Indy TCP客户端/服务器，其中客户端充当服务器 [英] Indy TCP Client/Server with the client acting as a server

问题描述

如何在以下情况下使用Indy的 TIdTCPClient 和 TIdTCPServer ：

How can Indy's TIdTCPClient and TIdTCPServer be used in the following scenario:

Client  ---------- initate connection -----------> Server
...
Client  <---------------command------------------- Server
Client  ----------------response-----------------> Server
...
Client  <---------------command------------------- Server
Client  ----------------response-----------------> Server

客户端启动连接，但充当 （等待命令并执行它们）。

The client initiates the connection, but acts as a "server" (waiting for commands and executing them).

OnExecute 方法 TIdTCPServer 无法正常运作在这种情况下（至少我没有得到它的工作良好）。

The OnExecute approach of TIdTCPServer does not work well in this case (at least I am not getting it to work well). How could I do this?

推荐答案

没有什么能阻止你这样做与Indy的TIdTCPServer组件。

There is nothing preventing you from doing this with Indy's TIdTCPServer component.

TIdTCPServer只设置连接。你需要实现其余的。

A TIdTCPServer only sets up the connection. You'll need to implement the rest. So the sequence of the actual sending and receiving can be whatever you want.

将此代码放在您的TIdTCPServer组件的OnExecute事件中：

Put this code in your TIdTCPServer component's OnExecute event:

var
  sName: String;
begin
  // Send command to client immediately after connection
  AContext.Connection.Socket.WriteLn('What is your name?');
  // Receive response from client
  sName := AContext.Connection.Socket.ReadLn;
  // Send a response to the client
  AContext.Connection.Socket.WriteLn('Hello, ' + sName + '.');
  AContext.Connection.Socket.WriteLn('Would you like to play a game?');
  // We're done with our session
  AContext.Connection.Disconnect;
end;

以下是如何设置TIdTCPServer的简单方法：

Here's how you can setup the TIdTCPServer really simply:

IdTCPServer1.Bindings.Clear;
IdTCPServer1.Bindings.Add.SetBinding('127.0.0.1', 8080);
IdTCPServer1.Active := True;

这告诉服务器只监听环回地址，端口8080.这可以防止

This tells the server to listen on the loopback address only, at port 8080. This prevents anyone outside of your computer from connecting to it.

然后，要连接您的客户端，您可以转到Windows命令提示符处，并键入以下内容：

Then, to connect your client, you can go to a Windows command prompt and type the following:

telnet 127.0.0.1 8080

以下是输出结果：

您的姓名是什么？

What is your name?

您好，Marcus。

您要玩游戏吗？

与主机的连接失败。

没有telnet？要在在Vista和7上安装telnet客户端，请按以下步骤操作。

Don't have telnet? Here's how to install telnet client on Vista and 7.

或者使用TIdTCP客户端，您可以这样做：

Or with a TIdTCP Client, you can do this:

var
  sPrompt: String;
  sResponse: String;
begin
  // Set port to connect to
  IdTCPClient1.Port := 8080;
  // Set host to connect to
  IdTCPClient1.Host := '127.0.0.1';
  // Now actually connect
  IdTCPClient1.Connect;
  // Read the prompt text from the server
  sPrompt := IdTCPClient1.Socket.ReadLn;
  // Show it to the user and ask the user to respond
  sResponse := InputBox('Prompt', sPrompt, '');
  // Send user's response back to server
  IdTCPClient1.Socket.WriteLn(sResponse);
  // Show the user the server's final message
  ShowMessage(IdTCPClient1.Socket.AllData);
end;

这里需要注意的一个重要的事情是ReadLn语句等待，直到有数据。这是背后的魔力。

An important thing to note here is that the ReadLn statements wait until there is data. That's the magic behind it all.

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