Multithreading DELPHI中使用Indy组件(idTCPServer/idTCPClient)的单服务器与多客户端实时监控系统
我在构建Indy服务器/客户端实时监控系统时遇到了一个重要问题。。。 我使用的是Delphi2010,Indy版本是10.5.5。。。。。。。。。 我的目的是,许多客户端PC连续(4~10fps)向服务器发送屏幕截图,服务器必须向一些监控PC发送这些屏幕截图帧。 换句话说Multithreading DELPHI中使用Indy组件(idTCPServer/idTCPClient)的单服务器与多客户端实时监控系统,multithreading,delphi,indy,indy10,server-push,Multithreading,Delphi,Indy,Indy10,Server Push,我在构建Indy服务器/客户端实时监控系统时遇到了一个重要问题。。。 我使用的是Delphi2010,Indy版本是10.5.5。。。。。。。。。 我的目的是,许多客户端PC连续(4~10fps)向服务器发送屏幕截图,服务器必须向一些监控PC发送这些屏幕截图帧。 换句话说 Many clients -----send streams--------> to Server Some monitors <---receive streams----- from Server 许多客户端
Many clients -----send streams--------> to Server
Some monitors <---receive streams----- from Server
许多客户端------向服务器发送流---------------->
某些监视器接收失败:'+IntToStr(recv_Stream.Size)+'byte';
recv_Stream.Free;
出口
结束;
如果recv_Stream.Size<1024,则
开始
recv_Stream.Seek(0,从开始);
ROutMsg:=AContext.Binding.PeerIP+'->已接收到captionString('+
IntToStr(recv_Stream.Size)+字节):“+StringFromStream(TStream(recv_Stream))+”;
recv_Stream.Free;
结束
其他的
开始
ROutMsg:=AContext.Binding.PeerIP+'->收到的屏幕截图:'+KBStr(recv_Stream.Size)+'KB';
如果G_Sendable=False,则
开始
send_Stream:=TMemoryStream.Create;
发送_-Stream.Clear;
recv_Stream.Seek(0,从开始);
send_Stream.Seek(0,从开始);
send_Stream.CopyFrom(recv_Stream,recv_Stream.Size);
G_Sendable:=真;
结束;
recv_Stream.Free;
结束;
结束;
Application.ProcessMessages;
WaitForSingleObject(句柄,1);
结束;
{另一方面--idTCPServerSend将向监视器发送屏幕截图流}
过程TIndyServerForm.IdTCPServer_SendExecute(AContext:TIdContext);
开始
如果G_Sendable那么
开始
send_Stream.Seek(0,从开始);
如果(SendStream(AContext,TStream(send_Stream))=False),则
开始
SOutMsg:=AContext.Binding.PeerIP+'->发送失败->'+KBStr(send_Stream.Size)+'KB';
免费发送;
G_Sendable:=假;
出口
结束;
SOutMsg:=AContext.Binding.PeerIP+'->发送成功->'+KBStr(send_Stream.Size)+'KB';
免费发送;
G_Sendable:=假;
结束;
Application.ProcessMessages;
WaitForSingleObject(句柄,1);
结束;
对于具有实时流交换的多客户端连接,我应该怎么做。。。
每台客户端PC每秒发送4~10次屏幕截图流。。。
这些流必须发送到相应的监视器
请给我一些建议……在“监视器”端,线程中的TIdTCPClient可以侦听来自服务器的传入屏幕截图数据。我在这里发布了一篇关于Indy(源代码)服务器端推送消息技术的博客文章:
需要额外的服务器端代码将传入数据定向到监控客户端。实际上,您只需要在上下文中添加“标记”(可以是布尔标志),指示此连接是否正在发送或监视屏幕截图数据。如何将自定义属性分配给连接上下文并对其进行迭代已经在这里的其他问题中得到了回答。您的代码甚至还没有接近线程安全,这就是您出现错误的原因。
IdTCPServer_Recv
中的每个客户端线程都将各自的屏幕快照接收到单个共享Recv_流
变量,然后将该数据复制到单个共享send_流
变量。然后,连接到IdTCPServer\u Send
的所有客户端将同时读取和发送相同的Send\u流。你把记忆踩得到处都是
您需要使用局部变量而不是共享变量来接收每个屏幕截图,并且需要为每个监视器客户端使用单独的TStream
对象。不要使用共享的TStream
进行发送,当然也不要使用全局布尔变量来让每个监视器客户端执行此操作。让IdTCPServer\u RecvExecute()
主动创建一个新的TMemoryStream
对象,并将其传递给每个需要发送当前屏幕截图的监视器客户端
尝试类似以下内容:
uses
..., IdThreadSafe;
type
TMonitorContext = class(TIdServerContext)
public
Screenshots: TIdThreadSafeObjectList;
ScreenshotEvent: THandle;
constructor Create(AConnection: TIdTCPConnection; AYarn: TIdYarn; AList: TThreadList = nil); override;
destructor Destroy; override;
end;
TScreenshotInfo = class
public
ClientIP: string;
ClientPort: TIdPort;
Data: TMemoryStream;
constructor Create;
destructor Destroy; override;
end;
constructor TMonitorContext.Create(AConnection: TIdTCPConnection; AYarn: TIdYarn; AList: TThreadList);
begin
inherited;
Screenshots := TIdThreadSafeObjectList.Create;
Screenshots.OwnsObjects := True;
ScreenshotEvent := CreateEvent(null, True, False, nil);
end;
destructor TMonitorContext.Destroy;
begin
Screenshots.Free;
CloseHandle(ScreenshotEvent);
inherited;
end;
constructor TScreenshotInfo.Create;
begin
inherited;
Data := TMemoryStream.Create;
end;
destructor TScreenshotInfo.Destroy;
begin
Data.Free;
inherited;
end;
{one side----idTCPServerRecv is to receive screenshot streams from clients}
procedure TIndyServerForm.IdTCPServer_RecvExecute(AContext: TIdContext);
var
recv_stream: TMemoryStream;
monitors, queue: TList;
i: Integer;
screenshot: TScreenshotInfo;
monitor: TMonitorContext;
begin
recv_stream := TMemoryStream.Create;
try
if not ReceiveStream(AContext, recv_stream) then
begin
ROutMsg := AContext.Binding.PeerIP + ' -> receiving failed: ' + IntToStr(recv_Stream.Size) + ' byte';
Exit;
end;
if recv_Stream.Size < 1024 then
begin
recv_Stream.Position := 0;
ROutMsg := AContext.Binding.PeerIP + ' -> captionString received(' +
IntToStr(recv_Stream.Size) + ' byte) : "' + StringFromStream(recv_Stream) + '"';
end
else
begin
ROutMsg := AContext.Binding.PeerIP + ' -> screenshot received: ' + KBStr(recv_Stream.Size) + ' KB';
monitors := IdTCPServer_Send.Contexts.LockList;
try
// alternatively, only queue the screenshot to particular monitors
// that are actually interested in this client...
for i := 0 to monitors.Count-1 do
begin
monitor := TMonitorContext(monitors[i]);
screenshot := TScreenshotInfo.Create;
try
recv_Stream.Position := 0;
screenshot.Data.CopyFrom(recv_stream, 0);
screenshot.Data.Position := 0;
queue := monitor.Screenshots.LockList;
try
queue.Add(screenshot);
SetEvent(monitor.ScreenshotEvent);
finally
monitor.Screenshots.UnlockList;
end;
except
screenshot.Free;
end;
end;
finally
IdTCPServer_Send.Contexts.UnlockList;
end;
end;
finally
recv_stream.Free;
end;
end;
{another side----idTCPServerSend is to send screenshot streams to monitors}
procedure TIndyServerForm.FormCreate(Sender: TObject);
begin
IdTCPServer_Send.ContextClass := TMonitorContext;
end;
procedure TIndyServerForm.IdTCPServer_SendExecute(AContext: TIdContext);
var
monitor: TMonitorContext;
queue: TList;
i: Integer;
screenshot: TScreenshotInfo;
begin
monitor := TMonitorContext(AContext);
if WaitForSingleObject(monitor.ScreenshotEvent, 1000) <> WAIT_OBJECT_0 then Exit;
screenshot := nil;
try
queue := monitor.Screenshots.LockList;
try
if queue.Count > 0 then
begin
screenshot := TScreenshotInfo(queue[0]);
queue.Delete(0);
end;
if queue.Count = 0 then
ResetEvent(monitor.ScreenshotEvent);
finally
monitor.Screenshots.UnlockList;
end;
if screenshot = nil then Exit;
// you should send screenshot.ClientIP and screenshot.ClientPort to
// this monitor so it knows which client the screenshot came from...
if not SendStream(AContext, screenshot.Data) then
begin
SOutMsg := AContext.Binding.PeerIP + ' -> sending failed -> ' + KBStr(screenshot.Data.Size) + ' KB';
Exit;
end;
SOutMsg := AContext.Binding.PeerIP + ' -> sending successful-> ' + KBStr(screenshot.Data.Size) + ' KB';
finally
screenshot.Free;
end;
end;
使用
…,IdThreadSafe;
类型
TMonitorContext=class(TIdServerContext)
公众的
截图:TIdThreadSafeObjectList;
截屏事件:坦德尔;
构造函数创建(a连接:TIdTCPConnection;AYarn:tidshrean;AList:TThreadList=nil);推翻
毁灭者毁灭;推翻
结束;
TScreenshotInfo=class
公众的
ClientIP:字符串;
客户端口:TIdPort;
数据:TMemoryStream;
构造函数创建;
毁灭者毁灭;推翻
结束;
构造函数TMonitorContext.Create(连接:TIdTCPConnection;AYarn:tidshrean;列表:TThreadList);
开始
继承;
屏幕截图:=TIdThreadSafeObjectList.Create;
Screenshots.OwnsObjects:=True;
ScreenshotEvent:=CreateEvent(null、True、False、nil);
结束;
析构函数TMonitorContext.Destroy;
开始
截图。免费;
CloseHandle(屏幕快照事件);
继承;
结束;
构造函数TScreenshotInfo.Create;
开始
继承;
数据:=TMemoryStream.Create;
结束;
析构函数TScreenshotInfo.Destroy;
开始
数据。免费;
继承;
结束;
{一边----idTCPServerRecv接收来自客户端的屏幕截图流}
程序TIndyServerForm.IdTCPServer_RecvExecute(AContext:TIdContext);
变量
recv_流:TMemoryStream;
监视器,队列:TList;
i:整数;
截图:TScreenshotInfo;
监视器:TMonitorContext;
开始
recv_stream:=TMemoryStream.Create;
尝试
如果没有接收流(AContext,recv_stream),则
开始
ROutMsg:=AContext.Binding.PeerIP+'->接收失败:'+IntToStr(recv_Stream.Size)+'byte';
出口
结束;
如果recv_Stream.Size<1024,则
开始
记录流位置:=0;
ROutMsg:=AContext.Binding.PeerIP+'->接收到字幕字符串('+
IntToStr(recv_Stream.Size)+'字节):“'+StringFromStream(recv_Stream)+'”;
结束
其他的
开始
ROutMsg:=AContext.Binding.PeerIP+'->收到的屏幕截图:'+KBStr(recv_Str
uses
..., IdThreadSafe;
type
TMonitorContext = class(TIdServerContext)
public
Screenshots: TIdThreadSafeObjectList;
ScreenshotEvent: THandle;
constructor Create(AConnection: TIdTCPConnection; AYarn: TIdYarn; AList: TThreadList = nil); override;
destructor Destroy; override;
end;
TScreenshotInfo = class
public
ClientIP: string;
ClientPort: TIdPort;
Data: TMemoryStream;
constructor Create;
destructor Destroy; override;
end;
constructor TMonitorContext.Create(AConnection: TIdTCPConnection; AYarn: TIdYarn; AList: TThreadList);
begin
inherited;
Screenshots := TIdThreadSafeObjectList.Create;
Screenshots.OwnsObjects := True;
ScreenshotEvent := CreateEvent(null, True, False, nil);
end;
destructor TMonitorContext.Destroy;
begin
Screenshots.Free;
CloseHandle(ScreenshotEvent);
inherited;
end;
constructor TScreenshotInfo.Create;
begin
inherited;
Data := TMemoryStream.Create;
end;
destructor TScreenshotInfo.Destroy;
begin
Data.Free;
inherited;
end;
{one side----idTCPServerRecv is to receive screenshot streams from clients}
procedure TIndyServerForm.IdTCPServer_RecvExecute(AContext: TIdContext);
var
recv_stream: TMemoryStream;
monitors, queue: TList;
i: Integer;
screenshot: TScreenshotInfo;
monitor: TMonitorContext;
begin
recv_stream := TMemoryStream.Create;
try
if not ReceiveStream(AContext, recv_stream) then
begin
ROutMsg := AContext.Binding.PeerIP + ' -> receiving failed: ' + IntToStr(recv_Stream.Size) + ' byte';
Exit;
end;
if recv_Stream.Size < 1024 then
begin
recv_Stream.Position := 0;
ROutMsg := AContext.Binding.PeerIP + ' -> captionString received(' +
IntToStr(recv_Stream.Size) + ' byte) : "' + StringFromStream(recv_Stream) + '"';
end
else
begin
ROutMsg := AContext.Binding.PeerIP + ' -> screenshot received: ' + KBStr(recv_Stream.Size) + ' KB';
monitors := IdTCPServer_Send.Contexts.LockList;
try
// alternatively, only queue the screenshot to particular monitors
// that are actually interested in this client...
for i := 0 to monitors.Count-1 do
begin
monitor := TMonitorContext(monitors[i]);
screenshot := TScreenshotInfo.Create;
try
recv_Stream.Position := 0;
screenshot.Data.CopyFrom(recv_stream, 0);
screenshot.Data.Position := 0;
queue := monitor.Screenshots.LockList;
try
queue.Add(screenshot);
SetEvent(monitor.ScreenshotEvent);
finally
monitor.Screenshots.UnlockList;
end;
except
screenshot.Free;
end;
end;
finally
IdTCPServer_Send.Contexts.UnlockList;
end;
end;
finally
recv_stream.Free;
end;
end;
{another side----idTCPServerSend is to send screenshot streams to monitors}
procedure TIndyServerForm.FormCreate(Sender: TObject);
begin
IdTCPServer_Send.ContextClass := TMonitorContext;
end;
procedure TIndyServerForm.IdTCPServer_SendExecute(AContext: TIdContext);
var
monitor: TMonitorContext;
queue: TList;
i: Integer;
screenshot: TScreenshotInfo;
begin
monitor := TMonitorContext(AContext);
if WaitForSingleObject(monitor.ScreenshotEvent, 1000) <> WAIT_OBJECT_0 then Exit;
screenshot := nil;
try
queue := monitor.Screenshots.LockList;
try
if queue.Count > 0 then
begin
screenshot := TScreenshotInfo(queue[0]);
queue.Delete(0);
end;
if queue.Count = 0 then
ResetEvent(monitor.ScreenshotEvent);
finally
monitor.Screenshots.UnlockList;
end;
if screenshot = nil then Exit;
// you should send screenshot.ClientIP and screenshot.ClientPort to
// this monitor so it knows which client the screenshot came from...
if not SendStream(AContext, screenshot.Data) then
begin
SOutMsg := AContext.Binding.PeerIP + ' -> sending failed -> ' + KBStr(screenshot.Data.Size) + ' KB';
Exit;
end;
SOutMsg := AContext.Binding.PeerIP + ' -> sending successful-> ' + KBStr(screenshot.Data.Size) + ' KB';
finally
screenshot.Free;
end;
end;