Failed to open stream: Permission denied in /var/www/html/export.php on line 24

Hi,

I'm playing around with a test script that exports a select query into a csv file. I'm getting the above error when I run the script (see below) and think it's related to the permission setting of my php user which is "www-data".

<?php // demo/db_to_csv.php
include("latch2.php"); 

$uid = access_control();
/**
 * Export a database table to a CSV file for use in Excel
 * https://www.experts-exchange.com/questions/29018496/Export-Data-from-MySql-Using-PHP.html
 */
error_reporting(E_ALL);
echo "<pre>";

// SET YOUR TABLE NAME HERE - OR MAYBE USE THE URL "GET" ARGUMENT
$table_name = 'productCode';

// OPEN THE CSV FILE - PUT YOUR FAVORITE NAME HERE
$csv
= 'storage'
. DIRECTORY_SEPARATOR
. 'EXPORT_'
. date('Ymdhis')
. "_$table_name"
. '.csv'
;
$fp  = fopen($csv, 'w');
if (!$fp) trigger_error("UNABLE TO OPEN $csv", E_USER_ERROR);

// GET THE COLUMN NAMES
$sql = "SHOW COLUMNS FROM $table_name";
if (!$res = $mysqli->query($sql))
{
    $err
    = 'QUERY FAILURE:'
    . ' ERRNO: '
    . $mysqli->errno
    . ' ERROR: '
    . $mysqli->error
    . ' QUERY: '
    . $sql
    ;
    trigger_error($err, E_USER_ERROR);
}
if ($res->num_rows == 0)
{
    trigger_error("ERROR: $table_name HAS NO COLUMNS", E_USER_ERROR);
}
else
{
    while ($show_columns = $res->fetch_object())
    {
        $my_columns[] = $show_columns->Field;
    }
}

// WRITE THE COLUMN NAMES TO THE CSV
if (!fputcsv($fp, $my_columns)) trigger_error("FAILURE WRITING COLUMN NAMES TO $csv", E_USER_ERROR);

// GET THE ROWS OF DATA
$sql = "SELECT * FROM $table_name";
if (!$res = $mysqli->query($sql))
{
    $err
    = 'QUERY FAILURE:'
    . ' ERRNO: '
    . $mysqli->errno
    . ' ERROR: '
    . $mysqli->error
    . ' QUERY: '
    . $sql
    ;
    trigger_error($err, E_USER_ERROR);
}

// ITERATE OVER THE DATA SET
while ($row = $res->fetch_row())
{
    // WRITE THE COMMA-SEPARATED VALUES.
    if (!fputcsv($fp, $row)) trigger_error("FAILURE WRITING DATA TO $csv", E_USER_ERROR);
}

// ALL DONE
fclose($fp);

// SHOW THE CLIENT A LINK
echo "<p><a href=\"$csv\">$csv</a></p>" . PHP_EOL;

Select allOpen in new window

What settings should I adjust to allow the script to run, without compromising the security of the site?

J