XML Prolog support

README.md

@@ -9,7 +9,7 @@ Implementation of Mozilla's [JXON](https://developer.mozilla.org/en-US/docs/JXON
 #### Example:
 
 ```js
-{name: 'myportal'} 
+{name: 'myportal'}
 <name>myportal</name>
 
 {user: {
@@ -56,7 +56,9 @@ trueIsEmpty: false,
 autoDate: false,
 ignorePrefixedNodes: false,
 parseValues: false,
-parserErrorHandler: undefined
+parserErrorHandler: undefined,
+forceXmlProlog: false,
+defaultXmlProlog: '<?xml version="1.0" encoding="UTF-8"?>'
 ```
 
 ### .stringToJs(xmlString)
@@ -73,7 +75,7 @@ parserErrorHandler: undefined
 - verbosity - Optional verbosity level of conversion, from 0 to 3. It is almost equivalent to our algorithms from #4 to #1 (default value is 1, which is equivalent to the algorithm #3).
 - freeze - Optional boolean expressing whether the created object must be freezed or not (default value is false).
 - nestedAttributes - Optional boolean expressing whether the the nodeAttributes must be nested into a child-object named keyAttributes or not (default value is false for verbosity levels from 0 to 2; true for verbosity level 3).
- 
+
 Example:
 ```js
 var myObject = JXON.build(xmlDoc);
@@ -84,7 +86,7 @@ var myObject = JXON.build(xmlDoc);
 - namespaceURI - Optional DOMString containing the namespace URI of the document to be created, or null if the document doesn't belong to one.
 - qualifiedNameStr - Optional DOMString containing the qualified name, that is an optional prefix and colon plus the local root element name, of the document to be created.
 - documentType - Optional DocumentType of the document to be created. It defaults to null.
- 
+
 Example:
 ```js
 var myObject = JXON.unbuild(myObject);
@@ -122,4 +124,5 @@ changes from version 1.x to 2.0 include:
 * (breaking) more usefull default settings (see above)
 * (breaking) stringify Dates to ISO format instead of GMT
 * improved xml namespace handling on node and browsers
+* improved xml prolog handling
 * renamed main source file to `jxon.js`

jxon.js

@@ -20,7 +20,7 @@
  * bugfixes and code cleanup by user @laubstein
  * https://github.com/tyrasd/jxon/pull/32
  *
- * adapted for nodejs and npm by @tyrasd (Martin Raifer <[email protected]>) 
+ * adapted for nodejs and npm by @tyrasd (Martin Raifer <[email protected]>)
  */
 
 (function(root, factory) {
@@ -54,11 +54,16 @@
     trueIsEmpty: false,
     autoDate: false,
     ignorePrefixedNodes: false,
-    parseValues: false
+    parseValues: false,
+    forceXmlProlog: false,
+    defaultXmlProlog: '<?xml version="1.0" encoding="UTF-8"?>'
   };
   var aCache = [];
   var rIsNull = /^\s*$/;
   var rIsBool = /^(?:true|false)$/i;
+  var rXmlProlog = /^(<\?xml.*?\?>[\n]?)/;
+  var rXmlPrologAttributes = /\b(version|encoding|standalone)="([^"]+?)"/g;
+  var oXmlProlog = {};
   var DOMParser;
 
   return new (function() {
@@ -76,6 +81,56 @@
       }
     };
 
+    /**
+     * Helper function: given a xml prolog (eg: <?xml version="1.0"?>),
+     * returns a object (eg: { version: "1.0" }).
+     */
+    function getPrologFromString(sXmlProlog) {
+      var matches = sXmlProlog.match(rXmlPrologAttributes);
+      var oReturn = {};
+      for (var i = 0; i < matches.length; i++) {
+        var currentAttribute = matches[i].split('=');
+        oReturn[currentAttribute[0]] = currentAttribute[1].replace(/["]/g, '');
+      }
+
+      return oReturn;
+    };
+
+    /**
+     * Helper function: given an object representing a xml prolog (eg: { version: "1.0", encoding: "UTF-8", standalone: "true" }),
+     * returns a string (eg: <?xml version="1.0" encoding="UTF-8" standalone="true"?>).
+     */
+    function getPrologFromObject(oProlog) {
+      var ret = [];
+      for (var prop in oProlog) {
+        if (oProlog.hasOwnProperty(prop)) {
+          ret.push(prop + '="' + oProlog[prop] + '"');
+        }
+      }
+
+      return ret.length ? '<?xml ' + ret.join(' ') + '?>' : '';
+    };
+
+    /**
+     * Helper function: check for empty object
+     */
+    function isEmptyObject(obj) {
+      for (var prop in obj) {
+        if (obj.hasOwnProperty(prop)) {
+          return false;
+        }
+      }
+
+      return true && JSON.stringify(obj) === JSON.stringify({});
+    };
+
+    /**
+     * Helper function: clone a object
+     */
+    function cloneObject(obj) {
+      return JSON.parse(JSON.stringify(obj));
+    };
+
     function parseText(sValue) {
       if (!opts.parseValues) {
         return sValue;
@@ -253,7 +308,12 @@
           if (isNodeJs) {
             oParentEl.setAttribute(sName.slice(1), vValue);
           }
-        // do nothing: special handling of xml namespaces is done via createElementNS()
+          // do nothing: special handling of xml namespaces is done via createElementNS()
+        } else if (sName === opts.attrPrefix + 'xmlProlog') {
+          // store xmlProlog
+          if (vValue) {
+            oXmlProlog = cloneObject(vValue);
+          }
         } else if (sName.charAt(0) === opts.attrPrefix) {
           oParentEl.setAttribute(sName.slice(1), vValue);
         } else if (vValue.constructor === Array) {
@@ -289,7 +349,14 @@
     }
     this.xmlToJs = this.build = function(oXMLParent, nVerbosity /* optional */ , bFreeze /* optional */ , bNesteAttributes /* optional */ ) {
       var _nVerb = arguments.length > 1 && typeof nVerbosity === 'number' ? nVerbosity & 3 : /* put here the default verbosity level: */ 1;
-      return createObjTree(oXMLParent, _nVerb, bFreeze || false, arguments.length > 3 ? bNesteAttributes : _nVerb === 3);
+      var oTree = createObjTree(oXMLParent, _nVerb, bFreeze || false, arguments.length > 3 ? bNesteAttributes : _nVerb === 3);
+
+      if (!isEmptyObject(oXmlProlog)) {
+        oTree[opts.attrPrefix + 'xmlProlog'] = cloneObject(oXmlProlog);
+        oXmlProlog = {};
+      }
+
+      return oTree;
     };
 
     this.jsToXml = this.unbuild = function(oObjTree, sNamespaceURI /* optional */ , sQualifiedName /* optional */ , oDocumentType /* optional */ ) {
@@ -304,15 +371,33 @@
         DOMParser = new xmlDom.DOMParser();
       }
 
+      if (rXmlProlog.test(xmlStr)) {
+        oXmlProlog = getPrologFromString(xmlStr.match(rXmlProlog)[0]);
+      }
+
       return DOMParser.parseFromString(xmlStr, 'application/xml');
     };
 
     this.xmlToString = function(xmlObj) {
+      var sReturn = '';
+
       if (typeof xmlObj.xml !== 'undefined') {
-        return xmlObj.xml;
+        sReturn = xmlObj.xml;
       } else {
-        return (new xmlDom.XMLSerializer()).serializeToString(xmlObj);
+        sReturn = (new xmlDom.XMLSerializer()).serializeToString(xmlObj);
       }
+
+      // if the original string has a prolog or forceXmlProlog option is true, we include a new one or replace the existent
+      if (!isEmptyObject(oXmlProlog) || opts.forceXmlProlog) {
+        if (rXmlProlog.test(sReturn)) {
+          // replace the prolog
+          sReturn = sReturn.replace(rXmlProlog, (getPrologFromObject(oXmlProlog) || opts.defaultXmlProlog));
+        } else {
+          sReturn = (getPrologFromObject(oXmlProlog) || opts.defaultXmlProlog) + sReturn;
+        }
+      }
+
+      return sReturn;
     };
 
     this.stringToJs = function(str) {

test/spec.js

@@ -7,19 +7,18 @@ var assert = require('chai').assert,
       $attr: 'value',
       _: 'root value'
     }
-  };
-
+};
 
 describe('JXON', function() {
   describe('.jsToXml > .xmlToJs', function() {
-    it('should return return identical object', function() {
+    it('should return identical object', function() {
       var xml = JXON.jsToXml(jsObj);
       var newJs = JXON.xmlToJs(xml);
       assert.deepEqual(jsObj, newJs);
     });
   });
   describe('.jsToString > .stringToJs', function() {
-    it('should return return identical object', function() {
+    it('should return identical object', function() {
       var str = JXON.jsToString(jsObj);
       var newJs = JXON.stringToJs(str);
       assert.deepEqual(jsObj, newJs);
@@ -76,7 +75,7 @@ describe('JXON', function() {
       });
 
       var strTwo = JXON.jsToString(JXON.stringToJs('<element><a>first position</a><a>second position</a></element>'));
-      
+
       assert.equal(strOne, strTwo);
     });
 
@@ -123,7 +122,7 @@ describe('JXON', function() {
       var str = JXON.jsToString(obj);
       assert.equal(str, '<test xmlns="foo" xmlns:y="moo"/>');
     });
-    it('as property', function() { // addigional test from #26
+    it('as property', function() { // additional test from #26
       var strNull = JXON.jsToString({
         'TrainingCenterDatabase': {
           '$xmlns': '6',
@@ -145,4 +144,22 @@ describe('JXON', function() {
       assert.equal(strNull, strEmptyObj);
     });
   });
+  describe('xml prolog', function() {
+    it('should be consistent', function() {
+      var originalString = '<?xml version="1.0"?><a>1</a>';
+      var xmlObject = JXON.stringToXml(originalString);
+      var jsonFromXml = JXON.xmlToJs(xmlObject);
+      var jsonFromString = JXON.stringToJs(originalString);
+
+      assert.equal(originalString, JXON.jsToString(jsonFromXml));
+      assert.equal(originalString, JXON.jsToString(jsonFromString));
+
+      // PhantomJS do not serialize the prolog, so we are forcing a default
+      JXON.config({
+        forceXmlProlog: true,
+        defaultXmlProlog: '<?xml version="1.0"?>'
+      });
+      assert.equal(originalString, JXON.xmlToString(xmlObject));
+    });
+  });
 });