itowns/lib/Source/C3DTilesGoogleSource.js

A JS/WebGL framework for 3D geospatial data visualization

import Fetcher from "../Provider/Fetcher.js";
import C3DTilesSource from "./C3DTilesSource.js";
function findSessionId(tile) {
  if (!tile) {
    return null;
  }
  if (tile.content && tile.content.uri) {
    const searchParams = new URLSearchParams(tile.content.uri.slice(tile.content.uri.indexOf('?') + 1));
    return searchParams.get('session');
  } else if (tile.children && tile.children.length > 0) {
    for (const c of tile.children) {
      const sessionId = findSessionId(c);
      if (sessionId) {
        return sessionId;
      }
    }
  }
  return null;
}

/**
 * An object defining the source connection to a 3DTiles asset from a [Google api](https://tile.googleapis.com).
 *
 * @extends C3DTilesSource
 *
 * @property {boolean} isC3DTilesGoogleSource - Used to checkout whether this source is a C3DTilesGoogleSource. Default is
 * true. You should not change this, as it is used internally for optimisation.
 * @property {string} url - The URL to the tileset json.
 * @property {string} baseUrl - The base URL to access tiles.
 */
class C3DTilesGoogleSource extends C3DTilesSource {
  /**
   * Create a new Source for 3D Tiles data from Google api (experimental).
   *
   * @extends C3DTilesSource
   *
   * @property {boolean} isC3DTilesGoogleSource - Used to checkout whether this source is a C3DTilesGoogleSource. Default is
   * true. You should not change this, as it is used internally for optimisation.
   * @param {Object} source An object that can contain all properties of a C3DTilesGoogleSource and {@link Source}.
   * @param {String} source.key Your google tiles map API access key
   */
  constructor(source) {
    if (!source.key) {
      throw new Error('[C3DTilesGoogleSource]: A API key for the google map tiles API is required');
    }
    // URL to the root tileset
    source.url = `https://tile.googleapis.com/v1/3dtiles/root.json?key=${source.key}`;
    super(source);
    this.isC3DTilesGoogleSource = true;
    this.baseUrl = 'https://tile.googleapis.com';
    this.key = source.key;
    this.whenReady = Fetcher.json(source.url, this.networkOptions).then(json => {
      if (json && json.root) {
        this.sessionId = findSessionId(json.root);
        if (this.sessionId === null) {
          throw new Error('[C3DTilesGoogleSource]: Cannot find sessionId from the tileset while it is mandatory to request tiles.');
        }
      }
      return json;
    });
  }

  /**
   * Adds the key and session to the tile url (non-standard behaviour, that is specific to Google 3D tiles),
   * see https://github.com/CesiumGS/3d-tiles/issues/746
   * @param {String} url the tile url
   * @returns {String} the tile url with Google map tiles api key and session parameters added at the end of the url
   */
  getTileUrl(url) {
    const extraParameters = `key=${this.key}&session=${this.sessionId}`;
    return /\?/.test(url) ? `${url}&${extraParameters}` : `${url}?${extraParameters}`;
  }
}
export default C3DTilesGoogleSource;