/// <summary>
/// Handles the asynchronous connect event.
/// </summary>
/// <param name="iEvent"></param>
private void ProcessConnect(SocketAsyncEventArgs iEvent)
{
if (iEvent.SocketError == SocketError.Success)
{ // notify connected event subscribers
ConnectedEvent(this, new EventArgs());
// Depending on the type of protocol, the initial size of the buffer
// and the buffer object itself will vary.
// For APP messages, it is important that we identify the length of the expected message first
// For HTTP messages, the length is stored in the Content-Length parameter
// For XML messages, the end of the message is identified by a null or SOH character
// create read buffers
_RspBfr = new byte[BUFFER_SIZE];
_DataBfr = new byte[BUFFER_SIZE];
Int32 cReadLength = BUFFER_SIZE;
byte[] aReadBuffer = _DataBfr;
if (_ProtocolType == AisProtocolType.App)
{ // use response read buffer
aReadBuffer = _RspBfr;
// read the length field first
cReadLength = LENGTH_SIZE;
// set APP read state to reading response length
_AppReadState = AppReadState.ReadingResponseLength;
}
_AsyncReadEventArgs = new SocketAsyncEventArgs();
// assign buffer but read only the length field
_AsyncReadEventArgs.SetBuffer(aReadBuffer, 0, cReadLength);
_AsyncReadEventArgs.Completed += new EventHandler <SocketAsyncEventArgs>(ReceiveComplete);
try
{ // asynchronous receive
if (!_RemoteSocket.ReceiveAsync(_AsyncReadEventArgs))
{ // if synchronous
ProcessReceive(_AsyncReadEventArgs);
}
}
catch (SocketException aEx)
{ Debug.WriteLine(aEx.Message);
// if socket is connected
if (_RemoteSocket.Connected)
{ // disconnect from server
_RemoteSocket.Close();
}
// notify disconnected event subscribers
DisconnectedEvent(this, new EventArgs());
// throw away our socket object
_RemoteSocket = null; }
}
else
{ // create socket error event object
SocketErrorEventArgs aSocketErrorEventArgs = new SocketErrorEventArgs();
aSocketErrorEventArgs.Status = (int)iEvent.SocketError;
aSocketErrorEventArgs.Error = "Connect failed";
// notify socket error event subscribers
SocketErrorEvent(this, aSocketErrorEventArgs);
//MessageBox.Show("Connect failed");
// delete socket
_RemoteSocket = null;
}
}
/// <summary>
/// Handles the HTTP response.
/// </summary>
/// <param name="iEvent">Socket event arguments object.</param>
private void ProcessHttp(SocketAsyncEventArgs iEvent)
{
// resize response buffer if not enough
if ((_RspLength + iEvent.BytesTransferred) < _RspBfr.Length)
{
Array.Resize(ref _RspBfr, _RspLength + iEvent.BytesTransferred);
}
// append new data to response buffer
Array.Copy(iEvent.Buffer, 0, _RspBfr, _RspLength, iEvent.BytesTransferred);
// update new response length
_RspLength += iEvent.BytesTransferred;
Int32 aBeg = 0;
Int32 aB = 0;
Int32 aEnd = _RspLength;
String aTemp = String.Empty;
Int32 aMsgLength = 0;
byte[] aCookie = null;
bool aClear = true;
// process response buffer loop
while (aBeg < aEnd)
{ // skip whitespaces
while ((Char.IsWhiteSpace((char)_RspBfr[aBeg])) && (aBeg < aEnd))
{
aBeg++;
}
// buffer overflow protection
if (aBeg == aEnd)
{
aClear = false;
break; // not enough bytes
}
// make sure we can read the protocol header
if (aBeg + HTTP_HDR.Length > aEnd)
{
aClear = false;
break; // not enough bytes
}
// read the protocol header
aTemp = System.Text.Encoding.ASCII.GetString(_RspBfr, aBeg, HTTP_HDR.Length);
if (aTemp != HTTP_HDR)
{ // EMIT PROTOCOL ERROR
SocketErrorEventArgs aSocketError = new SocketErrorEventArgs();
aSocketError.Error = "Unknown Procotol";
SocketErrorEvent(this, aSocketError);
break;
}
aB = aBeg;
// extract Set-Cookie and Content-Length loop
do
{ // scan past next newline
while (aB < aEnd && ((char)_RspBfr[aB++]) != '\n')
{
;
}
if (aB + SET_COOKIE.Length < aEnd &&
_RspBfr[aB] == 'S' &&
_RspBfr[aB + 1] == 'e' &&
_RspBfr[aB + 2] == 't' &&
_RspBfr[aB + 3] == '-' &&
_RspBfr[aB + 4] == 'C' &&
_RspBfr[aB + 5] == 'o' &&
_RspBfr[aB + 6] == 'o' &&
_RspBfr[aB + 7] == 'k' &&
_RspBfr[aB + 8] == 'i' &&
_RspBfr[aB + 9] == 'e')
{ // scan past the colon (:)
while ((aB < aEnd) && (_RspBfr[aB++] != ':'))
{
;
}
if (aB < aEnd)
{
Int32 aEol = 0;
if (_RspBfr[aB] == ' ')
{
aB++;
}
for (aEol = aB; (aEol < aEnd) && (_RspBfr[aEol] != '\r') &&
(_RspBfr[aEol] != '\n'); aEol++)
{
;
}
aCookie = new byte[aEol - aB];
Array.Copy(_RspBfr, aB, aCookie, 0, aEol - aB);
}
}
else if (aB + CONTENT_LENGTH.Length < aEnd &&
_RspBfr[aB] == 'C' &&
_RspBfr[aB + 1] == 'o' &&
_RspBfr[aB + 2] == 'n' &&
_RspBfr[aB + 3] == 't' &&
_RspBfr[aB + 4] == 'e' &&
_RspBfr[aB + 5] == 'n' &&
_RspBfr[aB + 6] == 't' &&
_RspBfr[aB + 7] == '-' &&
_RspBfr[aB + 8] == 'L' &&
_RspBfr[aB + 9] == 'e' &&
_RspBfr[aB + 10] == 'g' &&
_RspBfr[aB + 11] == 'n' &&
_RspBfr[aB + 12] == 't' &&
_RspBfr[aB + 13] == 'h')
{
while ((aB < aEnd) && _RspBfr[aB] < '0' || _RspBfr[aB] > '9')
{
aB++;
}
// get the content-length
if (aB < aEnd)
{
Int32 aEol = 0;
for (aEol = aB; (aEol < aEnd) && (_RspBfr[aEol] != '\r') &&
(_RspBfr[aEol] != '\n'); aEol++)
{
;
}
aTemp = Encoding.ASCII.GetString(_RspBfr, aB, (aEol - aB));
try
{ aMsgLength = Int32.Parse(aTemp); }
catch (FormatException)
{ Debug.WriteLine("Invalid Content-Length value."); }
}
}
else if (_RspBfr[aB] == '\r')
{
aB++;
}
} // extract Set-Cookie and Content-Length loop
while (aB < aEnd && (_RspBfr[aB++]) != '\n');
// partial. save the partial request.
// aBeg = Beginning of this message
// aB = Beginning of the body of request
if (aB + aMsgLength > aEnd)
{ // if aBeg has been moved past the beginning of the buffer
// just keep the partial
if (aBeg > 0)
{ // create new buffer
byte[] aNewBfr = new byte[aEnd - aBeg];
Array.Copy(_RspBfr, aBeg, aNewBfr, 0, aNewBfr.Length);
_RspBfr = aNewBfr;
}
aBeg = aB + aMsgLength;
// DO NOT CLEAR BUFFER
aClear = false;
// quit the main loop
break;
}
else
{
ResponseEventArgs aHtmlResponse = new ResponseEventArgs();
aHtmlResponse.ResponseBuffer = new byte[aMsgLength];
aHtmlResponse.CookieBuffer = aCookie;
Array.Copy(_RspBfr, aB, aHtmlResponse.ResponseBuffer, 0, aMsgLength);
// emit response signal
ResponseEvent(this, aHtmlResponse);
// move aBeg to end of body
aBeg += aMsgLength;
}
}
if (aClear)
{
_RspLength = 0;
}
// call asynchronous read again
_RemoteSocket.ReceiveAsync(iEvent);
} // end of process response buffer loop
/// <summary>
/// Handles the XML response.
/// </summary>
/// <param name="iEvent">Socket event arguments object.</param>
private void ProcessXml(SocketAsyncEventArgs iEvent)
{
// resize response buffer if not enough
if ((_RspLength + iEvent.BytesTransferred) < _RspBfr.Length)
{
Array.Resize(ref _RspBfr, _RspLength + iEvent.BytesTransferred);
}
// append new data to response buffer
Array.Copy(iEvent.Buffer, 0, _RspBfr, _RspLength, iEvent.BytesTransferred);
// update new response length
_RspLength += iEvent.BytesTransferred;
Int32 aBeg = 0;
Int32 aB = 0;
Int32 aEnd = _RspLength;
String aTemp = String.Empty;
bool aClear = true;
// process response buffer loop
while (aBeg < aEnd)
{ // skip whitespaces
while ((Char.IsWhiteSpace((char)_RspBfr[aBeg])) && (aBeg < aEnd))
{
aBeg++;
}
// buffer overflow protection
if (aBeg == aEnd)
{
aClear = false;
break; // not enough bytes
}
// make sure we can read the protocol header
if (aBeg + XML_HDR.Length > aEnd)
{
aClear = false;
break; // not enough bytes
}
// read the protocol header
aTemp = System.Text.Encoding.ASCII.GetString(_RspBfr, aBeg, XML_HDR.Length);
if (aTemp != XML_HDR)
{ // EMIT PROTOCOL ERROR
SocketErrorEventArgs aSocketError = new SocketErrorEventArgs();
aSocketError.Error = "Unknown Protocol";
SocketErrorEvent(this, aSocketError);
break;
}
for (aB = aBeg; aB < aEnd && _RspBfr[aB] > MSG_TERM; aB++)
{
;
}
// if read past the last character
if (aB == aEnd)
{ // DO NOT CLEAR BUFFER
aClear = false;
break;
}
// partial. save partial request.
// aBeg - Beginning of next response
// aB - end of this response
if (_RspBfr[aB] > MSG_TERM)
{ // if aBeg has been moved past the beginning of the buffer
if (aBeg > 0)
{
byte[] aNewBuffer = new byte[aEnd - aBeg];
Array.Copy(_RspBfr, aBeg, aNewBuffer, 0, aNewBuffer.Length);
_RspBfr = aNewBuffer;
}
// DO NOT CLEAR BUFFER
aClear = false;
break;
}
// NULL terminate the response
_RspBfr[aB] = (byte)MSG_NULL;
ResponseEventArgs aResponse = new ResponseEventArgs();
aResponse.ResponseBuffer = new byte[aB + 1];
Array.Copy(_RspBfr, aBeg, aResponse.ResponseBuffer, 0, aB + 1);
// emit response signal
ResponseEvent(this, aResponse);
// move aBeg to
aBeg = aB + 1;
}
if (aClear)
{
_RspLength = 0;
}
// call asynchronous read again
_RemoteSocket.ReceiveAsync(iEvent);
}
/// <summary>
/// Opens a persistent connection to the AIS server.
/// </summary>
/// <param name="iHostDnsIP">Hostname or IP Address of the server.</param>
/// <param name="iPort">Server port.</param>
/// <returns>true if the operation is successful.</returns>
/// <remarks>After this function is called, the following events can be received:
/// 1. ConnectedEvent - When connection to the server is successful.
/// 2. DisconnectedEvent - When connection to the server is closed/disconnected.
/// 3. SocketErrorEvent - When there's an error in one of the socket operations.
/// 4. ResponseEvent - When there's data received from the server.
/// </remarks>
public bool OpenConnection(ref String iHostDnsIP, UInt16 iPort)
{
bool aRet = false;
// check parameters and make sure no there's no existing socket connection
if (iHostDnsIP.Length > 0 && iPort > 0 && _RemoteSocket == null)
{
try
{ IPAddress aIPAdd = null;
if (!IPAddress.TryParse(iHostDnsIP, out aIPAdd))
{ // resolve host IP
IPHostEntry aIPHost = Dns.GetHostEntry(iHostDnsIP);
aIPAdd = aIPHost.AddressList[0];
}
// create end point object
IPEndPoint aEndPt = new IPEndPoint(aIPAdd, iPort);
// create our socket object
_RemoteSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
/*
* // establish connection with the server
* _RemoteSocket.Connect(aEndPt);
* // notify connected event subscribers
* ConnectedEvent(this, new EventArgs());
*
* // Depending on the type of protocol, the initial size of the buffer
* // and the buffer object itself will vary.
* // For APP messages, it is important that we identify the length of the expected message first
* // For HTTP messages, the length is stored in the Content-Length parameter
* // For XML messages, the end of the message is identified by a null or SOH character
* // create read buffers
* _RspBfr = new byte[BUFFER_SIZE];
* _DataBfr = new byte[BUFFER_SIZE];
* Int32 cReadLength = BUFFER_SIZE;
* byte[] aReadBuffer = _DataBfr;
* if (_ProtocolType == AisProtocolType.App)
* { // use response read buffer
* aReadBuffer = _RspBfr;
* // read the length field first
* cReadLength = LENGTH_SIZE;
* // set APP read state to reading response length
* _AppReadState = AppReadState.ReadingResponseLength;
* }
* _AsyncReadEventArgs = new SocketAsyncEventArgs();
* // assign buffer but read only the length field
* _AsyncReadEventArgs.SetBuffer(aReadBuffer, 0, cReadLength);
* _AsyncReadEventArgs.Completed += new EventHandler<SocketAsyncEventArgs>(ReceiveComplete);
*
* // asynchronous receive
* if (!_RemoteSocket.ReceiveAsync(_AsyncReadEventArgs))
* {
* // if synchronous
* ProcessReceive(_AsyncReadEventArgs);
* }*/
_AsyncConnEventArgs = new SocketAsyncEventArgs();
_AsyncConnEventArgs.RemoteEndPoint = aEndPt;
_AsyncConnEventArgs.Completed += new EventHandler <SocketAsyncEventArgs>(ConnectComplete);
if (!_RemoteSocket.ConnectAsync(_AsyncConnEventArgs))
{ // if synchronous
ProcessConnect(_AsyncConnEventArgs);
}
// return success
aRet = true; }
catch (SocketException aEx)
{ Debug.WriteLine(aEx.Message);
// if socket object was created successfully
if (_RemoteSocket != null)
{ // if socket is connected
if (_RemoteSocket.Connected)
{ // disconnect from server
_RemoteSocket.Close();
// notify disconnected event subscribers
DisconnectedEvent(this, new EventArgs());
}
// throw away our socket object
_RemoteSocket = null;
}
else
{ // create socket error event object
SocketErrorEventArgs aSocketErrorEventArgs = new SocketErrorEventArgs();
aSocketErrorEventArgs.Status = aEx.ErrorCode;
aSocketErrorEventArgs.Error = aEx.Message;
// notify socket error event subscribers
SocketErrorEvent(this, aSocketErrorEventArgs);
}
// return failure
aRet = false; }
}
return(aRet);
}
