forked from MapComplete/MapComplete
132 lines
5 KiB
TypeScript
132 lines
5 KiB
TypeScript
/**
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* Fetches a geojson file somewhere and passes it along
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*/
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import {UIEventSource} from "../../UIEventSource";
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import FilteredLayer from "../../../Models/FilteredLayer";
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import {Utils} from "../../../Utils";
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import {FeatureSourceForLayer, Tiled} from "../FeatureSource";
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import {Tiles} from "../../../Models/TileRange";
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import {BBox} from "../../BBox";
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import {GeoOperations} from "../../GeoOperations";
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export default class GeoJsonSource implements FeatureSourceForLayer, Tiled {
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public readonly features: UIEventSource<{ feature: any; freshness: Date }[]>;
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public readonly name;
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public readonly isOsmCache: boolean
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public readonly layer: FilteredLayer;
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public readonly tileIndex
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public readonly bbox;
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private readonly seenids: Set<string> = new Set<string>()
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/**
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* Only used if the actual source is a tiled geojson.
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* A big feature might be contained in multiple tiles.
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* However, we only want to load them once. The blacklist thus contains all ids of all features previously seen
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* @private
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*/
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private readonly featureIdBlacklist?: UIEventSource<Set<string>>
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public constructor(flayer: FilteredLayer,
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zxy?: [number, number, number],
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options?: {
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featureIdBlacklist?: UIEventSource<Set<string>>
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}) {
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if (flayer.layerDef.source.geojsonZoomLevel !== undefined && zxy === undefined) {
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throw "Dynamic layers are not supported. Use 'DynamicGeoJsonTileSource instead"
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}
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this.layer = flayer;
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this.featureIdBlacklist = options?.featureIdBlacklist
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let url = flayer.layerDef.source.geojsonSource.replace("{layer}", flayer.layerDef.id);
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if (zxy !== undefined) {
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const [z, x, y] = zxy;
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let tile_bbox = BBox.fromTile(z, x, y)
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let bounds: { minLat: number, maxLat: number, minLon: number, maxLon: number } = tile_bbox
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if (this.layer.layerDef.source.mercatorCrs) {
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bounds = tile_bbox.toMercator()
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}
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url = url
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.replace('{z}', "" + z)
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.replace('{x}', "" + x)
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.replace('{y}', "" + y)
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.replace('{y_min}', "" + bounds.minLat)
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.replace('{y_max}', "" + bounds.maxLat)
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.replace('{x_min}', "" + bounds.minLon)
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.replace('{x_max}', "" + bounds.maxLon)
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this.tileIndex = Tiles.tile_index(z, x, y)
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this.bbox = BBox.fromTile(z, x, y)
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} else {
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this.tileIndex = Tiles.tile_index(0, 0, 0)
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this.bbox = BBox.global;
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}
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this.name = "GeoJsonSource of " + url;
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this.isOsmCache = flayer.layerDef.source.isOsmCacheLayer;
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this.features = new UIEventSource<{ feature: any; freshness: Date }[]>([])
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this.LoadJSONFrom(url)
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}
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private LoadJSONFrom(url: string) {
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const eventSource = this.features;
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const self = this;
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Utils.downloadJson(url)
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.then(json => {
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if (json.features === undefined || json.features === null) {
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return;
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}
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if (self.layer.layerDef.source.mercatorCrs) {
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json = GeoOperations.GeoJsonToWGS84(json)
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}
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const time = new Date();
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const newFeatures: { feature: any, freshness: Date } [] = []
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let i = 0;
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let skipped = 0;
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for (const feature of json.features) {
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const props = feature.properties
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for (const key in props) {
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if (typeof props[key] !== "string") {
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// Make sure all the values are string, it crashes stuff otherwise
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props[key] = "" + props[key]
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}
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}
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if (props.id === undefined) {
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props.id = url + "/" + i;
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feature.id = url + "/" + i;
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i++;
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}
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if (self.seenids.has(props.id)) {
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skipped++;
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continue;
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}
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self.seenids.add(props.id)
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if (self.featureIdBlacklist?.data?.has(props.id)) {
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continue;
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}
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let freshness: Date = time;
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if (feature.properties["_last_edit:timestamp"] !== undefined) {
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freshness = new Date(props["_last_edit:timestamp"])
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}
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newFeatures.push({feature: feature, freshness: freshness})
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}
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if (newFeatures.length == 0) {
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return;
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}
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eventSource.setData(eventSource.data.concat(newFeatures))
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}).catch(msg => console.debug("Could not load geojson layer", url, "due to", msg))
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}
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}
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