// 初始化一個(gè) curl
$ch = curl_init();
// 設(shè)置請(qǐng)求的 url
curl_setopt($ch, CURLOPT_URL, $url);
// 
curl_setopt($ch, CURLOPT_HEADER, 0);
// 不直接輸出，而是通過(guò) curl_exec 返回
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
if (false === ($stream = curl_exec($ch))) {
 throw new \Exception(curl_errno($ch));
}
curl_close($ch);
return $stream;

class Request
{
 protected $bar;
 // 是否下載完成
 protected $downloaded = false;
 public function __construct()
 {
 // 初始化一個(gè)進(jìn)度條
 $this->bar = new CliProgressBar(100);
 $this->bar->display();
 $this->bar->setColorToRed();
 }
 
 function download($url)
 {
 $ch = curl_init();
 // 從配置文件中獲取根路徑
 curl_setopt($ch, CURLOPT_URL, $url);
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 0);
 // 開(kāi)啟進(jìn)度條
 curl_setopt($ch, CURLOPT_NOPROGRESS, 0);
 // 進(jìn)度條的觸發(fā)函數(shù)
 curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, 'progress');
 // ps: 如果目標(biāo)網(wǎng)頁(yè)跳轉(zhuǎn)，也跟著跳轉(zhuǎn)
 // curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
 if (false === ($stream = curl_exec($ch))) {
  throw new \Exception(curl_errno($ch));
 }
 curl_close($ch);
 return $stream;
 }
 
 /**
 * 進(jìn)度條下載.
 *
 * @param $ch
 * @param $countDownloadSize 總下載量
 * @param $currentDownloadSize 當(dāng)前下載量
 * @param $countUploadSize 
 * @param $currentUploadSize
 */
 public function progress($ch, $countDownloadSize, $currentDownloadSize, $countUploadSize, $currentUploadSize)
 {
  // 等于 0 的時(shí)候，應(yīng)該是預(yù)讀資源不等于0的時(shí)候即開(kāi)始下載
  // 這里的每一個(gè)判斷都是坑，多試試就知道了
 if (0 === $countDownloadSize) {
  return false;
 }
 // 有時(shí)候會(huì)下載兩次，第一次很小，應(yīng)該是重定向下載
 if ($countDownloadSize > $currentDownloadSize) {
  $this->downloaded = false;
  // 繼續(xù)顯示進(jìn)度條
 }
 // 已經(jīng)下載完成還會(huì)再發(fā)三次請(qǐng)求
 elseif ($this->downloaded) {
  return false;
 }
 // 兩邊相等下載完成并不一定結(jié)束，
 elseif ($currentDownloadSize === $countDownloadSize) {
  return false;
 }
 
 // 開(kāi)始計(jì)算
 $bar = $currentDownloadSize / $countDownloadSize * 100;
 $this->bar->progress($bar);
 }
}
(new Request)->download('http://www.shiguopeng.cn/database.sql');