statistics/byPeriodDataset.php

<?php
/*
 * Generates dataset for statistics of posts by date and sender
 * Copyright (C) 2020  Polyna <https://wandystan.eu/B196>
 *
 * This file is part of LDMW statistical scripts.
 *
 * LDMW statistical scripts are free software: you can redistribute them
 * and/or modify them under the terms of the GNU Affero General Public
 * License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * LDMW statistical scripts are distributed in the hope that they will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with LDMW statistical scripts.  If not, see
 * <https://www.gnu.org/licenses/>.
 */
require_once 'common.php';

// load document with month statistics
try {
	$document = load_remote_dom_document('https://wandystan.groups.io/g/wandystan/months');
} catch (Exception $e) {
	exit_error($e->getMessage());
}

$xpath = new DOMXPath($document);

// find all months with non-zero number of posts
$months = [];
$rows = $xpath->query('//table/tbody/tr');

foreach ($rows as $row) {
	$cols = $xpath->query('td', $row);
	$year = $cols[0]->nodeValue;

	for ($i = 1; $i < $cols->length; $i++) {
		if (
			$cols[$i]->firstChild->nodeType === XML_ELEMENT_NODE &&
			$cols[$i]->firstChild->tagName === 'a'
		) {
			$months []= $year . '-' . str_pad($i, 2, '0', STR_PAD_LEFT);
		}
	}
}

// construct a linked data object corresponding to gathered data
$ld = [
	'@context' => 'https://wandystan.eu/statistics/context.jsonld',
	'@type' => 'DataSet',
	'title' => [
		'en' => 'Posts by date and sender',
		'pl' => 'Wiadomości wg daty i wysyłającego'
	],
	'description' => [
		'en' => 'Statistics of number of posts sent by a given sender on a given date, grouped by period in which they were sent.',
		'pl' => 'Statystyki liczby wiadomości wysłanych przez danego wysyłającego w danym dniu, pogrupowane wg okresu w jakim zostały wysłane.'
	],
	'publisher' => 'https://wandystan.eu/',
	'structure' => 'structure/by-period',
	'slices' => array_map(function ($month) { return "by-period/$month-01/P1M"; }, $months)
];

header('Content-type: application/ld+json');
print json_encode($ld);