mapcomplete/Logic/FeatureSource/GeoJsonSource.ts

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import FeatureSource from "./FeatureSource";
import {UIEventSource} from "../UIEventSource";
import * as $ from "jquery";
import {control} from "leaflet";
import zoom = control.zoom;
import Loc from "../../Models/Loc";
import State from "../../State";
import {Utils} from "../../Utils";
import LayerConfig from "../../Customizations/JSON/LayerConfig";
/**
* Fetches a geojson file somewhere and passes it along
*/
export default class GeoJsonSource implements FeatureSource {
public readonly features: UIEventSource<{ feature: any; freshness: Date }[]>;
public readonly name;
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private onFail: ((errorMsg: any, url: string) => void) = undefined;
private readonly layerId: string;
private readonly seenids: Set<string> = new Set<string>()
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private constructor(locationControl: UIEventSource<Loc>,
flayer: { isDisplayed: UIEventSource<boolean>, layerDef: LayerConfig },
onFail?: ((errorMsg: any) => void)) {
this.layerId = flayer.layerDef.id;
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let url = flayer.layerDef.source.geojsonSource.replace("{layer}", flayer.layerDef.id);
this.name = "GeoJsonSource of " + url;
const zoomLevel = flayer.layerDef.source.geojsonZoomLevel;
this.features = new UIEventSource<{ feature: any; freshness: Date }[]>([])
if (zoomLevel === undefined) {
// This is a classic, static geojson layer
if (onFail === undefined) {
onFail = errorMsg => {
}
}
this.onFail = onFail;
this.LoadJSONFrom(url)
} else {
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this.ConfigureDynamicLayer(url, zoomLevel, locationControl, flayer)
}
}
private ConfigureDynamicLayer(url: string, zoomLevel: number, locationControl: UIEventSource<Loc>, flayer: { isDisplayed: UIEventSource<boolean>, layerDef: LayerConfig }){
// This is a dynamic template with a fixed zoom level
url = url.replace("{z}", "" + zoomLevel)
const loadedTiles = new Set<string>();
const self = this;
this.onFail = (msg, url) => {
console.warn(`Could not load geojson layer from`, url, "due to", msg)
loadedTiles.add(url); // We add the url to the 'loadedTiles' in order to not reload it in the future
}
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const neededTiles = locationControl.map(
location => {
// Yup, this is cheating to just get the bounds here
const bounds = State.state.leafletMap.data.getBounds()
const tileRange = Utils.TileRangeBetween(zoomLevel, bounds.getNorth(), bounds.getEast(), bounds.getSouth(), bounds.getWest())
const needed = new Set<string>();
for (let x = tileRange.xstart; x <= tileRange.xend; x++) {
for (let y = tileRange.ystart; y <= tileRange.yend; y++) {
let neededUrl = url.replace("{x}", "" + x).replace("{y}", "" + y);
needed.add(neededUrl)
}
}
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return needed;
}
, [flayer.isDisplayed]);
neededTiles.stabilized(250).addCallback((needed: Set<string>) => {
if (needed === undefined) {
return;
}
if (!flayer.isDisplayed.data) {
// No need to download! - the layer is disabled
return;
}
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if(locationControl.data.zoom < flayer.layerDef.minzoom){
return;
}
needed.forEach(neededTile => {
if (loadedTiles.has(neededTile)) {
return;
}
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loadedTiles.add(neededTile)
self.LoadJSONFrom(neededTile)
})
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})
}
/**
* Merges together the layers which have the same source
* @param flayers
* @param locationControl
* @constructor
*/
public static ConstructMultiSource(flayers: { isDisplayed: UIEventSource<boolean>, layerDef: LayerConfig }[], locationControl: UIEventSource<Loc>): GeoJsonSource[] {
const flayersPerSource = new Map<string, { isDisplayed: UIEventSource<boolean>, layerDef: LayerConfig }[]>();
for (const flayer of flayers) {
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const url = flayer.layerDef.source.geojsonSource?.replace(/{layer}/g, flayer.layerDef.id)
if (url === undefined) {
continue;
}
if (!flayersPerSource.has(url)) {
flayersPerSource.set(url, [])
}
flayersPerSource.get(url).push(flayer)
}
const sources: GeoJsonSource[] = []
flayersPerSource.forEach((flayers, key) => {
if (flayers.length == 1) {
sources.push(new GeoJsonSource(locationControl, flayers[0]));
return;
}
const zoomlevels = Utils.Dedup(flayers.map(flayer => "" + (flayer.layerDef.source.geojsonZoomLevel ?? "")))
if (zoomlevels.length > 1) {
throw "Multiple zoomlevels defined for same geojson source " + key
}
let isShown = new UIEventSource<boolean>(true, "IsShown for multiple layers: or of multiple values");
for (const flayer of flayers) {
flayer.isDisplayed.addCallbackAndRun(() => {
let value = false;
for (const flayer of flayers) {
value = flayer.isDisplayed.data || value;
}
isShown.setData(value);
});
}
const source = new GeoJsonSource(locationControl, {
isDisplayed: isShown,
layerDef: flayers[0].layerDef // We only care about the source info here
})
sources.push(source)
})
return sources;
}
private LoadJSONFrom(url: string) {
const eventSource = this.features;
const self = this;
$.getJSON(url, function (json, status) {
if (status !== "success") {
self.onFail(status, url);
return;
}
if (json.elements === [] && json.remarks.indexOf("runtime error") > 0) {
self.onFail("Runtime error (timeout)", url)
return;
}
const time = new Date();
const newFeatures: { feature: any, freshness: Date } [] = []
let i = 0;
let skipped = 0;
for (const feature of json.features) {
if (feature.properties.id === undefined) {
feature.properties.id = url + "/" + i;
feature.id = url + "/" + i;
i++;
}
if (self.seenids.has(feature.properties.id)) {
skipped++;
continue;
}
self.seenids.add(feature.properties.id)
let freshness: Date = time;
if (feature.properties["_last_edit:timestamp"] !== undefined) {
freshness = new Date(feature["_last_edit:timestamp"])
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}
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newFeatures.push({feature: feature, freshness: freshness})
}
console.debug("Downloaded " + newFeatures.length + " new features and " + skipped + " already seen features from " + url);
if (newFeatures.length == 0) {
return;
}
eventSource.setData(eventSource.data.concat(newFeatures))
}).fail(msg => self.onFail(msg, url))
}
}