Merge pull request #84 from annarieger/proxyfn-for-capabilities

Apply optional `proxyFn` by parsing of layers from GetCapabilities document.

README.md

@@ -159,6 +159,9 @@ Returns the layers from a parsed WMS GetCapabilities object.
 -   `capabilities` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** A capabilities object.
 -   `nameField` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** Configure the field which should be set as the
                               'name' property in the openlayers layer. (optional, default `'Name'`)
+-   `proxyFn` **[Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)** Optional proxy function which can be applied to
+                              `GetMap`, `GetFeatureInfo` and `GetLegendGraphic`
+                              requests to avoid CORS issues.
 
 Returns **[Array](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array)<OlLayerTile>** Array of OlLayerTile
 

src/CapabilitiesUtil/CapabilitiesUtil.js

@@ -3,6 +3,7 @@ import OlSourceImageWMS from 'ol/source/ImageWMS';
 import OlLayerImage from 'ol/layer/Image';
 
 import get from 'lodash/get.js';
+import isFunction from 'lodash/isFunction';
 
 /**
  * Helper class to parse capabilities of WMS layers
@@ -32,9 +33,12 @@ class CapabilitiesUtil {
    * @param {Object} capabilities A capabilities object.
    * @param {string} nameField Configure the field which should be set as the
    *                           'name' property in the openlayers layer.
+   * @param {Function} proxyFn Optional proxy function which can be applied to
+   *                           `GetMap`, `GetFeatureInfo` and `GetLegendGraphic`
+   *                           requests to avoid CORS issues.
    * @return {OlLayerTile[]} Array of OlLayerTile
    */
-  static getLayersFromWmsCapabilties(capabilities, nameField = 'Name') {
+  static getLayersFromWmsCapabilties(capabilities, nameField = 'Name', proxyFn) {
     const wmsVersion = get(capabilities,'version');
     const wmsAttribution = get(capabilities,'Service.AccessConstraints');
     const layersInCapabilities = get(capabilities,'Capability.Layer.Layer');
@@ -49,12 +53,12 @@ class CapabilitiesUtil {
       title: get(layerObj, 'Title'),
       name: get(layerObj, nameField),
       abstract: get(layerObj, 'Abstract'),
-      getFeatureInfoUrl: getFeatureInfoUrl,
+      getFeatureInfoUrl: isFunction(proxyFn) ? proxyFn(getFeatureInfoUrl) : getFeatureInfoUrl,
       getFeatureInfoFormats: get(wmsGetFeatureInfoConfig, 'Format'),
-      legendUrl: legendUrl,
+      legendUrl: isFunction(proxyFn) ? proxyFn(legendUrl) : legendUrl,
       queryable: get(layerObj, 'queryable'),
       source: new OlSourceImageWMS({
-        url: getMapUrl,
+        url: isFunction(proxyFn) ? proxyFn(getMapUrl) : getMapUrl,
         attributions: wmsAttribution,
         params: {
           'LAYERS': get(layerObj, 'Name'),

src/CapabilitiesUtil/CapabilitiesUtil.spec.js

@@ -176,6 +176,13 @@ describe('CapabilitiesUtil', () => {
         expect(layerSource.getParams()['LAYERS']).toBe(layerName);
         expect(layerSource.getParams()['VERSION']).toBe(capVersion);
       });
+
+      it('applies proxy function if provided', () => {
+        const proxyFn = jest.fn();
+        CapabilitiesUtil.getLayersFromWmsCapabilties(capabilitiesObj, 'name', proxyFn);
+        expect.assertions(1);
+        expect(proxyFn).toBeCalledTimes(3);
+      });
     });
   });
 });