MySQL在OUTFILE中的应用

Question

最近，我将一个项目转移到一个活动的VM实例中，它在使用XAMPP在我的macOS盒上进行开发和测试时工作得很好。实际上，web应用程序有3种导出选项: XML、PDF和CSV。XML工作良好，使用SELECT语句创建，然后循环遍历结果并将其推入XML文件。

但是，对于CSV和PDF导出(PDF使用TCPDF)，我使用了：

CSV

INTO OUTFILE '/tmp/$department_name+feedback+$timestamp.csv' FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n'";

PDF

INTO OUTFILE '/tmp/$department_name+feedback+$timestamp.txt' FIELDS TERMINATED BY ';' LINES TERMINATED BY '\n'";

但是，该文件从未被写入/tmp。我认为这是一个权限问题，但是该目录是由root拥有的，并且如预期的那样具有所有必要的权限。

工作的XML代码如下：

$fileLocation = '/tmp/' . $location_name . '+feedback+' . $timestamp . '+.xml';

$sql = "SELECT CONCAT (e.name,' ', e.surname) AS Fullname, f.score AS Score, d.department_name AS Department, f.feedback AS Feedback
            FROM employee AS e
            JOIN feedback AS f
            ON e.qr_id = f.qr_id
            JOIN departments as d
            ON e.department_id = d.department_id
            JOIN location AS l
            ON e.location_id = l.location_id
            AND e.location_id = '$location'
            AND e.company_id = '$company_id'
            AND f.`report_Time` BETWEEN SUBDATE(CURDATE(),
                                INTERVAL 1 MONTH) AND NOW()
                                ORDER BY f.score DESC";


$xml = new XMLWriter();

$xml->openURI($fileLocation);
$xml->startDocument();
$xml->setIndent(true);

$xml->startElement('feedback');

foreach ($mysqli->query($sql) as $row){
    $xml->startElement("Fullname");
    $xml->writeRaw($row['Fullname']);
    $xml->startElement("Score");
    $xml->writeRaw($row['Score']);
    $xml->startElement("Feedback");
    $xml->writeRaw($row['Feedback']);
    $xml->startElement("Department");
    $xml->writeRaw($row['Department']);

    $xml->endElement();
}

$xml->endElement();

header('Content-type: text/xml');
$xml->flush();


$file_url = $fileLocation;
header('Content-Type: application/xml');
header("Content-Transfer-Encoding: Binary");
header("Content-disposition: attachment; filename=\"" . basename($file_url) . "\"");
readfile($file_url);

因此，我不知道为什么XML在写入/tmp目录时工作，而PDF不工作，这是在Google平台VM实例上运行的。正如我之前所说的，CSV & PDF出口在我的macOS机器上工作得很好。

Answer 1

显示此结果：

SHOW VARIABLES LIKE 'secure_file_priv';

如果结果不为空，则只能在此目录中写入。