Hello,

I'm developping a tiny app with Redis (some kind of noSQL database) as storage back-end. Redis.pm (http://search.cpan.org/~melo/Redis-1.904/lib/Redis.pm) is fairly cool, however, I would like to protect Redis methods with eval{}, to be able to handle situations on which the Redis server disappears, and so on.

My first idea was to create a new class, let's say SRedis, that inherits from Redis :

package SRedis ;
our @ISA = qw(Redis) ;

[download]
As I'm a lazy boy, I just want to handle all original Redis methods with an AUTOLOAD method on my SRedis package. Code looks like this : 

## Wonderful catch-all
## Input  : Nothing
## Output : Asked data 
sub AUTOLOAD {
    # Input variables
    my ($instance_ref) = shift(@_) ;

    # Internal vars
    $tries = 0 ;

    # Determine initially called sub
    my $command = $AUTOLOAD ;
    
    # Format it to call corresponding method on Redis package
    $command =~ s/.*:// ;
    $command = 'SUPER::' . $command ;
    
    TRY:while($tries < $maxtries) {
        # Go on
        $errorcode = eval {@results = $instance_ref->$command(@_)} ;
        
        # Did it went well ?
        if(!defined($errorcode)) {
            # No - I should log something here
            
            # Update count
            $tries++ ;
            
            # Wait a little bit ?
            sleep(1) ;
            
            # Go back to work
            next TRY;
            }
            
        # Otherwise that's cool
        last TRY;            
        }
        
    # Return data
    return (@results) ;
    }

[download]

My problem is that I don't know what kind of data the original command may return. Could be a scalar, an array or a hash. In this piece of code, I assume that the command returns an array.

How can I handle any kind of return in the eval, and make AUTOLOAD return it correctly to the initial caller ?

Thank you in advance for your advices.

In reply to How to protect Redis calls with eval ? by leoboy

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