added simple xml parser

src/mol-util/data-source.ts

@@ -9,6 +9,7 @@
 
 import { Task, RuntimeContext } from '../mol-task';
 import { utf8Read } from '../mol-io/common/utf8';
+import { parseXml } from './xml-parser';
 // polyfill XMLHttpRequest in node.js
 const XHR = typeof document === 'undefined' ? require('xhr2') as {
     prototype: XMLHttpRequest;
@@ -25,7 +26,7 @@ const XHR = typeof document === 'undefined' ? require('xhr2') as {
 //     Gzip
 // }
 
-export interface AjaxGetParams<T extends 'string' | 'binary' | 'json' = 'string'> {
+export interface AjaxGetParams<T extends 'string' | 'binary' | 'json' | 'xml' = 'string'> {
     url: string,
     type?: T,
     title?: string,
@@ -49,10 +50,10 @@ export function readFromFile(file: File, type: 'string' | 'binary') {
 export function ajaxGet(url: string): Task<string>
 export function ajaxGet(params: AjaxGetParams<'string'>): Task<string>
 export function ajaxGet(params: AjaxGetParams<'binary'>): Task<Uint8Array>
-export function ajaxGet<T = any>(params: AjaxGetParams<'json'>): Task<T>
+export function ajaxGet<T = any>(params: AjaxGetParams<'json' | 'xml'>): Task<T>
 export function ajaxGet(params: AjaxGetParams<'string' | 'binary'>): Task<string | Uint8Array>
-export function ajaxGet(params: AjaxGetParams<'string' | 'binary' | 'json'>): Task<string | Uint8Array | object>
-export function ajaxGet(params: AjaxGetParams<'string' | 'binary' | 'json'> | string) {
+export function ajaxGet(params: AjaxGetParams<'string' | 'binary' | 'json' | 'xml'>): Task<string | Uint8Array | object>
+export function ajaxGet(params: AjaxGetParams<'string' | 'binary' | 'json' | 'xml'> | string) {
     if (typeof params === 'string') return ajaxGetInternal(params, params, 'string', false);
     return ajaxGetInternal(params.title, params.url, params.type || 'string', false /* params.compression === DataCompressionMethod.Gzip */, params.body);
 }
@@ -174,7 +175,7 @@ async function processAjax(ctx: RuntimeContext, asUint8Array: boolean, decompres
     }
 }
 
-function ajaxGetInternal(title: string | undefined, url: string, type: 'json' | 'string' | 'binary', decompressGzip: boolean, body?: string): Task<string | Uint8Array> {
+function ajaxGetInternal(title: string | undefined, url: string, type: 'json' | 'xml' | 'string' | 'binary', decompressGzip: boolean, body?: string): Task<string | Uint8Array> {
     let xhttp: XMLHttpRequest | undefined = void 0;
     return Task.create(title ? title : 'Download', async ctx => {
         try {
@@ -195,8 +196,10 @@ function ajaxGetInternal(title: string | undefined, url: string, type: 'json' |
 
             if (type === 'json') {
                 ctx.update({ message: 'Parsing JSON...', canAbort: false });
-                const data = JSON.parse(result);
-                return data;
+                return JSON.parse(result);
+            } else if (type === 'xml') {
+                ctx.update({ message: 'Parsing XML...', canAbort: false });
+                return parseXml(result);
             }
 
             return result;

src/mol-util/xml-parser.ts

@@ -0,0 +1,134 @@
+/**
+ * Copyright (c) 2019 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author Alexander Rose <alexander.rose@weirdbyte.de>
+ */
+
+export type XMLNodeAttributes = { [k: string]: any }
+export interface XMLNode {
+    name?: string
+    content?: string
+    attributes: XMLNodeAttributes
+    children?: XMLNode[]
+}
+export interface XMLDocument {
+    declaration?: XMLNode,
+    root?: XMLNode
+}
+
+export function getXMLNodeByName(name: string, children: XMLNode[]) {
+    for (let i = 0, il = children.length; i < il; ++i) {
+        if (children[i].name === name) return children[i]
+    }
+}
+
+const reStrip = /^['"]|['"]$/g
+const reTag = /^<([\w-:.]+)\s*/
+const reContent = /^([^<]*)/
+const reAttr = /([\w:-]+)\s*=\s*("[^"]*"|'[^']*'|\w+)\s*/
+
+function strip (val: string) {
+    return val.replace(reStrip, '')
+}
+
+/**
+ * Simple XML parser
+ * adapted from https://github.com/segmentio/xml-parser (MIT license)
+ */
+export function parseXml (xml: string): XMLDocument {
+    // trim and strip comments
+    xml = xml.trim().replace(/<!--[\s\S]*?-->/g, '')
+
+    return document()
+
+    function document () {
+        return {
+            declaration: declaration(),
+            root: tag()
+        }
+    }
+
+    function declaration () {
+        const m = match(/^<\?xml\s*/)
+        if (!m) return
+
+        // tag
+        const node: XMLNode = {
+            attributes: {}
+        }
+
+        // attributes
+        while (!(eos() || is('?>'))) {
+            const attr = attribute()
+            if (!attr) return node
+            node.attributes[attr.name] = attr.value
+        }
+        match(/\?>\s*/)
+        return node
+    }
+
+    function tag () {
+        const m = match(reTag)
+        if (!m) return
+
+        // name
+        const node: XMLNode = {
+            name: m[1],
+            attributes: {},
+            children: []
+        }
+
+        // attributes
+        while (!(eos() || is('>') || is('?>') || is('/>'))) {
+            const attr = attribute()
+            if (!attr) return node
+            node.attributes[attr.name] = attr.value
+        }
+
+        // self closing tag
+        if (match(/^\s*\/>\s*/)) {
+            return node
+        }
+        match(/\??>\s*/)
+
+        // content
+        node.content = content()
+
+        // children
+        let child
+        while ((child = tag())) {
+            node.children!.push(child)
+        }
+
+        // closing
+        match(/^<\/[\w-:.]+>\s*/)
+        return node
+    }
+
+    function content () {
+        const m = match(reContent)
+        if (m) return m[1]
+        return ''
+    }
+
+    function attribute () {
+        const m = match(reAttr)
+        if (!m) return
+        return { name: m[1], value: strip(m[2]) }
+    }
+
+    function match (re: RegExp) {
+        const m = xml.match(re)
+        if (!m) return
+        xml = xml.slice(m[0].length)
+        return m
+    }
+
+    function eos () {
+        return xml.length === 0
+    }
+
+    function is (prefix: string) {
+        return xml.indexOf(prefix) === 0
+    }
+}