PHP Random Sleep Function with Flush

Jun 9, 2008 · 1 minute read
Category: php scraping

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Sometimes you want your script to pause for a short period of time before repeating a loop or proceeding to the next step. This may be to reduce server load or even to simulate the natural pauses that a person would make whilst browsing a site. This kind of thing is especially true if you are building a system to scrape content such as product information from a suppliers web site and you do not want to hammer their server to death and get your IP banned.

 function sleep_flush($chunks=10){

    $c=0;

    while($c < $chunks){

        $rand = rand(2000000, 6000000);

        echo '<br> . . . sleeping for ' . round(($rand / 1000000),2) . ' seconds . . . zzzzzzzzzzzzzz<br>';

        flush();

        usleep($rand);

        $c++;

    }

}

This function will do just that for you. Also it has a built in flush which will help in preventing the script from being regarded as timed out if you are running it from the web browser.