[WORKAROUND] TFPHTTPClient.Put(...) not working
lazarus / 38-Networking and Web Programming

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eny · 2015-09-03 13:23

When using the methods FORMPOST(...), DELETE(...) or GET(...) from
TFPHTTPClient there is no problem.
However when using PUT the program blocks.
Has anyone ever used this and got it working?

It can be easily tested with the 2 examples in the fcl-web folder.
- compile and run httpserver\simplehttpserver.exe
- in program httpclient\httppost, change line
"FormPost(ParamStr(1),vars,f);" to "put(Paramstr(1), vars);"
- run the the program - it blocks (the original line with FormPost()
does work).

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derek.john.evans · 2015-09-03 14:17

I just tested it, and accidentally caused a "block", and lost a file
while doing so.

With FormPost(), the filename is opened for reading: ie:
Code: [Select]TFileStream.Create(AFileName,fmOpenRead or
fmShareDenyWrite); 
With Put, LocalFileName is actually the response, not a file to be
sent. ie:
Code: [Select]F:=TFileStream.Create(LocalFileName,fmCreate);   
Which is kinda odd to me. Indy has:
Code: [Select]procedure Put(AURL: string; ASource, AResponseContent:
TStream); overload; 
Which is what I thought a PUT was.

Anyway, it looks like fphttpclient doesn't have a working PUT. As for
your block. I selected a file that was locked by Lazarus, and I got a
block, until I closed Lazarus, and bingo, my file was cleared.

I think you need to use Indy or Synapse if you want a PUT.

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Leledumbo · 2015-09-03 17:15

Quote from: derek.john.evans on September 03, 2015, 04:17:28 pmI think
you need to use Indy or Synapse if you want a PUT.
Reporting it to the bugtracker is a wise thing to do, too.

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derek.john.evans · 2015-09-03 17:31

Quote from: Leledumbo on September 03, 2015, 07:15:41 pmReporting it
to the bugtracker is a wise thing to do, too.

yaa. I'm getting there   Only just got a SVN version of FP/Lazarus
setup yesterday, so now I can confirm if a issue is still there.

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eny · 2015-09-04 12:20

I dug a bit deeper and found a maze of overloaded methods, duplicated
code and functional errors in method definitions: the problem is that
PUT does not allow request body data while it should (like the POST
does). Because of this the property RequestBody does not have a value
and that blocks the http traffic. Probably making the server wait for
data.

The workaround: assign a valid stream handle to RequestBody before the
call.
Something like:Code: [Select]var hc: TFPHttpClient;
    ss: TStringStream;
begin
  hc := TFPHttpClient.Create(nil);
  ss := TStringStream.Create('');  // Bug in TStringStream: it does
not have a parameterless constructor
  ....
  ss.Position := 0;        // be sure to be sure
  hc.RequestBody := ss;
  hc.Put('http://my.put.url');
  ..
  ss.Free;
  hc.Free;
end;

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derek.john.evans · 2015-09-04 12:26

Cool   Good to know.

God, I must be blind! The comment for Put is:
// Put URL, and Requestbody. Return response in Stream, File,
TstringList or String;  

I guess I didn't know there was a field called Requestbody. O, the
shame!