bpo-34160: Add the sort attribute to the xml.dom.minidom.Node.writexml method

Doc/library/xml.dom.minidom.rst

@@ -132,7 +132,7 @@ module documentation.  This section lists the differences between the API and
           ... # Work with dom.
 
 
-.. method:: Node.writexml(writer, indent="", addindent="", newl="")
+.. method:: Node.writexml(writer, indent="", addindent="", newl="", sort=False)
 
    Write XML to the writer object.  The writer should have a :meth:`write` method
    which matches that of the file object interface.  The *indent* parameter is the
@@ -147,6 +147,11 @@ module documentation.  This section lists the differences between the API and
       The :meth:`writexml` method now preserves the attribute order specified
       by the user.
 
+   .. versionadded:: 3.8
+      The *sort* parameter sorts the XML attributes of the tags. For the
+      :class:`Document` node, an additional keyword argument *sort* can be used
+      to specify the sort of the attributes.
+
 .. method:: Node.toxml(encoding=None)
 
    Return a string or byte string containing the XML represented by

Doc/library/xml.dom.rst

@@ -576,6 +576,23 @@ inherits properties from :class:`Node`.
    particular namespace URI and localname.  The localname is the part of the
    namespace after the prefix.
 
+.. method:: Document.writexml(self, writer, indent="", addindent="", newl="", encoding=None, sort=False)
+
+   Write XML to the writer object.  The writer should have a :meth:`write` method
+   which matches that of the file object interface.  The *indent* parameter is the
+   indentation of the current node.  The *addindent* parameter is the incremental
+   indentation to use for subnodes of the current one.  The *newl* parameter
+   specifies the string to use to terminate newlines.
+
+   The keyword argument *encoding* can be used to specify the encoding field of
+   the XML header.
+
+   .. versionchanged:: 3.8
+      The :meth:`writexml` method now preserves the attribute order specified
+      by the user.
+
+   .. versionadded:: 3.8
+      The *sort* parameter sorts the XML attributes of the tags.
 
 .. _dom-element-objects:
 

Lib/test/test_minidom.py

@@ -1612,6 +1612,14 @@ def testProcessingInstructionNameError(self):
         pi = doc.createProcessingInstruction("y", "z")
         pi.nodeValue = "crash"
 
+    def test_minidom_attribute_sorted(self):
+        xml_str = '<?xml version="1.0" ?><curriculum status="public" company="example"/>'
+        sorted_xml_str = '<?xml version="1.0" ?><curriculum company="example" status="public"/>'
+        doc = parseString(xml_str)
+        output = io.StringIO()
+        doc.writexml(output, sort=True)
+        self.assertEqual(output.getvalue(), sorted_xml_str)
+
     def test_minidom_attribute_order(self):
         xml_str = '<?xml version="1.0" ?><curriculum status="public" company="example"/>'
         doc = parseString(xml_str)

Lib/xml/dom/minidom.py

@@ -847,27 +847,31 @@ def getElementsByTagNameNS(self, namespaceURI, localName):
     def __repr__(self):
         return "<DOM Element: %s at %#x>" % (self.tagName, id(self))
 
-    def writexml(self, writer, indent="", addindent="", newl=""):
+    def writexml(self, writer, indent="", addindent="", newl="", sort=False):
         # indent = current indentation
         # addindent = indentation to add to higher levels
         # newl = newline string
         writer.write(indent+"<" + self.tagName)
 
         attrs = self._get_attributes()
 
-        for a_name in attrs.keys():
+        attribute_names = attrs.keys()
+        if sort:
+            attribute_names = sorted(attribute_names)
+
+        for a_name in attribute_names:
             writer.write(" %s=\"" % a_name)
             _write_data(writer, attrs[a_name].value)
             writer.write("\"")
         if self.childNodes:
             writer.write(">")
             if (len(self.childNodes) == 1 and
                 self.childNodes[0].nodeType == Node.TEXT_NODE):
-                self.childNodes[0].writexml(writer, '', '', '')
+                self.childNodes[0].writexml(writer, '', '', '', sort=sort)
             else:
                 writer.write(newl)
                 for node in self.childNodes:
-                    node.writexml(writer, indent+addindent, addindent, newl)
+                    node.writexml(writer, indent+addindent, addindent, newl, sort=sort)
                 writer.write(indent)
             writer.write("</%s>%s" % (self.tagName, newl))
         else:
@@ -984,8 +988,8 @@ def _set_nodeName(self, value):
         self.target = value
     nodeName = property(_get_nodeName, _set_nodeName)
 
-    def writexml(self, writer, indent="", addindent="", newl=""):
-        writer.write("%s<?%s %s?>%s" % (indent,self.target, self.data, newl))
+    def writexml(self, writer, indent="", addindent="", newl="", sort=False):
+        writer.write("%s<?%s %s?>%s" % (indent,self.target, self.data, newl), sort=sort)
 
 
 class CharacterData(Childless, Node):
@@ -1084,7 +1088,7 @@ def splitText(self, offset):
         self.data = self.data[:offset]
         return newText
 
-    def writexml(self, writer, indent="", addindent="", newl=""):
+    def writexml(self, writer, indent="", addindent="", newl="", sort=False):
         _write_data(writer, "%s%s%s" % (indent, self.data, newl))
 
     # DOM Level 3 (WD 9 April 2002)
@@ -1179,10 +1183,10 @@ def __init__(self, data):
         CharacterData.__init__(self)
         self._data = data
 
-    def writexml(self, writer, indent="", addindent="", newl=""):
+    def writexml(self, writer, indent="", addindent="", newl="", sort=False):
         if "--" in self.data:
             raise ValueError("'--' is not allowed in a comment node")
-        writer.write("%s<!--%s-->%s" % (indent, self.data, newl))
+        writer.write("%s<!--%s-->%s" % (indent, self.data, newl), sort=sort)
 
 
 class CDATASection(Text):
@@ -1191,7 +1195,7 @@ class CDATASection(Text):
     nodeType = Node.CDATA_SECTION_NODE
     nodeName = "#cdata-section"
 
-    def writexml(self, writer, indent="", addindent="", newl=""):
+    def writexml(self, writer, indent="", addindent="", newl="", sort=False):
         if self.data.find("]]>") >= 0:
             raise ValueError("']]>' not allowed in a CDATA section")
         writer.write("<![CDATA[%s]]>" % self.data)
@@ -1324,7 +1328,7 @@ def cloneNode(self, deep):
         else:
             return None
 
-    def writexml(self, writer, indent="", addindent="", newl=""):
+    def writexml(self, writer, indent="", addindent="", newl="", sort=False):
         writer.write("<!DOCTYPE ")
         writer.write(self.name)
         if self.publicId:
@@ -1786,14 +1790,14 @@ def importNode(self, node, deep):
             raise xml.dom.NotSupportedErr("cannot import document type nodes")
         return _clone_node(node, deep, self)
 
-    def writexml(self, writer, indent="", addindent="", newl="", encoding=None):
+    def writexml(self, writer, indent="", addindent="", newl="", encoding=None, sort=False):
         if encoding is None:
             writer.write('<?xml version="1.0" ?>'+newl)
         else:
             writer.write('<?xml version="1.0" encoding="%s"?>%s' % (
                 encoding, newl))
         for node in self.childNodes:
-            node.writexml(writer, indent, addindent, newl)
+            node.writexml(writer, indent, addindent, newl, sort=sort)
 
     # DOM Level 3 (WD 9 April 2002)
 

Misc/NEWS.d/next/Library/2019-03-15-19-08-36.bpo-34160.aDomJL.rst

@@ -0,0 +1,5 @@
+Add the *sort* attribute to the :meth:`xml.dom.minidom.Node.writexml` method
+allowing to sort the attributes by name (``True``) or by the attribute order
+specified by the user (by default ``False``). Document
+:meth:`xml.dom.minidom.Document.writexml` method. Contributed by Stéphane
+Wirtel.