add asRawText() in mixin.text_convertable that does no substitution.

it should be used to get SearchableText that should be static.

product/ERP5/Document/TextDocument.py

@@ -128,7 +128,7 @@ class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin,
                                          **substitution_method_parameter_dict)
 
     def _convert(self, format, substitution_method_parameter_dict=None,
-                safe_substitute=True, charset=None, text_content=None, **kw):
+                safe_substitute=True, charset=None, text_content=None, substitute=True, **kw):
       """
         Convert text using portal_transforms or oood
       """
@@ -184,7 +184,7 @@ class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin,
           self.setConversion(result, original_mime_type, **kw)
         else:
           mime_type, result = self.getConversion(**kw)
-        if format in VALID_TEXT_FORMAT_LIST:
+        if substitute and format in VALID_TEXT_FORMAT_LIST:
           # only textual content can be sustituted 
           if substitution_method_parameter_dict is None:
             substitution_method_parameter_dict = {}

product/ERP5/mixin/text_convertable.py

@@ -49,6 +49,16 @@ class TextConvertableMixin:
     mime, data = self.convert(format='txt', **kw)
     return str(data)
 
+  security.declareProtected(Permissions.AccessContentsInformation,
+                            'asRawText')
+  def asRawText(self, **kw):
+    """
+    Converts the current document to plain text without substitution
+    """
+    kw.pop('format', None)
+    mime, data = self.convert(format='txt', substitute=False, **kw)
+    return str(data)
+
   security.declareProtected(Permissions.AccessContentsInformation,
                             'asTextContent')
   def asTextContent(self, **kw):