[SOLVED] LNet, synapse or other way - How to simply make a http file
download?
lazarus / 38-Networking and Web Programming

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lazguy · 2010-07-07 17:39

Hello everybody!!!

I need to download a .zip file, a .pdf file and a text file from
different http addresses on internet.

I downloaded LNet component but there is no example showing me how to
do this I need.
I also downloaded Synapse component but I found the help confused and
without examples, so i got confused.

I'm looking from something as simple as

httpfiledownload('http://somesite.com/somefile.zip','c:\somefolder\som
efile.zip')

that work both from windows and linux, and, if possible, with no need
of any external libraries or files.

If possible, if someone can post the code to do that i will be very
thank.


Thank you very much in advance.

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Laksen · 2010-07-07 17:56

Using synapse you could use something like this:

Include httpsend and classes in the uses list
Code: [Select]procedure DownloadFile(const Url, PathToSaveTo: string);
begin
   fs := TFileStream.Create(PathToSaveTo, fmOpenWrite or fmCreate);
   try
      HttpGetBinary(Url, fs);
   finally
      fs.Free;
   end;
end;

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lazguy · 2010-07-08 02:23

Thank you very, very much Laksen !!!!!!!!!!!!

it is exactly what i need!!!

Problem Solved.

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Almindor · 2010-07-10 12:00

In lNet you can use lnet/examples/console/lhttp/fpget

which is exactly like wget (less sophisticated but you get the point).
I guess you missed it?

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Lazaruszki · 2010-07-21 08:14

Hi,

I use Synaps and this code (Lasken) for file download, but i can't use
downloadsize value(httpsend.downloadsize) for progressbar at download
time.

What is the solution? Need i use multithread? ...or another

If somebody can give an working example,  i will be very thank, too.

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theo · 2010-07-21 13:57

You need to process OnStatus:

http://synapse.ararat.cz/doku.php/public:howto:onstatus

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Lazaruszki · 2010-07-23 22:42

Hi Theo,

I try everything and searching with google but the result is pffffffff

Here is my full unit code, if you have a lot of time correct it,
please:) .

I like write a program that download setup.exe via http and drawing  a
progressbar.

I have 3 errors...

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
   Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics,
Dialogs,
  StdCtrls, ExtCtrls, Buttons, ComCtrls, ExtDlgs, EditBtn, FileCtrl,
  httpsend,blcksock,typinfo, synamisc;

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    lblout: TLabel;
    Lblin: TLabel;
    Memo2: TMemo;
    ProgressBar1: TProgressBar;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ProgressBar1ContextPopup(Sender: TObject; MousePos:
TPoint;
      var Handled: Boolean);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;
  SizeIn,SizeOut: integer;
implementation

{ TForm1 }


type

  THookSocketStatus = procedure(Sender: TObject; Reason:
THookSocketReason;
    const Value: string) of object;

  TMemory=pointer;
   callback = class
       class procedure Status (Sender: TObject; Reason:
THookSocketReason;
const Value: String);
       class procedure Monitor (Sender: TObject; Writing: Boolean;
const
Buffer: TMemory; Len: Integer);
     end;


class procedure callback.Status(Sender: TObject; Reason:
THookSocketReason;
  const Value: String);
var v: String;
begin

  v := getEnumName (typeinfo(THookSocketReason), integer(Reason)) + '
' +
Value;

  Form1.Memo2.Lines.Add(v);

  if (reason=hr_readcount) then begin
                           inc(SizeIN,StrToInt64Def(Value,0));
                         //  ProgressBar1.Position := Round(1000 *
(CurrentBytes / TotalBytes));
                           end;
  if (reason=hr_writecount) then
     inc(SizeOUT,StrToInt64Def(Value,0));

  Form1.lblIN.Caption :=inttostr(SizeIN);
  Form1.lblOUT.Caption:=inttostr(SizeOUT);

  application.ProcessMessages;

end;

class procedure callback.Monitor (Sender: TObject; Writing: Boolean;
const
Buffer: TMemory; Len: Integer);
begin
  if not writing then
     inc(SizeIN, Len)
  else
     inc(SizeOUT, Len);

  Form1.lblIN.Caption :=inttostr(SizeIN);
  Form1.lblOUT.Caption:=inttostr(SizeOUT);

  application.ProcessMessages;

end;


procedure TForm1.Button1Click(Sender: TObject);

   var
  HTTP: THTTPSend;
  F: TFileStream;
  Start,Size: integer;
begin
  SizeIN:=0;
  SizeOUT:=0;

  Memo2.Lines.Add(CRLF+'GET');
  Memo2.Lines.Add('------------');

  Size:=HttpGetFileSize(Edit1.text); ///  ???

  HTTP := THTTPSend.Create;
  HTTP.Sock.OnStatus := callback.Status;

  //or
  HTTP.Sock.OnMonitor := callback.Monitor;


     F:=TFileStream.Create('hl.exe',fmcreate);

     HttpGetBinary('http://.../upgrade.exe',F);

     F.Free;



end;

procedure TForm1.FormCreate(Sender: TObject);
begin

end;

procedure TForm1.ProgressBar1ContextPopup(Sender: TObject; MousePos:
TPoint;
  var Handled: Boolean);
begin

end;

initialization
  {$I unit1.lrs}

end.

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Silvio Clécio · 2010-07-23 23:29

Try this:

http://lazarus-br.googlegroups.com/web/DownloadResumeSynapse.7z

Good luck.

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evoshroom · 2012-08-08 15:41

I just wanted to say, this thread delivers!

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Fahmy Rofiq · 2012-10-30 05:25

Quote from: silvioprog on July 24, 2010, 01:29:59 amTry this:

http://lazarus-br.googlegroups.com/web/DownloadResumeSynapse.7z

Good luck.

I can't download it, can you reupload please?

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Silvio Clécio · 2012-11-01 00:50

Please see other demo for resuming download in LazSolutions framework:

https://github.com/silvioprog/lazsolutions

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delphi887 · 2012-11-26 19:16

hi
how do if i want get a file in multi connection in multi part and then
join this parts to create file by synapse???
thanks