Add possibility to add external geojson

Logic/FeatureSource/FeaturePipeline.ts

@@ -11,6 +11,7 @@ import LayerConfig from "../../Customizations/JSON/LayerConfig";
 import LocalStorageSource from "./LocalStorageSource";
 import LayoutConfig from "../../Customizations/JSON/LayoutConfig";
 import Loc from "../../Models/Loc";
+import GeoJsonSource from "./GeoJsonSource";
 
 export default class FeaturePipeline implements FeatureSource {
 
@@ -30,6 +31,15 @@ export default class FeaturePipeline implements FeatureSource {
                 )
             );
 
+        const geojsonSources: GeoJsonSource [] = []
+        for (const flayer of flayers.data) {
+            const sourceUrl = flayer.layerDef.source.geojsonSource
+            if (sourceUrl !== undefined) {
+                geojsonSources.push(new WayHandlingApplyingFeatureSource(flayers, 
+                    new GeoJsonSource(flayer.layerDef.id, sourceUrl)))
+            }
+        }
+
         const amendedLocalStorageSource =
             new RememberingSource(
                 new WayHandlingApplyingFeatureSource(flayers,
@@ -37,11 +47,12 @@ export default class FeaturePipeline implements FeatureSource {
                 ));
 
         newPoints = new FeatureDuplicatorPerLayer(flayers, newPoints);
-        
+
         const merged = new FeatureSourceMerger([
             amendedOverpassSource,
             amendedLocalStorageSource,
-            newPoints
+            newPoints,
+            ...geojsonSources
         ]);
 
         const source =

Logic/FeatureSource/FeatureSourceMerger.ts

@@ -22,7 +22,6 @@ export default class FeatureSourceMerger implements FeatureSource {
         let all = {}; // Mapping 'id' -> {feature, freshness}
         for (const source of this._sources) {
             if(source?.features?.data === undefined){
-                console.log("Not defined");
                 continue;
             }
             for (const f of source.features.data) {

Logic/FeatureSource/GeoJsonSource.ts

@@ -0,0 +1,52 @@
+import FeatureSource from "./FeatureSource";
+import {UIEventSource} from "../UIEventSource";
+import * as $ from "jquery";
+import {Layer} from "leaflet";
+
+/**
+ * Fetches a geojson file somewhere and passes it along
+ */
+export default class GeoJsonSource implements FeatureSource {
+    features: UIEventSource<{ feature: any; freshness: Date }[]>;
+
+    constructor(layerId: string, url: string, onFail: ((errorMsg: any) => void) = undefined) {
+        if (onFail === undefined) {
+            onFail = errorMsg => {
+                console.warn(`Could not load geojson layer from`, url, "due to", errorMsg)
+            }
+        }
+        this.features = new UIEventSource<{ feature: any; freshness: Date }[]>(undefined)
+        const eventSource = this.features;
+        $.getJSON(url, function (json, status) {
+            if (status !== "success") {
+                console.log("Fetching geojson failed failed")
+                onFail(status);
+                return;
+            }
+
+            if (json.elements === [] && json.remarks.indexOf("runtime error") > 0) {
+                console.log("Timeout or other runtime error");
+                onFail("Runtime error (timeout)")
+                return;
+            }
+            const time = new Date();
+            const features: { feature: any, freshness: Date } [] = []
+            let i = 0;
+            for (const feature of json.features) {
+                if (feature.properties.id === undefined) {
+                    feature.properties.id = url + "/" + i;
+                    feature.id = url + "/" + i;
+                    i++;
+                }
+                feature._matching_layer_id = layerId;
+                features.push({feature: feature, freshness: time})
+            }
+            console.log("Loaded features are", features)
+            eventSource.setData(features)
+
+        }).fail(onFail)
+
+    }
+
+
+}