Read text file from HTTP URL

[Relative]

Hi Coders!

I can read simple txt file with this code:

Code: [Select]

program ReadFile;
uses
 Sysutils;
Var UserFile : Text;
    FileName, TFile : String;
Begin
  AssignFile(UserFile, 'File.txt');
  //AssignFile(UserFile, 'http://192.168.0.3/file.txt');
  Reset(UserFile);
  Repeat
    Readln(UserFile,TFile);
    Writeln(TFile);
  Until Eof(UserFile);
  Close(UserFile);
  Readln;
End.
But, how can I read file from http URL? If I try it, the program stop working.

Thank you!

Relative

[User137]

You are going to need to download the file first. At least for Delphi someone made a simple component HTTPGet, but i don't think it compiles with freepascal
http://www.utilmind.com/delphi2.html

Anyway, you need a unit/class that can download stuff.

[tomek]

There is http://wiki.lazarus.freepascal.org/Synapse

[Relative]

Thank you. I'm checking...

[Pascaluvr]

Try this simple routine:

Code: [Select]


function DownloadURL_NOCache(const aUrl: string;
                                   var s: String;
                                   Progress: cbProgressBar): Boolean;
Const
  sBUF  = 32000;  // 1024
var
   hSession: HINTERNET;
   hService: HINTERNET;
   lpBuffer: array[0..sBUF + 1] of Char;
   dwBytesRead: DWORD;
   i:           LongInt;
begin
   Result := False;
   s := '';
   i := 0;
   if Progress <> nil then
     Progress(aURL, i);
   // hSession := InternetOpen( 'MyApp', INTERNET_OPEN_TYPE_DIRECT, nil, nil, 0);
   hSession := InternetOpen('MyApp',
                            INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);
   try
     if Assigned(hSession) then
     begin
       hService := InternetOpenUrl(hSession, PChar(aUrl), nil, 0,
                                   INTERNET_FLAG_RELOAD, 0);
       if Assigned(hService) then
         try
           while True do
           begin
             dwBytesRead := sBuf;
             InternetReadFile(hService, @lpBuffer, sBUF, dwBytesRead);
             if dwBytesRead = 0 then break;
             lpBuffer[dwBytesRead] := #0;
             s := s + lpBuffer;
             I := i + 1;
             if i > 99 then i := 1;
             if Progress <> nil then
               Progress(aURL, i);
           end;
           Result := True;
         finally
           InternetCloseHandle(hService);
         end;
     end;
   finally
     InternetCloseHandle(hSession);
     if Progress <> nil then
       Progress(aURL, 99);
   end;
end;


[Relative]

Try this simple routine:

I get lot of error messages:

Code: [Select]

fxc_cloner_v036.pas(10,59) Error: Identifier not found "cbProgressBar"
fxc_cloner_v036.pas(14,23) Error: Identifier not found "HINTERNET"
fxc_cloner_v036.pas(14,23) Error: Error in type definition
fxc_cloner_v036.pas(15,23) Error: Identifier not found "HINTERNET"
fxc_cloner_v036.pas(15,23) Error: Error in type definition
fxc_cloner_v036.pas(23,16) Error: Operator is not overloaded
fxc_cloner_v036.pas(24,14) Error: Illegal expression
fxc_cloner_v036.pas(24,14) Fatal: Syntax error, ";" expected but "(" found

[Pascaluvr]

sorry, my bad

You will need wininet in the uses clause.

The progressbar references are a call back to another window that has a status bar ...  set to nil for now

[Relative]

Wininet done. It works.

But how do you mean: 'set to nil for now'?

Sorry, I'm a very beginner Pascal user.

[BigChimp]

Note: I don't think wininet will be cross-platform. If you want to have cross-platform support, look at e.g. synapse or lnet.

Set Bla to nil would be something like:

Code: [Select]

Bla:=nil;


[Pascaluvr]

Wininet done. It works.

But how do you mean: 'set to nil for now'?

Sorry, I'm a very beginner Pascal user.

Off to bed now... I will show you the progressBar code tomorrow.  Its not proportional to the the task ... just lets users know its working and not stalled.

[Relative]

Ok. Thank you in advance. Good night!

[joseme]

You can use Indy for this task, it may be simpler:

Code: [Select]

function TfrmActualiza.descargarActualizacion(OrigFile, DestFile: String): Boolean;
var f:tfilestream;
  IdHTTP1: TIdHTTP;
begin
  IdHTTP1 := TIdHTTP.Create(nil);
  f:=tfilestream.create(destFile, fmcreate);
  try
    idhttp1.head(origFile);   //To know if file exists
    idhttp1.get(origFile, f); // and retrieve it
  except
    ShowMessage('File '+origFile+' does not exist or is unretrievable');
    Result := False;
  end;
    freeandnil(f);
    IdHTTP1.Destroy;
end;


[Relative]

You can use Indy for this task, it may be simpler:

Could you help me please! How can I use this code? I got some error messages:

Code: [Select]

fxc_cloner_v037.pas(8,24) Error: Identifier not found "TfrmActualiza"
fxc_cloner_v037.pas(8,46) Error: class identifier expected
fxc_cloner_v037.pas(9,18) Error: Identifier not found "tfilestream"
fxc_cloner_v037.pas(9,18) Error: Error in type definition
fxc_cloner_v037.pas(10,19) Error: Identifier not found "TIdHTTP"
fxc_cloner_v037.pas(10,19) Error: Error in type definition
fxc_cloner_v037.pas(12,21) Error: Identifier not found "TIdHTTP"
fxc_cloner_v037.pas(13,17) Error: Identifier not found "tfilestream"
fxc_cloner_v037.pas(13,43) Error: Identifier not found "fmcreate"
fxc_cloner_v037.pas(15,13) Error: Illegal qualifier
fxc_cloner_v037.pas(16,13) Error: Illegal qualifier
fxc_cloner_v037.pas(18,16) Error: Identifier not found "ShowMessage"
fxc_cloner_v037.pas(22,13) Error: Illegal qualifier

[joseme]

That is because TfrmActualiza is the name of the form in my project, you should replace with your own form name. Also, you should add IdHTTP and FileUtils to the uses of your unit.

[Relative]

I added idHTTP to the uses and I got:

Code: [Select]

fxc_cloner_v037.pas(6,22) Fatal: Can't find unit IdHTTP used by fxc_cloner_v037