A datasnap server method that returns base64 string gives me an error when I test it on a pdf file. Other pdf files work correctly, only difference is this pdf file is quite larger than the others - 78MB.
HTTP/1.1 500 Internal Server Error
SERVER:
function TdmData.GetJobDocumentFile: string;
var fp : string;
begin
Result := Emptystr;
with fdQuery1 do
begin
Close;
SQL.Clear;
SQL.Text := ' select doc_filename from DBA.documents';
Open;
fp := fieldbyname('doc_filename').asString;
Close;
UnPrepare;
end;
if (fp <> Emptystr) and FileExists(fp) then
begin
Result := EncodeFile(fp);
end;
end;
function TdmData.EncodeFile(const FileName: string): AnsiString;
var Stream: TMemoryStream;
begin
Result := EmptyAnsiStr;
Stream := TMemoryStream.Create;
try
Stream.LoadFromFile(Filename);
Result := EncodeBase64(stream.Memory, stream.Size);
finally
Stream.Free;
end;
end;
function TServerMethods1.GetDocumentFile : string;
begin
try
Result := dmData.GetJobDocumentFiledata;
finally
GetInvocationMetadata.CloseSession := True;
end;
end;
CLIENT:
function TdmData.GetJobDocumentFileData: string;
var ServerMethods1Client : TServerMethods1Client;
begin
ServerMethods1Client := nil;
ServerMethods1Client := TServerMethods1Client.Create(DSRestConnection1);
try
Result := ServerMethods1Client.GetJobDocumentFileData;
finally
ServerMethods1Client.Free;
ServerMethods1Client := nil;
end;
end;
Am I missing something here? Are there limitations when sending/receiving large strings via datasnap?
Any additional information would be great, thanks.
Related
I'm having trouble to receive a byte array containg a PNG file.
When the code is executed in OnClientRead event it works fine, already when transfered for a thread, happens an error of MemoryStream that says:
Out of memory while expanding memory stream.
At this point:
if SD.State = ReadingSize then
I want to know how to solve this specific trouble and also how can I check if I'm receiving a data that contains a file or a simple String?
The code:
type
TSock_Thread = class(TThread)
private
Socket: TCustomWinSocket;
public
constructor Create(aSocket: TCustomWinSocket);
procedure Execute; override;
end;
type
TInt32Bytes = record
case Integer of
0: (Bytes: array[0..SizeOf(Int32)-1] of Byte);
1: (Value: Int32);
end;
TSocketState = (ReadingSize, ReadingStream);
TSocketData = class
public
Stream: TMemoryStream;
Png: TPngImage;
State: TSocketState;
Size: TInt32Bytes;
Offset: Integer;
constructor Create;
destructor Destroy; override;
end;
{ ... }
constructor TSock_Thread.Create(aSocket: TCustomWinSocket);
begin
inherited Create(true);
Socket := aSocket;
FreeOnTerminate := true;
end;
procedure TSock_Thread.Execute;
var
s: String;
BytesReceived: Integer;
BufferPtr: PByte;
SD: TSocketData;
Item: TListItem;
begin
inherited;
while Socket.Connected do
begin
if Socket.ReceiveLength > 0 then
begin
s := Socket.ReceiveText;
{ SD := TSocketData(Socket.Data);
if SD.State = ReadingSize then
begin
while SD.Offset < SizeOf(Int32) do
begin
BytesReceived := Socket.ReceiveBuf(SD.Size.Bytes[SD.Offset],
SizeOf(Int32) - SD.Offset);
if BytesReceived <= 0 then
Exit;
Inc(SD.Offset, BytesReceived);
end;
SD.Size.Value := ntohl(SD.Size.Value);
SD.State := ReadingStream;
SD.Offset := 0;
SD.Stream.Size := SD.Size.Value;
end;
if SD.State = ReadingStream then
begin
if SD.Offset < SD.Size.Value then
begin
BufferPtr := PByte(SD.Stream.Memory);
Inc(BufferPtr, SD.Offset);
repeat
BytesReceived := Socket.ReceiveBuf(BufferPtr^,
SD.Size.Value - SD.Offset);
if BytesReceived <= 0 then
Exit;
Inc(BufferPtr, BytesReceived);
Inc(SD.Offset, BytesReceived);
until SD.Offset = SD.Size.Value;
end;
try
SD.Stream.Position := 0;
SD.Png.LoadFromStream(SD.Stream);
SD.Stream.Clear;
except
SD.Png.Assign(nil);
end;
Item := Form1.ListView1.Selected;
if (Item <> nil) and (Item.Data = Socket) then
Form1.img1.Picture.Graphic := SD.Png;
SD.State := ReadingSize;
SD.Offset := 0;
end; }
end;
Sleep(100);
end;
end;
procedure TForm1.ServerSocket1Accept(Sender: TObject; Socket: TCustomWinSocket);
var
TST: TSock_Thread;
begin
TST := TSock_Thread.Create(Socket);
TST.Resume;
end;
UPDATE:
The code in the answer is not working for me because ServerType=stThreadBlocking blocks all clients connections with the server. And because of this, I'm searching for something like this (ServerType=stNonBlocking, TThread and OnAccept event):
type
TSock_Thread = class(TThread)
private
Png: TPngImage;
Socket: TCustomWinSocket;
public
constructor Create(aSocket: TCustomWinSocket);
procedure Execute; override;
procedure PngReceived;
end;
// ...
// ===============================================================================
constructor TSock_Thread.Create(aSocket: TCustomWinSocket);
begin
inherited Create(true);
Socket := aSocket;
FreeOnTerminate := true;
end;
// ===============================================================================
procedure TSock_Thread.PngReceived;
var
Item: TListItem;
begin
Item := Form1.ListView1.Selected;
if (Item <> nil) and (Item.Data = Socket) then
Form1.img1.Picture.Graphic := Png;
end;
procedure TSock_Thread.Execute;
var
Reciving: Boolean;
DataSize: Integer;
Data: TMemoryStream;
s, sl: String;
begin
inherited;
while Socket.Connected do
begin
if Socket.ReceiveLength > 0 then
begin
s := Socket.ReceiveText;
if not Reciving then
begin
SetLength(sl, StrLen(PChar(s)) + 1);
StrLCopy(#sl[1], PChar(s), Length(sl) - 1);
DataSize := StrToInt(sl);
Data := TMemoryStream.Create;
Png := TPngImage.Create;
Delete(s, 1, Length(sl));
Reciving := true;
end;
try
Data.Write(s[1], Length(s));
if Data.Size = DataSize then
begin
Data.Position := 0;
Png.LoadFromStream(Data);
Synchronize(PngReceived);
Data.Free;
Reciving := false;
end;
except
Png.Assign(nil);
Png.Free;
Data.Free;
end;
end;
Sleep(100);
end;
end;
procedure TForm1.ServerSocket1Accept(Sender: TObject; Socket: TCustomWinSocket);
var
TST: TSock_Thread;
begin
TST := TSock_Thread.Create(Socket);
TST.Resume;
end;
This code has an error of conversion of data at this line:
DataSize := StrToInt(sl);
How can I fix this?
how solve this specific trouble
You are not using TServerSocket threading the way it is meant to be used.
If you want to use TServerSocket in stThreadBlocking mode (see my other answer for how to use TServerSocket in stNonBlocking mode), the correct way is to:
derive a thread class from TServerClientThread
override its virtual ClientExecute() method to do your I/O work (via TWinSocketStream)
use the TServerSocket.OnGetThread event to instantiate the thread.
If you don't do this, TServerSocket will create its own default threads (to fire the OnClient(Read|Write) events in the main thread), which will interfere with your manual threads.
Also, you don't need the state machine that I showed you in my answer to your other question. That was for event-driven code. Threaded I/O code can be written linearly instead.
Try something more like this:
type
TSock_Thread = class(TServerClientThread)
private
Png: TPngImage;
procedure PngReceived;
protected
procedure ClientExecute; override;
end;
type
TInt32Bytes = record
case Integer of
0: (Bytes: array[0..SizeOf(Int32)-1] of Byte);
1: (Value: Int32);
end;
procedure TSock_Thread.ClientExecute;
var
SocketStrm: TWinSocketStream;
Buffer: TMemoryStream;
Size: TInt32Bytes;
Offset: Integer;
BytesReceived: Integer;
BufferPtr: PByte;
begin
SocketStrm := TWinSocketStream.Create(ClientSocket, 5000);
try
Buffer := TMemoryStream.Create;
try
Png := TPngImage.Create;
try
while ClientSocket.Connected do
begin
if not SocketStrm.WaitForData(100) then Continue;
Offset := 0;
while Offset < SizeOf(Int32) do
begin
BytesReceived := SocketStrm.Read(Size.Bytes[Offset], SizeOf(Int32) - Offset);
if BytesReceived <= 0 then Exit;
Inc(Offset, BytesReceived);
end;
Size.Value := ntohl(Size.Value);
Buffer.Size := Size.Value;
BufferPtr := PByte(Buffer.Memory);
Offset := 0;
while Offset < Size.Value do
begin
BytesReceived := SocketStrm.Read(BufferPtr^, Size.Value - Offset);
if BytesReceived <= 0 then Exit;
Inc(BufferPtr, BytesReceived);
Inc(Offset, BytesReceived);
end;
Buffer.Position := 0;
try
Png.LoadFromStream(Buffer);
except
Png.Assign(nil);
end;
Synchronize(PngReceived);
end;
finally
Png.Free;
end;
finally
Buffer.Free;
end;
finally
SocketStrm.Free;
end;
end;
procedure TSock_Thread.PngReceived;
var
Item: TListItem;
begin
Item := Form1.ListView1.Selected;
if (Item <> nil) and (Item.Data = ClientSocket) then
Form1.img1.Picture.Graphic := Png;
end;
procedure TForm1.ServerSocket1GetThread(Sender: TObject; ClientSocket: TServerClientWinSocket; var SocketThread: TServerClientThread);
begin
SocketThread := TSock_Thread.Create(False, ClientSocket);
end;
how i can check if i'm receiving a data that contains a file or a simple String?
The client needs to send that information to your server. You are already sending a value to specify the data size before sending the actual data. You should also preceed the data with a value to specify the data's type. Then you can handle the data according to its type as needed.
how to stop Pipleline tasks correctly, I've tried but when i press Abort button i get an AV, i'm not too good at debugging,i have reached to DoOnStop(task); in OtlParallel then i couldn't figure out what to do next, i believe there is something missing ?
type
procedure SetInProcess(const Value: Boolean);
private
FInProcess: Boolean;
property inProcess: Boolean read FInProcess write SetInProcess;
public
FStopAll: Boolean;
procedure FlushData;
procedure Retriever(const input: TOmniValue; var output: TOmniValue);
...
procedure TForm1.SetInProcess(const Value: Boolean);
var
I: Integer;
begin
if Value = InProcess then exit;
memo1.ReadOnly := Value;
FInProcess := Value;
if Value then
Memo1.Lines.Clear;
Timer1.Enabled := Value;
If not Value then
begin
FlushData;
pipeline := nil;
end;
end;
procedure TForm1.Timer1Timer(Sender: TObject);
begin
If not InProcess then exit;
FlushData;
if Pipeline.Output.IsFinalized then
InProcess := False;
end;
procedure TForm1.StartButton(Sender: TObject);
var
i : integer;
urlList : TStrings;
U, S : string;
value : TOmniValue;
begin
urlList := Memo2.Lines;
pipeline := Parallel.Pipeline;
pipeline.Stage(Retriver).NumTasks(StrToInt(Edit12.Text)).Run;
for U in urlList do
pipeline.Input.Add(U);
pipeline.Input.CompleteAdding;
inProcess := True;
end;
procedure TForm1.FlushData;
var v: TOmniValue;
begin
if pipeline = nil then exit;
if pipeline.Output = nil then exit;
Memo1.Lines.BeginUpdate;
try
while pipeline.Output.TryTake(v) do
Memo1.Lines.Add(v.AsString);
if FStopAll then
begin
Pipeline.Cancel;
end;
Memo1.Lines.EndUpdate;
except
on E: Exception do
begin
Memo1.Lines.Add(E.Message);
end;
end;
Memo1.Lines.EndUpdate;
end;
procedure TForm1.Retriver(const input: TOmniValue; var output: TOmniValue);
var
lHTTP : TIdHTTP;
Params : TStrings;
Reply,String1,String2 : string;
begin
X := Input.AsString;
Params := TStringList.Create;
string1 := Extract1(X);
string2 := Extract2(X);;
Params.Add('username=' + string1);
Params.Add('password=' + string2);
lHTTP := TIdHTTP.Create(nil);
try
...
Reply := lHTTP.Post('https://www.instagram.com/accounts/login/ajax/', Params);
if AnsiContainsStr(Reply, 'no')
then
begin
Alive.Add(string1+string2+' Client ok'); ///Alive is Global Var stringlist created earlier
end;
except
on E: EIdHTTPProtocolException do
Exit
end;
lHTTP.Free;
end;
procedure TForm1.AbortButton(Sender: TObject);
begin
try
FStopAll := False;
finally
FStopAll := True;
end;
end;
In your case of over-simplified one-stage pipeline suffice would be moving check into the worker stage itself.
procedure Retriever(const input: TOmniValue; var output: TOmniValue);
var
....
begin
if FStopAll then exit;
X := Input.AsString;
....
PS. I want to repeat that your code leaks memory badly, and that you ignored all my notes I stated before.
PPS. This code not also makes little sense (there is not point in flip-vloppign the variable to one value then to another) but is syntactically incorrect and would not compile. Thus it is not the same code you actually run. It is some different code.
procedure TForm1.AbortButton(Sender: TObject);
begin
try
FStopAll := False;
finally
FStopAll := True;
end;
end;
Function
function DownloadString(AUrl: string): string;
var
LHttp: TIdHttp;
begin
LHttp := TIdHTTP.Create;
try
LHttp.HandleRedirects := true;
result := LHttp.Get('http://127.0.0.1/a.php?n='+AUrl);
finally
LHttp.Free;
end;
end;
Boot
procedure TForm1.Button1Click(Sender: TObject);
var
LUrlArray: TArray<String>;
begin
LUrlArray := form1.listbox1.Items.ToStringArray;
TThread.CreateAnonymousThread(
procedure
var
LResult: string;
LUrl: string;
begin
for LUrl in LUrlArray do
begin
LResult := DownloadString(LUrl);
TThread.Synchronize(nil,
procedure
begin
if Pos('DENEGADA',LResult)>0 then
begin
Memo1.Lines.Add(LResult);
end
else
begin
Memo1.Lines.Add(LResult + 'DIE');
end;
end
);
end;
end
).Start;
end;
Listbox Lines
http://127.0.0.1/a.php?n=4984
http://127.0.0.1/a.php?n=4986
http://127.0.0.1/a.php?n=4989
in this case only one thread will download all URL's content but I would like to make it creates a thread for each item...
example:
thread1 - check item1 listbox - http://127.0.0.1/a.php?n=4984
thread2 - check next item 4986
thread3 - check next item 4989
how make this? Is there any way to do this ?, I believe that this method will be more effective.
In order to create separate threads, you have to bind the url variable value like this:
procedure TForm1.Button1Click(Sender: TObject);
var
LUrlArray: TArray<String>;
LUrl: String;
function CaptureThreadTask(const s: String) : TProc;
begin
Result :=
procedure
var
LResult : String;
begin
LResult := DownloadString(s);
TThread.Synchronize(nil,
procedure
begin
if Pos('DENEGADA',LResult)>0 then
begin
Memo1.Lines.Add(LResult);
end
else
begin
Memo1.Lines.Add(LResult + 'DIE');
end;
end
);
end;
end;
begin
LUrlArray := form1.listbox1.Items.ToStringArray;
for LUrl in LUrlArray do
// Bind variable LUrl value like this
TThread.CreateAnonymousThread( CaptureThreadTask(LUrl)
).Start;
end;
See Anonymous Methods Variable Binding
You can try using ForEach pattern of omnithreadlibrary :
http://otl.17slon.com/book/chap04.html#highlevel-foreach
http://otl.17slon.com/book/chap04.html#leanpub-auto-iomniblockingcollection
Draft is like that:
TMyForm = class(TForm)
private
DownloadedStrings: iOmniBlockingCollection;
published
DownloadingProgress: TTimer;
MemoSourceURLs: TMemo;
MemoResults: TMemo;
...
published
procedure DownloadingProgressOnTimer( Sender: TObject );
procedure StartButtonClick ( Sender: TObject );
.....
private
property InDownloadProcess: boolean write SetInDownloadProcess;
procedure FlushCollectedData;
end;
procedure TMyForm.StartButtonClick ( Sender: TObject );
begin
DownloadedStrings := TOmniBlockingCollection.Create;
Parallel.ForEach<string>(MemoSourceURLs.Lines)
.NumTasks(10) // we do not want to overload computer by millions of threads when given a long list. We are not "fork bomb"
// .PreserveOrder - usually not a needed option
.Into(DownloadedStrings) // - or you would have to manually seal the container by calling .CompleteAdding AFTER the loop is over in .OnStop option
.NoWait
.Execute(
procedure (const URL: string; var res: TOmniValue)
var Data: string; Success: Boolean;
begin
if my_IsValidUrl(URL) then begin
Success := my_DownloadString( URL, Data);
if Success and my_IsValidData(Data) then begin
if ContainsText(Data, 'denegada') then
Data := Data + ' DIE';
res := Data;
end;
end
);
InDownloadProcess := true;
end;
procedure TMyForm.SetInDownloadProcess(const process: Boolean);
begin
if process then begin
StartButton.Hide;
Prohibit-Form-Closing := true;
MemoSourceURLs.ReadOnly := true;
MemoResults.Clear;
with DownloadingProgress do begin
Interval := 333; // update data in form 3 times per second - often enough
OnTimer := DownloadingProgressOnTimer;
Enabled := True;
end;
end else begin
DownloadingProgress.Enabled := false;
if nil <> DownloadedStrings then
FlushCollectedData; // one last time
Prohibit-Form-Closing := false;
MemoSourceURLs.ReadOnly := false;
StartButton.Show;
end;
end;
procedure TMyForm.FlushCollectedData;
var s: string; value: TOmniValue;
begin
while DownloadedStrings.TryTake(value) do begin
s := value;
MemoResults.Lines.Add(s);
end;
PostMessage( MemoResults.Handle, .... ); // not SendMessage, not Perform
// I do not remember, there was something very easy to make the memo auto-scroll to the last line added
end;
procedure TMyForm.DownloadingProgressOnTimer( Sender: TObject );
begin
if nil = DownloadedStrings then begin
InDownloadProcess := false;
exit;
end;
FlushCollectedData;
if DownloadedStrings.IsCompleted then begin
InDownloadProcess := false; // The ForEach loop is over, everything was downloaded
DownloadedStrings := nil; // free memory
end;
end;
http://docwiki.embarcadero.com/Libraries/XE4/en/System.StrUtils.ContainsText
http://docwiki.embarcadero.com/Libraries/Seattle/en/Vcl.ExtCtrls.TTimer_Properties
PS. note that the online version of the book is old, you perhaps would have to update it to features in the current version of the omnithreadlibrarysources.
PPS: your code has a subtle error:
for LUrl in LUrlArray do
begin
LResult := DownloadString(LUrl);
Given your implementation of DownloadString that means in the case of HTTP error your function would re-return the previous value of LResult again and again and again and.... until the no-error downloading happened.
That is why I changed your function definition to be clear when error happens and no output data is given.
UPDATE Problem Still Exists.
Is it possible to run code in already running thread? for example:
thread1 is running some code & i want to run code from thread2 in thread1.
I want to run code in idTCPServer thread to send some data to client
Edit:
After research seems that my problem is that when Client data is received or is receiving same time another thread is trying to write to that socket.
Edit:
procedure TMainFrm.UserSRVExecute(AContext: TIdContext);
var
Command : String;
msSize : Int64;
ms : TMemoryStream;
decompressedMS : TMemoryStream;
H : TIdNotify;
begin
// Application.ProcessMessages;
Command := AContext.Connection.Socket.ReadLn;
// messagebox(0,'snd','',$40);
if logb then mainfrm.mconnections.Lines.Add(command + ' - BEGIN');
if Command <> '' then // keepalive
begin
//Application.ProcessMessages;
msSize := AContext.Connection.Socket.ReadInt64;
ms := TMemoryStream.Create;
decompressedMS := TMemoryStream.Create;
try
AContext.Connection.Socket.ReadStream(ms, msSize);
ms.Position := 0;
DecompressStream(MS,decompressedMS);
decompressedMS.Position := 0;
Client_ProcessData(AContext,Command,decompressedMS);
finally
ms.Free;
decompressedMS.Free;
if logb then mainfrm.mconnections.Lines.Add(command + ' - END');
end;
end;
end;
procedure Client_ProcessData(AContext: TIdContext; cmd : String; data : TMemoryStream);
var
Hnd : THandle;
clData : TStringArray;
TmpStr1 : String;
Tmp : String;
TN : TIdNotify;
Sync : TMySync;
I,I2 : Integer;
begin
Hnd := AContext.Connection.Socket.Binding.Handle;
if cmd = 'scr' then // RECEIVE COMMAND TO SEND TO CLIENT TO RECEIVE DATA FROM CLIENT
begin
Tmp := StreamToString(data);
{Sync := TMySync2.Create(True);
try
Sync.cmd := cmd;
Sync.hnd := Hnd;
Sync.tmp := TmpStr1;
Sync.Resume;
finally
//Sync.Free;
end; }
log('>>> CLFROMAS: '+IntToStr(HND)+':::'+cmd+':::');
// SendCMDToSocket(MainFrm.UserSRV,StrToInt(Trim(Tmp)),'scr'+IntToStr(Hnd));
I2 := StrToInt(Trim(Tmp));
for I := 0 to 100 do
if USRVData[i].hnd = I2 then
begin
// cs.Acquire;
USRVData[i].CTX.Connection.Socket.WriteLn('scr'+IntToStr(Hnd)); // PLACED ALL CONTEXTs IN GLOBAL VARIABLE + ALL SOCKET HANDLES. <--- HERE IS THE PROBLEM
// cs.Release;
Break;
end;
// log('>>> CLFROMAS: '+IntToStr(HND)+':::'+cmd+':::'+streamtostring(data));
Exit;
end;
if Copy(cmd,1,Length('scr4u')) = 'scr4u' then // RECEIVE DATA FROM CLIENT TO SEND IT TO ADMIN CLIENT REQUEST ABOVE
begin
if Length(cmd) > Length('scr4u') then
begin
Delete(cmd,1,Length('scr4u'));
Data.Position := 0;
{ Sync := TMySync.Create;
try
Sync.cmd := cmd;
Sync.hnd := Hnd;
Sync.data := TMemoryStream.Create;
Sync.data.CopyFrom(data,data.Size);
Sync.data.Position := 0;
Sync.DoNotify;
finally
Sync.data.Free;
Sync.Free;
end; }
SendStreamToSocket(MainFrm.UserSRV,strtoint(cmd),'scr4u',Data);
log('>>>>> ADMIN: '+IntToStr(HND)+':::'+cmd+':::'{+streamtostring(data)});
end else TmpStr1 := '';
Exit;
end;
...
UPDATE
procedure TMainFrm.UserSRVExecute(AContext: TIdContext);
var
Command : String;
msSize : Int64;
ms : TMemoryStream;
decompressedMS : TMemoryStream;
H : TIdNotify;
I : Integer;
List, Messages : TStringList;
begin
Messages := nil;
try
List := TMyContext(AContext).OutgoingMessages.Lock;
try
if List.Count > 0 then
begin
Messages := TStringList.Create;
Messages.Assign(List);
List.Clear;
end;
finally
TMyContext(AContext).OutgoingMessages.Unlock;
end;
if Messages <> nil then
begin
for I := 0 to Messages.Count-1 do
begin
AContext.Connection.IOHandler.WriteLn(Messages.Strings[I]);
end;
end;
finally
Messages.Free;
end;
if AContext.Connection.IOHandler.InputBufferIsEmpty then
begin
AContext.Connection.IOHandler.CheckForDataOnSource(100);
AContext.Connection.IOHandler.CheckForDisconnect;
if AContext.Connection.IOHandler.InputBufferIsEmpty then
Exit;
end;
Command := AContext.Connection.Socket.ReadLn;
if logb then mainfrm.mconnections.Lines.Add(command + ' - BEGIN');
if Command <> '' then
begin
msSize := AContext.Connection.Socket.ReadInt64;
ms := TMemoryStream.Create;
decompressedMS := TMemoryStream.Create;
try
AContext.Connection.Socket.ReadStream(ms, msSize);
ms.Position := 0;
DecompressStream(MS,decompressedMS);
decompressedMS.Position := 0;
Client_ProcessData(AContext,Command,decompressedMS);
finally
ms.Free;
decompressedMS.Free;
if logb then mainfrm.mconnections.Lines.Add(command + ' - END');
end;
end;
end;
Is it possible to run code in already running thread? for example: thread1 is running some code & i want to run code from thread2 in thread1.
No. Thread1 needs to be explicitly coded to stop what it is currently doing, do something else, and then go back to what it was previous doing. All Thread2 can do is signal Thread1 to perform that stop+continue at its earliest convenience.
I want to run code in idTCPServer thread to send some data to client
Your TIdTCPServer.OnExecute event handler needs to check for that data periodically and send it when it is available.
You can use the TIdContext.Data property, or derive a custom class from TIdServerContext and assign it to the TIdTCPServer.ContextClass property, to provide a per-client thread-safe buffer for your outbound data. Your OnExecute handler can then access that buffer when needed.
For example:
type
TMyContext = class(TIdServerContext)
public
constructor Create(AConnection: TIdTCPConnection; AYarn: TIdYarn; AList: TIdContextThreadList = nil); override;
destructor Destroy; override;
OutgoingMessages: TIdThreadSafeStringList;
end;
constructor TMyContext.Create(AConnection: TIdTCPConnection; AYarn: TIdYarn; AList: TIdContextThreadList = nil);
begin
inherited;
OutgoingMessages := TIdThreadSafeStringList.Create;
end;
destructor TMyContext.Destroy;
begin
OutgoingMessages.Free;
inherited;
end;
procedure TMyForm.FormCreate(Sender: TObject);
begin
// this must be set before activating the server...
IdTCPServer1.ContextClass := TMyContext;
end;
procedure TMyForm.IdTCPServer1Execute(AContext: TIdContext);
var
List, Messages: TStringList;
begin
// check for outgoing data...
Messages := nil;
try
List := TMyContext(AContext).OutgoingMessages.LockList;
try
if List.Count > 0 then
begin
Messages := TStringList.Create;
Messages.Assign(List);
List.Clear;
end;
finally
TMyContext(AContext).OutgoingMessages.UnlockList;
end;
if Messages <> nil then
begin
// send Messages using AContext.Connection.IOHandler as needed...
end;
finally
Messages.Free;
end;
// check for incoming data...
if AContext.Connection.IOHandler.InputBufferIsEmpty then
begin
AContext.Connection.IOHandler.CheckForDataOnSource(100);
AContext.Connection.IOHandler.CheckForDisconnect;
if AContext.Connection.IOHandler.InputBufferIsEmpty then
Exit;
end;
// process incoming data as needed...
end;
procedure TForm1.SomeProcedure;
var
List: TIdContextList;
Context: TMyContext;
begin
List := IdTCPServer1.Contexts.LockList;
try
Context := TMyContext(List[SomeIndex]);
Context.OutgoingMessages.Add('something');
finally
IdTCPServer1.Contexts.UnlockList;
end;
end;
i am facing the following problem.
Me and a friend of mine, have set up a wireless network using uhf data modem.
When i am trying to send a file (e.g. photo) and the connection is ok there is no problem. But when i am trying to send a file and for some reason there is no connection for a while, the form freezes until there is a reestablishment. Can anyone help me please? Here is the code i use from both server and client side (Delphi 2010).
Client Side (Transmits file [this form freezes if connection is lost for a while or permanently]):
procedure TForm17.BtnSendFile(Sender: TObject);
var
FS: TFileStream;
filename: string;
begin
filetotx := 'temp.jpg';
FS := TFileStream.Create(filetotx, fmOpenRead, fmShareDenyWrite);
FS.Position := 0;
try
Form1.IdTCPClient1.Socket.LargeStream := true;
Form1.IdTCPClient1.Socket.WriteLn('PIC');
Form1.IdTCPClient1.Socket.Write(FS, 0, true);
finally
FS.Free;
end;
end;
Server Side (receives file)
procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
s, filename:string;
FS: TFileStream;
Jpg: TJpegImage;
begin
S := AContext.Connection.Socket.ReadLn;
if S = 'PIC' then
begin
filename := 'PIC_' + datetostr(date) + ' ' + timetostr(time) + '.jpg';
filename := StringReplace(filename, '/', '-', [rfReplaceAll]);
filename := StringReplace(filename, ':', '_', [rfReplaceAll]);
filename := extractfilepath(Application.exename) + 'PIC\' + filename;
FS := TFileStream.Create(filename, fmCreate);
FS.Position := 0;
AContext.Connection.Socket.LargeStream := true;
AContext.Connection.Socket.ReadStream(FS);
Jpg := TJpegImage.Create;
FS.Position := 0;
Jpg.LoadFromStream(FS);
form26.image1.Picture.Assign(Jpg);
try
Jpg.Free;
FS.Free;
finally
//send feedback file received
AContext.Connection.Socket.WriteLn('PICOK');
TIdNotify.NotifyMethod(form26.Show);
end;
end;
Client Side (receives feedback 'PICOK')
type
TReadingThread = class(TThread)
protected
FConn: TIdTCPConnection;
procedure Execute; override;
procedure DoTerminate; override;
public
constructor Create(AConn: TIdTCPConnection); reintroduce;
end;
constructor TReadingThread.Create(AConn: TIdTCPConnection);
begin
TLog.AddMsg('Client Thread Created');
FConn := AConn;
inherited Create(False);
end;
procedure TReadingThread.Execute;
begin
while not Terminated do
begin
if S='MSGOK' then
.
.
else if S = 'PICOK' then
begin
Do Something
end
end;
end;
procedure TReadingThread.DoTerminate;
begin
TLog.AddMsg('Disconnected');
inherited;
end;
Your client code is sending the file in the context of the main UI thread. That is why the UI freezes - there are no messages being processed while the send is busy. Either move that code into a worker thread (preferred), or else drop a TIdAntiFreeze component onto your Form.
Your server code is fine as far as the actual file transfer is concerned, however your try/finally block is wrong, and you are directly accessing a TImage without synchronizing with the main UI thread. You are already synchronizing when calling form26.Show, you just need to synchronize when calling form26.image1.Picture.Assign(Jpg) as well. Try this instead:
procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
S, Filename: string;
FS: TFileStream;
Jpg: TJpegImage;
begin
S := AContext.Connection.Socket.ReadLn;
if S = 'PIC' then
begin
Filename := ExtractFilePath(Application.ExeName) + 'PIC\' + FormatDateTime('"PIC_"mm"-"dd"-"yyyy" "hh"_"nn"_"ss".jpg"', Now);
FS := TFileStream.Create(Filename, fmCreate);
try
AContext.Connection.Socket.LargeStream := true;
AContext.Connection.Socket.ReadStream(FS);
FS.Position := 0;
Jpg := TJpegImage.Create;
try
Jpg.LoadFromStream(FS);
TThread.Synchronize(nil,
procedure
begin
Form26.Image1.Picture.Assign(Jpg);
Form26.Show;
end;
);
finally
Jpg.Free;
end;
finally
FS.Free;
end;
//send feedback file received
AContext.Connection.Socket.WriteLn('PICOK');
end;
end;
Or this:
type
TMyNotify = class(TIdNotify)
protected
procedure DoNotify; override;
public
Jpg: TJpegImage;
constructor Create;
destructor Destroy; override;
end;
constructor TMyNotify.Create(Stream: TStream);
begin
inherited;
Jpg := TJpegImage.Create;
Jpg.LoadFromStream(Stream);
end;
destructor TMyNotify.Destroy;
begin
Jpg.Free;
inherited;
end;
procedure TMyNotify.DoNotify;
begin
Form26.Image1.Picture.Assign(Jpg);
Form26.Show;
end;
procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
S, Filename: string;
FS: TFileStream;
begin
S := AContext.Connection.Socket.ReadLn;
if S = 'PIC' then
begin
Filename := ExtractFilePath(Application.ExeName) + 'PIC\' + FormatDateTime('"PIC_"mm"-"dd"-"yyyy" "hh"_"nn"_"ss".jpg"', Now);
FS := TFileStream.Create(Filename, fmCreate);
try
AContext.Connection.Socket.LargeStream := true;
AContext.Connection.Socket.ReadStream(FS);
FS.Position := 0;
TMyNotify.Create(FS).Notify;
finally
FS.Free;
end;
//send feedback file received
AContext.Connection.Socket.WriteLn('PICOK');
end;
end;