我无法接收包含PNG文件的字节数组。当代码在OnClientRead
事件中执行时,它工作正常,已经转移到一个线程时,发生MemoryStream
的错误,说:
扩展内存流时内存不足。
在此刻:
if SD.State = ReadingSize then
我想知道如何解决这个特定的麻烦,我怎么能检查我是否收到包含文件或简单的String
的数据?
代码:
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;
更新:
答案中的代码对我不起作用,因为ServerType=stThreadBlocking
会阻止所有客户端与服务器的连接。因此,我正在寻找类似的东西(ServerType=stNonBlocking
,TThread
和OnAccept
事件):
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;
此代码在此行有一个数据转换错误:DataSize := StrToInt(sl);
我怎样才能解决这个问题?
如何解决这个具体的麻烦
您没有按照使用方式使用TServerSocket
线程。
如果你想在TServerSocket
模式下使用stThreadBlocking
(参见my other answer如何在TServerSocket
模式下使用stNonBlocking
),正确的方法是:
TServerClientThread
派生一个线程类ClientExecute()
方法来进行I / O工作(通过TWinSocketStream
)TServerSocket.OnGetThread
事件来实例化线程。如果你不这样做,TServerSocket
将创建自己的默认线程(在主线程中触发OnClient(Read|Write)
事件),这将干扰你的手动线程。
此外,你不需要我在my answer向your other question展示的状态机。这是针对事件驱动的代码。线程I / O代码可以线性写入。
尝试更像这样的东西:
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;
我如何检查我是否收到包含文件或简单字符串的数据?
客户端需要将该信息发送到您的服务器。在发送实际数据之前,您已经发送了一个值来指定数据大小。您还应该在数据前面加上一个值来指定数据的类型。然后,您可以根据需要根据其类型处理数据。