Add support for using CDATA for escaping.

CDATA escaping is disabled by default, but may be enabled by setting:

    self.use_cdata = True

Closes issue #114

sleekxmpp/xmlstream/tostring.py

@@ -63,9 +63,11 @@ def tostring(xml=None, xmlns='', stanza_ns='', stream=None,
 
     default_ns = ''
     stream_ns = ''
+    use_cdata = False
     if stream:
         default_ns = stream.default_ns
         stream_ns = stream.stream_ns
+        use_cdata = stream.use_cdata
 
     # Output the tag name and derived namespace of the element.
     namespace = ''
@@ -81,7 +83,7 @@ def tostring(xml=None, xmlns='', stanza_ns='', stream=None,
 
     # Output escaped attribute values.
     for attrib, value in xml.attrib.items():
-        value = xml_escape(value)
+        value = escape(value, use_cdata)
         if '}' not in attrib:
             output.append(' %s="%s"' % (attrib, value))
         else:
@@ -105,24 +107,24 @@ def tostring(xml=None, xmlns='', stanza_ns='', stream=None,
         # If there are additional child elements to serialize.
         output.append(">")
         if xml.text:
-            output.append(xml_escape(xml.text))
+            output.append(escape(xml.text, use_cdata))
         if len(xml):
             for child in xml:
                 output.append(tostring(child, tag_xmlns, stanza_ns, stream))
         output.append("</%s>" % tag_name)
     elif xml.text:
         # If we only have text content.
-        output.append(">%s</%s>" % (xml_escape(xml.text), tag_name))
+        output.append(">%s</%s>" % (escape(xml.text, use_cdata), tag_name))
     else:
         # Empty element.
         output.append(" />")
     if xml.tail:
         # If there is additional text after the element.
-        output.append(xml_escape(xml.tail))
+        output.append(escape(xml.tail, use_cdata))
     return ''.join(output)
 
 
-def xml_escape(text):
+def escape(text, use_cdata=False):
     """Convert special characters in XML to escape sequences.
 
     :param string text: The XML text to convert.
@@ -132,12 +134,24 @@ def xml_escape(text):
         if type(text) != types.UnicodeType:
             text = unicode(text, 'utf-8', 'ignore')
 
-    text = list(text)
     escapes = {'&': '&amp;',
                '<': '&lt;',
                '>': '&gt;',
                "'": '&apos;',
                '"': '&quot;'}
+
+    if not use_cdata:
+        text = list(text)
         for i, c in enumerate(text):
             text[i] = escapes.get(c, c)
         return ''.join(text)
+    else:
+        escape_needed = False
+        for c in text:
+            if c in escapes:
+                escape_needed = True
+                break
+        if escape_needed:
+            escaped = map(lambda x : "<![CDATA[%s]]>" % x, text.split("]]>"))
+            return "<![CDATA[]]]><![CDATA[]>]]>".join(escaped)
+        return text

sleekxmpp/xmlstream/xmlstream.py

@@ -212,6 +212,10 @@ class XMLStream(object):
         #: If set to ``True``, attempt to use IPv6.
         self.use_ipv6 = True
 
+        #: Use CDATA for escaping instead of XML entities. Defaults
+        #: to ``False``.
+        self.use_cdata = False
+
         #: An optional dictionary of proxy settings. It may provide:
         #: :host: The host offering proxy services.
         #: :port: The port for the proxy service.

tests/test_tostring.py

@@ -1,7 +1,7 @@
 from sleekxmpp.test import *
 from sleekxmpp.stanza import Message
 from sleekxmpp.xmlstream.stanzabase import ET, ElementBase
-from sleekxmpp.xmlstream.tostring import tostring, xml_escape
+from sleekxmpp.xmlstream.tostring import tostring, escape
 
 
 class TestToString(SleekTest):
@@ -30,7 +30,7 @@ class TestToString(SleekTest):
     def testXMLEscape(self):
         """Test escaping XML special characters."""
         original = """<foo bar="baz">'Hi & welcome!'</foo>"""
-        escaped = xml_escape(original)
+        escaped = escape(original)
         desired = """&lt;foo bar=&quot;baz&quot;&gt;&apos;Hi"""
         desired += """ &amp; welcome!&apos;&lt;/foo&gt;"""