bpo-37534: Adding ability to add Standalone Document Declaration when generating XML documents

Lib/test/test_minidom.py

@@ -1152,6 +1152,19 @@ def testEncodings(self):
 
         doc.unlink()
 
+    def testStandalone(self):
+        doc = parseString('<foo>&#x20ac;</foo>')
+        self.assertEqual(doc.toxml(),
+                         '<?xml version="1.0" ?><foo>\u20ac</foo>')
+        self.assertEqual(doc.toxml(standalone=None),
+                         '<?xml version="1.0" ?><foo>\u20ac</foo>')
+        self.assertEqual(doc.toxml(standalone=True),
+             '<?xml version="1.0" standalone=\'yes\'?><foo>\u20ac</foo>')
+        self.assertEqual(doc.toxml(standalone=False),
+             '<?xml version="1.0" standalone=\'no\'?><foo>\u20ac</foo>')
+
+        doc.unlink()
+
     class UserDataHandler:
         called = 0
         def handle(self, operation, key, data, src, dst):

Lib/xml/dom/minidom.py

@@ -43,10 +43,11 @@ class Node(xml.dom.Node):
     def __bool__(self):
         return True
 
-    def toxml(self, encoding=None):
-        return self.toprettyxml("", "", encoding)
+    def toxml(self, encoding=None, standalone=None):
+        return self.toprettyxml("", "", encoding, standalone)
 
-    def toprettyxml(self, indent="\t", newl="\n", encoding=None):
+    def toprettyxml(self, indent="\t", newl="\n", encoding=None,
+                    standalone=None):
         if encoding is None:
             writer = io.StringIO()
         else:
@@ -56,7 +57,7 @@ def toprettyxml(self, indent="\t", newl="\n", encoding=None):
                                       newline='\n')
         if self.nodeType == Node.DOCUMENT_NODE:
             # Can pass encoding only to document, to put it into XML header
-            self.writexml(writer, "", indent, newl, encoding)
+            self.writexml(writer, "", indent, newl, encoding, standalone)
         else:
             self.writexml(writer, "", indent, newl)
         if encoding is None:
@@ -1787,12 +1788,21 @@ 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):
-        if encoding is None:
-            writer.write('<?xml version="1.0" ?>'+newl)
+    def writexml(self, writer, indent="", addindent="", newl="", encoding=None,
+                 standalone=None):
+        # In case standalone declaration is set
+        if standalone is not None:
+            standalone = "standalone='{}'".format('yes' if standalone else 'no')
         else:
-            writer.write('<?xml version="1.0" encoding="%s"?>%s' % (
-                encoding, newl))
+            standalone = ''
+
+        writer.write(
+            '<?xml version="1.0" {encoding}{standalone}?>{newline}'.format(
+                encoding="encoding=\"{}\"".format(encoding) if encoding else '',
+                standalone=standalone,
+                newline=newl)
+        )
+
         for node in self.childNodes:
             node.writexml(writer, indent, addindent, newl)
 

Misc/ACKS

@@ -1883,3 +1883,4 @@ Robert Leenders
 Tim Hopper
 Dan Lidral-Porter
 Ngalim Siregar
+Henrik Harutyunyan

Misc/NEWS.d/next/Library/2019-08-20-00-02-37.bpo-37534.TvjAUi.rst

@@ -0,0 +1,2 @@
+When using minidom module to generate XML documents the ability to add Standalone Document Declaration is added.
+All the changes are made to generate a document in compliance with Extensible Markup Language (XML) 1.0 (Fifth Edition) W3C Recommendation (available here: https://www.w3.org/TR/xml/#sec-prolog-dtd).