Replace xml2js with fast-xml-parser

Author: Jan Kumer

package-lock.json

@@ -9,14 +9,13 @@
     "@turf/area": "^6.0.1",
     "@turf/helpers": "^6.1.4",
     "@types/proj4": "^2.5.2",
-    "@types/xml2js": "^0.4.4",
     "axios": "^0.21.1",
+    "fast-xml-parser": "^4.4.1",
     "moment": "^2.24.0",
     "polygon-clipping": "^0.14.3",
     "proj4": "^2.9.0",
     "query-string": "^6.4.2",
-    "terraformer-wkt-parser": "^1.2.1",
-    "xml2js": "^0.4.19"
+    "terraformer-wkt-parser": "^1.2.1"
   },
   "engines": {
     "node": ">=18"
@@ -30,7 +29,6 @@
     "@types/jest": "^25.1.3",
     "@types/node-fetch": "^2.5.7",
     "@types/service-worker-mock": "^2.0.4",
-    "@types/xml2js": "^0.4.4",
     "@typescript-eslint/eslint-plugin": "^7.17.0",
     "@typescript-eslint/parser": "^7.17.0",
     "axios-mock-adapter": "^1.18.1",

package.json

@@ -286,3 +286,14 @@ export const PLANET_FALSE_COLOR_TEMPLATES = [
 export const EQUATOR_RADIUS = 6378137.0;
 export const DEGREE_TO_RADIAN = Math.PI / 180;
 export const RADIAN_TO_DEGREE = 180 / Math.PI;
+
+export const XmlParserOptions = Object.freeze({
+  attributesGroupName: '$',
+  attributeNamePrefix: '',
+  textNodeName: '_',
+  ignoreAttributes: false,
+  isArray: (name: string, jpath: string, isLeafNode: boolean, isAttribute: boolean) => {
+    const isA = !isAttribute && !['Capabilities', 'WMS_Capabilities', 'WMT_MS_Capabilities'].includes(name);
+    return isA;
+  },
+});

src/layer/const.ts

@@ -1,14 +1,23 @@
 import axios, { AxiosRequestConfig } from 'axios';
 import { stringify, parseUrl, stringifyUrl } from 'query-string';
-import { parseStringPromise } from 'xml2js';
-import { EQUATOR_RADIUS, OgcServiceTypes, SH_SERVICE_HOSTNAMES_V3, SH_SERVICE_ROOT_URL } from './const';
+
 import { getAxiosReqParams, RequestConfiguration } from '../utils/cancelRequests';
 import { CACHE_CONFIG_30MIN, CACHE_CONFIG_30MIN_MEMORY } from '../utils/cacheHandlers';
-import type { GetCapabilitiesWmtsXml } from './wmts.utils';
+import { XMLParser } from 'fast-xml-parser';
+import proj4 from 'proj4';
 import { getAuthToken } from '../auth';
 import { BBox } from '../bbox';
 import { CRS_EPSG3857 } from '../crs';
-import proj4 from 'proj4';
+import {
+  EQUATOR_RADIUS,
+  OgcServiceTypes,
+  SH_SERVICE_HOSTNAMES_V3,
+  SH_SERVICE_ROOT_URL,
+  XmlParserOptions,
+} from './const';
+import { GetCapabilitiesWmtsXml } from './wmts.utils';
+
+export const xmlParser = new XMLParser(XmlParserOptions);
 
 interface Capabilities {
   Service: [];
@@ -67,7 +76,7 @@ export async function fetchGetCapabilitiesXml(
   };
   const url = createGetCapabilitiesXmlUrl(baseUrl, ogcServiceType);
   const res = await axios.get(url, axiosReqConfig);
-  const parsedXml = await parseStringPromise(res.data);
+  const parsedXml = xmlParser.parse(res.data);
   return parsedXml;
 }
 

src/layer/utils.ts

@@ -163,15 +163,19 @@ export function toPixel(
 }
 
 function parseXmlWmtsLayers(parsedXml: GetCapabilitiesWmtsXml): GetCapabilitiesXmlLayer[] {
-  return parsedXml.Capabilities.Contents[0].Layer.map((l) => {
-    return {
-      Name: l['ows:Identifier'],
-      Title: l['ows:Title'],
-      Abstract: l['ows:Abstract'],
-      Style: l.Style,
-      ResourceUrl: getResourceUrl(l),
-    };
-  });
+  try {
+    return parsedXml.Capabilities.Contents[0].Layer.map((l) => {
+      return {
+        Name: l['ows:Identifier'],
+        Title: l['ows:Title'],
+        Abstract: l['ows:Abstract'],
+        Style: l.Style,
+        ResourceUrl: getResourceUrl(l),
+      };
+    });
+  } catch (x) {
+    console.error(x);
+  }
 }
 export async function fetchLayersFromWmtsGetCapabilitiesXml(
   baseUrl: string,