PHP使用curl下载文件时输出下载进度

curl_download_progress.php

<?php
// 现在输出是没问题了，但是实际保存为文件还有问题
// from: http://stackoverflow.com/questions/13958303/curl-download-progress-in-php
// 原文中的代码有bug，作了修改
$url = 'http://ipv4.speedtest-sgp1.digitalocean.com/10mb.test';
echo "<pre>";
echo "Loading ...";

ob_flush();
flush();
downloadFileWithCURL($url, './10mb.test');
echo "Done";
ob_flush();
flush();


function downloadFileWithCURL($url, $localFilePath) {



    function progressCallback($resource, $download_size = 0, $downloaded = 0, $upload_size = 0, $uploaded = 0) {    
        /**
         * $resource parameter was added in version 5.5.0 breaking backwards compatibility;
         * if we are using PHP version lower than 5.5.0, we need to shift the arguments
         * @see http://php.net/manual/en/function.curl-setopt.php#refsect1-function.curl-setopt-changelog
         */
        if (version_compare(PHP_VERSION, '5.5.0') < 0) {
            $uploaded = $upload_size;
            $upload_size = $downloaded;
            $downloaded = $download_size;
            $download_size = $resource;
        }
        
        // Handle progress
        if ($download_size > 0) echo round($downloaded / $download_size * 100, 2) . "\n";
        ob_flush();
        flush();
        sleep(1);
         // just to see effect
    }

    $fp = fopen($localFilePath, 'w+');

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_FILE, $fp);

    //curl_setopt($ch, CURLOPT_BUFFERSIZE,128);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, 'progressCallback');
    curl_setopt($ch, CURLOPT_NOPROGRESS, false);
     // needed to make progress function work
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
    curl_exec($ch);
    curl_close($ch);

    fclose($fp);
}