Diss/05_Database/PHP/query_to_csv.php

<?php

function query_to_csv(string $query, bool $print_header = false, string $filename = 'result') {
	$pdo = new PDO('mysql:host=localhost;dbname=observer', 'observerro', 'KhOp1w8U');

	$statement = $pdo->prepare($query);

	require('http_errors.php');

	if (!$statement->execute()) {
		HttpResponse::internal_server_error()->set_and_exit();
	}

	$out = fopen('php://output', 'w');
	if ($out === false) {
		HttpResponse::internal_server_error()->set_and_exit();
	}

	if (substr($filename, -4) !== '.csv') {
		$filename = $filename . '.csv';
	}

	header('Content-Type: text/csv');
	header('Content-Disposition: filename=' . $filename);
	if ($print_header) {
		$columns = array();
		for ($i = 0; $i < $statement->columnCount(); $i++) {
			$columns[] = $statement->getColumnMeta($i)['name'];
		}
		fputcsv($out, $columns);
	}

	while ($row = $statement->fetch(PDO::FETCH_NUM)) {
		fputcsv($out, $row);
	}
}