iTowns / itowns / 17292947856

import { Extent, CRS } from '@itowns/geographic';

/**

 * This interface describes parsing options.

 * @typedef {Object} ParsingOptions

 * @property {Source} in - data informations contained in the file.

 * @property {FeatureBuildingOptions|Layer} out - options indicates how the features should be built.

 */

let uid = 0;

/**

 * Sources are object containing informations on how to fetch resources, from a

 * set source.

 *

 * To extend a Source, it is necessary to implement two functions:

 * `urlFromExtent` and `extentInsideLimit`.

 *

 * @extends InformationsData

 *

 * @property {boolean} isSource - Used to checkout whether this source is a

 * Source. Default is true. You should not change this, as it is used internally

 * for optimisation.

 * @property {number} uid - Unique uid mainly used to store data linked to this

 * source into Cache.

 * @property {string} url - The url of the resources that are fetched.

 * @property {string} format - The format of the resources that are fetched.

 * @property {function} fetcher - The method used to fetch the resources from

 * the source. iTowns provides some methods in {@link Fetcher}, but it can be

 * specified a custom one. This method should return a `Promise` containing the

 * fetched resource. If this property is set, it overrides the chosen fetcher

 * method with `format`.

 * @property {Object} networkOptions - Fetch options (passed directly to

 * `fetch()`), see [the syntax for more information](

 * https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Syntax).

 * By default, set to `{ crossOrigin: 'anonymous' }`.

 * @property {string} crs - The crs projection of the resources.

 * @property {string} attribution - The intellectual property rights for the

 * resources.

 * @property {Extent} extent - The extent of the resources.

 * @property {function} parser - The method used to parse the resources attached

 * to the layer. iTowns provides some parsers, visible in the `Parser/` folder.

 * If the method is custom, it should return a `Promise` containing the parsed

 * resource. If this property is set, it overrides the default selected parser

 * method with `source.format`. If `source.format` is also empty, no parsing

 * action is done.

 * <br><br>

 * When calling this method, two parameters are passed:

 * <ul>

 *  <li>the fetched data, i.e. the data to parse</li>

 *  <li>an {@link ParsingOptions}  containing severals properties, set when this method is

 *  called: it is specific to each call, so the value of each property can vary

 *  depending on the current fetched tile for example</li>

 * </ul>

 */

class Source {

    /**

     * @param {Object} source - An object that can contain all properties of a

     * Source. Only the `url` property is mandatory.

     */

        if (source.crs) {

            CRS.isValid(source.crs);

        }

        this.crs = source.crs;

        this.isSource = true;

        this.uid = uid++;

        this.attribution = source.attribution;

        /** @type {Promise<any>} */

        this.whenReady = Promise.resolve();

        if (source.extent && !(source.extent.isExtent)) {

            this.extent = new Extent(this.crs).setFromExtent(source.extent);

        } else {

            this.extent = source.extent;

        }

    }

    handlingError(err) {

        throw new Error(err);

    }

    /**

     * Generates an url from an extent. This url is a link to fetch the

     * resources inside the extent.

     *

     * @param {Extent} extent - Extent to convert in url.

     * @return {string} The URL constructed from the extent.

     */

    // eslint-disable-next-line

    urlFromExtent(extent) {

        throw new Error('In extended Source, you have to implement the method urlFromExtent!');

    }

    // eslint-disable-next-line

    getDataKey(extent) {

    // eslint-disable-next-line

    loadData(extent, out) {

    /**

     * Called when layer added.

     *

     * @param {object} options

     */

    // eslint-disable-next-line

    onLayerAdded(options) {}

    /**

     * Called when layer removed.

     *

     * @param {options}  [options={}] options

     */

    // eslint-disable-next-line

    /**

     * Tests if an extent is inside the source limits.

     *

     * @param {Extent} extent - Extent to test.

     * @return {boolean} True if the extent is inside the limit, false otherwise.

     */

    // eslint-disable-next-line

    extentInsideLimit(extent) {

        throw new Error('In extented Source, you have to implement the method extentInsideLimit!');

    }

}

export default Source;