当客户端连接时，Indy TCPServer 给出“Connection reset by peer”错误

Question

我正在尝试使用 Delphi firemonkey 应用程序创建 TCP 服务器。

我的资源文件Unit1.fmx如下。

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 480
  ClientWidth = 640
  FormFactor.Width = 320
  FormFactor.Height = 480
  FormFactor.Devices = [Desktop]
  OnActivate = FormShow
  OnCreate = FormCreate
  DesignerMasterStyle = 0
  object Label1: TLabel
    Position.X = 504.000000000000000000
    Position.Y = 248.000000000000000000
    Text = 'Label1'
  end
  object TCPServer: TIdTCPServer
    Bindings = <>
    DefaultPort = 0
    OnAfterBind = TCPServerAfterBind
    OnConnect = TCPServerOnConnect
    OnExecute = TCPserverExecute
    Left = 560
    Top = 184
  end
end

我的代码文件在这里。

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Platform,
  IdCustomTCPServer, IdTCPServer, IdBaseComponent, IdComponent, IdUDPBase, IdContext,
  IdSocketHandle, IdUDPServer, FMX.Controls.Presentation, FMX.StdCtrls, Windows;

type
  TForm1 = class(TForm)
    TCPServer: TIdTCPServer;
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure TCPserverExecute(AContext: TIdContext);
    procedure TCPServerOnConnect(AContext: TIdContext);
    procedure TCPServerAfterBind(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

type
  TMyLoggingService = class(TInterfacedObject, IFMXLoggingService)
  public
    procedure Log(const Format: string; const Params: array of const);
  end;

var
  Form1: TForm1;
  MyLoggingService: IFMXLoggingService;

implementation

{$R *.fmx}

procedure TMyLoggingService.Log(const Format: string; const Params: array of const);
begin
  // do whatever you want...
  OutputDebugString(PChar(Format));
end;


procedure TForm1.FormCreate(Sender: TObject);
var
  Binding : TIdSocketHandle;
begin
  MyLoggingService := TMyLoggingService.Create;
  if TPlatformServices.Current.SupportsPlatformService( IFMXLoggingService ) then
    TPlatformServices.Current.RemovePlatformService( IFMXLoggingService );
  // register my service
  TPlatformServices.Current.AddPlatformService( IFMXLoggingService, MyLoggingService );
  TCPServer.DefaultPort := 16000;
  TCPServer.Bindings.Clear;
  Binding := TCPServer.Bindings.Add;
  Binding.IP := '127.0.0.1';
  Binding.Port := 16000;
  //if Assigned(MyLoggingService) then
  MyLoggingService.Log('FormCreate!',[]);
end;

procedure TForm1.FormShow(Sender: TObject);
begin
 TCPServer.Active := True;
end;

procedure TForm1.TCPServerAfterBind(Sender: TObject);
begin
  MyLoggingService.Log('After Bind',[]);
end;

procedure TForm1.TCPServerOnConnect(AContext: TIdContext);
begin
  MyLoggingService.Log('Recieved Connection From Client ',[]);
end;

procedure TForm1.TCPServerExecute(AContext: TIdContext);
Var
C : String;
begin
 C:= AContext.Connection.Socket.ReadLn();
 //if Assigned(MyLoggingService) then
 MyLoggingService.Log('TserverExecute !',[]);

 MyLoggingService.Log('Recived Data !',[C]);
 if C = 'TESTSTRING' then
 begin
   AContext.Connection.Socket.Writeln('SENT');
 end;


end;

end.

我的问题是在我记录消息的系统日志中，这是我得到的。

Debug Output: FormCreate! Process Project1.exe (3340)
Debug Output: After Bind Process Project1.exe (3340)
Debug Output: Recieved Connection From Client  Process Project1.exe (3340)
First chance exception at 9BC42D. Exception class EIdSocketError with message
'Socket Error # 10054
Connection reset by peer.'.
Process Project1.exe (3340)

connection reset by peer。我的问题是为什么我的代码会发生这种情况？我做错了什么，我该如何解决？

在远程端，我有一个非常简单的 python 脚本，如下所示。

import socket

# Set up a TCP/IP socket
s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

# Connect as client to a selected server
# on a specified port
s.connect(('127.0.0.1',16000))

# Protocol exchange - sends and receives
data = 'TESTSTRING';
s.send(data.encode())
while True:
    resp = s.recv(1024)
    if resp == "": 
        print('NOTHING')
        break
    else:
        print(resp)
        break

# Close the connection when completed
s.close()
print("\ndone")

Answer 1

服务器代码没有问题。客户端在其端断开连接，服务器端的 调试器 只是检测 Indy 引发的异常以处理断开连接。 这是正常行为。

但是，您的客户端代码存在问题。在服务器端，您正在使用 TIdIOHandler.ReadLn()，它期望客户端发送一行由 LF 字符（或 CRLF 字符串）分隔的文本。但是您的客户端脚本根本没有发送该分隔符，因此 ReadLn() 不会退出，因此服务器不会调用 TIdIOHandler.WriteLn() 来发送响应。在客户端，s.recv() 可能会失败（因为没有收到响应）并且脚本结束，断开套接字，导致服务器端的 ReadLn() 将异常返回到 TIdTCPServer 所以它可以停止线程关闭套接字。

当客户端连接时，Indy TCPServer 给出“Connection reset by peer”错误

Indy TCPServer is giving `Connection reset by peer` error when client connects

delphi

debugging

tcp

indy10

firemonkey