android - TIdIOHandler.Write 程序不适用于移动设备

Question

我正在尝试从移动设备(iOS、Android)向 TCP 服务器发送流。对于服务器端和客户端，我使用的是 Indy 组件。

当我尝试从移动设备中运行的 FMX 应用程序发送流时​​，会出现此问题。如果我从 Windows 运行客户端代码，客户端会将流发送到服务器应用程序。但是我从移动设备运行相同的代码，但没有发送流。

这是服务器和客户端的最小、完整且可验证的示例，可以重现问题。

服务器端。服务器是一个 VCL 应用程序。

unit uServer;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, IdBaseComponent, IdComponent,
  IdCustomTCPServer, IdTCPServer, Vcl.StdCtrls, IdContext;

type
  TFrmServer = class(TForm)
    IdTCPServer1: TIdTCPServer;
    MemoLog: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure IdTCPServer1Execute(AContext: TIdContext);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  FrmServer: TFrmServer;

implementation

uses
  IdGlobal,
  IdIOHandler,
  System.StrUtils;

{$R *.dfm}

procedure TFrmServer.FormCreate(Sender: TObject);
begin
  IdTCPServer1.Bindings.Clear;
  IdTCPServer1.DefaultPort := 28888;
  IdTCPServer1.Active := True;
  MemoLog.Lines.Add('Running');
end;

procedure TFrmServer.IdTCPServer1Execute(AContext: TIdContext);
var
  LHandler  : TIdIOHandler;
  s: string;
  LMemoryStream : TMemoryStream;
  AFormatSettings: TFormatSettings;
  d : Int64;
begin
  try
    LHandler := AContext.Connection.IOHandler;
    s := LHandler.ReadLn(LF, IdTimeoutDefault, MaxInt);
    AFormatSettings := TFormatSettings.Create;
    if (s <> '') then
    begin
       if StartsText('<',  s) and EndsText('>',  s)  then
       begin
            TThread.Queue(nil,
              procedure
              begin
                MemoLog.Lines.Add(Format('%s', [s], AFormatSettings));
              end
            );
            LMemoryStream := TMemoryStream.Create;
            try
                LHandler.LargeStream := True;
                LHandler.ReadStream(LMemoryStream, -1, False);
                d := LMemoryStream.Size;
                TThread.Queue(nil,
                  procedure
                  begin
                    MemoLog.Lines.Add(Format('Stream Size %d', [d], AFormatSettings));
                  end
                );
            finally
              LMemoryStream.Free;
            end;
       end
       else
         LHandler.InputBuffer.Clear;
    end;
  except
    on E: Exception do
    begin
      s := E.Message;
      TThread.Queue(nil,
        procedure
        begin
          MemoLog.Lines.Add(Format('Exception %s', [s], AFormatSettings));
        end
      );
    end;
  end;
end;

end.

客户端(FMX 应用程序)

unit uClient;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, FMX.ScrollBox,
  FMX.Memo, FMX.Controls.Presentation, FMX.StdCtrls;

type
  TFrmClient = class(TForm)
    IdTCPClient1: TIdTCPClient;
    Button1: TButton;
    MemoLog: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    procedure Send;
  public
    { Public declarations }
  end;

var
  FrmClient: TFrmClient;

implementation

{$R *.fmx}

type

  TSendThread = class(TThread)
  private
    FTCPClient : TIdTCPClient;
  public
    procedure Execute; override;
    constructor Create(ATCPClient : TIdTCPClient); reintroduce;
  end;

procedure TFrmClient.Button1Click(Sender: TObject);
begin
   Send;
end;

procedure TFrmClient.FormCreate(Sender: TObject);
begin
 try
  IdTCPClient1.Port := 28888;
  IdTCPClient1.Host := '192.168.1.134'; //change this to the ip of the  TCP server.
  IdTCPClient1.ConnectTimeout := 5000;
  IdTCPClient1.Connect();
  MemoLog.Lines.Add('Connected');

  except on E: Exception do
     MemoLog.Lines.Add('Exception ' + E.Message);
 end;
end;

procedure TFrmClient.Send;
begin
  if IdTCPClient1.Connected then
    TSendThread.Create(IdTCPClient1);
end;

{ TSendThread }

constructor TSendThread.Create(ATCPClient: TIdTCPClient);
begin
  inherited Create(False);
  FTCPClient := ATCPClient;
end;

procedure TSendThread.Execute;
var
  LStream : TStream;
  d : Int64;
begin
   LStream := TMemoryStream.Create;
   try
     //Send a text from all the platforms works perfect.
     FTCPClient.IOHandler.WriteLn('<Hello>');
     LStream.Size := 1024;
     LStream.Position := 0;
     d := LStream.Size;
     FTCPClient.IOHandler.LargeStream := True;
     //this only works from Windows
     FTCPClient.IOHandler.Write(LStream,  d, True);
   finally
     LStream.Free;
   end;
end;

end.

问题是，如何使用 Indy 组件从移动设备发送流？

更新:

安卓权限

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Answer 1

终于找到问题了，我误以为数据没有发送，流发送了，但是服务器无法处理流，因为 TIdIOHandler.ReadStream 函数没有正确读取流的大小。当在 AByteCount 参数中传递 -1 值时会发生这种情况。然后 TIdIOHandler.ReadInt64 或 TIdIOHandler.ReadInt32 函数用于读取流的大小，并且在内部这些函数尝试使用 转换整数的字节顺序>GStack.NetworkToHost 函数。

我解决了在不转换字节顺序的情况下读取流大小的问题。

我替换了这一行

LHandler.ReadStream(LMemoryStream, -1, False);

对于这段代码

LHandler.LargeStream := True;
LHandler.ReadBytes(LBytes, SizeOf(Int64), False);
d := BytesToInt64(LBytes);
LHandler.ReadStream(LMemoryStream, d, False);