Perl Catch Variable in Error

Question

I have a Perl script and I am trying to make it print out the value for $article when it errors. The script looks like:

eval{
    for my $article($output =~ m/<value lang_id="">(.*?)<\/value>/g)
    { 
        $article =~ s/ /+/g;
        $agent->get("someurl");

        $agent->follow_link(url_regex => qr/(?i:pdf)/ );

        my $pdf_data = $agent->content;
        open my $ofh, '>:raw', "$article.pdf"
        or die "Could not write: $!";
        print {$ofh} $pdf_data;
        close $ofh;
        sleep 10;
    }
};
if($@){
    print "error: ...: $@\n";
}

So if there is no .pdf file the code sends an error which is what I want. But what I need to know is it somehow possible to get the name of the $article that caused the error? I was trying to use some kind of global variable with no luck.

Cornel Ghiban · Accepted Answer · 2012-01-18 20:11:19Z

4

Why don't you put the eval inside the for loop? Something like this:

for my $article($output =~ m/<value lang_id="">(.*?)<\/value>/g)
{ 
   $article =~ s/ /+/g;
   eval{
      # ...
   }
   if ($@) {
      print STDERR "Error handling article: ", $article, " ", $!, "\n";
   }
}

answered Jan 18, 2012 at 20:11

Cornel Ghiban

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5 Comments

chrstahl89 Over a year ago

For some reason when I do that it prints every pdf not just the ones equal to $article from the for loop

Ilmari Karonen Over a year ago

ITYM print STDERR "Error handling article $article: $@\n"; (not $!). And you can use warn instead of print STDERR. But in general, this should work; if it doesn't work for @chrstahl89, the problem is probably somewhere inside the eval.

Ilmari Karonen Over a year ago

@chrstahl89: Can you post the actual code that "prints every pdf"?

chrstahl89 Over a year ago

Posted it to my original question

chrstahl89 Over a year ago

It was my code that was wrong in another part, this was the correct solution I just did not know it at the time. Thanks!

Ilmari Karonen · Accepted Answer · 2012-01-18 21:02:57Z

1

If that's your only problem, just declare my $article; before the eval, and remove the my from the for loop. But from your reply to Cornel Ghiban, I suspect it isn't.

answered Jan 18, 2012 at 21:02

Ilmari Karonen

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Comments

JRFerguson · Accepted Answer · 2012-01-18 20:15:48Z

0

Include the file name in the die>/ string:

open my $ofh, '>:raw', "$article.pdf" or die "Could not write '$article': $!";

I assume that you want to write and not read. Unless you have a permission issue or a full file system, a write is likely to succeed and you will never see an error.

answered Jan 18, 2012 at 20:15

JRFerguson

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3 Comments

chrstahl89 Over a year ago

This will not work because the error is from getting the link, it never goes to write.

JRFerguson Over a year ago

That wasn't clear to me in your original question. That said, follow-link returns undef when the page has no links or the link can;t be found. You could throw an exception for that.

chrstahl89 Over a year ago

I think that will be the answer, just have to figure out how to throw an error for that. Well catch the error...it already throws it.

Dimanoid · Accepted Answer · 2012-01-20 14:28:02Z

0

Your script does not need to die, you can just set a flag or save message to the log or store error for late handling.

my @errors=();
................
open my $ofh, '>:raw', "$article.pdf" or do { push @errors,"$article: $!" };
if(-e $ofh) {
    # work with the file
}
................
if(@errors) {
    # do something
}

answered Jan 20, 2012 at 14:28

Dimanoid

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