convert a google sheet containing longitude and latitude fields into a csv file recognized by umap of osm

gsheet2umap.php

<?php
    if (! (isset($_GET['html']) && filter_var($_GET['html'], FILTER_VALIDATE_URL))) {
	echo 'needs "html" variable on command line';
	return;
    }
    $url = $_GET['html'];
    $htmlContent = file_get_contents($url);
    $tmpHtmlFile = tempnam(sys_get_temp_dir(), 'html_');
    $tmpCsvFile = tempnam(sys_get_temp_dir(), 'csv_');
    file_put_contents($tmpHtmlFile, $htmlContent);
    exec("html2csv.py < " . escapeshellarg($tmpHtmlFile) . " > " . escapeshellarg($tmpCsvFile));
    $csvContent = file($tmpCsvFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    unlink($tmpHtmlFile);

    foreach ($csvContent as $index => $row) {
	$cols = str_getcsv($row);
	array_shift($cols);
	$iLong = -1;
	$iLat = -1;
	foreach ($cols as $i => $c) {
	    $ans = strpos(strtolower($c), "lon");
	    if ($iLong < 0 && $ans !== false && $ans == 0)
		$iLong = $i;
	    $ans = strpos(strtolower($c), "lat");
	    if ($iLat < 0 && $ans !== false && $ans == 0)
		$iLat = $i;
	}
	if ($iLong >= 0 && $iLat >= 0) {
	    $headerRow = $cols;
	    break;
	}
    }
    if ($iLong<0 || $iLat<0) {
	echo 'cannot find "lon" and "lat" header at the same time in any row';
	return;
    }
    $filteredCsv = array(implode(',', $headerRow));

    foreach (array_slice($csvContent, $index + 1) as $row) {
	$cols = str_getcsv($row);
	array_shift($cols);
	if (is_numeric($cols[$iLat]) && is_numeric($cols[$iLong]))
	    $filteredCsv[] = implode(',', $cols);
    }
    unlink($tmpCsvFile);

    header('Content-Type: text/plain');
    echo implode("\n", $filteredCsv);
?>