PHP code to download CSV file not working - php

Question

I have the below code, where I generate random numbers and try to download them as a CSV file.
If I try the CSV code snippet alone on a different file it works, but in this code, it just does not work. I do see the random numbers echoed, but it does not download the CSV file.
<?php
$dataarray=array();
function convert_to_csv($input_array, $output_file_name, $delimiter)
{
$temp_memory = fopen('php://memory', 'w');
foreach ($input_array as $line)
{
fputcsv($temp_memory, $line, $delimiter);
}
fseek($temp_memory, 0);
header('Content-Type: application/csv');
header('Content-Disposition: attachement; filename="' . $output_file_name . '";');
fpassthru($temp_memory);
}
for ($i = 0; $i <= 25000; $i++)
{
$num = (rand(50,110));
array_push($dataarray,"$num");
echo "Hearbeat #" .$i . "\t\t ------ " . $num;
echo "<br>";
}
convert_to_csv($dataarray, 'data_as_csv.csv', ',');
?>

Answer 1

Outputting data before sending headers with header() means that header() calls will have no effect. So it is reasonable not to send anything before headers.
As another answer mentioned - second argument to fputcsv must be array, so I changed the call to fputcsv too.
If you want all values to written to csv file with comma as separator - pass $input_array directly to fputcsv.
So, your code can look like:
<?php
$dataarray=array();
function convert_to_csv($input_array, $output_file_name, $delimiter)
{
$temp_memory = fopen('php://memory', 'w');
// Option 1 - every number will be on a new line
foreach ($input_array as $line)
{
// add `array($line)` not `$line`
fputcsv($temp_memory, array($line), $delimiter);
}
// Option 2 - all numbers will be in
// one line with `$delimiter` as separator
fputcsv($temp_memory, $input_array, $delimiter);
fseek($temp_memory, 0);
header('Content-Type: application/csv');
header('Content-Disposition: attachement; filename="' . $output_file_name . '";');
fpassthru($temp_memory);
}
for ($i = 0; $i <= 25000; $i++)
{
$num = (rand(50,110));
array_push($dataarray,"$num");
// this two lines are nor needed
//echo "Hearbeat #" .$i . "\t\t ------ " . $num;
//echo "<br>";
}
convert_to_csv($dataarray, 'data_as_csv.csv', ',');

Answer 2

Actually, the problem is in your convert_to_csv function.
fputcsv expects the second parameter to be an array, and in you case is a string. You have 2 options depending on what you want:
1) Each number in a separate line: just change the fputcsv function call to: fputcsv($temp_memory, [$line], $delimiter);
2) All numbers in the same line separated by $delimiter:
function convert_to_csv($input_array, $output_file_name, $delimiter)
{
$temp_memory = fopen('php://memory', 'w');
fputcsv($temp_memory, $fields, $delimiter);
fseek($temp_memory, 0);
header('Content-Type: application/csv');
header('Content-Disposition: attachement; filename="' . $output_file_name . '";');
fpassthru($temp_memory);
}
And (I'm sure you already know), for the file to be downloaded automatically you must not echo anything.