--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sat/plugins/plugin_xep_0315.py	Sat Jan 12 15:01:20 2019 +0100
@@ -0,0 +1,118 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+# SAT plugin to implement XEP-0315 (Data Forms XML Element)
+# Copyright (C) 2009-2019 Jérôme Poisson (goffi@goffi.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from sat.core.i18n import _
+from sat.core.constants import Const as C
+from sat.core.log import getLogger
+from wokkel import data_form
+from twisted.words.xish import domish
+
+log = getLogger(__name__)
+
+PLUGIN_INFO = {
+    C.PI_NAME: "Data Forms XML Element",
+    C.PI_IMPORT_NAME: "XEP-0315",
+    C.PI_TYPE: "XEP",
+    C.PI_PROTOCOLS: ["XEP-0315"],
+    C.PI_DEPENDENCIES: [],
+    C.PI_MAIN: "XEP_0315",
+    C.PI_HANDLER: "no",
+    C.PI_DESCRIPTION: _("""Implementation of Data Forms XML Element"""),
+}
+
+NS_XML_ELEMENT = "urn:xmpp:xml-element"
+
+
+class Field(data_form.Field):
+    """Field class adding implementation for XML Element"""
+
+
+    def __init__(self, fieldType='text-single', var=None, value=None,
+                       values=None, options=None, label=None, desc=None,
+                       required=False, ext_type=None):
+        """
+        @ext_type(None, unicode): extended type, can be:
+            - xml: field is an XML Element
+            - None: field is a base (XEP-0004) type
+        """
+
+        super(Field, self).__init__(fieldType, var, value, values, options, label, desc,
+                                    required)
+        self.ext_type = ext_type
+
+    def typeCheck(self):
+        if self.ext_type is not None:
+            # we use an extended type
+            if self.fieldType not in (None, 'hidden'):
+                raise ValueError('Invalid main type for a extended type field')
+            if len(self.values) != 1:
+                raise ValueError('extended type must have one and only one value')
+            if self.options:
+                raise ValueError('options must not be set for extented type')
+            if self.ext_type == u'xml':
+                if not isinstance(self.value, domish.Element):
+                    raise ValueError('invalid value, a domish.Element is expected')
+            else:
+                raise ValueError(
+                    'Unknown extended type: {ext_type}'.format(ext_type=self.ext_type))
+        return super(Field, self).typeCheck()
+
+    def toElement(self, asForm=False):
+        if self.ext_type is None:
+            return super(Field, self).toElement(asForm)
+        else:
+            self.typeCheck()
+            field_elt = domish.Element((data_form.NS_X_DATA, 'field'))
+            if self.fieldType:
+                field_elt['type'] = self.fieldType
+
+            if self.var is not None:
+                field_elt['var'] = self.var
+
+            wrapper_elt = field_elt.addElement((NS_XML_ELEMENT, u'wrapper'))
+            wrapper_elt.addChild(self.value)
+
+            if asForm:
+                if self.label is not None:
+                    field_elt['label'] = self.label
+
+                if self.desc is not None:
+                    field_elt.addElement('desc', content=self.desc)
+
+                if self.required:
+                    field_elt.addElement('required')
+
+            return field_elt
+
+    @staticmethod
+    def fromElement(element):
+        field = super(Field, Field).fromElement(element)
+        if element.wrapper and element.wrapper.uri == NS_XML_ELEMENT:
+            field.ext_type = u"xml"
+            field.value = element.wrapper.firstChildElement()
+        return field
+
+
+class XEP_0315(object):
+
+    def __init__(self, host):
+        self.host = host
+        if data_form.Field is not Field:
+            log.debug(u"installing data_form data extension")
+            data_form.Field = Field