Add construct_whitelister_element_rules for TinyMCE.

wagtailtinymce/wagtail_hooks.py

@@ -36,6 +36,7 @@
 
 from wagtail.wagtailadmin.templatetags.wagtailadmin_tags import hook_output
 from wagtail.wagtailcore import hooks
+from wagtail.wagtailcore.whitelist import attribute_rule, allow_without_attributes
 
 
 def to_js_primitive(string):
@@ -132,3 +133,50 @@ def docs_richtexteditor_js():
         to_js_primitive(static('wagtailtinymce/js/tinymce-plugins/wagtaildoclink.js')),
         to_js_primitive(translation.to_locale(translation.get_language())),
     )
+
+
+@hooks.register('construct_whitelister_element_rules')
+def whitelister_element_rules():
+    common = {
+        'style': True,
+        'width': True,
+        'margin-left': True,
+        'margin-right': True,
+        'height': True,
+        'border-color': True,
+        'text-align': True,
+        'background-color': True,
+        'vertical-align': True,
+        'font-family': True,
+        'valign': True,
+    }
+
+    table_rule = attribute_rule(dict(common, **{
+        'border': True,
+        'cellpadding': True,
+        'cellspacing': True,
+    }))
+    row_rule = attribute_rule(common)
+    cell_rule = attribute_rule(dict(common, **{
+        'colspan': True,
+        'scope': True,
+        'rowspan': True,
+    }))
+
+    return {
+        'blockquote': allow_without_attributes,
+        'pre': allow_without_attributes,
+        'span': allow_without_attributes,
+        'code': allow_without_attributes,
+
+        'table': table_rule,
+        'thead': allow_without_attributes,
+        'tfoot': allow_without_attributes,
+        'tbody': allow_without_attributes,
+        'colgroup': allow_without_attributes,
+        'col': allow_without_attributes,
+        'caption': allow_without_attributes,
+        'tr': row_rule,
+        'th': cell_rule,
+        'td': cell_rule,
+    }