//____________________________________________________________________________
// initializes the server by preallocating reusable buffers and
// context objects (SocketAsyncEventArgs objects).
//It is NOT mandatory that you preallocate them or reuse them. But, but it is
//done this way to illustrate how the API can
// easily be used to create reusable objects to increase server performance.
internal void Init()
{
// Allocate one large byte buffer block, which all I/O operations will
//use a piece of. This gaurds against memory fragmentation.
this.theBufferManager.InitBuffer();
// preallocate pool of SocketAsyncEventArgs objects for accept operations
for (Int32 i = 0; i < this.socketListenerSettings.MaxAcceptOps; i++)
{
// add SocketAsyncEventArg to the pool
this.poolOfAcceptEventArgs.Push(CreateNewSaeaForAccept(poolOfAcceptEventArgs));
}
//The pool that we built ABOVE is for SocketAsyncEventArgs objects that do
// accept operations.
//Now we will build a separate pool for SAEAs objects
//that do receive/send operations. One reason to separate them is that accept
//operations do NOT need a buffer, but receive/send operations do.
//ReceiveAsync and SendAsync require
//a parameter for buffer size in SocketAsyncEventArgs.Buffer.
// So, create pool of SAEA objects for receive/send operations.
SocketAsyncEventArgs eventArgObjectForPool;
Int32 tokenId;
for (Int32 i = 0; i < this.socketListenerSettings.NumberOfSaeaForRecSend; i++)
{
//Allocate the SocketAsyncEventArgs object for this loop,
//to go in its place in the stack which will be the pool
//for receive/send operation context objects.
eventArgObjectForPool = new SocketAsyncEventArgs();
// assign a byte buffer from the buffer block to
//this particular SocketAsyncEventArg object
this.theBufferManager.SetBuffer(eventArgObjectForPool);
tokenId = poolOfRecSendEventArgs.AssignTokenId() + 1000000;
//Attach the SocketAsyncEventArgs object
//to its event handler. Since this SocketAsyncEventArgs object is
//used for both receive and send operations, whenever either of those
//completes, the IO_Completed method will be called.
eventArgObjectForPool.Completed += new EventHandler <SocketAsyncEventArgs>(IO_Completed);
//We can store data in the UserToken property of SAEA object.
DataHoldingUserToken theTempReceiveSendUserToken = new DataHoldingUserToken(eventArgObjectForPool, eventArgObjectForPool.Offset, eventArgObjectForPool.Offset + this.socketListenerSettings.BufferSize, this.socketListenerSettings.ReceivePrefixLength, this.socketListenerSettings.SendPrefixLength, tokenId);
//We'll have an object that we call DataHolder, that we can remove from
//the UserToken when we are finished with it. So, we can hang on to the
//DataHolder, pass it to an app, serialize it, or whatever.
theTempReceiveSendUserToken.CreateNewDataHolder();
eventArgObjectForPool.UserToken = theTempReceiveSendUserToken;
// add this SocketAsyncEventArg object to the pool.
this.poolOfRecSendEventArgs.Push(eventArgObjectForPool);
}
}
//____________________________________________________________________________
// initializes the server by preallocating reusable buffers and
// context objects (SocketAsyncEventArgs objects).
//It is NOT mandatory that you preallocate them or reuse them. But, but it is
//done this way to illustrate how the API can
// easily be used to create reusable objects to increase server performance.
internal void Init()
{
if (Program.watchProgramFlow == true) //for testing
{
Program.testWriter.WriteLine("Init method");
}
if (Program.watchThreads == true) //for testing
{
DealWithThreadsForTesting("Init()");
}
// Allocate one large byte buffer block, which all I/O operations will
//use a piece of. This gaurds against memory fragmentation.
this.theBufferManager.InitBuffer();
if (Program.watchProgramFlow == true) //for testing
{
Program.testWriter.WriteLine("Starting creation of accept SocketAsyncEventArgs pool:");
}
// preallocate pool of SocketAsyncEventArgs objects for accept operations
for (Int32 i = 0; i < this.socketListenerSettings.MaxAcceptOps; i++)
{
// add SocketAsyncEventArg to the pool
this.poolOfAcceptEventArgs.Push(CreateNewSaeaForAccept(poolOfAcceptEventArgs));
}
//The pool that we built ABOVE is for SocketAsyncEventArgs objects that do
// accept operations.
//Now we will build a separate pool for SAEAs objects
//that do receive/send operations. One reason to separate them is that accept
//operations do NOT need a buffer, but receive/send operations do.
//ReceiveAsync and SendAsync require
//a parameter for buffer size in SocketAsyncEventArgs.Buffer.
// So, create pool of SAEA objects for receive/send operations.
SocketAsyncEventArgs eventArgObjectForPool;
if (Program.watchProgramFlow == true) //for testing
{
Program.testWriter.WriteLine("Starting creation of receive/send SocketAsyncEventArgs pool");
}
Int32 tokenId;
for (Int32 i = 0; i < this.socketListenerSettings.NumberOfSaeaForRecSend; i++)
{
//Allocate the SocketAsyncEventArgs object for this loop,
//to go in its place in the stack which will be the pool
//for receive/send operation context objects.
eventArgObjectForPool = new SocketAsyncEventArgs();
// assign a byte buffer from the buffer block to
//this particular SocketAsyncEventArg object
this.theBufferManager.SetBuffer(eventArgObjectForPool);
tokenId = poolOfRecSendEventArgs.AssignTokenId() + 1000000;
//Attach the SocketAsyncEventArgs object
//to its event handler. Since this SocketAsyncEventArgs object is
//used for both receive and send operations, whenever either of those
//completes, the IO_Completed method will be called.
eventArgObjectForPool.Completed += new EventHandler<SocketAsyncEventArgs>(IO_Completed);
//We can store data in the UserToken property of SAEA object.
DataHoldingUserToken theTempReceiveSendUserToken = new DataHoldingUserToken(eventArgObjectForPool, eventArgObjectForPool.Offset, eventArgObjectForPool.Offset + this.socketListenerSettings.BufferSize, this.socketListenerSettings.ReceivePrefixLength, this.socketListenerSettings.SendPrefixLength, tokenId);
//We'll have an object that we call DataHolder, that we can remove from
//the UserToken when we are finished with it. So, we can hang on to the
//DataHolder, pass it to an app, serialize it, or whatever.
theTempReceiveSendUserToken.CreateNewDataHolder();
eventArgObjectForPool.UserToken = theTempReceiveSendUserToken;
// add this SocketAsyncEventArg object to the pool.
this.poolOfRecSendEventArgs.Push(eventArgObjectForPool);
}
}
//____________________________________________________________________________
// This method is invoked by the IO_Completed method
// when an asynchronous receive operation completes.
// If the remote host closed the connection, then the socket is closed.
// Otherwise, we process the received data. And if a complete message was
// received, then we do some additional processing, to
// respond to the client.
private void ProcessReceive(SocketAsyncEventArgs receiveSendEventArgs)
{
DataHoldingUserToken receiveSendToken = (DataHoldingUserToken)receiveSendEventArgs.UserToken;
// If there was a socket error, close the connection. This is NOT a normal
// situation, if you get an error here.
// In the Microsoft example code they had this error situation handled
// at the end of ProcessReceive. Putting it here improves readability
// by reducing nesting some.
if (receiveSendEventArgs.SocketError != SocketError.Success)
{
receiveSendToken.Reset();
CloseClientSocket(receiveSendEventArgs);
//Jump out of the ProcessReceive method.
return;
}
// If no data was received, close the connection. This is a NORMAL
// situation that shows when the client has finished sending data.
if (receiveSendEventArgs.BytesTransferred == 0)
{
receiveSendToken.Reset();
CloseClientSocket(receiveSendEventArgs);
return;
}
//The BytesTransferred property tells us how many bytes
//we need to process.
Int32 remainingBytesToProcess = receiveSendEventArgs.BytesTransferred;
//If we have not got all of the prefix already,
//then we need to work on it here.
if (receiveSendToken.receivedPrefixBytesDoneCount < this.socketListenerSettings.ReceivePrefixLength)
{
remainingBytesToProcess = prefixHandler.HandlePrefix(receiveSendEventArgs, receiveSendToken, remainingBytesToProcess);
if (remainingBytesToProcess == 0)
{
// We need to do another receive op, since we do not have
// the message yet, but remainingBytesToProcess == 0.
StartReceive(receiveSendEventArgs);
//Jump out of the method.
return;
}
}
// If we have processed the prefix, we can work on the message now.
// We'll arrive here when we have received enough bytes to read
// the first byte after the prefix.
bool incomingTcpMessageIsReady = messageHandler.HandleMessage(receiveSendEventArgs, receiveSendToken, remainingBytesToProcess);
if (incomingTcpMessageIsReady == true)
{
if (Program.watchData == true)
{
Program.testWriter.WriteLine(receiveSendToken.TokenId + ", Message in DataHolder = " + Encoding.ASCII.GetString(receiveSendToken.theDataHolder.dataMessageReceived) + "\r\n");
}
//for testing only
if (Program.msDelayAfterGettingMessage > -1)
{
//A Thread.Sleep here can be used to simulate delaying the
//return of the SocketAsyncEventArgs object for receive/send
//to the pool. Simulates doing some work here.
if (Program.watchData == true)
{
Program.testWriter.WriteLine(receiveSendToken.TokenId + " waiting after read.\r\n");
}
Thread.Sleep(Program.msDelayAfterGettingMessage);
}
// Pass the DataHolder object to the Mediator here. The data in
// this DataHolder can be used for all kinds of things that an
// intelligent and creative person like you might think of.
receiveSendToken.theMediator.HandleData(receiveSendToken.theDataHolder);
// Create a new DataHolder for next message.
receiveSendToken.CreateNewDataHolder();
//Reset the variables in the UserToken, to be ready for the
//next message that will be received on the socket in this
//SAEA object.
receiveSendToken.Reset();
receiveSendToken.theMediator.PrepareOutgoingData();
StartSend(receiveSendToken.theMediator.GiveBack());
}
else
{
// Since we have NOT gotten enough bytes for the whole message,
// we need to do another receive op. Reset some variables first.
// All of the data that we receive in the next receive op will be
// message. None of it will be prefix. So, we need to move the
// receiveSendToken.receiveMessageOffset to the beginning of the
// receive buffer space for this SAEA.
receiveSendToken.receiveMessageOffset = receiveSendToken.bufferOffsetReceive;
// Do NOT reset receiveSendToken.receivedPrefixBytesDoneCount here.
// Just reset recPrefixBytesDoneThisOp.
receiveSendToken.recPrefixBytesDoneThisOp = 0;
StartReceive(receiveSendEventArgs);
}
}
