Well, I think we have all those bases covered. If you're willing to look at the code, that'd be great. I just got interested in this as an academic pursuit, but obviously if something is wrong with Critical or message handling, everyone cares.
Here are screenshots showing the results. In my testing introducing a delay of at least 10 ms into the send loop ensured all messages were received. Even a 1 ms would at times be enough. However, no delay of anykind always drops messages, and there's no error that I can see.
With a delay:
Without a delay (showing results after clicking send twice):
If I connect to the server with telnet, no messages are lost even with a 0 ms delay.
Here's the server and client code I'm using, a stripped down and slightly modified version of the code previously posted. My server only sends, and the client only connects and receives
Server:
Code:
; -------------------------------------------------
; ------------SERVERSCRIPT------------------
; -------------------------------------------------
; CONFIGURATION SECTION:
; Specify Your own Network's address and port.
Network_Address = 127.0.0.1
Network_Port = 8765
; ----------------------------
; END OF CONFIGURATION SECTION
; ----------------------------
Gui, Add, Text,, Send:
Gui, Add, Edit, w100 vSendText
Gui, Add, Text,, Repeat:
Gui, Add, Edit, w40 vRepeat, 5
Gui, Add, Text,, Delay (ms):
Gui, Add, Edit, w40 vDelay, 50
Gui, Add, Button, gSendviaNet, Send
Gui, Show
Gosub Connection_Init
return
Connection_Init:
OnExit, ExitSub ; For connection cleanup purposes.
; set up a very basic server:
socket := PrepareForIncomingConnection(Network_Address, Network_Port)
if socket = -1 ; Connection failed (it already displayed the reason).
ExitApp
; Find this script's main window:
Process, Exist ; This sets ErrorLevel to this script's PID (it's done this way to support compiled scripts).
DetectHiddenWindows On
ScriptMainWindowId := WinExist("ahk_class AutoHotkey ahk_pid " . ErrorLevel)
DetectHiddenWindows Off
; Set up the connection to notify this script via message whenever new data has arrived.
; This avoids the need to poll the connection and thus cuts down on resource usage.
FD_READ = 1 ; Received when data is available to be read.
;FD_WRITE =
FD_CLOSE = 32 ; Received when connection has been closed.
FD_CONNECT = 20 ; Received when connection has been made.
if DllCall("Ws2_32\WSAAsyncSelect", "UInt", socket, "UInt", ScriptMainWindowId, "UInt", NotificationMsg, "Int", FD_CLOSE|FD_CONNECT)
{
MsgBox % "WSAAsyncSelect() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError")
ExitApp
}
Loop ; Wait for incomming connections
{
; accept requests that are in the pipeline of the socket
conectioncheck := DllCall("Ws2_32\accept", "UInt", socket, "UInt", &SocketAddress, "Int", SizeOfSocketAddress)
; Ws2_22/accept returns the new Connection-Socket if a connection request was in the pipeline
; on failure it returns an negative value
if conectioncheck > 1
{
MsgBox Incoming connection accepted
break
}
sleep 500 ; wait half 1 second then accept again
}
return
SendviaNet:
Gui, Submit, NoHide
SendData(conectioncheck,SendText,Repeat,Delay)
SentText =
return
PrepareForIncomingConnection(IPAddress, Port)
; This can connect to most types of TCP servers, not just Network.
; Returns -1 (INVALID_SOCKET) upon failure or the socket ID upon success.
{
VarSetCapacity(wsaData, 32) ; The struct is only about 14 in size, so 32 is conservative.
result := DllCall("Ws2_32\WSAStartup", "UShort", 0x0002, "UInt", &wsaData) ; Request Winsock 2.0 (0x0002)
; Since WSAStartup() will likely be the first Winsock function called by this script,
; check ErrorLevel to see if the OS has Winsock 2.0 available:
if ErrorLevel
{
MsgBox WSAStartup() could not be called due to error %ErrorLevel%. Winsock 2.0 or higher is required.
return -1
}
if result ; Non-zero, which means it failed (most Winsock functions return 0 upon success).
{
MsgBox % "WSAStartup() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError")
return -1
}
AF_INET = 2
SOCK_STREAM = 1
IPPROTO_TCP = 6
socket := DllCall("Ws2_32\socket", "Int", AF_INET, "Int", SOCK_STREAM, "Int", IPPROTO_TCP)
if socket = -1
{
MsgBox % "socket() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError")
return -1
}
; Prepare for connection:
SizeOfSocketAddress = 16
VarSetCapacity(SocketAddress, SizeOfSocketAddress)
InsertInteger(2, SocketAddress, 0, AF_INET) ; sin_family
InsertInteger(DllCall("Ws2_32\htons", "UShort", Port), SocketAddress, 2, 2) ; sin_port
InsertInteger(DllCall("Ws2_32\inet_addr", "Str", IPAddress), SocketAddress, 4, 4) ; sin_addr.s_addr
; Bind to socket:
if DllCall("Ws2_32\bind", "UInt", socket, "UInt", &SocketAddress, "Int", SizeOfSocketAddress)
{
MsgBox % "bind() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError") . "?"
return -1
}
if DllCall("Ws2_32\listen", "UInt", socket, "UInt", "SOMAXCONN")
{
MsgBox % "LISTEN() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError") . "?"
return -1
}
return socket ; Indicate success by returning a valid socket ID rather than -1.
}
SendData(wParam,SendData, Repeat, Delay)
{
socket := wParam
; SendDataSize := VarSetCapacity(SendData)
; SendDataSize += 1
Loop % Repeat
{
SendIt := SendData . "(" . A_Index . ")"
SendDataSize := VarSetCapacity(SendIt)
SendDataSize += 1
sendret := DllCall("Ws2_32\send", "UInt", socket, "Str", SendIt, "Int", SendDatasize, "Int", 0)
WinsockError := DllCall("Ws2_32\WSAGetLastError")
if WinsockError <> 0 ; WSAECONNRESET, which happens when Network closes via system shutdown/logoff.
; Since it's an unexpected error, report it. Also exit to avoid infinite loop.
MsgBox % "send() indicated Winsock error " . WinsockError
sleep,Delay
}
;send( sockConnected,> welcome, strlen(welcome) + 1, NULL);
}
InsertInteger(pInteger, ByRef pDest, pOffset = 0, pSize = 4)
; The caller must ensure that pDest has sufficient capacity. To preserve any existing contents in pDest,
; only pSize number of bytes starting at pOffset are altered in it.
{
Loop %pSize% ; Copy each byte in the integer into the structure as raw binary data.
DllCall("RtlFillMemory", "UInt", &pDest + pOffset + A_Index-1, "UInt", 1, "UChar", pInteger >> 8*(A_Index-1) & 0xFF)
}
guiclose:
ExitSub: ; This subroutine is called automatically when the script exits for any reason.
; MSDN: "Any sockets open when WSACleanup is called are reset and automatically
; deallocated as if closesocket was called."
DllCall("Ws2_32\WSACleanup")
ExitApp
Client:
Code:
; -------------------------------------------------
;-----------CLIENTSCRIPT----------------------
; -------------------------------------------------
; CONFIGURATION SECTION:
; Specify address and port of the server.
Network_Address = 127.0.0.1
Network_Port = 8765
; ----------------------------
; END OF CONFIGURATION SECTION
; ----------------------------
Gui, Add, Button, gConnection_Init, Connect
Gui, Add, Edit, R10 vMyEdit
Gui, Add, Button, gClear, Clear
Gui, Show
LinesReceived:=0
return
Connection_Init:
OnExit, ExitSub ; For connection cleanup purposes.
; Connect to any type of server:
socket := ConnectToAddress(Network_Address, Network_Port)
if socket = -1 ; Connection failed (it already displayed the reason).
ExitApp
; Find this script's main window:
Process, Exist ; This sets ErrorLevel to this script's PID (it's done this way to support compiled scripts).
DetectHiddenWindows On
ScriptMainWindowId := WinExist("ahk_class AutoHotkey ahk_pid " . ErrorLevel)
DetectHiddenWindows Off
; When the OS notifies the script that there is incoming data waiting to be received,
; the following causes a function to be launched to read the data:
NotificationMsg = 0x5555 ; An arbitrary message number, but should be greater than 0x1000.
OnMessage(NotificationMsg, "ReceiveData")
; Set up the connection to notify this script via message whenever new data has arrived.
; This avoids the need to poll the connection and thus cuts down on resource usage.
FD_READ = 1 ; Received when data is available to be read.
FD_CLOSE = 32 ; Received when connection has been closed.
if DllCall("Ws2_32\WSAAsyncSelect", "UInt", socket, "UInt", ScriptMainWindowId, "UInt", NotificationMsg, "Int", FD_READ|FD_CLOSE)
{
MsgBox % "WSAAsyncSelect() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError")
ExitApp
}
return
Clear:
ShowReceived=
LinesReceived:=0
GuiControl,, MyEdit,
return
ConnectToAddress(IPAddress, Port)
; Returns -1 (INVALID_SOCKET) upon failure or the socket ID upon success.
{
VarSetCapacity(wsaData, 32) ; The struct is only about 14 in size, so 32 is conservative.
result := DllCall("Ws2_32\WSAStartup", "UShort", 0x0002, "UInt", &wsaData) ; Request Winsock 2.0 (0x0002)
; Since WSAStartup() will likely be the first Winsock function called by this script,
; check ErrorLevel to see if the OS has Winsock 2.0 available:
if ErrorLevel
{
MsgBox WSAStartup() could not be called due to error %ErrorLevel%. Winsock 2.0 or higher is required.
return -1
}
if result ; Non-zero, which means it failed (most Winsock functions return 0 upon success).
{
MsgBox % "WSAStartup() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError")
return -1
}
AF_INET = 2
SOCK_STREAM = 1
IPPROTO_TCP = 6
socket := DllCall("Ws2_32\socket", "Int", AF_INET, "Int", SOCK_STREAM, "Int", IPPROTO_TCP)
if socket = -1
{
MsgBox % "socket() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError")
return -1
}
; Prepare for connection:
SizeOfSocketAddress = 16
VarSetCapacity(SocketAddress, SizeOfSocketAddress)
InsertInteger(2, SocketAddress, 0, AF_INET) ; sin_family
InsertInteger(DllCall("Ws2_32\htons", "UShort", Port), SocketAddress, 2, 2) ; sin_port
InsertInteger(DllCall("Ws2_32\inet_addr", "Str", IPAddress), SocketAddress, 4, 4) ; sin_addr.s_addr
; Attempt connection:
if DllCall("Ws2_32\connect", "UInt", socket, "UInt", &SocketAddress, "Int", SizeOfSocketAddress)
{
MsgBox % "connect() indicated Winsock error " . DllCall("Ws2_32\WSAGetLastError") . "?"
return -1
}
return socket ; Indicate success by returning a valid socket ID rather than -1.
}
ReceiveData(wParam, lParam)
; By means of OnMessage(), this function has been set up to be called automatically whenever new data
; arrives on the connection.
{
Critical
global ShowReceived
global MyEdit
global LinesReceived
socket := wParam
ReceivedDataSize = 4096 ; Large in case a lot of data gets buffered due to delay in processing previous data.
VarSetCapacity(ReceivedData, ReceivedDataSize, 0) ; 0 for last param terminates string for use with recv().
Data := ""
Loop ; This loop solves the issue of the notification message being discarded due to thread-already-running.
{
ReceivedDataLength := DllCall("Ws2_32\recv", "UInt", socket, "Str", ReceivedData, "Int", ReceivedDataSize, "Int", 0)
if ReceivedDataLength = 0 ; The connection was gracefully closed,
ExitApp ; The OnExit routine will call WSACleanup() for us.
if ReceivedDataLength = -1
{
WinsockError := DllCall("Ws2_32\WSAGetLastError")
if ( WinsockError = 10035 ) { ; WSAEWOULDBLOCK, which means "no more data to be read".
break
}
if WinsockError <> 10054 ; WSAECONNRESET, which happens when Network closes via system shutdown/logoff.
; Since it's an unexpected error, report it. Also exit to avoid infinite loop.
MsgBox % "recv() indicated Winsock error " . WinsockError
ExitApp ; The OnExit routine will call WSACleanup() for us.
}
Data .= ReceivedData
}
; Otherwise, process the data received.
Loop, parse, Data, `n, `r
{
LinesReceived++
if (LinesReceived = 1) {
ShowReceived = %LinesReceived%: %A_LoopField%
} else {
ShowReceived = %ShowReceived%`n%LinesReceived%: %A_LoopField%
}
;Tooltip % ShowReceived
GuiControl,, MyEdit, %ShowReceived%
}
return 1 ; Tell the program that no further processing of this message is needed.
}
InsertInteger(pInteger, ByRef pDest, pOffset = 0, pSize = 4)
; The caller must ensure that pDest has sufficient capacity. To preserve any existing contents in pDest,
; only pSize number of bytes starting at pOffset are altered in it.
{
Loop %pSize% ; Copy each byte in the integer into the structure as raw binary data.
DllCall("RtlFillMemory", "UInt", &pDest + pOffset + A_Index-1, "UInt", 1, "UChar", pInteger >> 8*(A_Index-1) & 0xFF)
}
guiclose:
ExitSub: ; This subroutine is called automatically when the script exits for any reason.
; MSDN: "Any sockets open when WSACleanup is called are reset and automatically
; deallocated as if closesocket was called."
DllCall("Ws2_32\WSACleanup")
ExitApp