使用PHP导出数据后下载的文件为空

Question

I have this PHP script to update a specific table of MySQL db:

<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
//Include connection file
require_once('../connection/connect.php');

header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=reports.csv");
header("Pragma: no-cache");
header("Expires: 0");

$sql = "SELECT * FROM patient";
$stmt = $conn->prepare($sql);

$stmt->execute();
//var_dump($stmt->fetch(PDO::FETCH_ASSOC));
$data = fopen('backup.csv', 'w');
while ($row = $stmt->fetch(PDO::FETCH_ASSOC))
{
    // Export every row to a file
    fputcsv($data, $row);
}
?>

I created a file in the same directory called: backup.csv and the data are updated correctly each time I execute this script. But the problem is that I can't add a header to table inside the .csv file.

And the downloaded file is empty. I need to download backup.csv and not reports.csv.

I tried:

header("Content-Disposition: attachment; filename="'.$data.'";");

But it didn't helped. The file is still empty.

Answer 1

Your problem is that you have not actually sent the file that you have created.

This is a better structure but remember you also have to sent the file you have built to the browser

<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
//Include connection file
require_once('../connection/connect.php');

$sql = "SELECT * FROM patient";
$stmt = $conn->prepare($sql);

$stmt->execute();

$data = fopen('backup.csv', 'w');
while ($row = $stmt->fetch(PDO::FETCH_ASSOC))
{
    // Export every row to a file
    fputcsv($data, $row);
}
fclose($data);                 // <- close file

header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=reports.csv");
header("Pragma: no-cache");
header("Expires: 0");
readfile('backup.csv');        // <- new line
?>