListener.AcceptSocket();
if(mySocket.Connected)
{
Byte[] bReceive = new Byte[1024];
int i = mySocket.Receive(bReceive,bReceive.Length,SocketFlags.None);
string sBuffer = Encoding.ASCII.GetString(bReceive).TrimEnd('\0');
iStartPos = sBuffer.IndexOf("HTTP",1);
sHttpVersion = sBuffer.Substring(iStartPos,8); //http version (ex: "HTTP/1.1")
if (sBuffer.StartsWith("GET / "))
{
Logs.Add("WebServer|Connected:" + mySocket.RemoteEndPoint.ToString());
sResponse = ArrayToJson();
}
else if (sBuffer.StartsWith("POST"))
{
Console.WriteLine("Debug1");
//This is a POST request, so more data is waiting to be retreived...
bReceive = new Byte[2048];
i = mySocket.Receive(bReceive,bReceive.Length,SocketFlags.None);
sBuffer = Encoding.ASCII.GetString(bReceive).TrimEnd('\0');
Console.WriteLine("Debug2");
//Parsing the request
string[] sParams = sBuffer.Split(',');
Console.WriteLine(sParams.Length);
Console.WriteLine("Debug3: {0} - {1} - {2} - {3} - {4}", sParams[0], sParams[1], sParams[2], sParams[3], sParams[4]);
//I do what needs to be done here
Logs.Add("WebServer|BotStartRequest:" + mySocket.RemoteEndPoint.ToString());
sResponse = "Accepted";
}
//Sending response and closing socket
SendHeader(sHttpVersion, "text/html", sResponse.Length, sCode, ref mySocket);
SendToBrowser(sResponse, ref mySocket);
mySocket.Close();
}
}
}
}
}
Implementing HTTP/1.1 is not a simple task. The basic protocol looks quite simple, but it's really hard to get even a minimal server implementation right: You have at least to think about persistent connections, in the case of POST of the Expect: 100-continue header, correctly parsing the header, and much more.
I strongly recommend you have a look at existing libraries/code. For example, the HttpListener class is built into the .NET Framework and probably already provides all you'll ever need.
If you really want to implement a server from scratch, have a look at Microsoft Cassini, a simple HTTP server written in C# licensed under Ms-PL.
Related
Here is how i read data from my stream now:
public List<ServerClient> clients = new List<ServerClient>();
while (true)
{
Update();
}
private void Update()
{
//Console.WriteLine("Call");
if (!serverStarted)
{
return;
}
foreach (ServerClient c in clients.ToList())
{
// Is the client still connected?
if (!IsConnected(c.tcp))
{
c.tcp.Close();
disconnectList.Add(c);
Console.WriteLine(c.connectionId + " has disconnected.");
CharacterLogout(c.connectionId);
continue;
//Console.WriteLine("Check for connection?\n");
}
else
{
// Check for message from Client.
NetworkStream s = c.tcp.GetStream();
if (s.DataAvailable)
{
string data = c.streamReader.ReadLine();
if (data != null)
{
OnIncomingData(c, data);
}
}
//continue;
}
}
for (int i = 0; i < disconnectList.Count - 1; i++)
{
clients.Remove(disconnectList[i]);
disconnectList.RemoveAt(i);
}
}
When data is read it is send to OnIncomingData function which is processing the data. I don't have problems there.
Here is how i send data to the stream:
public void Send(string header, Dictionary data)
{
if (stream.CanRead)
{
socketReady = true;
}
if (!socketReady)
{
return;
}
JsonData SendData = new JsonData();
SendData.header = "1x" + header;
foreach (var item in data)
{
SendData.data.Add(item.Key.ToString(), item.Value.ToString());
}
SendData.connectionId = connectionId;
string json = JsonConvert.SerializeObject(SendData);
var howManyBytes = json.Length * sizeof(Char);
writer.WriteLine(json);
writer.Flush();
Debug.Log("Client World:" + json);
}
Here is my:
public class ServerClient
{
public TcpClient tcp;
public int accountId;
public StreamReader streamReader;
public int connectionId;
public ServerClient(TcpClient clientSocket)
{
tcp = clientSocket;
}
}
Here is my OnConnection function:
private void OnConnection(IAsyncResult ar)
{
connectionIncrementor++;
TcpListener listener = (TcpListener)ar.AsyncState;
NetworkStream s = clients[clients.Count - 1].tcp.GetStream();
clients.Add(new ServerClient(listener.EndAcceptTcpClient(ar)));
clients[clients.Count - 1].connectionId = connectionIncrementor;
clients[clients.Count - 1].streamReader = new StreamReader(s, true);
StartListening();
//Send a message to everyone, say someone has connected!
Dictionary<string, string> SendDataBroadcast = new Dictionary<string, string>();
SendDataBroadcast.Add("connectionId", clients[clients.Count - 1].connectionId.ToString());
Broadcast("001", SendDataBroadcast, clients, clients[clients.Count - 1].connectionId);
Console.WriteLine(clients[clients.Count - 1].connectionId + " has connected.");
}
Normally everything works fine. However if i try to send more request per 1 second the problem occurs. The message received is not full and complete. It just receives a portion of the message sent.
From Debug.Log("Client World:" + json); i can see that the message is full and complete but on the server i see that it is not.
This is not happening if i send less requests.
So for that reason i think i should create a MemoryStream and puts a message there and read it after. However i'm really not sure how i can do that. Can you help ?
The whole code is not very good, but I'll concentrate on your specific problem. It's most likely related to data buffering by StreamReader. StreamReader has buffer size (which you can pass to constructor) which defaults to 1024 bytes. When you call ReadLine - it's perfectly possible for stream reader to read more than one line from the underlying stream. In your case - you have while loop in which you enumerate connected clients and in every iteration of the loop you create new StreamReader and read one line from it. When message rate is low - all looks fine, because between your loop iterations only one line arrives. Now suppose client quickly sent 2 json messages, each of which is 800 bytes, and they both arrived into your socket. Now you call StreamReader.ReadLine. Because buffer size is 1024 - it will read 1024 bytes from socket (NetworkStream) and return first 800 to you (as a line). You process that line and discard StreamReader going to the next iteration of your while loop. By doing that you also discard part of the message (224 bytes of the next message), because they were already read from the socket into StreamReader buffer. I think from that it should be clear how to solve that problem - don't create new StreamReader every time but create one per client (for example store as a member of ServerClient) and use that.
The client looks more suspicious to me than the server.
StreamWriter is not thread-safe. Are you calling it in a thread-safe manner when using ClientWorldServer.Send? Lock up or queue your calls to ClientWorldServer.Send using a lock or BlockingCollection or some other synchronisation primitive. There is also a thread-safe wrapper of streamwriter you might be able to use.
I am trying to send commands to the server , like for example requesting the server to send back the list of files in it's directory. The problem is that when I send the "list" command to the server, I have to send it twice in order for the server to send back the list of files to the client. I am sure that the server receives the command in both times as on the server side I print the result that is supposed to be sent to the client on the console and it appears both times.
I am using C# and TCPListeners to listen for incoming responses or commands, and TCPClient to send responses or commands between the server and the client.
The client code
private TcpListener tcpListener = new TcpListener(9090);
private void button3_Click(object sender, EventArgs e)
{
Byte[] bytesToSend = ASCIIEncoding.ASCII.GetBytes("list");
try
{
TcpClient clientSocket = new TcpClient(serverIPFinal, 8080);
if (clientSocket.Connected)
{
NetworkStream networkStream = clientSocket.GetStream();
networkStream.Write(bytesToSend, 0, bytesToSend.Length);
// networkStream.Close();
// clientSocket.Close();
thdListener = new Thread(new ThreadStart(listenerThreadList));
thdListener.Start();
}
}
catch
{
isConnectedLbl.Text = "Server not running";
}
}
//Listener Thread to receive list of files.
public void listenerThreadList()
{
tcpListener.Start();
while (true)
{
handlerSocket = tcpListener.AcceptSocket();
if (handlerSocket.Connected)
{
Control.CheckForIllegalCrossThreadCalls = false;
lock (this)
{
if (handlerSocket != null)
{
nSockets.Add(handlerSocket);
}
}
ThreadStart thdstHandler = new
ThreadStart(handlerThreadList);
Thread thdHandler = new Thread(thdstHandler);
thdHandler.Start();
}
}
}
//Handler Thread to receive list of files.
public void handlerThreadList()
{
Socket handlerSocketList = (Socket)nSockets[nSockets.Count - 1];
NetworkStream networkStreams = new NetworkStream(handlerSocketList);
int requestRead = 0;
string dataReceived;
byte[] buffer = new byte[1024];
//int iRx = soc.Receive(buffer);
requestRead = networkStreams.Read(buffer, 0, 1024);
char[] chars = new char[requestRead];
System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder();
int charLen = d.GetChars(buffer, 0, requestRead, chars, 0);
dataReceived = new System.String(chars);
Console.WriteLine(dataReceived);
MessageBox.Show(dataReceived);
//tcpListener.Stop();
thdListener.Abort();
}
The Server code:
TcpListener tcpListener = new TcpListener(8080);
public void listenerThreadCommands()
{
tcpListener.Start();
while (true)
{
handlerSocket = tcpListener.AcceptSocket();
if (handlerSocket.Connected)
{
Control.CheckForIllegalCrossThreadCalls = false;
connections.Items.Add(
handlerSocket.RemoteEndPoint.ToString() + " connected.");
// clientIP = handlerSocket.RemoteEndPoint.ToString();
lock (this)
{
nSockets.Add(handlerSocket);
}
ThreadStart thdstHandler = new
ThreadStart(handlerThreadCommands);
Thread thdHandler = new Thread(thdstHandler);
thdHandler.Start();
//tcpListener.Stop();
//handlerSocket.Close();
}
}
}
//Handler Thread to receive commands
public void handlerThreadCommands()
{
Socket handlerSocketCommands = (Socket)nSockets[nSockets.Count - 1];
NetworkStream networkStream = new NetworkStream(handlerSocketCommands);
int requestRead = 0;
string dataReceived;
byte[] buffer = new byte[1024];
requestRead = networkStream.Read(buffer, 0, 1024);
char[] chars = new char[requestRead];
System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder();
int charLen = d.GetChars(buffer, 0, requestRead, chars, 0);
dataReceived = new System.String(chars);
//connections.Items.Add(dataReceived);
if (dataReceived.Equals("list"))
{
localDate = DateTime.Now;
Files = Directory.GetFiles(System.IO.Directory.GetCurrentDirectory())
.Select(Path.GetFileName)
.ToArray();
String FilesString = "";
for (int i = 0; i < Files.Length; i++)
{
FilesString += Files[i] + "\n";
}
String clientIP = handlerSocketCommands.RemoteEndPoint.ToString();
int index = clientIP.IndexOf(":");
clientIP = clientIP.Substring(0, index);
WriteLogFile(logFilePath, clientIP, localDate.ToString(), " ", "list");
Console.WriteLine(clientIP);
Console.WriteLine(FilesString);
Byte[] bytesToSend = ASCIIEncoding.ASCII.GetBytes(FilesString);
try
{
WriteLogFile(logFilePath, clientIP, localDate.ToString(), " ", "list-response");
TcpClient clientSocket = new TcpClient(clientIP, 9090);
if (clientSocket.Connected)
{
NetworkStream networkStreamS = clientSocket.GetStream();
networkStreamS.Write(bytesToSend, 0, bytesToSend.Length);
networkStreamS.Close();
clientSocket.Close();
networkStream.Close();
//tcpListener.Stop();
// handlerSocketAuthenticate.Close();
}
}
catch
{
Console.WriteLine("Cant send");
}
}
else if (dataReceived.Equals("downloadfile"))
{
// handlerSocketAuthenticate.Close();
// tcpListener.Stop();
networkStream.Close();
thdListenerDownload = new Thread(new ThreadStart(listenerThreadDownloading));
thdListenerDownload.Start();
}
else
{
String clientIP1 = handlerSocketCommands.RemoteEndPoint.ToString();
int index = clientIP1.IndexOf(":");
clientIP1 = clientIP1.Substring(0, index);
// handlerSocketAuthenticate.Close();
CommandExecutor(dataReceived, clientIP1);
}
}
There are so many different things wrong with the code you posted, it's hard to know where to start, and it's impossible to have confidence that in the context of a Stack Overflow, one could sufficiently address all of the deficiencies. That said, in the interest of helping, it seems worth a try:
Sockets are bi-directional. There is no need for the client to use TcpListener at all. (By convention, the "server" is the endpoint that "listens" for new connections, and the "client" is the endpoint that initiates new connections, by connecting to a listening server.)You should just make a single connection from client to server, and then use that socket both for sending to and receiving from the server.
You are setting the CheckForIllegalCrossThreadCalls property to false. This is evil. The exceptions that occur are there to help you. Setting that property to false disables the exceptions, but does nothing to prevent the problems that the exceptions are designed to warn you about.You should use some mechanism to make sure that when you access UI objects, you do so only in the thread that owns those objects. The most primitive approach to this is to use Control.Invoke(). In modern C#, you are better off using async/await. With TcpClient, this is easy: you already are using GetStream() to get the NetworkStream object that represents the socket, so just use the asynchronous methods on that object, such as ReadAsync(), or if you wrap the stream in a StreamWriter and StreamReader, use the asynchronous methods on that object, such as ReadLineAsync().
You are checking the Connected property of the TcpClient object. This is pointless. When the Connect() method returns, you are connected. If you weren't, an exception would have been thrown.
You are not sufficiently synchronizing access to your nSockets object. In particular, you use its indexer in the handlerThreadList() method. This is safe when using the object concurrently only if you have guaranteed that no other thread is modifying the object, which is not the case in your code.
You are writing to the stream using ASCII encoding, but reading using UTF8 encoding. In practice, this is not really a problem, because ASCII includes only the code points 0-127, and those map exactly to the same character code points in UTF8. But it's really bad form. Pick one encoding, stick with it.
You are accepting using AcceptSocket(), but then just wrapping that in a NetworkStream anyway. Why not just use AcceptTcpClient() and call GetStream() on that? Both Socket and TcpClient are fine APIs, but it's a bit weird to mix and match in the same program, and will likely lead to some confusion later on, trying to keep straight which you're using where and why.
Your code assumes that the handlerThreadCommands() method will always be called in exactly the same order in which connections are accepted. That is, you retrieve the current socket with nSockets[nSockets.Count - 1]. But, due to the way Windows thread scheduling works, it is entirely possible that two or more connections could be accepted before any one of the threads meant to handle the connection is started, with the result that only the most recent connection is handled, and it is handled by those multiple threads.
You are assuming that command strings will be received as complete units. But this isn't how TCP works. TCP guarantees only that if you receive a byte, it will be in order relative to all the bytes sent before it. But you can receive any number of bytes. In particular, you can receive just a single byte, or you can receive multiple commands concatenated with each other, or you can receive half a command string, then the other half later, or the second half of one command and the first half of the next, etc. In practice, these problems don't show up in early testing because the server isn't operating under load, but later on they very well may be. And the code needs to be designed from the outset to work properly under these conditions; trying to patch bad code later is much more difficult.
I can't say that's the above are the only things wrong with the code, but they are most glaring, and in any case I think the above is sufficient food for thought for you at the moment.
Bottom line: you really should spend more time looking at good networking examples, and really getting to understand how they work and why they are written the way they do. You'll need to develop a good mental model for yourself of how the TCP protocol works, and make sure you are being very careful to follow the rules.
One resource I recommend highly is The Winsock Programmer's FAQ. It was written long ago, for a pre-.NET audience, but most of the information contained within is still very much relevant when using the higher-level networking APIs.
Alternatively, don't try to write low-level networking code yourself. There are a number of higher-level APIs that use various serialization techniques to encode whole objects and handle all of the lower-level network transport mechanics for you, allowing you to concentrate on the value-added features in your own program, instead of trying to reinvent the wheel.
Alright, so I'm pretty new to C# and I'm definitely pretty new to graphical programming. I'm using Visual Studio 2015 and writing my application in C#.
I have this hunk of code that I've been toying around with for a while. Essentially my program will send the HELLO, to the server, but the server isn't sending HELLO back. I have no firewall in the middle of client and server right now, but the process is getting hung waiting for the reply back. I honestly don't even want to do it this way, I want the listener to always run in the background while the user does other stuff so that my program functions, well normal. So I come to you oh great Stackoverflow... because I am definitely doing it wrong! Could someone please point me the right direction?
Current Code:
private void button1_Click(object sender, EventArgs e)
{
byte[] data = new byte[512];
byte[] result;
SHA512 shaM = new SHA512Managed();
result = shaM.ComputeHash(Encoding.UTF8.GetBytes(this.password.Text));
var hash = BitConverter.ToString(result).Replace("-", "");
this.send_message("127.0.0.1", 10545, 10545, "HELLO");
this.send_message("127.0.0.1", 10545, 10545, "AUTH:" + this.login.Text + ":" + hash);
//ListenForData.Start();
}
private void send_message(string server, int localPort, int remotePort, string message)
{
label4.Text = "Listening on port:" + localPort;
IPEndPoint lep = new IPEndPoint(IPAddress.Any, localPort);
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
IPAddress loginServer = IPAddress.Parse(server.ToString());
byte[] sendbuf = Encoding.ASCII.GetBytes(message);
IPEndPoint ep = new IPEndPoint(loginServer, remotePort);
s.SendTo(sendbuf, ep);
try
{
UdpClient udpClient = new UdpClient(lep);
byte[] bytes = udpClient.Receive(ref lep);
label4.Text = ep.ToString();
} catch ( Exception ex )
{
Console.WriteLine(ex.ToString());
}
}
UDPATE:
private static void UDPListener(object obj)
{
Task.Run(async () =>
{
using (var udpClient = new UdpClient(10545))
{
string rMessage = "";
string[] rArgs = new string[0];
while (true)
{
//IPEndPoint object will allow us to read datagrams sent from any source.
var receivedResults = await udpClient.ReceiveAsync();
rMessage += Encoding.ASCII.GetString(receivedResults.Buffer);
rArgs = rMessage.Split(new char[] { ':' });
if( rArgs[0] == "HELLO")
{
Console.Write("Received HELLO from server.");
byte[] data = new byte[512];
byte[] result;
SHA512 shaM = new SHA512Managed();
result = shaM.ComputeHash(Encoding.UTF8.GetBytes(obj.password.Text));
var hash = BitConverter.ToString(result).Replace("-", "");
send_message("127.0.0.1", 10545, 10545, "AUTH:" + obj.login.Text + ":" + hash);
}
}
}
});
}
You can safely ignore the advice from Blindy. The UdpClient.ReceiveAsync() method is specifically designed around the Task paradigm, and is much more efficient than dedicating a thread to receiving data. Because the Task is awaitable, it's also easier to integrate the ReceiveAsync() approach with a GUI program (e.g. Winforms or WPF). That said, for all that to work, you want to execute the ReceiveAsync() call in the UI thread, rather than in another Task.
Unfortunately, lacking a good, minimal, complete code example that clearly illustrates your question, it's not possible to say for sure how that would look. But it most likely would involve making your UDPListener() method an async method and calling it from the UI thread. Also, since you say the method can't access non-static members, the obvious solution to that is to make the method itself non-static. E.g.:
private static async Task UDPListener(object obj)
{
using (var udpClient = new UdpClient(10545))
{
string rMessage = "";
string[] rArgs = new string[0];
while (true)
{
//IPEndPoint object will allow us to read datagrams sent from any source.
var receivedResults = await udpClient.ReceiveAsync();
rMessage += Encoding.ASCII.GetString(receivedResults.Buffer);
rArgs = rMessage.Split(new char[] { ':' });
if( rArgs[0] == "HELLO")
{
Console.Write("Received HELLO from server.");
byte[] data = new byte[512];
byte[] result;
SHA512 shaM = new SHA512Managed();
result = shaM.ComputeHash(Encoding.UTF8.GetBytes(obj.password.Text));
var hash = BitConverter.ToString(result).Replace("-", "");
send_message("127.0.0.1", 10545, 10545, "AUTH:" + obj.login.Text + ":" + hash);
}
}
}
}
It is not clear from your updated question whether you have fixed your failed to receive a reply yet. But if you have not changed your send_message() method, it has some obvious problems, especially in the context of creating a separate UdpClient instance to receive datagrams.
The most obvious issue is that you do not create the UdpClient instance which you're expecting to use to receive the response until after you have sent the message. This is wrong for two reasons:
It's entirely possible that the remote endpoint will send the response before you've created the socket. If that happens, the datagram will just be dropped.
More importantly, the usual design for a server is to send a response to the remote endpoint that sent it the message in the first place. I.e. in this case that would be the socket s. Even if you did create the udpClient object before calling s.SendTo(), the reply would actually be sent to the s socket, not the udpClient.Client socket.
Again, without a good code example it's not possible to know what your server actually does. But whether it behaves like a normal server, or is some non-standard implementation, the code you've posted cannot reliably receive a response from the server.
You should fix your design so that your client creates only a single socket (e.g. an initial UdpClient instance). You would prepare for communication by calling ReceiveAsync(), and only once you've done that, thus ensuring you're ready to receive a response, then you can send data.
Make sure that you create only this single object.
Note also that client-side implementations typically do not bind to a specific port. Instead, you let the OS assign a port. Only the server needs to bind to a specific port, so that inbound requests from unknown endpoints can know to what port to send their request. The server's receive operation will include the port number of the client, so the server will know to what port to send its response, without the client having selected any special port number.
Finally, I strongly recommend you study existing socket programming tutorials, and especially the Winsock Programmer's FAQ. None of the material there is directly applicable to the .NET socket API, but most of the issues you will have trouble with are exactly the kinds of things documented there. It is not possible to use the .NET socket API without also having a good basic comprehension of socket programming generally.
If the above does not get you headed in the right direction, please make sure that any future questions you ask include a good code example, as described in the link I provided above. Note that for any networking question, a complete code example includes both the client and server. It is not possible for anyone to fully understand your question, never mind to test and fix your code example, without implementations of both.
I have webserver receive data by async sockets:
var e = new SocketAsyncEventArgs();
e.Completed += new EventHandler<SocketAsyncEventArgs>(e_Completed);
while (true)
{ allDone.Reset();
mySocket.AcceptAsync(e);
allDone.WaitOne();
}
and the other method:
public void e_Completed(object sender, SocketAsyncEventArgs e)
{
var socket = (Socket)sender;
ThreadPool.QueueUserWorkItem(handleTcpRequest, e.AcceptSocket);
e.AcceptSocket = null;
socket.AcceptAsync(e);
}
this is the handleTcpRequest method.in this part I receive data from socket and do operation:
public void handleTcpRequest(object state)
{
string sBuffer = "";
string BufferTotal = "";
byte[] secureMessage;
Byte[] bReceive = new Byte[1024];
var mySocket = (Socket)state;
do
{
try
{
firstBufferRead = mySocket.Receive(bReceive, bReceive.Length, 0);
}
catch (Exception ex)
{
Console.WriteLine("Error Occurred (:))) " + ex.Message);
}
sBuffer += Encoding.GetEncoding(1252).GetString(bReceive, 0, firstBufferRead);
BufferTotal += Encoding.UTF8.GetString(bReceive, 0, firstBufferRead);
} while (mySocket.Available != 0);
.
.
.
.
mySocket.Close();
}
whats wrong?
sometimes connection resets and closes. this happens when distance is far or post data not multipart. but in multipart happens rarely. more with forms not in multipart.
when and where should I close socket?
when I work with socket in handleTcpRequest method its local. isn't it correct? I can't find the origin of the problem
The only way to know that you've received everything in a HTTP request is to understand the HTTP request. And to understand a HTTP request you have to choices:
Use a complete HTTP server
Create a HTTP parser
The reason to why your code fails for multi-part data is probably because the other party sends one part at a time, which means that your code manages to do a mySocket.Available != 0 before the rest is sent.
If you want to do the latter you have to read the HTTP header (in format headerName: headervalue, do note that there are also white space rules that you have to consider). Search for a header named content-length, parse it's value as an integer. Then wait for two line feeds in a row (\r\n\r\n). Finally start count bytes until you have received the number of bytes that was specified in the content-length header.
ohh.. ony more thing.. pray to God that Transfer-Encoding: Chunkedis not used.
My advice is that you give up on using sockets directly as it's apparent that you don't understand how they work or how to do research on them.
If response has a header of Connection: Close, then the socket closes automatically.
I have created TCP Server application in Java, and a client application in C#. When i am sending data, the client sometimes receives data out of order, and sometimes parts miss entirely. Basically, the code i use in the server (java) looks like this (stripped):
ServerSocket welcomeSocket = new ServerSocket(port);
Socket connectionSocket = welcomeSocket.accept();
outputStream = new DataOutputStream(socket.getOutputStream()); //Create stream
outputStream.writeBytes(message + "\n");
outputStream.flush();
I use "\n" as a delimiter. On the client side (C#) i use the following code:
private const char Delimiter = '\n';
tcpclnt = new TcpClient();
tcpclnt.NoDelay = true;
tcpclnt.Client.DontFragment = true;
tcpclnt.Connect(ip, port);
//This function is executed in a separate thread
public void Receive()
{
try
{
stream = tcpclnt.GetStream();
streamreader = new StreamReader(stream);
this.Connected = true;
while (Connected)
{
string line = ReadLine(streamreader);
Console.WriteLine("Received data: " + line);
}
}
}
private string ReadLine(StreamReader reader)
{
bool finished = false;
string line = "";
while (finished == false)
{
int asciiNumber = reader.Read();
char character = Convert.ToChar(asciiNumber);
if (!character.Equals(Delimiter))
line += character;
else finished = true;
}
return line;
}
The code is not very complicated. However, the data sent from the server is not always received correctly in the client. As an example, I should receive the following two strings:
"5_8_1" and "6_LEVELDATA"
What i get (sometimes) however, is this: "5_8_61" and "_LEVELDATA"
Another example: "5_4_1" and "6_LEVELDATA" result in one single string: "5_6_LEVELDATA"
This seems like some small problem, but it does in fact pretty much ruin my application. I have read a lot of posts, but the only answers i have read are either "this shouldnt happen with TCP" or "send the length of the tcp message first" which would not help in any way in this case, because the problem isn't the data being split up in multiple packages, it simply isn't arriving in the right order, which is something TCP should do.
I am 100% sure the string is always complete before it is being sent by the Java application.
I really wonder what i'm doing wrong here. Is something messed up bad in my code? I would appreciate any help with this problem. Thanks in advance.
After trying Wireshark, it appears my problem existed in the server. Apparently every TCP-message was sent in a seperate thread. Thank you for all of your comments! My problem is solved now.