I have a policy file server up and running. For a while I was getting the AccessDenied because the policy file was not set properly. Now I no longer receive that error, so I know that's not the issue. I have a simple server running that simple loops on accepting client connections from any address. I also wrote a simple client, so I know the server works. In Silverlight I set my args and then call ConnectAsync. It return immedately on localhost (makes sense) and when I check the event args LastOperation is Connect and SocketError is Success. However, when I check my socket, it is not connected at all. Any ideas..? Been banging my head against a wall for hours over this.
A few other things I've tried. I moved the servers off my local box onto another server. Still didn't work. I did a packet capture and noticed that it is receiving the Poilcy File, but after that, there is no packet sent out by the browser to even attempt to connect to the other server.
public void Connect(string ip)
{
SocketAsyncEventArgs saea = new SocketAsyncEventArgs();
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
var endpoint = new IPEndPoint(IPAddress.Parse(ip), 4502);
saea.UserToken = socket;
saea.RemoteEndPoint = endpoint;
saea.Completed += new EventHandler<SocketAsyncEventArgs>(AsyncEventComplete);
var completedSync = socket.ConnectAsync(saea);
if (completedSync)
{
AsyncEventComplete(null, saea);
}
Result = ip;
}
void AsyncEventComplete(object sender, SocketAsyncEventArgs e)
{
switch (e.LastOperation)
{
case SocketAsyncOperation.Connect:
MessageBox.Show("CONNECTED");
break;
case SocketAsyncOperation.Receive:
MessageBox.Show("DATA RECEIEVED");
// do stuff
break;
}
}
I think you should use e.SocketError and not e.LastOperation
You could also use e.ConnectSocket (in Silverlight only)
You should also add a "not" in this condition : if ( ! completedSync )
Related
I want to connect two F746ZG boards so that they can communicate via TCP. I am using the STM implementation of LwIP with the netconn API. The IP address is supplied via DHCP, but it is always the same address. Also, the address matches the expected value. The problem I am facing is that the client seemingly can't establish a connection. I am binding the connection to port 8880. Since I ran into this issue, I have written a debug client that should just periodically send a predefined message to a server. Here is the code for the client:
static void tcpecho_client_thread(void const *arg)
{
struct netconn *xNetConn = NULL;
err_t bind_err, connect_err;
char* b_data = "OK"; // Data to be sent
uint16_t b_len = sizeof ( b_data );
IP4_ADDR(&local_ip, IP_ADDR0_CLIENT, IP_ADDR1_CLIENT, IP_ADDR2_CLIENT, IP_ADDR3_CLIENT);
IP4_ADDR(&pc_ip, IP_ADDR0_PC, IP_ADDR0_PC, IP_ADDR2_PC, IP_ADDR3_PC);
xNetConn = netconn_new ( NETCONN_TCP );
if (xNetConn != NULL){
bind_err = netconn_bind ( xNetConn, &local_ip, TCP_PORT_NETCONN );
if(bind_err == ERR_OK){
// Try to connect to server
for(;;){
connect_err = netconn_connect ( xNetConn, &pc_ip, TCP_PORT_NETCONN);
if (connect_err == ERR_OK){
// We are connected
while(1){
BSP_LED_On(LED1);
netconn_write(xNetConn, b_data, b_len, NETCONN_COPY);
vTaskDelay(1000); // To see the result easily in Comm Operator
}
}
}
}else{
// Failed to bind the connection
BSP_LED_On(LED3);
}
}else{
// Failed to allocate a new connection
BSP_LED_On(LED3);
}
}
When I debug this, netconn_connect never manages to actually connect to something. Since I am able to ping the board and get a response, I am confused, what is going wrong here. I have tried to use Hercules to set up a TCP server on my PC so that the board can connect to that, but that also doesn't work. Using Wireshark, I can see the responses to my ping command coming in, but I don't see anything that would indicate the board trying to connect to my PC.
I have tested the corresponding server on the second board, but that runs fine. I can connect to it with Hercules and send data, so I doubt there is anything fundamentally wrong with the LwIP stack.
What I could guess is that I messed up the netconn_bind, I am not 100% sure what IP you are supposed to bind the connection to. The way it currently is, is how I read the documentation. For the server, I have bound it to IP_ADDR_ANY. Besides that, my implementation mostly matches with the examples you can find online (e.g. LwIP Wiki).
I have figured out the problem. After I delete the netconn_bind call, everything works fine for me.
I'm working with a fingerprint sensor on Arduino, but sometimes, on runtime, my WPF app throws an exception on sp.Open() saying "COM3" Access denied"
Here's the code on c#:
public string ConfigPort()
{
SerialPort sp = new SerialPort();
sp.BaudRate = 9600;
sp.PortName = AutodetectArduinoPort();
sp.Open();
string s = "";
while (true)
{
s = sp.ReadLine();
Console.WriteLine(s);
return s;
}
}
Here's the AutodetectArduinoPort method:
public string AutodetectArduinoPort()
{
ManagementScope connectionScope = new ManagementScope();
SelectQuery serialQuery = new SelectQuery("SELECT * FROM Win32_SerialPort");
ManagementObjectSearcher searcher = new ManagementObjectSearcher(connectionScope, serialQuery);
try
{
foreach (ManagementObject item in searcher.Get())
{
string desc = item["Description"].ToString();
string deviceId = item["DeviceID"].ToString();
if (desc.Contains("Arduino"))
{
return deviceId;
}
}
}
catch (ManagementException e)
{
/* Do Nothing */
}
return null;
}
Any solution??
This happens quite a lot with Arduino, personally I think there's a problem with the FTDI driver....certainly wouldn't be the first issue with them. What I do when this happens is physically unplug the device from the USB port, wait for the notification sound from Windows and then plug it back in again. This seems to "reset" the port and force whatever is holding it open to release it, and you're good to go again. You may need to do this quite a bit over time, so the only other tip I have is to use a cheap USB hub so that you wind up wearing out the port pins on that rather than your expensive laptop/desktop.
The error you're getting means that the port is already open. Make sure that you only call ConfigPort() once, and after you're done processing data from the Arduino, close the port with sp.Close(). I would suggest converting sp into a global variable, and subscribing to the OnClosing event of your WPF window, so you can close the port when the user closes the application.
I am trying to retrieve a file from an ftp server with anonymous authentication using java.net.URLConnection.
try {
url = new URL("ftp://ftp2.sat.gob.mx/Certificados/FEA/000010/000002/02/03/05/00001000000202030500.cer");
URLConnection con = url.openConnection();
InputStream in = con.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = in.read(buffer)) >= 0)
{
baos.write(buffer, 0, bytesRead);
}
baos.flush();
arr = baos.toByteArray();
in.close();
} catch (Exception e) {
throw new Exception("Error SAT: " + e.getMessage());
}
The file i am trying to get is this, its in an anonymous authentication ftp site:
ftp://ftp2.sat.gob.mx/Certificados/FEA/000010/000002/02/03/05/00001000000202030500.cer
But every time I get this error:
Permission denied: Attempt to bind port without permission.
I am using GoogleAppEngine Java 1.7
Any kind of advise is welcome.
I'm not a Java guy, but I suspect you're trying to use "active" FTP, which is likely the default.
Active FTP works by binding to a port on the receiving computer (the client in this case) to which the sending server can connect to send the file; the port number is sent over in the get request. This doesn't work in many environments, e.g. NAT.
The usual solution is to use "passive" mode, which behaves more like HTTP and doesn't require any port binding. If there's a way in Java to twiddle that connection to use passive mode, it should bypass the permissions issue.
Most likely you have a non billing-enabled app, according to this post and this AppEngine Socket Java API documentation you just have to enable billing, if you have no budget set the limits to $0.
As writen in my title,
background:
I have 2 different type of applications (WPF-silverlight) which can talk each other - Doctor application and Patient application - but it doesn't mean only 2 apps will run, for instance:
i can run 3 doctor app and 7 patient app.
and all of those apps is communicate using wcf via tcp connection.
the communication is real time (like messenger app)
flow
everytime there's an app online(run) i registering its connection at wcf, because i need to let the other apps know (real time) there's new client connected or there's new client disconnected.
problem:
it's fine to let the other app know that there;s incoming app/client,
but my problem is, how to let the other app know if this client was disconnected,
it's fine if the user close the application properly (eg. click the close button) - so in wpf, i can call the wcf to unregister the connection,
but how if the connection was terminated abnormal (eg. directly unplug your pc's power cable)
is there any way for me to know this client still connected or not?
i realize this problem when i pres f5 in my VS2008 and close, and open again and close (repeated) and then, when i debug, there's a lot of connection is still stored there but actually the client is already destroyed.
so anybody have know this best solution?
example is much appreciated
my code snippet:
Dictionary<Guid, Client> Connections = new Dictionary<Guid, Client>();
// above is the variable where i put the connections
object syncObj = new object();
public ITcpServiceCallback CurrentCallback { get { return OperationContext.Current.GetCallbackChannel<ITcpServiceCallback>(); } }
// this function is called when the program started
public List<Client> ShakeHand( Client client, RoleType appType ) {
if( GetClientsByCallback( CurrentCallback ).Count < 1 && GetClientsByID( client.ID ).Count < 1 ) {
List<Client> retVal = new List<Client>();
lock( syncObj ) {
if( appType == RoleType.Doctor ) {
List<Client> doctors = Helpers.GetDoctor( AppDomain.CurrentDomain.BaseDirectory + "App_Data/doctor.xml" );
foreach( Client doctor in doctors ) {
doctor.Status = ConnectionStatus.Offline;
foreach( Client con in Connections.Values ) {
if( con.Role == RoleType.Doctor && con.ID == doctor.ID ) {
doctor.Status = ConnectionStatus.Online;
break;
}
}
retVal.Add( doctor );
}
} else { //b la.. bla similiar like if above
}
client.Callback = CurrentCallback;
client.Status = ConnectionStatus.Online;
// this is the code where i add the connection
Connections.Add( Guid.NewGuid(), client );
}
return retVal;
}
return null;
}
Thank you in Advance
I think what you really need to implement is a publisher / subscriber service. All the doctor and patients applications have a link to the pub/sub service. When one an application starts up, it subscribes to the service and begins receiving notifications from all the other applications. When an application closes it unsubscribes from the events.
Take a look at this:
http://msdn.microsoft.com/en-us/library/ms752254.aspx
and this:
http://msdn.microsoft.com/en-us/magazine/cc163537.aspx
I have an IPC problem. I have created into a windows service a NamedPipeServer:
serverPipe = new NamedPipeServerStream(Constants.PIPE_NAME, PipeDirection.InOut, 1, PipeTransmissionMode.Message, PipeOptions.Asynchronous);
Thread thread = new Thread(new ThreadStart(pipeWork));
thread.Start();
where pipeWork is
private static void pipeWork()
{
try
{
byte[] buffer = new byte[1024];
while (true)
{
if (!serverPipe.IsConnected)
serverPipe.WaitForConnection();
int nr = serverPipe.Read(buffer, 0, buffer.Length);
String str=Encoding.Default.GetString(buffer);
…
}
}
catch (Exception ex)
{
}
}
and into a Windows forms I have the client
clientPipe = new NamedPipeClientStream(".", PhotoServiceClassLibrary.Constants.PIPE_NAME, PipeDirection.InOut,PipeOptions.Asynchronous);
clientPipe.Connect();
clientPipe.ReadMode = PipeTransmissionMode.Message;
pipeThread=new Thread(new ThreadStart(pipeWork));
pipeThread.Start();
where pipeWork is
private void pipeWork()
{
try
{
while (true)
{
using (StreamReader sr = new StreamReader(clientPipe))
{
string message;
while ((message = sr.ReadLine()) != null)
{
…
}
}
}
}
catch (Exception ex)
{
}
}
I want when the service begin an action to disable a ContextMenuStrip from the windows forms, for that the service writes a message into a StreamWriter sw:
StreamWriter write = null;
write = new StreamWriter(serverPipe);
if (serverPipe.IsConnected)
{
write.Write(message);
write.Flush();
}
The code is correct because I created for testing another windows forms which implements the same things like the windows service and the communication between
windows forms pipe server -> windows forms pipe client is working well.
The problem is that the windows form - client pipe doesn't receive the message from windows service - server pipe.
I know that WCF can be a better idea but i want to understand why is not working at low-level IPC. Why? I've seen an very strange behavior. My service interact 2 times with the windows forms:
1.My service is designed for downloading some photos. When he begin download he sends a message to the windows forms to announcing him that.
2.When i stop the service he sends a message to windows forms and he stops also.
i've just discovered that both messages arrive at windows agent only after the service is stoped. Can someone explain why?
I hope this isn't your real code. It's good that you've got try/catch blocks around the code of your ThreadStart handlers (otherwise an exception would just quietly delete the thread). However, if you're not logging the exception in the catch block, then it's really just as bad.
You've got a mystery (server doesn't receive message), and you're hiding information (an exception has occurred). If you weren't hiding information, you might have the answer for your mystery (server doesn't receive message because an exception has occurred).
I'm trying to implement the same thing.
I noticed you're passing the PipeTransmissionMode.Message enumeration in the NamedPipeServerStream (serverPipe) constructor. That means the stream will contain strings.
But in pipeWork, you're reading them in as an array of bytes.
Look in the example in this article on MSDN:
http://msdn.microsoft.com/en-us/library/system.io.pipes.namedpipeclientstream.aspx