如何使用TIdTCPServer连续发送消息？ [英] How to continuously send messages with TIdTCPServer?

问题描述

我需要创建一个delphi应用程序，在该应用程序启动时，服务器也将启动，并立即开始发送消息，但是我还没有找到示例或教程，并且Indy手册将近5000页并不清楚我该怎么做...

I need to create a delphi application where when it's started the server is started as well and starts sending messages immediately, but I haven't found an example or tutorial and the nearly 5000 page Indy manual doesn't make it clear to me how I can do this...

推荐答案

此示例使用带有主要表单的Delphi 2009 VCL应用程序，该表单仅包含一个可视组件，一个名为 MemoLog的TMemo。

This example uses a Delphi 2009 VCL application with a main form, which contains only one visual component, a TMemo named "MemoLog".

客户端和服务器都在FormCreate事件中启动。请注意，客户端代码不会处理连接丢失，但是可以在线程内使用单独的重新连接循环来实现。

Client and server are both started in the FormCreate event. Note that the client code does not handle connection loss, but this can be implemented with a separate re-connect loop within the thread.

procedure TServerPushExampleForm.FormCreate(Sender: TObject);
begin
  ExampleServer := TMyPushServer.Create;
  ExampleServer.DefaultPort := 8088;
  ExampleServer.Active := True;

  ExampleClient := TMyPushClientThread.Create('localhost', 8088,
    MemoLog.Lines);
end;

服务器

服务器代码使用TIdTCPCustomServer子类，它等待一个随机时间，然后将字符串发送到客户端。

Server

The server code uses a TIdTCPCustomServer subclass which waits for a random time and then sends a string to the client.

function TMyPushServer.DoExecute(AContext: TIdContext): Boolean;
begin
  Result := inherited;

  // simulate hard work
  Sleep(Random(3000));

  AContext.Connection.IOHandler.WriteLn(
    'Completed at ' + TimeToStr(Now), IndyTextEncoding_UTF8);
end;

客户端

客户端代码使用TThread子类可以异步运行而不会阻塞主VCL线程。它包含一个私有TIdTCPClient实例，并定期尝试从连接中接收字符串。

Client

The client code uses a TThread subclass to run asynchronously without blocking the main VCL thread. It contains a private TIdTCPClient instance, and periodically tries to receive a string from the connection.

...
  S := TCPClient.IOHandler.ReadLn(IndyTextEncoding_UTF8);
...

完整的Delphi表单代码

下面是示例主表单的完整代码。

Full Delphi Form Code

Below is the full code for the example main form.

unit Unit1;

interface

uses
  IdCustomTCPServer, IdTCPClient, IdContext,
  SysUtils, Classes, Forms, StdCtrls, Controls;

type
  TMyPushClientThread = class(TThread)
  private
    TCPClient: TIdTCPClient;
    FLog: TStrings;
  public
    constructor Create(AHost: string; APort: Word; ALog: TStrings);
    destructor Destroy; override;
    procedure Execute; override;
  end;

  TMyPushServer = class (TIdCustomTCPServer)
  protected
    function DoExecute(AContext: TIdContext): Boolean; override;
  end;

  TServerPushExampleForm = class(TForm)
    MemoLog: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    ExampleClient: TMyPushClientThread;
    ExampleServer: TMyPushServer;
  end;

var
  ServerPushExampleForm: TServerPushExampleForm;

implementation

uses
  IdGlobal;

{$R *.dfm}

procedure TServerPushExampleForm.FormCreate(Sender: TObject);
begin
  ExampleServer := TMyPushServer.Create;
  ExampleServer.DefaultPort := 8088;
  ExampleServer.Active := True;

  ExampleClient := TMyPushClientThread.Create('localhost', 8088, MemoLog.Lines);
end;

procedure TServerPushExampleForm.FormDestroy(Sender: TObject);
begin
  ExampleServer.Free;
  ExampleClient.Terminate;
  ExampleClient.WaitFor;
  ExampleClient.Free;
end;

{ TMyPushServer }

function TMyPushServer.DoExecute(AContext: TIdContext): Boolean;
begin
  Result := inherited;

  // simulate hard work
  Sleep(Random(3000));

  AContext.Connection.IOHandler.WriteLn(
    'Completed at ' + TimeToStr(Now), IndyTextEncoding_UTF8);
end;

{ TMyPushClientThread }

constructor TMyPushClientThread.Create(AHost: string; APort: Word; ALog: TStrings);
begin
  inherited Create(False);

  FLog := ALog;

  TCPClient := TIdTCPClient.Create;
  TCPClient.Host := AHost;
  TCPClient.Port := APort;
  TCPClient.ReadTimeout := 500;
end;

destructor TMyPushClientThread.Destroy;
begin
  TCPClient.Free;
  inherited;
end;

procedure TMyPushClientThread.Execute;
var
  S: string;
begin
  TCPClient.Connect;

  while not Terminated do
  begin
    S := TCPClient.IOHandler.ReadLn(IndyTextEncoding_UTF8);

    if not TCPClient.IOHandler.ReadLnTimedout then
    begin
      TThread.Queue(nil,
        procedure
        begin
          FLog.Append(S);
        end);
    end;

  end;

  TCPClient.Disconnect;
end;

end.

（摘自 https://mikejustin.wordpress.com/2014/04/19/indy-10-tidtcpserver-server- side-message-push-example / ）

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