Extending the Hallo Editor


As of Wagtail 2.0, the hallo.js editor is deprecated. We have no intentions to remove it from Wagtail as of yet, but it will no longer receive bug fixes. Please be aware of the known hallo.js issues should you want to keep using it.

To use hallo.js on Wagtail 2.x, add the following to your settings:

    'default': {
        'WIDGET': 'wagtail.admin.rich_text.HalloRichTextArea'

The legacy hallo.js editor’s functionality can be extended through plugins. For information on developing custom hallo.js plugins, see the project’s page: https://github.com/bergie/hallo

Once the plugin has been created, it should be registered through the feature registry’s register_editor_plugin(editor, feature_name, plugin) method. For a hallo.js plugin, the editor parameter should always be 'hallo'.

A plugin halloblockquote, implemented in myapp/js/hallo-blockquote.js, that adds support for the <blockquote> tag, would be registered under the feature name block-quote as follows:

from wagtail.admin.rich_text import HalloPlugin
from wagtail.core import hooks

def register_embed_feature(features):
        'hallo', 'block-quote',

The constructor for HalloPlugin accepts the following keyword arguments:

  • name - the plugin name as defined in the JavaScript code. hallo.js plugin names are prefixed with the "IKS." namespace, but the name passed here should be without the prefix.
  • options - a dictionary (or other JSON-serialisable object) of options to be passed to the JavaScript plugin code on initialisation
  • js - a list of JavaScript files to be imported for this plugin, defined in the same way as a Django form media definition
  • css - a dictionary of CSS files to be imported for this plugin, defined in the same way as a Django form media definition
  • order - an index number (default 100) specifying the order in which plugins should be listed, which in turn determines the order buttons will appear in the toolbar

When writing the front-end code for the plugin, Wagtail’s Hallo implementation offers two extension points:

  • In JavaScript, use the [data-hallo-editor] attribute selector to target the editor, eg. var $editor = $('[data-hallo-editor]');.
  • In CSS, use the .halloeditor class selector.

Whitelisting rich text elements

After extending the editor to support a new HTML element, you’ll need to add it to the whitelist of permitted elements - Wagtail’s standard behaviour is to strip out unrecognised elements, to prevent editors from inserting styles and scripts (either deliberately, or inadvertently through copy-and-paste) that the developer didn’t account for.

Elements can be added to the whitelist through the feature registry’s register_converter_rule(converter, feature_name, ruleset) method. When the hallo.js editor is in use, the converter parameter should always be 'editorhtml'.

The following code will add the <blockquote> element to the whitelist whenever the block-quote feature is active:

from wagtail.admin.rich_text.converters.editor_html import WhitelistRule
from wagtail.core.whitelist import allow_without_attributes

def register_blockquote_feature(features):
    features.register_converter_rule('editorhtml', 'block-quote', [
        WhitelistRule('blockquote', allow_without_attributes),

WhitelistRule is passed the element name, and a callable which will perform some kind of manipulation of the element whenever it is encountered. This callable receives the element as a BeautifulSoup Tag object.

The wagtail.core.whitelist module provides a few helper functions to assist in defining these handlers: allow_without_attributes, a handler which preserves the element but strips out all of its attributes, and attribute_rule which accepts a dict specifying how to handle each attribute, and returns a handler function. This dict will map attribute names to either True (indicating that the attribute should be kept), False (indicating that it should be dropped), or a callable (which takes the initial attribute value and returns either a final value for the attribute, or None to drop the attribute).