134 lines
5.2 KiB
JavaScript
134 lines
5.2 KiB
JavaScript
/**
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* @module ol/featureloader
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*/
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import {VOID} from './functions.js';
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import FormatType from './format/FormatType.js';
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/**
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* {@link module:ol/source/Vector} sources use a function of this type to
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* load features.
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*
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* This function takes an {@link module:ol/extent~Extent} representing the area to be loaded,
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* a `{number}` representing the resolution (map units per pixel) and an
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* {@link module:ol/proj/Projection} for the projection as
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* arguments. `this` within the function is bound to the
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* {@link module:ol/source/Vector} it's called from.
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*
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* The function is responsible for loading the features and adding them to the
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* source.
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* @typedef {function(this:(import("./source/Vector").default|import("./VectorTile.js").default), import("./extent.js").Extent, number,
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* import("./proj/Projection.js").default): void} FeatureLoader
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* @api
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*/
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/**
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* {@link module:ol/source/Vector} sources use a function of this type to
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* get the url to load features from.
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*
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* This function takes an {@link module:ol/extent~Extent} representing the area
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* to be loaded, a `{number}` representing the resolution (map units per pixel)
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* and an {@link module:ol/proj/Projection} for the projection as
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* arguments and returns a `{string}` representing the URL.
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* @typedef {function(import("./extent.js").Extent, number, import("./proj/Projection.js").default): string} FeatureUrlFunction
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* @api
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*/
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/**
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* @param {string|FeatureUrlFunction} url Feature URL service.
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* @param {import("./format/Feature.js").default} format Feature format.
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* @param {function(this:import("./VectorTile.js").default, Array<import("./Feature.js").default>, import("./proj/Projection.js").default, import("./extent.js").Extent): void|function(this:import("./source/Vector").default, Array<import("./Feature.js").default>): void} success
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* Function called with the loaded features and optionally with the data
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* projection. Called with the vector tile or source as `this`.
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* @param {function(this:import("./VectorTile.js").default): void|function(this:import("./source/Vector").default): void} failure
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* Function called when loading failed. Called with the vector tile or
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* source as `this`.
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* @return {FeatureLoader} The feature loader.
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*/
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export function loadFeaturesXhr(url, format, success, failure) {
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return (
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/**
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* @param {import("./extent.js").Extent} extent Extent.
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* @param {number} resolution Resolution.
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* @param {import("./proj/Projection.js").default} projection Projection.
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* @this {import("./source/Vector").default|import("./VectorTile.js").default}
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*/
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function(extent, resolution, projection) {
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const xhr = new XMLHttpRequest();
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xhr.open('GET',
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typeof url === 'function' ? url(extent, resolution, projection) : url,
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true);
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if (format.getType() == FormatType.ARRAY_BUFFER) {
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xhr.responseType = 'arraybuffer';
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}
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/**
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* @param {Event} event Event.
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* @private
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*/
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xhr.onload = function(event) {
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// status will be 0 for file:// urls
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if (!xhr.status || xhr.status >= 200 && xhr.status < 300) {
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const type = format.getType();
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/** @type {Document|Node|Object|string|undefined} */
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let source;
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if (type == FormatType.JSON || type == FormatType.TEXT) {
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source = xhr.responseText;
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} else if (type == FormatType.XML) {
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source = xhr.responseXML;
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if (!source) {
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source = new DOMParser().parseFromString(xhr.responseText, 'application/xml');
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}
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} else if (type == FormatType.ARRAY_BUFFER) {
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source = /** @type {ArrayBuffer} */ (xhr.response);
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}
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if (source) {
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success.call(this, format.readFeatures(source, {
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extent: extent,
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featureProjection: projection
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}),
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format.readProjection(source));
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} else {
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failure.call(this);
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}
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} else {
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failure.call(this);
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}
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}.bind(this);
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/**
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* @private
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*/
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xhr.onerror = function() {
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failure.call(this);
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}.bind(this);
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xhr.send();
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}
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);
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}
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/**
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* Create an XHR feature loader for a `url` and `format`. The feature loader
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* loads features (with XHR), parses the features, and adds them to the
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* vector source.
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* @param {string|FeatureUrlFunction} url Feature URL service.
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* @param {import("./format/Feature.js").default} format Feature format.
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* @return {FeatureLoader} The feature loader.
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* @api
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*/
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export function xhr(url, format) {
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return loadFeaturesXhr(url, format,
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/**
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* @param {Array<import("./Feature.js").default>} features The loaded features.
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* @param {import("./proj/Projection.js").default} dataProjection Data
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* projection.
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* @this {import("./source/Vector").default|import("./VectorTile.js").default}
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*/
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function(features, dataProjection) {
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const sourceOrTile = /** @type {?} */ (this);
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if (typeof sourceOrTile.addFeatures === 'function') {
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/** @type {import("./source/Vector").default} */ (sourceOrTile).addFeatures(features);
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}
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}, /* FIXME handle error */ VOID);
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}
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