cakephp + crul 获得url的返回的文件流

1.获得url的文件流

     function _curl_get($url) {      
	    $ch = curl_init();    
	    curl_setopt($ch, CURLOPT_URL, $url);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);// 返回字符串，而非直接输出

		curl_setopt($ch, CURLOPT_HEADER, 0);   // 不返回header部分

	    $data = curl_exec($ch);        
	    curl_close($ch);      
	    if ($data)   
	        return $data;     
	    else
	        return false;     
	} 

2.测试

function test_url(){
        $url = "http://211.151.59.44/s3c/samples/download/15009";
        $data = $this->_curl_get($url);
        $tmpFile = SAMPLE_TMP_PATH."a.sis";
        $this->FileHelper->delFile($tmpFile);
        $this->FileHelper->createFile($tmpFile,$data);
        $this->_download("a.sis", $tmpFile);
        
    }

3.下载

function _download($fileName, $downloadFile) {
        $speed = 8.5; // 8,5 kb/s download rate limit
        if (file_exists($downloadFile) && is_file($downloadFile)) {
            header('Cache-control: private');
            header('Content-Type: application/octet-stream');
            header('Content-Length: ' . filesize($downloadFile));
            header('Content-Disposition: filename=' . $fileName);
            flush();
            $fd = fopen($downloadFile, 'r');
            while (!feof($fd)) {
                echo fread($fd, round($speed * 1024));
                flush();
                sleep(1);
            }
            fclose($fd);
            $this->log($downloadFile . 'file_exists', 'down');
        } else {
            $this->log($downloadFile . ': file_exists not');
            return;
        }
    }