Most spiders are based around an array used as a queue. You push the first (set of) urls onto the queue and then start the spider, it pulls a url off the queue, fetches it, extracts any links and pushes them onto the queue and loops.

To support retries, instead of pushing just the url, push a url/count pair. Either as an anon array 

push @urls, [ $tries, $url ];

[download]

Or you could concatenate them into a string if lots of 2-element arrays proves to be a memory problem.

Preset $tries to 3 or 5 or whatever, and each time you fail, decrement the count and push it back on the queue if it hasn't reached 0 yet. When it reaches 0 give up and report the failure.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco.
Rule 1 has a caveat! -- Who broke the cabal?

In reply to Re: catching failures and retrying by BrowserUk
in thread catching failures and retrying by mickey

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