Class Protocol

js/src/adapters.ts:172–283

 * MapLibre GL JS protocol. Must be added once globally.
 */
export class Protocol {
  /** @hidden */
  tiles: Map<string, PMTiles>;
  metadata: boolean;
  errorOnMissingTile: boolean;

  /**
   * Initialize the MapLibre PMTiles protocol.
   *
   * * metadata: also load the metadata section of the PMTiles. required for some "inspect" functionality
   * and to automatically populate the map attribution. Requires an extra HTTP request.
   * * errorOnMissingTile: When a vector MVT tile is missing from the archive, raise an error instead of
   * returning the empty array. Not recommended. This is only to reproduce the behavior of ZXY tile APIs
   * which some applications depend on when overzooming.
   */
  constructor(options?: { metadata?: boolean; errorOnMissingTile?: boolean }) {
    this.tiles = new Map<string, PMTiles>();
    this.metadata = options?.metadata || false;
    this.errorOnMissingTile = options?.errorOnMissingTile || false;
  }

  /**
   * Add a {@link PMTiles} instance to the global protocol instance.
   *
   * For remote fetch sources, references in MapLibre styles like pmtiles://http://...
   * will resolve to the same instance if the URLs match.
   */
  add(p: PMTiles) {
    this.tiles.set(p.source.getKey(), p);
  }

  /**
   * Fetch a {@link PMTiles} instance by URL, for remote PMTiles instances.
   */
  get(url: string) {
    return this.tiles.get(url);
  }

  /** @hidden */
  tilev4 = async (
    params: RequestParameters,
    abortController: AbortController
  ) => {
    if (params.type === "json") {
      const pmtilesUrl = params.url.substr(10);
      let instance = this.tiles.get(pmtilesUrl);
      if (!instance) {
        instance = new PMTiles(pmtilesUrl);
        this.tiles.set(pmtilesUrl, instance);
      }

      if (this.metadata) {
        const data = await instance.getTileJson(params.url);
        abortController.signal.throwIfAborted();
        return { data };
      }

      const h = await instance.getHeader();