Using IdHTTP

[giomach 1]

I'm likely to have further elementary questions about IdHTTP, so if someone can recommend a reference on using it to access REST in the context of Delphi (and preferably a written reference rather than a video), that might save time and bother.

 

Meanwhile, here's my first simple question.

 

The Delphi statement

                            s := IdHTTP1.Get (url+filename);

where s is a string successfully fetches data from a remote server.

But when the remote file is actually a sound file, having it in a string is not much use to me.

How can I get it into a sound file on my local machine?

 

Thanks in advance for your advice.
 

 

[ioan 45]

Try something like this:

 

var
  s: TStream;
begin
  s := TFileStream.Create('soundfile.mp3', fmCreate);
  try
    IdHttp1.Get(your_file_url, s);
  finally
    s.Free;
  end;
end;

 

[giomach 1]

Thanks Ioan, that worked great.

 

My next question to all 🙂  Many of the files I'll be looking for will not exist on the server.  Is there a way to test for the existence of a remote file without actually trying to download it, and importantly would that be quicker than what I'm doing, which is trying to download and checking whether the size is non-zero?  (I will treat a non-existing remote file and an existing file of zero size in the same way, so I don't need to distinguish those two cases.)

Edited March 23 by giomach
spelling correction

[Remy Lebeau 1436]

4 hours ago, giomach said:

Is there a way to test for the existence of a remote file without actually trying to download it

Yes - use TIdHTTP.Head() instead of TIdHTTP.Get().  A HEAD request is identical to a GET request except that no body data is sent, but the response headers will be the same.

4 hours ago, giomach said:

and importantly would that be quicker than what I'm doing, which is trying to download and checking whether the size is non-zero?  (I will treat a non-existing remote file and an existing file of zero size in the same way, so I don't need to distinguish those two cases.)

A HEAD response will include the 'Content-Length' header, so yes, you can determine the file's size without actually downloading the file.

 

However, if you are going to download the file anyway then there is really no point in checking for its existence beforehand, just download the file and handle whatever error may arise, such as HTTP 404 when the file does not exist.

[giomach 1]

Many thanks!