itowns/lib/Source/C3DTilesIonSource.js

A JS/WebGL framework for 3D geospatial data visualization

import Fetcher from "../Provider/Fetcher.js";
import C3DTilesSource from "./C3DTilesSource.js";

/**
 * An object defining the source connection to a 3DTiles asset of a [Cesium ion server](https://cesium.com/learn/ion/).
 *
 * @extends Source
 *
 * @property {boolean} isC3DTilesIonSource - Used to checkout whether this source is a C3DTilesIonSource. Default is
 * true. You should not change this, as it is used internally for optimisation.
 * @property {string} url - The URL of the tileset json.
 * @property {string} baseUrl - The base URL to access tiles.
 * @property {string} accessToken - The Cesium ion access token used to retrieve the resource.
 * @property {string} assetId - The id of the asset on Cesium ion.
 */
class C3DTilesIonSource extends C3DTilesSource {
  /**
   * Create a new Source for 3D Tiles data from Cesium ion.
   *
   * @extends Source
   *
   * @param {Object} source An object that can contain all properties of a C3DTilesIonSource and {@link Source}.
   * Only `accessToken` and `assetId` are mandatory.
   */
  constructor(source) {
    if (!source.accessToken) {
      throw new Error('New 3D Tiles Ion Source: access token is required');
    }
    if (!source.assetId) {
      throw new Error('New 3D Tiles Ion Source: asset id is required');
    }

    // Url to query cesium ion the first time to retrieve metadata of the asset with assetId
    source.url = `https://api.cesium.com/v1/assets/${source.assetId}/endpoint?access_token=${source.accessToken}`;
    super(source);
    this.isC3DTilesIonSource = true;
    this.accessToken = source.accessToken;
    this.assetId = source.assetId;

    // get asset metadata
    this.whenReady = Fetcher.json(source.url, this.networkOptions).then(json => {
      if (json.type !== '3DTILES') {
        throw new Error(`${json.type} datasets from Cesium ion are not supported with C3DTilesIonSource. ` + 'Only 3D Tiles datasets are supported.');
      }
      this.url = json.url; // Store url to the tileset.json
      this.baseUrl = json.url.slice(0, json.url.lastIndexOf('/') + 1); // baseUrl for tiles queries
      this.networkOptions.headers = {};
      this.networkOptions.headers.Authorization = `Bearer ${json.accessToken}`;
      this.attribution = json.attributions;
      return Fetcher.json(this.url, this.networkOptions);
    });
  }
}
export default C3DTilesIonSource;