Mohammed Nasman Mohammed Nasman - 1 month ago 19
HTTP Question

What's the simplest way to call Http GET url using Delphi?

There's a web services I want to call in my application, I can use it with importing the WSDL or by just use "HTTP GET" with the URL and parameters, so I prefer the later because it's simple thing.

I know I can use indy idhttp.get, to do the job, but this is very simple thing and I don't want to add complex indy code to my application.

UPDATE: sorry if I was not clear, I meant by "not to add complex indy code", that I don't want add indy components for just this simple task, and prefer more lighter way for that.

Answer

You could use the WinINet API like this:

uses WinInet;

function GetUrlContent(const Url: string): string;
var
  NetHandle: HINTERNET;
  UrlHandle: HINTERNET;
  Buffer: array[0..1024] of Char;
  BytesRead: dWord;
begin
  Result := '';
  NetHandle := InternetOpen('Delphi 5.x', INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);

  if Assigned(NetHandle) then 
  begin
    UrlHandle := InternetOpenUrl(NetHandle, PChar(Url), nil, 0, INTERNET_FLAG_RELOAD, 0);

    if Assigned(UrlHandle) then
      { UrlHandle valid? Proceed with download }
    begin
      FillChar(Buffer, SizeOf(Buffer), 0);
      repeat
        Result := Result + Buffer;
        FillChar(Buffer, SizeOf(Buffer), 0);
        InternetReadFile(UrlHandle, @Buffer, SizeOf(Buffer), BytesRead);
      until BytesRead = 0;
      InternetCloseHandle(UrlHandle);
    end
    else
      { UrlHandle is not valid. Raise an exception. }
      raise Exception.CreateFmt('Cannot open URL %s', [Url]);

    InternetCloseHandle(NetHandle);
  end
  else
    { NetHandle is not valid. Raise an exception }
    raise Exception.Create('Unable to initialize Wininet');
end;

source: http://www.scalabium.com/faq/dct0080.htm

The WinINet API uses the same stuff InternetExplorer is using so you also get any connection and proxy settings set by InternetExplorer for free.