08c10-2.php

介绍PHP5的给类型函数应用

<?php
// We are going to be outputting a graphic so start with the proper headers
header('Content-type: image/jpeg');

// Register a shutdown function, so if we fail, the basic file is returned
function shutdown() {
    // If we never managed to read the file:
    if (!(isset($GLOBALS['data'])) || !($GLOBALS['data'])) {
        // Output the cached file, ensure a full absolute path:
        readfile(dirname(__FILE__) . '/hubble_news.cache');
    }
}
register_shutdown_function('shutdown');

// Set a quick timeout value so if we don't get it quickly it uses the cache
set_time_limit(5);

// Try to read in the remote file:
if ($data = @file_get_contents(
        'http://hubblesite.org/news/latest_big.php')) {
    // Quickly reset the timer so we don't timeout while writing the cache
    set_time_limit(60);

    // We got the file, so echo out the contents
    echo $data;

    // Now we need to save this to the cache file as well.
    // Give file_put_contents the LOCK_EX flag which makes it
    // attempt to get an exclusive lock before writing to the file.
    ignore_user_abort(true);
    file_put_contents(dirname(__FILE__) . '/hubble_news.cache', 
        $data, LOCK_EX);
}
?>