comment on

This is a typical error, see Server error, see CGI Help Guide , Troubleshooting Perl CGI scripts, CGI::Carp, DebugCGI , CGI::Carp::Fatals

The checklists work, but here you go , first try

 #!/usr/bin/perl --
use strict;
use warnings;
use CGI ();
use CGI::Carp qw(fatalsToBrowser);
use JSON ();

my $q     = CGI->new;
my $data = $q->param('POSTDATA') ;
#~ my $data = $q->param('POSTDATA') || '{"a":100,"b":300}';

my $json  = JSON->new->utf8;
my $input = $json->decode( $data );
my $a = $input->{a};
my $b = $input->{b};
my $c = $a + $b;

print $q->header("application/json");
print $json->encode({ c => $c });
[download]

then try

 #!/usr/bin/perl --
use strict;
use warnings;
use CGI ();
use CGI::Carp qw(fatalsToBrowser);
use JSON ();

Main( @ARGV );
exit( 0 );
sub Main {
    binmode STDOUT;
    my $q  = CGI->new;
    my $cb = AddJsonGetBytes( $q );
    print $q->header("application/json"), $cb;
    return;
}
sub AddJsonGetBytes {
    my( $q ) = @_;
    my $data = $q->param('POSTDATA') ;
    my $json  = JSON->new->utf8;
    my $input = $json->decode( $data );
    my $a = $input->{a};
    my $b = $input->{b};
    my $c = $a + $b;
    return $json->encode({ c => $c });
}
[download]

then try

#!/usr/bin/perl --
use strict;
use warnings;
use CGI ();
use CGI::Carp qw(fatalsToBrowser);
use JSON ();

Main( @ARGV );
exit( 0 );
sub Main {
    binmode STDOUT;
    my $q  = CGI->new;
    my $cb = AddJsonGetBytes( $q );
    print $q->header("application/json"), $cb;
    return;
}
sub AddJsonGetBytes {
    my( $q ) = @_;
    my $json  = JSON->new->utf8;
    my $data = $q->param('POSTDATA') ;
    if( not defined $data ){
        return $json->encode({ error => 'no valid input' });
    }
    my $input = $json->decode( $data );
    my $a = $input->{a};
    my $b = $input->{b};
    my $c = $a + $b;
    return $json->encode({ c => $c });
}
[download]

then try

#!/usr/bin/perl --
use strict;
use warnings;
use CGI ();
use CGI::Carp qw(fatalsToBrowser);
use JSON ();

Main( @ARGV );
exit( 0 );
sub Main {
    binmode STDOUT;
    my $q  = CGI->new;
    my $json  = JSON->new->utf8;
    my $cb = AddJsonGetBytes( $q , $json );
    print $q->header("application/json"), $cb;
    return;
}
sub AddJsonGetBytes {
    my( $q, $json  ) = @_;
    my $data = $q->param('POSTDATA') ;
    if( not defined $data ){
        return $json->encode({ error => 'no valid input' });
    }
    my $input = $json->decode( $data );
    my $a = $input->{a};
    my $b = $input->{b};
    my $c = $a + $b;
    return $json->encode({ c => $c });
}
[download]

In reply to Re^7: json return value by Anonymous Monk
in thread json return value by stenasc

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