Issue #1470548: XMLGenerator now works with binary output streams.

Lib/xml/sax/saxutils.py

@@ -4,18 +4,10 @@ convenience of application and driver writers.
 """
 
 import os, urllib.parse, urllib.request
+import io
 from . import handler
 from . import xmlreader
 
-# See whether the xmlcharrefreplace error handler is
-# supported
-try:
-    from codecs import xmlcharrefreplace_errors
-    _error_handling = "xmlcharrefreplace"
-    del xmlcharrefreplace_errors
-except ImportError:
-    _error_handling = "strict"
-
 def __dict_replace(s, d):
     """Replace substrings of a string using a dictionary."""
     for key, value in d.items():
@@ -76,14 +68,50 @@ def quoteattr(data, entities={}):
     return data
 
 
+def _gettextwriter(out, encoding):
+    if out is None:
+        import sys
+        return sys.stdout
+
+    if isinstance(out, io.TextIOBase):
+        # use a text writer as is
+        return out
+
+    # wrap a binary writer with TextIOWrapper
+    if isinstance(out, io.RawIOBase):
+        # Keep the original file open when the TextIOWrapper is
+        # destroyed
+        class _wrapper:
+            __class__ = out.__class__
+            def __getattr__(self, name):
+                return getattr(out, name)
+        buffer = _wrapper()
+        buffer.close = lambda: None
+    else:
+        # This is to handle passed objects that aren't in the
+        # IOBase hierarchy, but just have a write method
+        buffer = io.BufferedIOBase()
+        buffer.writable = lambda: True
+        buffer.write = out.write
+        try:
+            # TextIOWrapper uses this methods to determine
+            # if BOM (for UTF-16, etc) should be added
+            buffer.seekable = out.seekable
+            buffer.tell = out.tell
+        except AttributeError:
+            pass
+    return io.TextIOWrapper(buffer, encoding=encoding,
+                            errors='xmlcharrefreplace',
+                            newline='\n',
+                            write_through=True)
+
 class XMLGenerator(handler.ContentHandler):
 
     def __init__(self, out=None, encoding="iso-8859-1", short_empty_elements=False):
-        if out is None:
-            import sys
-            out = sys.stdout
         handler.ContentHandler.__init__(self)
-        self._out = out
+        out = _gettextwriter(out, encoding)
+        self._write = out.write
+        self._flush = out.flush
         self._ns_contexts = [{}] # contains uri -> prefix dicts
         self._current_context = self._ns_contexts[-1]
         self._undeclared_ns_maps = []
@@ -91,12 +119,6 @@ class XMLGenerator(handler.ContentHandler):
         self._short_empty_elements = short_empty_elements
         self._pending_start_element = False
 
-    def _write(self, text):
-        if isinstance(text, str):
-            self._out.write(text)
-        else:
-            self._out.write(text.encode(self._encoding, _error_handling))
-
     def _qname(self, name):
         """Builds a qualified name from a (ns_url, localname) pair"""
         if name[0]:
@@ -125,6 +147,9 @@ class XMLGenerator(handler.ContentHandler):
         self._write('<?xml version="1.0" encoding="%s"?>\n' %
                         self._encoding)
 
+    def endDocument(self):
+        self._flush()
+
     def startPrefixMapping(self, prefix, uri):
         self._ns_contexts.append(self._current_context.copy())
         self._current_context[uri] = prefix
@@ -157,9 +182,9 @@ class XMLGenerator(handler.ContentHandler):
 
         for prefix, uri in self._undeclared_ns_maps:
             if prefix:
-                self._out.write(' xmlns:%s="%s"' % (prefix, uri))
+                self._write(' xmlns:%s="%s"' % (prefix, uri))
             else:
-                self._out.write(' xmlns="%s"' % uri)
+                self._write(' xmlns="%s"' % uri)
         self._undeclared_ns_maps = []
 
         for (name, value) in attrs.items():

Misc/NEWS

@@ -172,6 +172,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #1470548: XMLGenerator now works with binary output streams.
+
 - Issue #6975: os.path.realpath() now correctly resolves multiple nested
   symlinks on POSIX platforms.