Add "metablock" template tag

tests/test_tags.py

@@ -1,5 +1,6 @@
 import pytest
 from datetime import timedelta
+from django.template import engines
 from django.utils import timezone
 
 from wagtail.core.models import Page
@@ -27,6 +28,19 @@ def page_tree():
     return (root, pages)
 
 
+@pytest.fixture
+def render_template():
+    """
+    Returns a helper function that takes a template string, and returns the
+    rendered output.
+    """
+    template_engine = engines['django']
+    def func(template_string):
+        load_tags_string = '{% load wagtailextensions_tags %}'
+        return template_engine.from_string(load_tags_string + template_string).render()
+    return func
+
+
 def test_bleanclean_cleandata():
     cleaned = bleachclean('Hello')
 
@@ -117,3 +131,21 @@ def test_menu_tag(page_tree, rf):
     assert out['menuitems'][1].slug == 'test_2'
     assert len(out['menuitems'][0].children) == 1
     assert out['menuitems'][0].children[0].slug == 'child_1'
+
+
+def test_metablock_with_no_modifications(render_template):
+    template_string = '{% metablock %}Hello{% endmetablock %}'
+    expected_output = 'Hello'
+    output = render_template(template_string)
+    assert output == expected_output
+
+
+def test_metablock_with_modifications(render_template):
+    template_string = """{% metablock %}
+        The world's "fastest"
+
+        <a href="">supercomputers</a> , period <-> Jane & John Doe.
+    {% endmetablock %}"""
+    expected_output = 'The world&#39;s &quot;fastest&quot; supercomputers, period &lt;-&gt; Jane &amp; John Doe.'
+    output = render_template(template_string)
+    assert output == expected_output

wagtail_extensions/templatetags/wagtailextensions_tags.py

@@ -1,9 +1,9 @@
 from datetime import datetime
 from urllib.parse import urlsplit
 
-from django.template import Library
-from django.template.defaultfilters import stringfilter
-from django.utils import timezone
+from django.template import Library, Node
+from django.template.defaultfilters import escape, stringfilter
+from django.utils import html, timezone
 
 import bleach
 from wagtailgeowidget.app_settings import (
@@ -99,3 +99,32 @@ def menu(context, parent, calling_page=None):
         # required by the pageurl tag that we want to use within this template
         'request': context['request'],
     }
+
+
+@register.tag
+def metablock(parser, token):
+    """
+    Remove newlines, excessive whitespace, and HTML tags; and escape the
+    content of meta blocks.
+    """
+    nodelist = parser.parse(('endmetablock',))
+    parser.delete_first_token()
+    return MetaBlockNode(nodelist)
+
+
+class MetaBlockNode(Node):
+    def __init__(self, nodelist):
+        self.nodelist = nodelist
+
+    def render(self, context):
+        output = self.nodelist.render(context)
+        output = output.replace("\n", "")
+        output = " ".join(output.split()).replace(" ,", ",").replace(" .", ".")
+        output = html.strip_tags(unescape(output))
+        return escape(output)
+
+
+def unescape(text):
+    return text.replace(
+        "&amp;", "&").replace("&lt;", "<").replace("&gt;", ">").replace(
+        "&quot;", '"').replace("&#39;", "'")