How to read all bytes from server using Indy Client in Delphi?

Question

I am using Indy client to read the message the server is sending to me (client). It sends 512 bytes of data to me in one go. This 512 bytes of data is composed of two datatypes (Word and String). For example, it sends Word of 2 bytes, then again Word of 2 bytes and then String of 50 bytes and so on. I am trying following code to cope with this problem:

var BufferArray : Array[0..512] of Byte;

 if IdTCPClient1.IOHandler.InputBufferIsEmpty then
 begin
      if IdTCPClient1.IOHandler.CheckForDataOnSource(1000) then
      begin
          Edit1.Text := idtcpclient1.IOHandler.ReadBytes(BufferArray ,512, true);
      end;
 end;

I am getting error on line Edit1.Text := idtcpclient1.IOHandler.ReadBytes(BufferArray ,512, true); Error: Type of actual and formal var parameter must be identical.

Is it right approach I am using. I want to store whole 512 bytes on Edit1.Text and then will do whatever I want to do with that data. Please help me in getting all 512 bytes from the server.

Update: Alternating Approach

I am using this approach to read word and string values

WordArray : array[0..5] of word;

 if IdTCPClient1.IOHandler.InputBufferIsEmpty then
 begin
      if IdTCPClient1.IOHandler.CheckForDataOnSource(1000) then
      begin
        i := 0;
        while i < 6 do //Read all the words
        begin
            //Fill WORD data in array
            WordArray[i] :=  (IdTCPClient1.Socket.ReadWord(True));
        end;
      end;
end;

Similar approach for string like

WordArray[i] := (IdTCPClient1.Socket.ReadString(50));

Thats working fine, but I have to remain the connection open while I read all the data in loop. If in between connection goes, I lose everything and have to request the whole package again from server.

Use a dynamic array for BufferArray, change your declaration to var BufferArray: TBytes;. — TLama
Yes, did same. It worked. Thanks. Now I have further problems. How can I iterate through this BufferArray? I want to store everything from it to a string array. — user1556433
Sorry, I'm giving up this Q&A; you're asking me to resolve the whole communication part of your client. That's what I have no time nor motivation. The document you've posted says nothing about byte order for word values nor how the strings are sent or terminated (all the things we've asked from you). To your update, why are you now trying to read word values from socket if you wanted to read the whole 512B packet before ? Have you ever seen my answer and understood what is for (by the last update, I've modified the byte order for word values) ? — TLama
@Tlama yet why u did that order reversal that tedious explicit way ? docwiki.embarcadero.com/Libraries/XE2/en/System.Swap — Arioch 'The

TLama TLama · Accepted Answer · 2012-12-13T00:58:57

It's hard to answer you, unless you precisely describe what's written in documentation you have. So far we know that your 512B packet consists from 6 words and 10x50B strings. So, take this just as starting point, until you tell us more:

procedure TForm1.Button1Click(Sender: TObject);
var
  I: Integer;
  Buffer: TBytes;
  WordArray: array[0..5] of Word;
  StringArray: array[0..9] of AnsiString;
begin
  if IdTCPClient1.IOHandler.InputBufferIsEmpty then
  begin
    if IdTCPClient1.IOHandler.CheckForDataOnSource(1000) then
      IdTCPClient1.IOHandler.ReadBytes(Buffer, 512, False);

    for I := 0 to High(WordArray) do
    begin
      WordRec(WordArray[I]).Hi := Buffer[I * 2];
      WordRec(WordArray[I]).Lo := Buffer[I * 2 + 1];
    end;
    for I := 0 to High(StringArray) do
      SetString(StringArray[I], PAnsiChar(@Buffer[I * 50 + 12]), 50);

    // here you have the arrays prepared to be processed
  end;
end;

How to read all bytes from server using Indy Client in Delphi?

2 Answers