Re^3: handling WWW::Mechanize Error GETing

Hi,

Using if($@) is unreliable,

The correct pattern is

$temp = eval { $mech->get($imgsrc) };
if( not $temp ){
...
}
[download]

But we're using mech so we dont need to store the response in $temp

So even better

eval { $mech->get( $imgsrc ); };
if( not $mech->res->is_success ){
    ...
}
[download]

Or even better


if( not eval { $mech->get( $imgsrc ); 1 } ){
    ...
}
[download]

Or simply the generic version , it doesn't rely on $@

eval { $mech->get( $imgsrc ); 1 }
    or do {
        ...
};
[download]

For explanation why using if($@) is unreliable see Devel::EvalError -- Reliably detect if and why eval() failed

Comment on Re^3: handling WWW::Mechanize Error GETing Select or Download Code

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Re^4: handling WWW::Mechanize Error GETing by haukex (Archbishop) on Dec 29, 2016 at 11:25 UTC
Hi, In general you are right about `eval { ...; 1 } or do { ... }` being better than `eval { ... }; if ($@) { ... }`, however note this `eval { $mech->get( $imgsrc ); }; if( not $mech->res->is_success ){ ... }` [download] is quite different from all the other snippets of code so far: it only checks `$mech->res->is_success`, as opposed to all the other examples which would report any error inside an eval, so personally I'd recommend those other patterns over this particular example. Regards, -- Hauke D	[reply] [d/l] [select]
Re^5: handling WWW::Mechanize Error GETing by Anonymous Monk on Dec 29, 2016 at 21:59 UTC
:) All the code is incomplete , none reports any errors `"# alert the error"` is a comment, $mech contains all the parts needed to make up the error message ... but the OP just wanted to avoid dying and give it another url, so :)	[reply] [d/l]