Making external links open in a new window in wagtail

Have been struggling with the same problem and couldn’t achieve it using wagtailhooks. My initial solution was to manipulate the content in base.html, using a filter. The filter to cut pieces of code works perfectly when placed in the content block, example:

{{ self.body|cut: ‘ href="http:’}}

Above filter deletes parts of the content, but unfortunately ‘replace’ is not available as a filter (I´m using Python 3.x). Therefor my next approach was building a custom_filter to create ´replace´ as filter option. Long story short: It partly worked but only if the content was converted from the original ‘StreamValue’ datatype to ‘string’. This conversion resulted in content with all html tags shown, so the replacement did not result in working html. I couldn´t get the content back to StreamValue again and no other Python datatype remedied the issue. Eventually JQuery got the job done for me:

$(document).ready(function(){
$('a[href^="http://"]').attr('target', '_blank');
});        

This code adds ‘target="_blank"’ to each link containing ‘http://’, so all internal links stay in the existing tab. It needs to be placed at the end of your base.html (or similar) and of course you need to load JQuery before you run it. Got my answer from here . Don’t know if JQuery is the correct and best way to do it, but it works like a charm for me with minimal coding.

Starting with Wagtail v2.5, there is an API to do customisations like this as part of Wagtail’s rich text processing: Rewrite handlers, with the register_rich_text_features hook.

Here is an example of using this new API to make a rewrite handler that sets a target="_blank" attribute to all external links:

from django.utils.html import escape
from wagtail.core import hooks
from wagtail.core.rich_text import LinkHandler


class NewWindowExternalLinkHandler(LinkHandler):
    # This specifies to do this override for external links only.
    # Other identifiers are available for other types of links.
    identifier = 'external'

    @classmethod
    def expand_db_attributes(cls, attrs):
        href = attrs["href"]
        # Let's add the target attr, and also rel="noopener" + noreferrer fallback.
        # See https://github.com/whatwg/html/issues/4078.
        return '<a href="%s" target="_blank" rel="noopener noreferrer">' % escape(href)


@hooks.register('register_rich_text_features')
def register_external_link(features):
    features.register_link_type(NewWindowExternalLinkHandler)

In this example I'm also adding rel="noopener" to fix a known security issue with target="_blank".

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Compared to previous solutions to this problem, this new approach is the most reliable: it’s completely server-side and only overrides how links are rendered on the site’s front-end rather than how they are stored, and only relies on documented APIs instead of internal ones / implementation details.