Add loader and strategy to ol.source.Vector

2015-04-03 20:13:50 +02:00
parent e86fd4afd4
commit 09b90c8424
7 changed files with 251 additions and 16 deletions
--- a/src/ol/featureloader.js
+++ b/src/ol/featureloader.js
@@ -0,0 +1,116 @@
+goog.provide('ol.FeatureLoader');
+goog.provide('ol.featureloader');
+
+goog.require('goog.asserts');
+goog.require('goog.events');
+goog.require('goog.net.EventType');
+goog.require('goog.net.XhrIo');
+goog.require('goog.net.XhrIo.ResponseType');
+goog.require('ol.format.FormatType');
+goog.require('ol.xml');
+
+
+/**
+ * @typedef {function(this:ol.source.Vector, ol.Extent, number,
+ *                    ol.proj.Projection)}
+ */
+ol.FeatureLoader;
+
+
+/**
+ * @param {string} url Feature URL service.
+ * @param {ol.format.Feature} format Feature format.
+ * @param {function(this:ol.source.Vector, Array.<ol.Feature>)} success
+ *     Function called with the loaded features. Called with the vector
+ *     source as `this`.
+ * @return {ol.FeatureLoader} The feature loader.
+ */
+ol.featureloader.loadFeaturesXhr = function(url, format, success) {
+  return (
+      /**
+       * @param {ol.Extent} extent Extent.
+       * @param {number} resolution Resolution.
+       * @param {ol.proj.Projection} projection Projection.
+       * @this {ol.source.Vector}
+       */
+      function(extent, resolution, projection) {
+        var xhrIo = new goog.net.XhrIo();
+        var type = format.getType();
+        var responseType;
+        // FIXME maybe use ResponseType.DOCUMENT?
+        if (type == ol.format.FormatType.BINARY &&
+            ol.has.ARRAY_BUFFER) {
+          responseType = goog.net.XhrIo.ResponseType.ARRAY_BUFFER;
+        } else {
+          responseType = goog.net.XhrIo.ResponseType.TEXT;
+        }
+        xhrIo.setResponseType(responseType);
+        goog.events.listen(xhrIo, goog.net.EventType.COMPLETE,
+            /**
+             * @param {Event} event Event.
+             * @private
+             * @this {ol.source.Vector}
+             */
+            function(event) {
+              var xhrIo = event.target;
+              goog.asserts.assertInstanceof(xhrIo, goog.net.XhrIo,
+                  'event.target/xhrIo is an instance of goog.net.XhrIo');
+              if (xhrIo.isSuccess()) {
+                var type = format.getType();
+                /** @type {ArrayBuffer|Document|Node|Object|string|undefined} */
+                var source;
+                if (type == ol.format.FormatType.BINARY &&
+                    ol.has.ARRAY_BUFFER) {
+                  source = xhrIo.getResponse();
+                  goog.asserts.assertInstanceof(source, ArrayBuffer,
+                      'source is an instance of ArrayBuffer');
+                } else if (type == ol.format.FormatType.JSON) {
+                  source = xhrIo.getResponseText();
+                } else if (type == ol.format.FormatType.TEXT) {
+                  source = xhrIo.getResponseText();
+                } else if (type == ol.format.FormatType.XML) {
+                  if (!goog.userAgent.IE) {
+                    source = xhrIo.getResponseXml();
+                  }
+                  if (!goog.isDefAndNotNull(source)) {
+                    source = ol.xml.parse(xhrIo.getResponseText());
+                  }
+                } else {
+                  goog.asserts.fail('unexpected format type');
+                }
+                if (goog.isDefAndNotNull(source)) {
+                  var features = format.readFeatures(source,
+                      {featureProjection: projection});
+                  success.call(this, features);
+                } else {
+                  goog.asserts.fail('undefined or null source');
+                }
+              } else {
+                // FIXME
+              }
+              goog.dispose(xhrIo);
+            }, false, this);
+        xhrIo.send(url);
+      });
+};
+
+
+/**
+ * Create an XHR feature loader for a `url` and `format`. The feature loader
+ * loads features (with XHR), parses the features, and adds them to the
+ * vector source.
+ * @param {string} url Feature URL service.
+ * @param {ol.format.Feature} format Feature format.
+ * @return {ol.FeatureLoader} The feature loader.
+ * @api
+ */
+ol.featureloader.xhr = function(url, format) {
+  return ol.featureloader.loadFeaturesXhr(url, format,
+      /**
+       * @param {Array.<ol.Feature>} features The loaded features.
+       * @this {ol.source.Vector}
+       */
+      function(features) {
+        this.addFeatures(features);
+      });
+};