/// <summary>
/// Connects to a server named pipe.
/// </summary>
/// <param name="pipeName">The pipe name.</param>
/// <param name="serverName">The server name.</param>
/// <returns>The pipe handle, which also contains the pipe state.</returns>
/// <remarks>This method is used by clients to establish a pipe connection with a server pipe.</remarks>
#endregion
public static PipeHandle ConnectToPipe(string pipeName, string serverName)
{
PipeHandle handle = new PipeHandle();
// Build the name of the pipe.
string name = @"\\" + serverName + @"\pipe\" + pipeName;
for (int i = 1; i <= ATTEMPTS; i++)
{
handle.State = InterProcessConnectionState.ConnectingToServer;
// Try to connect to the server
handle.Handle = NamedPipeNative.CreateFile(name, NamedPipeNative.GENERIC_READ | NamedPipeNative.GENERIC_WRITE, 0, null, NamedPipeNative.OPEN_EXISTING, 0, 0);
if (handle.Handle.ToInt32() != NamedPipeNative.INVALID_HANDLE_VALUE)
{
// The client managed to connect to the server pipe
handle.State = InterProcessConnectionState.ConnectedToServer;
// Set the read mode of the pipe channel
uint mode = NamedPipeNative.PIPE_READMODE_MESSAGE;
if (NamedPipeNative.SetNamedPipeHandleState(handle.Handle, ref mode, IntPtr.Zero, IntPtr.Zero))
{
break;
}
if (i >= ATTEMPTS)
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Error setting read mode on pipe " + name + " . Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
if (i >= ATTEMPTS)
{
if (NamedPipeNative.GetLastError() != NamedPipeNative.ERROR_PIPE_BUSY)
{
handle.State = InterProcessConnectionState.Error;
// After a certain number of unsuccessful attempt raise an exception
throw new NamedPipeIOException("Error connecting to pipe " + name + " . Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
else
{
handle.State = InterProcessConnectionState.Error;
throw new NamedPipeIOException("Pipe " + name + " is too busy. Internal error: " + NamedPipeNative.GetLastError().ToString(), NamedPipeNative.GetLastError());
}
}
else
{
// The pipe is busy so lets wait for some time and try again
if (NamedPipeNative.GetLastError() == NamedPipeNative.ERROR_PIPE_BUSY)
{
NamedPipeNative.WaitNamedPipe(name, WAIT_TIME);
}
}
}
return(handle);
}
/// <summary>
/// Tries to connect to a named pipe.
/// </summary>
/// <param name="pipeName">The name of the pipe.</param>
/// <param name="serverName">The name of the server.</param>
/// <param name="handle">The resulting pipe handle.</param>
/// <returns>Return true if the attempt succeeds.</returns>
/// <remarks>This method is used mainly when stopping the pipe server. It unblocks the existing pipes, which wait for client connection.</remarks>
#endregion
public static bool TryConnectToPipe(string pipeName, string serverName, out PipeHandle handle)
{
handle = new PipeHandle();
// Build the pipe name string
string name = @"\\" + serverName + @"\pipe\" + pipeName;
handle.State = InterProcessConnectionState.ConnectingToServer;
// Try to connect to a server pipe
handle.Handle = NamedPipeNative.CreateFile(name, NamedPipeNative.GENERIC_READ | NamedPipeNative.GENERIC_WRITE, 0, null, NamedPipeNative.OPEN_EXISTING, 0, 0);
if (handle.Handle.ToInt32() != NamedPipeNative.INVALID_HANDLE_VALUE)
{
handle.State = InterProcessConnectionState.ConnectedToServer;
return(true);
}
else
{
handle.State = InterProcessConnectionState.Error;
return(false);
}
}
