[SOLVED] synapse: how to get a timeout for http-downloads to work?

[Hartmut]

My program shall download a website with synapse. Sometimes this website is not available. Then my code runs into a timeout of 130 seconds, which is too much. I want a timeout of max. 4 seconds.

Here is a demo of my code from a bigger program:

Code: Pascal  [Select][+][-]

1. {$mode objfpc}{$H+}
2.  
3. uses sysutils, classes, httpsend;
4.  
5. const URL = 'http://xxx.yyy.com';
6.  
7. function myHttpGetText(url: string; HTTP: THTTPSend; var SL: TStringList): boolean;
8.    {loads URL 'url' from a Webserver into a StringList}
9.    var ok: boolean;
10.    begin
11.    ok:=false;
12.    SL:=TStringList.Create;
13.    HTTP.Clear; {Reset headers, document and Mimetype}
14.  
15.    if HTTP.HTTPMethod('GET',url) then
16.        begin
17.        SL.LoadFromStream(HTTP.Document);
18.        ok:=true;
19.        end;
20.    exit(ok);
21.    end;
22.  
23. function download_Website(url: string; var SL: TStringList): boolean;
24.    var HTTP: THTTPSend;
25.        ok: boolean;
26.    begin
27.    HTTP:=THTTPSend.Create;
28.    HTTP.Timeout:=4000;
29.    HTTP.Sock.SetTimeout(4000);
30.    ok:=myHttpGetText(url, HTTP, SL);
31.    HTTP.Free;
32.    exit(ok);
33.    end;
34.  
35. var SL: TStringList;
36.     t: TDateTime;
37.     sec: double;
38.     ok: boolean;
39.  
40. begin
41. t:=now;
42. ok:=download_Website(URL, SL);
43. sec:=(now-t)*86400.0; {time in seconds}
44. writeln('Time: ', sec:0:2, ' seconds');
45.  
46. if not ok then writeln('ERROR') else writeln(SL.Text);
47. SL.Free;
48. end.

I use FPC 3.2.0 on Linux Ubuntu 18.04 with synapse stable version 40 and trunk r266 (both have the same result).

What I'm doing wrong? Thanks in advance.

[balazsszekely]

@Hartmut
On windows immediately returns with the message "Error". I don't have to wait even 4 seconds.

[Hartmut]

Thank you GetMem for your reply. Yes, if the URL does not exist at all, then immediately "ERROR" is returned. But with my real URL - if it is currently unavailable - then I have a timeout of 130 seconds, which is too long for me.

[rvk]

You probably want to set HTTP.Sock.ConnectionTimeout to whatever you want.

See my post here:

Sorry, I spoke too soon. What is said above still holds but the connect timeout was discussed on the Synapse list in 2012 and the non-blockingmode (which is mentioned above) was implemented in revision #160.

You also need to set the HTTPSender.Sock.ConnectionTimeout which handles the Connect timeout in non-blockingmode after which the socket is switched back to blocking mode.

Example:

Code: Pascal  [Select][+][-]

1. const
2.   URL = '10.255.255.1'; // <-- this is always non response
3. var
4.   HTTPSender: THTTPSend;
5.   HTTPGetResult: boolean;
6.   Tm: TDateTime;
7. begin
8.   HTTPSender := THTTPSend.Create;
9.   try
10.     HTTPSender.Timeout := 1 * 1000;
11.     HTTPSender.Sock.ConnectionTimeout := 1 * 1000;
12.     Tm := Now;
13.     HTTPGetResult := HTTPSender.HTTPMethod('GET', URL);
14.     Tm := Now - Tm;
15.     ShowMessage(Format('%d: done in %.3f seconds', [HTTPSender.ResultCode, Tm * 24 * 60 * 60]));
16.   finally
17.     HTTPSender.Free;
18.   end;
19. end;

PS. When ConnectionTimeOut > 0 then Synapse will connect in non-blocking mode.
In blocking mode (the default) there is no way to set the timeout.
See http://www.ararat.cz/synapse/doku.php/public:howto:connecttimeout

[Hartmut]

Great! 'HTTPSender.Sock.ConnectionTimeout' works perfectly. Thanks a lot rvk.
Again I like synapse and it's capabilities.