Convert a list of the same maps into a CSV file.

json2csv.php

#!/usr/bin/php
<?php 
// usage: cat some-output.json | ./json2csv.php > some-output.csv

function error($msg, $ret = 1) {
  die('ERROR: ' . $msg . PHP_EOL);
  exit($ret);
}

$data = json_decode(file_get_contents('php://stdin'), true);
if (!is_array($data) || !count($data) > 0) {
  error('invalid input json');
}

fputcsv(STDOUT, array_keys($data[0]));

foreach ($data as $row) {
  fputcsv(STDOUT, array_values($row));
}