feat: add collections option to OGCVectorTile source

src/ol/source/OGCMapTile.js

@@ -33,13 +33,17 @@ import {error as logError} from '../console.js';
  * @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
  * @property {number} [transition] Duration of the opacity transition for rendering.
  * To disable the opacity transition, pass `transition: 0`.
+ * @property {Array<string>} [collections] A list of geospatial data sub-resources to include. If not provided, the entire dataset will
+ * be included. This option is not applicable when requesting the tileset for a single collection.
  */
 
 /**
  * @classdesc
  * Layer source for map tiles from an [OGC API - Tiles](https://ogcapi.ogc.org/tiles/) service that provides "map" type tiles.
  * The service must conform to at least the core (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/core)
- * and tileset (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/tileset) conformance classes.
+ * and tileset (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/tileset) conformance classes. For supporting the `collections`
+ * option, the service must conform to the collections selection
+ * (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/collections-selection) conformance class.
  * @api
  */
 class OGCMapTile extends TileImage {
@@ -65,6 +69,7 @@ class OGCMapTile extends TileImage {
       projection: this.getProjection(),
       mediaType: options.mediaType,
       context: options.context || null,
+      collections: options.collections,
     };
 
     getTileSetInfo(sourceInfo)

src/ol/source/OGCVectorTile.js

@@ -33,13 +33,17 @@ import {error as logError} from '../console.js';
  * @property {number|import("../array.js").NearestDirectionFunction} [zDirection=1]
  * Choose whether to use tiles with a higher or lower zoom level when between integer
  * zoom levels. See {@link module:ol/tilegrid/TileGrid~TileGrid#getZForResolution}.
+ * @property {Array<string>} [collections] A list of geospatial data sub-resources to include. If not provided, the entire dataset will
+ * be included. This option is not applicable when requesting the tileset for a single collection.
  */
 
 /**
  * @classdesc
  * Layer source for map tiles from an [OGC API - Tiles](https://ogcapi.ogc.org/tiles/) service that provides "vector" type tiles.
  * The service must conform to at least the core (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/core)
- * and tileset (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/tileset) conformance classes.
+ * and tileset (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/tileset) conformance classes. For supporting the `collections`
+ * option, the service must conform to the collections selection
+ * (http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/collections-selection) conformance class.
  *
  * Vector tile sets may come in a variety of formats (e.g. GeoJSON, MVT).  The `format` option is used to determine
  * which of the advertised media types is used.  If you need to force the use of a particular media type, you can
@@ -71,6 +75,7 @@ class OGCVectorTile extends VectorTileSource {
       mediaType: options.mediaType,
       supportedMediaTypes: options.format.supportedMediaTypes,
       context: options.context || null,
+      collections: options.collections,
     };
 
     getTileSetInfo(sourceInfo)

src/ol/source/ogcTileUtil.js

@@ -6,6 +6,7 @@ import TileGrid from '../tilegrid/TileGrid.js';
 import {getJSON, resolveUrl} from '../net.js';
 import {get as getProjection} from '../proj.js';
 import {getIntersection as intersectExtents} from '../extent.js';
+import {error as logError} from '../console.js';
 
 /**
  * See https://ogcapi.ogc.org/tiles/.
@@ -96,14 +97,50 @@ const knownVectorMediaTypes = {
  * @property {Array<string>} [supportedMediaTypes] The supported media types.
  * @property {import("../proj/Projection.js").default} projection The source projection.
  * @property {Object} [context] Optional context for constructing the URL.
+ * @property {Array<string>} [collections] Optional collections to append the URL with.
  */
 
+/**
+ * @param {string} tileUrlTemplate Tile URL template.
+ * @param {Array<string>} collections List of collections to include as query parameter.
+ * @return {string} The tile URL template with appended collections query parameter.
+ */
+export function appendCollectionsQueryParam(tileUrlTemplate, collections) {
+  if (!collections.length) {
+    return tileUrlTemplate;
+  }
+
+  // making sure we can always construct a URL instance.
+  const url = new URL(tileUrlTemplate, 'file://');
+
+  if (url.pathname.split('/').includes('collections')) {
+    logError(
+      'The "collections" query parameter cannot be added to collection endpoints',
+    );
+    return tileUrlTemplate;
+  }
+  // According to conformance class
+  // http://www.opengis.net/spec/ogcapi-tiles-1/1.0/conf/collections-selection
+  // commata in the identifiers of the `collections` query parameter
+  // need to be URLEncoded, while the commata separating the identifiers
+  // should not.
+  const encodedCollections = collections
+    .map((c) => encodeURIComponent(c))
+    .join(',');
+
+  url.searchParams.append('collections', encodedCollections);
+  const baseUrl = tileUrlTemplate.split('?')[0];
+  const queryParams = decodeURIComponent(url.searchParams.toString());
+  return `${baseUrl}?${queryParams}`;
+}
+
 /**
  * @param {Array<Link>} links Tileset links.
  * @param {string} [mediaType] The preferred media type.
+ * @param {Array<string>} [collections] Optional collections to append the URL with.
  * @return {string} The tile URL template.
  */
-export function getMapTileUrlTemplate(links, mediaType) {
+export function getMapTileUrlTemplate(links, mediaType, collections) {
   let tileUrlTemplate;
   let fallbackUrlTemplate;
   for (let i = 0; i < links.length; ++i) {
@@ -129,19 +166,25 @@ export function getMapTileUrlTemplate(links, mediaType) {
     }
   }
 
+  if (collections) {
+    tileUrlTemplate = appendCollectionsQueryParam(tileUrlTemplate, collections);
+  }
+
   return tileUrlTemplate;
 }
 
 /**
  * @param {Array<Link>} links Tileset links.
  * @param {string} [mediaType] The preferred media type.
  * @param {Array<string>} [supportedMediaTypes] The media types supported by the parser.
+ * @param {Array<string>} [collections] Optional collections to append the URL with.
  * @return {string} The tile URL template.
  */
 export function getVectorTileUrlTemplate(
   links,
   mediaType,
   supportedMediaTypes,
+  collections,
 ) {
   let tileUrlTemplate;
   let fallbackUrlTemplate;
@@ -184,6 +227,10 @@ export function getVectorTileUrlTemplate(
     }
   }
 
+  if (collections) {
+    tileUrlTemplate = appendCollectionsQueryParam(tileUrlTemplate, collections);
+  }
+
   return tileUrlTemplate;
 }
 
@@ -362,12 +409,14 @@ function parseTileSetMetadata(sourceInfo, tileSet) {
     tileUrlTemplate = getMapTileUrlTemplate(
       tileSet.links,
       sourceInfo.mediaType,
+      sourceInfo.collections,
     );
   } else if (tileSet.dataType === 'vector') {
     tileUrlTemplate = getVectorTileUrlTemplate(
       tileSet.links,
       sourceInfo.mediaType,
       sourceInfo.supportedMediaTypes,
+      sourceInfo.collections,
     );
   } else {
     throw new Error('Expected tileset data type to be "map" or "vector"');