Use fetch for tile loads, move loading logic to LiveAtlasTileLayer

src/index.d.ts

@@ -17,7 +17,7 @@
 import {State} from "@/store";
 import {DynmapUrlConfig} from "@/dynmap";
 import LiveAtlasMapDefinition from "@/model/LiveAtlasMapDefinition";
-import {PathOptions, PointTuple, PolylineOptions} from "leaflet";
+import {Coords, DoneCallback, PathOptions, PointTuple, PolylineOptions} from "leaflet";
 import {CoordinatesControlOptions} from "@/leaflet/control/CoordinatesControl";
 import {ClockControlOptions} from "@/leaflet/control/ClockControl";
 import {LogoControlOptions} from "@/leaflet/control/LogoControl";
@@ -313,3 +313,20 @@ interface LiveAtlasChat {
 	source?: string;
 	timestamp: number;
 }
+
+export interface LiveAtlasTile {
+	active?: boolean;
+	coords: Coords;
+	current: boolean;
+	el: LiveAtlasTileElement;
+	loaded?: Date;
+	retain?: boolean;
+	complete: boolean;
+}
+
+export interface LiveAtlasTileElement extends HTMLImageElement {
+	tileName?: string;
+	url: string;
+	callback: DoneCallback;
+	abortController: AbortController;
+}

src/leaflet/tileLayer/DynmapTileLayer.ts

@@ -17,29 +17,15 @@
  * limitations under the License.
  */
 
-import {Coords, DoneCallback, DomUtil} from 'leaflet';
+import {Coords, DoneCallback} from 'leaflet';
 import {useStore} from "@/store";
-import {Coordinate} from "@/index";
+import {Coordinate, LiveAtlasTile} from "@/index";
-import {LiveAtlasTileLayerOptions, LiveAtlasTileLayer} from "@/leaflet/tileLayer/LiveAtlasTileLayer";
+import {LiveAtlasTileLayer, LiveAtlasTileLayerOptions} from "@/leaflet/tileLayer/LiveAtlasTileLayer";
 import {computed, watch} from "@vue/runtime-core";
 import {ComputedRef} from "@vue/reactivity";
 import {WatchStopHandle} from "vue";
 import {ActionTypes} from "@/store/action-types";
 
-export interface DynmapTile {
-	active?: boolean;
-	coords: Coords;
-	current: boolean;
-	el: DynmapTileElement;
-	loaded?: Date;
-	retain?: boolean;
-	complete: boolean;
-}
-
-export interface DynmapTileElement extends HTMLImageElement {
-	tileName: string;
-}
-
 export interface TileInfo {
 	prefix: string;
 	nightday: string;
@@ -56,11 +42,7 @@ const store = useStore();
 
 // noinspection JSUnusedGlobalSymbols
 export class DynmapTileLayer extends LiveAtlasTileLayer {
-	private readonly _cachedTileUrls: Map<any, any> = Object.seal(new Map());
 	private readonly _namedTiles: Map<any, any> = Object.seal(new Map());
-	private readonly _loadQueue: DynmapTileElement[] = [];
-	private readonly _loadingTiles: Set<DynmapTileElement> = Object.seal(new Set());
-	private readonly _tileTemplate: DynmapTileElement;
 	private readonly _baseUrl: string;
 
 	private readonly _night: ComputedRef<boolean>;
@@ -69,26 +51,12 @@ export class DynmapTileLayer extends LiveAtlasTileLayer {
 	private readonly _updateUnwatch: WatchStopHandle;
 	private _updateFrame: number = 0;
 
-	// @ts-ignore
-	declare options: DynmapTileLayerOptions;
-
 	constructor(options: LiveAtlasTileLayerOptions) {
 		super('', options);
 
 		this._mapSettings = options.mapSettings;
-		this._tileTemplate = DomUtil.create('img', 'leaflet-tile') as DynmapTileElement;
-		this._tileTemplate.style.width = this._tileTemplate.style.height = this.options.tileSize + 'px';
-		this._tileTemplate.alt = '';
-		this._tileTemplate.tileName = '';
-		this._tileTemplate.setAttribute('role', 'presentation');
 		this._baseUrl = store.state.currentMapProvider!.getTilesUrl();
 
-		Object.seal(this._tileTemplate);
-
-		if(this.options.crossOrigin || this.options.crossOrigin === '') {
-			this._tileTemplate.crossOrigin = this.options.crossOrigin === true ? '' : this.options.crossOrigin;
-		}
-
 		this._pendingUpdates = computed(() => !!store.state.pendingTileUpdates.length);
 		this._updateUnwatch = watch(this._pendingUpdates, (newValue, oldValue) => {
 			if(newValue && !oldValue && !this._updateFrame) {
@@ -117,75 +85,35 @@ export class DynmapTileLayer extends LiveAtlasTileLayer {
 	}
 
 	private getTileUrlFromName(name: string, timestamp?: number) {
-		let url = this._cachedTileUrls.get(name);
-
-		if (!url) {
 		const path = escape(`${this._mapSettings.world.name}/${name}`);
-			url = `${this._baseUrl}${path}`;
+		let url = `${this._baseUrl}${path}`;
 
 		if(typeof timestamp !== 'undefined') {
 			url += (url.indexOf('?') === -1 ? `?timestamp=${timestamp}` : `&timestamp=${timestamp}`);
 		}
 
-			this._cachedTileUrls.set(name, url);
-		}
-
 		return url;
 	}
 
 	private updateNamedTile(name: string, timestamp: number) {
 		const tile = this._namedTiles.get(name);
-		this._cachedTileUrls.delete(name);
 
 		if (tile) {
 			tile.dataset.src = this.getTileUrlFromName(name, timestamp);
-			this._loadQueue.push(tile);
+			this.loadQueue.push(tile);
-			this._tickLoadQueue();
+			this.tickLoadQueue();
 		}
 	}
 
 	createTile(coords: Coords, done: DoneCallback) {
-		//Clone template image instead of creating a new one
+		const tile = super.createTile(coords, done);
-		const tile = this._tileTemplate.cloneNode(false) as DynmapTileElement;
 
 		tile.tileName = this.getTileName(coords);
-		tile.dataset.src = this.getTileUrl(coords);
-
 		this._namedTiles.set(tile.tileName, tile);
-		this._loadQueue.push(tile);
-
-		//Use addEventListener here
-		tile.onload = () => {
-			this._tileOnLoad(done, tile);
-			this._loadingTiles.delete(tile);
-			this._tickLoadQueue();
-		};
-		tile.onerror = () => {
-			this._tileOnError(done, tile, {name: 'Error', message: 'Error'});
-			this._loadingTiles.delete(tile);
-			this._tickLoadQueue();
-		};
-
-		this._tickLoadQueue();
 
 		return tile;
 	}
 
-	_tickLoadQueue() {
-		if (this._loadingTiles.size > 6) {
-			return;
-		}
-
-		const tile = this._loadQueue.shift();
-
-		if (!tile) {
-			return;
-		}
-
-		this._loadingTiles.add(tile);
-		tile.src = tile.dataset.src as string;
-	}
-
 	// stops loading all tiles in the background layer
 	_abortLoading() {
 		let tile;
@@ -195,18 +123,12 @@ export class DynmapTileLayer extends LiveAtlasTileLayer {
 				continue;
 			}
 
-			tile = this._tiles[i] as DynmapTile;
+			tile = this._tiles[i] as LiveAtlasTile;
 
 			if (tile.coords.z !== this._tileZoom) {
 				if (tile.loaded && tile.el && tile.el.tileName) {
 					this._namedTiles.delete(tile.el.tileName);
 				}
-
-				if(this._loadQueue.includes(tile.el)) {
-					this._loadQueue.splice(this._loadQueue.indexOf(tile.el), 1);
-				}
-
-				this._loadingTiles.delete(tile.el);
 			}
 		}
 
@@ -214,7 +136,7 @@ export class DynmapTileLayer extends LiveAtlasTileLayer {
 	}
 
 	_removeTile(key: string) {
-		const tile = this._tiles[key] as DynmapTile;
+		const tile = this._tiles[key] as LiveAtlasTile;
 
 		if (!tile) {
 			return;
@@ -224,15 +146,6 @@ export class DynmapTileLayer extends LiveAtlasTileLayer {
 
 		if (tileName) {
 			this._namedTiles.delete(tileName);
-			this._cachedTileUrls.delete(tileName);
-			this._loadingTiles.delete(tile.el);
-
-			if(this._loadQueue.includes(tile.el)) {
-				this._loadQueue.splice(this._loadQueue.indexOf(tile.el), 1);
-			}
-
-			tile.el.onerror = null;
-			tile.el.onload = null;
 		}
 
 		// @ts-ignore

src/leaflet/tileLayer/LiveAtlasTileLayer.ts

@@ -14,8 +14,10 @@
  * limitations under the License.
  */
 
-import {TileLayer, TileLayerOptions, Util} from 'leaflet';
 import LiveAtlasMapDefinition from "@/model/LiveAtlasMapDefinition";
+import {Coords, DomUtil, DoneCallback, TileLayer, TileLayerOptions, Util} from "leaflet";
+import {LiveAtlasTile, LiveAtlasTileElement} from "@/index";
+import falseFn = Util.falseFn;
 
 export interface LiveAtlasTileLayerOptions extends TileLayerOptions {
 	mapSettings: LiveAtlasMapDefinition;
@@ -27,10 +29,29 @@ export abstract class LiveAtlasTileLayer extends TileLayer {
 	protected _mapSettings: LiveAtlasMapDefinition;
 	declare options: LiveAtlasTileLayerOptions;
 
+	private readonly tileTemplate: LiveAtlasTileElement;
+	protected readonly loadQueue: LiveAtlasTileElement[] = [];
+	private readonly loadingTiles: Set<LiveAtlasTileElement> = Object.seal(new Set());
+
+	private static genericLoadError = new Error('Tile failed to load');
+
 	protected constructor(url: string, options: LiveAtlasTileLayerOptions) {
 		super(url, options);
 
 		this._mapSettings = options.mapSettings;
+		this.tileTemplate = DomUtil.create('img', 'leaflet-tile') as LiveAtlasTileElement;
+		this.tileTemplate.style.width = this.tileTemplate.style.height = this.options.tileSize + 'px';
+		this.tileTemplate.alt = '';
+		this.tileTemplate.tileName = '';
+		this.tileTemplate.callback = falseFn;
+		this.tileTemplate.setAttribute('role', 'presentation');
+
+		if(this.options.crossOrigin || this.options.crossOrigin === '') {
+			this.tileTemplate.crossOrigin = this.options.crossOrigin === true ? '' : this.options.crossOrigin;
+		}
+
+		Object.seal(this.tileTemplate);
+
 		options.maxZoom = this._mapSettings.nativeZoomLevels + this._mapSettings.extraZoomLevels;
 		options.maxNativeZoom = this._mapSettings.nativeZoomLevels;
 		options.zoomReverse = true;
@@ -43,4 +64,133 @@ export abstract class LiveAtlasTileLayer extends TileLayer {
 			throw new TypeError("mapSettings missing");
 		}
 	}
+
+	// @method createTile(coords: Object, done?: Function): HTMLElement
+	// Called only internally, overrides GridLayer's [`createTile()`](#gridlayer-createtile)
+	// to return an `<img>` HTML element with the appropriate image URL given `coords`. The `done`
+	// callback is called when the tile has been loaded.
+	createTile(coords: Coords, done: DoneCallback) {
+		const tile = this.tileTemplate.cloneNode(false) as LiveAtlasTileElement;
+		this.loadQueue.push(tile);
+
+		tile.onload = () => {
+			URL.revokeObjectURL(tile.src); //Revoke the object URL as we don't need it anymore
+
+			this._tileOnLoad(done, tile);
+			this.loadingTiles.delete(tile);
+			this.tickLoadQueue();
+		};
+
+		tile.onerror = () => {
+			this._tileOnError(done, tile, LiveAtlasTileLayer.genericLoadError);
+			this.loadingTiles.delete(tile);
+			this.tickLoadQueue();
+		};
+
+		tile.url = this.getTileUrl(coords);
+		tile.callback = done;
+
+		this.tickLoadQueue();
+
+		return tile;
+	}
+
+	private async fetchTile(tile: LiveAtlasTileElement) {
+		if(tile.abortController && !tile.abortController.signal.aborted) {
+			tile.abortController.abort();
+		}
+
+		tile.abortController = new AbortController();
+
+		try {
+			//Retrieve image via a fetch instead of just setting the src
+			//This works around the fact that browsers usually don't make a request for an image that was previously loaded,
+			//without resorting to changing the URL (which would break caching).
+			const response = await fetch(tile.url, {signal: tile.abortController.signal});
+
+			//Call leaflet's error handler if request fails for some reason
+			if (!response.ok) {
+				this._tileOnError(tile.callback, tile, new Error('Response was not ok'));
+				return;
+			}
+
+			//Get image data and convert into object URL so it can be used as a src
+			//The tile onload listener will take it from here
+			const blob = await response.blob();
+			tile.src = URL.createObjectURL(blob);
+		} catch(e) {
+			if (e instanceof DOMException && e.name === 'AbortError') {
+				return;
+			}
+
+			console.error(e);
+
+			this._tileOnError(tile.callback, tile, e);
+		}
+	}
+
+	protected tickLoadQueue() {
+		if (this.loadingTiles.size > 6) {
+			return;
+		}
+
+		const tile = this.loadQueue.shift();
+
+		if (!tile) {
+			return;
+		}
+
+		this.loadingTiles.add(tile);
+		this.fetchTile(tile);
+	}
+
+	_abortLoading() {
+		let tile;
+
+		for (const i in this._tiles) {
+			if (!Object.prototype.hasOwnProperty.call(this._tiles, i)) {
+				continue;
+			}
+
+			tile = this._tiles[i] as LiveAtlasTile;
+
+			if (tile.coords.z !== this._tileZoom) {
+				if (!tile.loaded && tile.el && tile.el.abortController) {
+					tile.el.abortController.abort();
+				}
+
+				if(this.loadQueue.includes(tile.el)) {
+					this.loadQueue.splice(this.loadQueue.indexOf(tile.el), 1);
+				}
+
+				this.loadingTiles.delete(tile.el);
+			}
+		}
+
+		super._abortLoading.call(this);
+	}
+
+	_removeTile(key: string) {
+		const tile = this._tiles[key] as LiveAtlasTile;
+
+		if (!tile) {
+			return;
+		}
+
+		this.loadingTiles.delete(tile.el);
+
+		if(this.loadQueue.includes(tile.el)) {
+			this.loadQueue.splice(this.loadQueue.indexOf(tile.el), 1);
+		}
+
+		tile.el.onerror = null;
+		tile.el.onload = null;
+
+		if(!tile.loaded && tile.el.abortController) {
+			tile.el.abortController.abort();
+		}
+
+		// @ts-ignore
+		super._removeTile(key);
+	}
 }