lib.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * A Moodle block that shows a map of users
 *
 * English and french versions included / versions anglaise et française incluses.
 *
 * @package    block_usersmap
 * @category   blocks
 * @copyright  2016 Mathias Chouet, Tela Botanica
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * Generates the block contents : map and / or text
 */
function usersmap_generate_content($config) {
    global $DB;
    global $CFG;
    global $COURSE;
    global $PAGE;

    $PAGE->requires->css('/blocks/usersmap/css/leaflet.css');
    $PAGE->requires->css('/blocks/usersmap/css/MarkerCluster.css');
    $PAGE->requires->css('/blocks/usersmap/css/MarkerCluster.Default.css');
    $PAGE->requires->css('/blocks/usersmap/css/Control.FullScreen.css');
    $PAGE->requires->css('/blocks/usersmap/css/usersmap.css');

    $PAGE->requires->js('/blocks/usersmap/js/leaflet.js', true);
    $PAGE->requires->js('/blocks/usersmap/js/leaflet.markercluster.js', true);
    $PAGE->requires->js('/blocks/usersmap/js/Control.FullScreen.js', true);

    $content = '';

    // Leaflet Map.
    $content .= '<div id="usersmap-map" class="">';
    $content .= '</div>';

    // Inline Javascript code because declaration order is important.
    $jsinitmapcode = '';
    $jsinitmapcode .= '<script type="text/javascript">' . PHP_EOL;

    // Build base layer based on settings.
    $tileservermode = get_config('usersmap', 'Tileserver');
    switch ($tileservermode) {
        case 'osm':
            $jsinitmapcode .= "baseLayer = L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',"
                . "{maxZoom: 20, attribution: 'Map data © <a href=\"http://openstreetmap.org\">OpenStreetMap</a> contributors'});";
            break;
        case 'gstreets':
            $jsinitmapcode .= "baseLayer = L.tileLayer('http://{s}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}',"
                . "{maxZoom: 20, subdomains:['mt0','mt1','mt2','mt3']});";
            break;
        case 'gsatellite':
            $jsinitmapcode .= "baseLayer = L.tileLayer('http://{s}.google.com/vt/lyrs=s,h&x={x}&y={y}&z={z}',"
                . "{maxZoom: 20, subdomains:['mt0','mt1','mt2','mt3']});";
            break;
        case 'custom':
        default:
            $layerurl = get_config('usersmap', 'Tileserver_Url_Scheme');
            if (empty($layerurl)) {
                throw new Exception(get_string('error_tilserver_url_not_set', 'block_usersmap'));
            }
            $layermaxzoom = get_config('usersmap', 'Tileserver_Max_Zoom');
            if (empty($layermaxzoom)) {
                $layermaxzoom = 20;
            }
            $layerattribution = get_config('usersmap', 'Tileserver_Attribution');
            $jsinitmapcode .= "baseLayer = L.tileLayer('$layerurl',"
                . "{maxZoom: $layermaxzoom, attribution: '$layerattribution'});";
            break;
    }

    $jsinitmapcode .= "var usersmap = L.map('usersmap-map', {scrollWheelZoom: false, fullscreenControl: true,
                                      fullscreenControlOptions: {position: 'topleft'}});" . PHP_EOL;
    $jsinitmapcode .= "baseLayer.addTo(usersmap);" . PHP_EOL;
    // Clustering layer.
    $jsinitmapcode .= "usersLayer = new L.MarkerClusterGroup({disableClusteringAtZoom : 10});";
    $jsinitmapcode .= "usersLayer.addTo(usersmap);" . PHP_EOL;
    // Change default icon because generated path is not understood by Moodle.
    $markerurl = new moodle_url('/blocks/usersmap/js/images/marker-icon.png');
    $jsinitmapcode .= "var newDefaultMarkerIcon = L.icon({iconUrl: '$markerurl', iconSize: [24,36], iconAnchor: [12,36]});";
    $jsinitmapcode .= "L.Marker.mergeOptions({icon: newDefaultMarkerIcon});";
    $jsinitmapcode .= '</script>' . PHP_EOL;

    // Append inline JS to content (this is a useless comment).
    $content .= $jsinitmapcode;

    // Get all available users locations.
    // @TODO Load GeoJSON directly from the database ? Which performance ?

    // Select users according to the instance config.
    $whattodisplay = 'aeu';
    if (isset($config->whattodisplay)) {
        $whattodisplay = $config->whattodisplay;
    }
    $onlineusersonly = in_array($whattodisplay, array('omu', 'oeu'));
    $enrolledusersonly = in_array($whattodisplay, array('aeu', 'oeu'));

    $r0 = "SELECT bu.id as id, bu.lat as lat, bu.lon as lon, bu.city as city, count(*) as nb "
        . "FROM " . $CFG->prefix . "block_usersmap bu ";
    $join = " LEFT JOIN user u ON u.id = bu.userid";
    $where = array("bu.lat IS NOT NULL", "bu.lon IS NOT NULL", "u.deleted = 0", "u.suspended = 0", "u.confirmed = 1");

    if ($onlineusersonly) {
        $where[] = "UNIX_TIMESTAMP() - u.lastaccess < 900"; // 15 mn.
    }
    if ($enrolledusersonly && ($COURSE->id > 1)) { // Course n°1 is platform home.
        $join .= " LEFT JOIN user_enrolments ue ON ue.userid = bu.userid LEFT JOIN enrol e ON e.id = ue.enrolid";
        $where[] = "e.courseid = " . $COURSE->id;
    }
    $r0 .= $join
        . " WHERE " . implode(' AND ', $where)
        . " GROUP BY bu.lat, bu.lon"; // City should always be the same for a given lat,lon pair.

    $res = $DB->get_records_sql($r0, array());

    $jsmarkerscode = '<script type="text/javascript">' . PHP_EOL;
    if ($res) {
        // Generate JS code for markers.
        $markerid = 1;
        foreach ($res as $r) {
            // Add multiple instance of the marker so that the clustering
            // plugin shows the right number of users in its icons.
            $realnbusers = $r->nb;
            for ($i = 0; $i < $realnbusers; $i++) {
                $jsmarkerscode .= 'var marker_' . $markerid . ' = L.marker([' . $r->lat . ', ' . $r->lon . ']);' . PHP_EOL;
                $jsmarkerscode .= 'usersLayer.addLayer(marker_' . $markerid . ');' . PHP_EOL;
                $jsmarkerscode .= 'marker_' . $markerid . '.bindPopup("' . $r->city . ' : ' . $r->nb . '").openPopup();';
                $markerid++;
            }
        }
        $jsmarkerscode .= 'usersmap.fitBounds(usersLayer.getBounds());' . PHP_EOL;
        $jsmarkerscode .= 'usersmap.setZoom(1);' . PHP_EOL;
    } else {
        $jsmarkerscode .= "usersmap.setView({lat:43.614203, lng:3.860752}, 1);" . PHP_EOL; // Center on Montpellier, best city in the world.
    }
    $jsmarkerscode .= '</script>' . PHP_EOL;
    $content .= $jsmarkerscode;

    // Count all active users in Moodle.
    $displaynbmoodleusers = false;
    if (isset($config->displaynbmoodleusers)) {
        $displaynbmoodleusers = $config->displaynbmoodleusers;
    }
    if ($displaynbmoodleusers) {
        $r1 = "SELECT count(*) as nb FROM " . $CFG->prefix . "user WHERE confirmed = 1 AND deleted = 0 AND suspended = 0";
        $res = $DB->get_records_sql($r1, array());
        $singleresult = array_shift($res);
        $nbusers = $singleresult->nb;
        $stringformat = get_string('config_display_nb_moodle_users_format_default', 'block_usersmap');
        if (isset($config->displaynbmoodleusers_format)) {
            $stringformat = $config->displaynbmoodleusers_format;
        }
        $message = str_replace('{nb}', $nbusers, $stringformat);
        $content .= "<p>$message</p>";
    }

    // Count all users enrolled in the current course.
    $displaynbenrolledusers = false;
    if (isset($config->displaynbenrolledusers)) {
        $displaynbenrolledusers = $config->displaynbenrolledusers;
    }
    if ($displaynbenrolledusers) {
        if ($COURSE->id != 1) { // Course n°1 is platform home.
            $r2 = "SELECT count(DISTINCT userid) as nb "
                . "FROM " . $CFG->prefix . "user_enrolments ue "
                . "LEFT JOIN " . $CFG->prefix . "enrol e ON e.id = ue.enrolid "
                . "WHERE e.courseid = " . $COURSE->id;
            $res = $DB->get_records_sql($r2, array());
            $singleresult = array_shift($res);
            $nbenrolledusers = $singleresult->nb;
            $stringformat = get_string('config_display_nb_enrolled_users_format_default', 'block_usersmap');
            if (isset($config->displaynbenrolledusers_format)) {
                $stringformat = $config->displaynbenrolledusers_format;
            }
            $message = str_replace('{nb}', $nbenrolledusers, $stringformat);
            $content .= "<p>$message</p>";
        }
    }

    return $content;
}

/**
 * Called by the cron (scheduled task) to retrieve geolocation data based on
 * users cities
 */
function usersmap_update_geolocation($updateeveryone=false) {
    global $DB;
    global $CFG;

    if ($updateeveryone) { // Clear data once in a while.
        $DB->delete_records("block_usersmap");
    }

    // Query all users having a city set in their profile.
    $q = "SELECT id, city, country FROM " . $CFG->prefix . "user WHERE city != '' AND deleted = 0";
    if (! $updateeveryone) { // Only update users having no geolocation yet.
        $q .= " AND id NOT IN (SELECT userid FROM " . $CFG->prefix . "block_usersmap)";
    }
    $q .= " LIMIT 100"; // 100 at a time to spare the geolocation server's life.

    $res = $DB->get_records_sql($q, array());

    // Setup the geolocation service befor the loop.
    $geolocationservice = get_config('usersmap', 'Geolocation_Server');
    $baseurl = '';
    $latfield = 'lat';
    $lonfield = 'lon';
    switch($geolocationservice) {
        case 'geonames':
            $baseurl = "http://api.geonames.org/searchJSON?maxRows=1";
            $geonamesusername = get_config('usersmap', 'Geonames_Username');
            if (empty($geonamesusername)) {
                echo "ERROR Geolocation_Server is set to 'Geonames' but Geonames_Username is not set";
                return false;
            }
            $baseurl .= "&username=$geonamesusername";
            break;
        case 'custom':
        default:
            $baseurl = get_config('usersmap', 'Geolocation_Url_Scheme');
            if (empty($baseurl)) {
                echo "ERROR Geolocation_Server is set to 'custom' but Geolocation_Url_Scheme is not set";
                return false;
            }
            if (get_config('usersmap', 'Geolocation_Lat_Field') != '') {
                $latfield = get_config('usersmap', 'Geolocation_Lat_Field');
            }
            if (get_config('usersmap', 'Geolocation_Lon_Field') != '') {
                $lonfield = get_config('usersmap', 'Geolocation_Lon_Field');
            }
            break;
    }

    // Get geolocation data for each user.
    if ($res) {
        foreach ($res as $r) {
            $newrecord = new StdClass();
            $newrecord->userid = $r->id;
            $newrecord->city = $r->city;
            switch($geolocationservice) {
                case 'geonames':
                    $url = $baseurl;
                    $url .= "&q=" . urlencode(trim($r->city));
                    $url .= "&country=" . urlencode(trim($r->country));
                    $info = file_get_contents($url);
                    if ($info) {
                        $info = json_decode($info, true);
                        if (isset($info['geonames']) && isset($info['geonames'][0])) {
                            $newrecord->lat = $info['geonames'][0]['lat'];
                            $newrecord->lon = $info['geonames'][0]['lng'];
                        }
                    }
                    break;
                case 'custom':
                default:
                    $url = str_replace('{city}', urlencode(trim($r->city)), $baseurl);
                    $url = str_replace('{country}', urlencode(trim($r->country)), $url);
                    $info = file_get_contents($url);
                    if ($info) {
                        $info = json_decode($info, true);
                        $newrecord->lat = $info[$latfield];
                        $newrecord->lon = $info[$lonfield];
                    }
                    break;
            }
            // Inserting one at a time because of quotes issue.
            $DB->insert_record("block_usersmap", $newrecord);
            /* Locations not found are also inserted. To get the percentage of
             * geolocation, run this query :
             * SELECT a.nb, b.nb, a.nb/b.nb as pourcentage FROM
             *    (SELECT count(*) as nb FROM block_usersmap WHERE lat IS NOT NULL AND lon IS NOT NULL) as a,
             *  (SELECT count(*) as nb FROM block_usersmap) as b;
             */
        }
    }
}