Error: Send buffer full, try again later
lazarus / 38-Networking and Web Programming

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Awesome Programmer · 2017-04-14 15:26

Hello, I wrote a min program that is suppose to send files, but it is
telling me, "Error: Send buffer full, try again later." I am not sure
why. Here is the code that sends file.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i const 
BufferSize = 1024;var  Fs: TFileStream;  TotalCount: Integer;  Buffer:
Pointer;  BytesToRead: Integer;  begin  Fs :=
TFileStream.Create('pathtoyourfile', fmOpenRead or fmshareDenyWrite); 
try    TotalCount := 0;    GetMem(Buffer, BufferSize);    repeat     
if TotalCount + BufferSize > Fs.Size then        BytesToRead :=
FS.Size - TotalCount      else        BytesToRead := BufferSize;     
Fs.Read(Buffer^, BytesToRead);      aSocket.Send(Buffer, BufferSize); 
    TotalCount := TotalCount + BytesToRead;    until TotalCount >=
FS.Size;    FreeMem(Buffer);  finally    Fs.Free;  end;              
  end;
Any hints or help will be greatly appreciated.

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wp · 2017-04-14 15:43

Nobody can help you if you don't tell us what FCon is.

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Awesome Programmer · 2017-04-14 15:52

Sorry....
FCon is actually the socket. I corrected the code above.

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howardpc · 2017-04-14 16:14

Does it help if you change the repeat until condition to this?
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i until
(TotalCount >= FS.Size) or (BytesToRead < BufferSize);

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Awesome Programmer · 2017-04-17 14:07

I am still getting the same error - Error: Send Buffer full try again
later - by the server or the host.

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balazsszekely · 2017-04-17 14:58

What is your platform? Lazarus/FPC version? What component? LNet,
Indy, Syanpse? It looks like you copied this code:
http://forum.lazarus.freepascal.org/index.php/topic,35272.msg233478.ht
ml#msg233478
which was a hypothetical example, I don't think will work in real
life, however you can find working code below, if lnet is what are you
after: http://forum.lazarus.freepascal.org/index.php/topic,35272.msg23
3630.html#msg233630

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Remy Lebeau · 2017-04-17 16:35

Quote from: reltek on April 14, 2017, 05:26:24 pmCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
aSocket.Send(Buffer, BufferSize);
Using BufferSize when calling Send() is wrong.  You need to use
BytesToRead instead.  Actually, you should be using the return value
of TFileStream.Read() instead, eg:

Code: [Select]const
  BufferSize = 1024;
var
  Fs: TFileStream;
  Buffer: Pointer;
  BytesRead: Integer; 
begin
  Fs := TFileStream.Create('pathtoyourfile', fmOpenRead or
fmshareDenyWrite);
  try
    GetMem(Buffer, BufferSize);
    try
      repeat
        BytesRead := Fs.Read(Buffer^, BufferSize);
        if BytesRead <= 0 then Break;
        aSocket.Send(Buffer, BytesRead);
      until False;
    finally
      FreeMem(Buffer);
    end;
  finally
    Fs.Free;
  end;                 
end;

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Awesome Programmer · 2017-04-19 15:06

Quote from: Remy Lebeau on April 17, 2017, 06:35:14 pmQuote from:
reltek on April 14, 2017, 05:26:24 pmCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
aSocket.Send(Buffer, BufferSize);
Using BufferSize when calling Send() is wrong.  You need to use
BytesToRead instead.  Actually, you should be using the return value
of TFileStream.Read() instead, eg:

Code: [Select]const
  BufferSize = 1024;
var
  Fs: TFileStream;
  Buffer: Pointer;
  BytesRead: Integer; 
begin
  Fs := TFileStream.Create('pathtoyourfile', fmOpenRead or
fmshareDenyWrite);
  try
    GetMem(Buffer, BufferSize);
    try
      repeat
        BytesRead := Fs.Read(Buffer^, BufferSize);
        if BytesRead <= 0 then Break;
        aSocket.Send(Buffer, BytesRead);
      until False;
    finally
      FreeMem(Buffer);
    end;
  finally
    Fs.Free;
  end;                 
end;

Hi Remy. Thank you for that awesome sample code. I was wondering if
you could also show me how you would do the receiving of the file. I
just want to make sure I am doing it right. Thank you.

Here is my code:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
constBufferSize = 1024;var  Fs: TFileStream;  Buffer: Pointer; 
ReadBytes:Integer;  Fnet : TLConnection;begin fs :=
TFileStream.Create('local file name', fmCreate);   try 
 GetMem(Buffer, BufferSize);      while True do   begin     
 ReadBytes := fNet.Get(Buffer, BufferSize);              if (ReadBytes
= 0) then            break       else            fs.write(Buffer,
ReadBytes);              Application.ProcessMessages;       Sleep(1); 
 end;  Finally   fs.free;   freemem(Buffer);  end;end;

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Remy Lebeau · 2017-04-19 17:58

Quote from: reltek on April 19, 2017, 05:06:56 pmI was wondering if
you could also show me how you would do the receiving of the file. I
just want to make sure I am doing it right.

The sender needs to indicate when the file is finished so the receiver
knows when to stop reading.  There are only two ways to do that
reliably - close the connection at the end of the file, or else send
the file size before sending the file data.  Your current code expects
the first, but the second is preferred instead, eg:

Code: [Select]procedure sendRaw(Fnet: TLConnection; var Buffer;
BufferSize: Integer);
var
  Ptr: PByte;
  NumSent: Integer;
begin
  Ptr := PByte(@Buffer);
  while BufferSize > 0 do
  begin
    NumSent := Fnet.Send(Ptr, BufferSize);
    if NumSent <= 0 then raise Exception.Create('socket send error');
    Inc(Ptr, NumSent);
    Dec(BufferSize, NumSent);
  end;
end;

...

const
  BufferSize = 1024;
var
  Fs: TFileStream;
  FileSize, FileSizeTmp: Int64;
  Buffer: Pointer;
  BytesRead: Integer; 
  Fnet: TLConnection;
begin
  Fnet := ...;
  Fs := TFileStream.Create('pathtoyourfile', fmOpenRead or
fmshareDenyWrite);
  try
    FileSize := Fs.Size;

    // you may have to find a 3rd party implementation
    // of htonll(), or implement it manually...
    FileSizeTmp = htonll(FileSizeTmp);
    sendRaw(Fnet, FileSizeTmp, sizeof(FileSizeTmp));

    if FileSize > 0 then
    begin
      GetMem(Buffer, BufferSize);
      try
        repeat
          if FileSize > BufferSize then
            BytesRead := BufferSize
          else
            BytesRead := Integer(FileSize);
          BytesRead := Fs.Read(Buffer^, BytesRead);
          if BytesRead <= 0 then raise Exception.Create('file read
error');
          sendRaw(Fnet, Buffer, BytesRead);
          Dec(FileSize, BytesRead);
        until FileSize = 0;
      finally
        FreeMem(Buffer);
      end;
    end;
  finally
    Fs.Free;
  end;                 
end;

Code: [Select]procedure readRaw(Fnet: TLConnection; var Buffer;
BufferSize: Integer);
var
  Ptr: PByte;
  NumRead: Integer;
begin
  Ptr := PByte(@Buffer);
  while BufferSize > 0 do
  begin
    NumRead := Fnet.Get(Ptr, BufferSize);
    if NumRead <= 0 then raise Exception.Create('socket read error');
    Inc(Ptr, NumRead);
    Dec(BufferSize, NumRead);
  end;
end;

...

const
  BufferSize = 1024;
var
  Fs: TFileStream;
  FileSize: Int64;
  Buffer: Pointer;
  ReadBytes: Integer;
  Fnet: TLConnection;
begin
  Fnet := ...;
  Fs := TFileStream.Create('local file name', fmCreate);
  try
    readRaw(Fnet, FileSize, sizeof(FileSize));

    // you may have to find a 3rd party implementation
    // of ntohll(), or implement it manually...
    FileSize := ntohll(FileSize);

    if FileSize > 0 then
    begin
      GetMem(Buffer, BufferSize);
      try
        repeat
          if FileSize > BufferSize then
            ReadBytes := BufferSize
          else
            ReadBytes := Integer(FileSize);
          readRaw(Fnet, Buffer, ReadBytes);
          Fs.WriteBuffer(Buffer^, ReadBytes);
          Dec(FileSize, ReadBytes);
        until FileSize = 0;
      finally
        FreeMem(Buffer);
      end;
    end;
  finally
    Fs.free;
  end;
end;

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Awesome Programmer · 2017-04-19 20:38

Thank you so much, Remi.