Socket.Available != 0, Socket.Read --> Exception

  • Thread starter Thread starter Tomasz Naumowicz
  • Start date Start date
T

Tomasz Naumowicz

Hello Everybody,

I have the following problem with Socket:
Socket.Available reports data in the buffer (e.g. 1849 bytes) but I can't
read it because Socket.Read throws an exception
The exception ist being thrown because the connection is already closed. How
could I read the data from the buffer?

background information:
I open multiple connections to my Windows 2003 Web Server (simple HTTP GET).

pseudocode:
while (true) {
foreach open socket {
if should read
read
if should write
write
}

if new connection needed
create new connection
}

The IIS sends the data and closes the connection imediatelly. Sometimes my
application is not ready to "read" because it's doing something else at the
moment.
Shouldn't I be able to access the buffer even if the connection is closed by
the server?

Thanks!
tomek
 
Your socket may be set up differently, but here is the basic flow you should
have:

//IP socketcreated
int port = 11000;

IPHostEntry hostEntry =
Dns.Resolve("www.mysite.com");
IPEndPoint endPoint= new
IPEndPoint(hostEntry.AddressList[0], port);
Socket socket = new Socket(endPoint.Address.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp);
try
{
socket.Connect(lep);
}
//NOTE: This is not the best catch
catch (Exception e)
{
//Would normally throw up the stack here
//Can also flag to avoid the rest of the code
}


Once the socket is set up, you will do one of the following:

//SEND
string messageString = "{Assume a request here?}";
byte[] message = Encoding.ASCII.GetBytes(messageString);

//This will block until all is sent
int sent = socket.Send(message, 0,
message.Length, SocketFlags.None);



//RECEIVE

//This is one way
byte[] bytes = new byte[1024];


while(socket.Avaialable > 0)
{
socket.Receive(bytes, 0, socket.Available
, SocketFlags.None);

//Do something with buffer here
}


//Or, if the messages are known to be short
int socketAvailable = socket.Avaialable;
byte[] bytes = new byte[socketAvailable];

socket.Receive(bytes, 0, socket.Available
, SocketFlags.None);

The question now is what you are doing specifically (code sample)?


---

Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

***************************
Think Outside the Box!
***************************
 
Your socket may be set up differently, but here is the basic flow you
should
have: (cut, cut, cut)
The question now is what you are doing specifically (code sample)?
Click to expand...

Hi,
I need to keep a certain request rate (requests/second), that's why I'm
using a loop to maintain my sockets.
With every single socket I follow the basic flow. My problem is that
sometimes I'm not able to read all data from the buffer
while(socket.Avaialable > 0)
{
socket.Receive(bytes, 0, socket.Available
, SocketFlags.None);
Click to expand...

because sometimes socket.Receive is throwing an exception.

I need to access the buffer even if the connection is closed:
socket.Available != 0 && socket.Connected = false

socket.Receive throws an exception because the connection is closed...

any ideas?
tomasz naumowicz
 
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