http://www.perlmonks.org?node_id=621102

Inspired by Develop your own weather maps and alerts with Perl and GD, I have put together a script which downloads the base radar image from a specific site at a specified interval. 
use strict;
use LWP::Simple;
use POSIX;


my $refresh = 1800;

do {



    my $base="http://radar.weather.gov/ridge/RadarImg/N0R/MTX_N0R_0.gi
+f";
    
    my $timestring = strftime( "%Y%m%d_%H%M%S", gmtime() );

    

    my $savefilename = "SLCRadar_".$timestring.".gif";
    my $status = getstore($base,$savefilename);
        print $status."\n" ;


sleep $refresh;

} while ($refresh);

[download]
See my Standard Code Disclaimer

Replies are listed 'Best First'.
Re: Automated downloading of NOAA radar images
by merlyn (Sage) on Jun 13, 2007 at 23:28 UTC
    I don't see $refresh changing in the loop, so I'm not sure why you have a do-while $refresh. If you just want an infinite loop, a naked block with a redo at the end will do nice.

    -- Randal L. Schwartz, Perl hacker

[reply]
      Thanks for the tip, merlyn, I have "refactored" my code as follows:

      use strict;
use LWP::Simple;
use POSIX;


my $refresh = 1800;

{
&imagegrab;
sleep $refresh;
redo;
}




sub imagegrab     {
    my $base="http://radar.weather.gov/ridge/RadarImg/N0R/MTX_N0R_0.gi
+f";
    
    my $timestring = strftime( "%Y%m%d_%H%M%S", gmtime() );

    

    my $savefilename = "SLCRadar_".$timestring.".gif";
    my $status = getstore($base,$savefilename);
        print $status."\n" ;

        }

      [download]

      It does seem a cleaner way to handle this...
      See my Standard Code Disclaimer
[reply]
[d/l]
      I know it doesn't really matter in this case but generally speaking isn't a while(1) block a better choice for infinite looping? I would think performance would be the same (I assume a while block collapses down to a naked-redo block) which leaves code readability. And letting the reader know at the beginning of the block that it's an infinite loop is a lot better than forcing the reader to wade through several lines of code before discovering that. Is that a good assessment or am I missing something?
[reply]

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