Re: [twsocket] Pinging multipe hosts
Yes, I know that I have to use ICS in sync mode and depend on events. Even
I, like many others am not used to think & code like that though, am trying
to manage. Actually, I believe I got it. Thing is I don't know how to
implement it in my current function. Below is my code where I need to
complete my pre-tests. I will appreciate, If you can advise as to how to
manage what I am trying to do. Or, you may tell me it is not possible as an
answer and I stop losing rest of my remaining hair. Use another way to do
it.
function TDeneme.GetLicense(ClientTime:TDateTime;
ClientIP,ClientUUID,LicenseType:string):string; stdcall;
var
Err:string;
begin
if MinutesBetween(now, ClientTime) > 10 then begin
Result := '***ERROR: ClientTime';
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType,
Result);
Result := StringToTableToXML(Result);
Exit;
end;
if ClientIP = EmptyStr then begin
Result := '***ERROR: ClientIP empty';
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType,
Result);
Result := StringToTableToXML(Result);
Exit;
end;
if ClientUUID = EmptyStr then begin
Result := '***ERROR: ClientUUID empty';
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType,
Result);
Result := StringToTableToXML(Result);
Exit;
end;
if LicenseType = EmptyStr then begin
Result := '***ERROR: LicenseType empty';
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType,
Result);
Result := StringToTableToXML(Result);
Exit;
end;
// Is Client alive? First PING it.
if not PingClient(ClientIP, 500, Err) then begin
Result := '***ERROR: Ping fail. ClientIP:' + ClientIP + '.';
if Err <> EmptyStr then Result := Result + ' ' + Err;
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType,
Result);
Result := StringToTableToXML(Result);
Exit;
end;
// PING OK. DO DIRECT TCP CONNECTION
if not TestClientConnection(ClientIP, Err) then begin
Result := '***ERROR: Client TCP connection fail.';
if Err <> EmptyStr then Result := Result + ' ' + Err;
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType,
Result);
Result := StringToTableToXML(Result);
end;
// Code will continue from here once above is solved.
Result := 'LICENSE WILL BE GRANTED;
WriteLicenseLog('GetLicense', ClientIP, ClientUUID, LicenseType, Result);
Result := StringToTableToXML(Result);
end;
-Original Message-
From: TWSocket [mailto:twsocket-boun...@lists.elists.org] On Behalf Of Angus
Robertson - Magenta Systems Ltd
Sent: Sunday, March 13, 2016 7:35 PM
To: twsocket@lists.elists.org
Subject: Re: [twsocket] Pinging multipe hosts
> Pretty confused and stuck at the moment. Give this to my literally
> *no knowledge* of using sockets. Below is as far as it gets.
> WSocket.Connect;
> Sleep(3500); // Assuming that amount of time is enough for a local tcp
> connection.
which is I'm afraid a perfect example of why you would be better starting
off with my TMagIpLog component, even if you only look at the source code
and modify it for your purposes, although certainly the client side will do
everthing you need. The component is not designed as a high traffic server,
I mostly use for one-one connections between applications.
The most important thing is ICS is generally used in async mode, you NEVER
have wait loops or sleep, there is an event that fires when a connection
successeds or fails, and that is what riggers you next step.
The exception is multi-threaded applications that do nothing else until the
next ICS call.
Angus
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Re: [twsocket] Pinging multipe hosts
Actually, I started to implement TWSocket in my code before I got your
e-mail, Angus. Pretty confused and stuck at the moment. Give this to my
literally *no knowledge* of using sockets. Below is as far as it gets. I
copy-paste from sample applications. Changed some code as to my
understanding.
In my scenario, "server connects to client".
I don't get to see 'HEY!' message in my client application (check below
code), but my server application claims connection is just fine.
Server side code:
WSocket is a private variable.
Server is a webservice VCL application when I am debugging, but will be a
windows service application when finished.
function TDeneme.TestClientConnection(IP:string):Boolean;
begin
WSocket := TWSocket.Create(nil);
try
WSocket.OnSessionConnected := SocketSessionConnected;
WSocket.Proto := 'tcp';
WSocket.SocketFamily := sfIPv4;
WSocket.Addr := IP;
WSocket.LocalAddr := '0.0.0.0';
WSocket.Port := DM.WSOCKET_CLI_PORT;
WSocket.LocalPort := DM.WSOCKET_SRV_PORT;
WSocket.LineMode := True;
WSocket.LineEnd:= #13#10;
{ Connect is asynchronous (non-blocking). When the session is }
{ connected (or fails to), we have an OnSessionConnected event }
{ This is where actual sending of data is done.}
WSocket.Tag := -1;
WSocket.Connect;
Sleep(3500); // Assuming that amount of time is enough for a local tcp
connection.
Result := WSocket.Tag = 0;
WSocket.Close;
finally
WSocket.Free;
end;
end;
procedure TDeneme.SocketSessionConnected(Sender: TObject; ErrCode: Word);
var Buf:string;
begin
WSocket.Tag := ErrCode;
if ErrCode = 0 then begin
Buf := 'HEY!' + #13#10;
try
WSocket.SendStr(Buf);
except
end;
end;
end;
--
Client side code:
Client application is a vcl windows application.
procedure TForm4.FormCreate(Sender: TObject);
begin
// Wait for a TCP connection
with WSocket1 do begin
Proto := 'tcp';
SocketFamily := sfIPv4;
Addr := '0.0.0.0';
Port := '0';
LocalAddr := '0.0.0.0';
LocalPort := DM.WSOCKET_CLI_PORT;
LineMode := True;
LineEnd:= #13#10;
Listen;
end;
end;
procedure TForm4.WSocket1DataAvailable(Sender: TObject; ErrCode: Word);
var
Buffer : array [0..1023] of AnsiChar;
Len: Integer;
Src: TSockAddrIn6;
SrcLen : Integer;
begin
if FSenderAddr.sin6_family = AF_INET then begin
SrcLen := SizeOf(TSockAddrIn);
Len:= WSocket1.ReceiveFrom(@Buffer, SizeOf(Buffer),
PSockAddr(@Src)^, SrcLen);
if Len >= 0 then begin
if (PSockAddr(@FSenderAddr).sin_addr.S_addr = INADDR_ANY) or
(PSockAddr(@FSenderAddr).sin_addr.S_addr =
PSockAddr(@Src).Sin_addr.S_addr) then begin
Buffer[Len] := #0;
Label1.Caption := String(Buffer);
end;
end;
end;
end;
procedure TForm4.WSocket1SessionClosed(Sender: TObject; ErrCode: Word);
begin
Label1.Caption := 'Connection closed.';
end;
procedure TForm4.WSocket1SessionConnected(Sender: TObject; ErrCode: Word);
begin
Label1.Caption := 'Connected. Listening.';
end;
-Original Message-
From: TWSocket [mailto:twsocket-boun...@lists.elists.org] On Behalf Of Angus
Robertson - Magenta Systems Ltd
Sent: Sunday, March 13, 2016 11:04 AM
To: twsocket@lists.elists.org
Subject: Re: [twsocket] Pinging multipe hosts
> I will be writing both server and client softwares. No need for a web
> server.
In which case the server should only ever listen for TCP connections from
clients, which open the connection and send a hello packet once a minute to
prove they are alive, expecting a response so they know the server is alive.
Your can start with my TMagIpLog component, which can be configured as the
client or server, and handles all the opening, retrying and closing of
connections, allowing lines of text (ie your protocol) to be send
back and forward.
http://www.magsys.co.uk/delphi/magics.asp
You only need to add a couple of events in your code and it should all be
working in an hour.
For my old bus project, we had three 'activity servers' that the client PCs
contacted in rotation in case of hardware or other problems, and we had a
fall back of a UDP listener on the client that listened to UDP broadcasts
from the server to force all the clients to immediately call home, and a few
others things. Our protocol document was about 50 pages with 40 different
commands or something, quite complicated, things like retrieving CCTV from
the buses.
Angus
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Re: [twsocket] Pinging multipe hosts
> I will be writing both server and client softwares. No need for a web
server.
Then it is easy for you to add an application level ping. That is each
server will response to a simple command ("Hello") with a simple answer
("OK").
One or more clients can periodically send that "Hello " command and verify
it receives the correct "OK" answer with a reasonable time.
This is called an "end-to-end" application check.
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Embarcadero MVP
http://www.overbyte.be
http://francois-piette.blogspot.com
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Re: [twsocket] Pinging multipe hosts
> I will be writing both server and client softwares. No need for a > web server. In which case the server should only ever listen for TCP connections from clients, which open the connection and send a hello packet once a minute to prove they are alive, expecting a response so they know the server is alive. Your can start with my TMagIpLog component, which can be configured as the client or server, and handles all the opening, retrying and closing of connections, allowing lines of text (ie your protocol) to be send back and forward. http://www.magsys.co.uk/delphi/magics.asp You only need to add a couple of events in your code and it should all be working in an hour. For my old bus project, we had three 'activity servers' that the client PCs contacted in rotation in case of hardware or other problems, and we had a fall back of a UDP listener on the client that listened to UDP broadcasts from the server to force all the clients to immediately call home, and a few others things. Our protocol document was about 50 pages with 40 different commands or something, quite complicated, things like retrieving CCTV from the buses. Angus -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
