dhis2-maps-api/src/cluster/Cluster.js

Maps API for DHIS2 based on Leaflet

// Support both client and server clustering
// Currently not in use
import L from 'leaflet';
import clientCluster from './ClientCluster';
import serverCluster from './ServerCluster';

export const Cluster = L.Layer.extend({
    options: {
        clientClusterLimit: 2000,
        fitBounds: true,
        color: '#333',
        opacity: 1,
    },

    initialize(options) {
        L.setOptions(this, options);
        this.initCluster();
    },

    onAdd(map) {
        if (this._clusterLayer) {
            map.addLayer(this._clusterLayer);
        }
    },

    onRemove(map) {
        if (this._clusterLayer && map.hasLayer(this._clusterLayer)) {
            map.removeLayer(this._clusterLayer);
        }
    },

    initCluster() {
        const query = L.Util.template(this.options.query, this.options);

        fetch(this.options.api + encodeURIComponent(query))
            .then(response => response.json())
            .then(data => this.onInitLoad(data.rows[0]))
            .catch(ex => {
                window.console.log('parsing failed', ex); // TODO
            });
    },

    onInitLoad(data) {
        const options = this.options;

        if (options.fitBounds) {
            this._map.fitBounds(this._boxToBounds(data.extent));
        }

        if (options.clustering !== 'server' && data.count <= options.clientClusterLimit) {
            this.initClientCluster();
        } else {
            this.initServerCluster(data.count);
        }
    },

    initClientCluster() {
        this._clusterLayer = clientCluster(L.extend(this.options, {
            query: 'SELECT uid, ST_AsGeoJSON(the_geom) AS geom FROM {table}',
        })).addTo(this._map);
    },

    initServerCluster(count) {
        this._clusterLayer = serverCluster(L.extend(this.options, {
            query: 'SELECT COUNT(uid) AS count, CASE WHEN COUNT(uid) <= 20 THEN array_agg(uid) END AS ids, ST_AsGeoJSON(ST_Centroid(ST_Collect(the_geom)),5) AS center, ST_Extent(the_geom) AS bounds FROM (SELECT cartodb_id AS uid, the_geom FROM {table}) sq WHERE the_geom && ST_MakeEnvelope({bounds}, 4326) GROUP BY ST_SnapToGrid(ST_Transform(the_geom, 3785), {size})',
            domain: [1, count],
        })).addTo(this._map);
    },

    setOpacity(opacity) {
        this.options.opacity = opacity;
        if (this._clusterLayer) {
            this._clusterLayer.setOpacity(opacity);
        }
    },

    // Converts a PostGIS box2d to Leaflet bounds
    _boxToBounds(box) {
        const coords = box.match(/[0-9\.\-]+/g);
        return [[coords[1], coords[0]], [coords[3], coords[2]]];
    },

});

export default function cluster(options) {
    return new Cluster(options);
}