Add API endpoint for pattern rendering via POST

Author: thibaudcolas

pattern_library/monkey_utils.py

@@ -31,15 +31,15 @@ def node_render(context):
 
  # Load pattern's config
  current_template_name = parser.origin.template_name
- pattern_config = get_pattern_config(current_template_name)
+ tag_overrides = context.get('__pattern_library_tag_overrides', {})
 
  # Extract values for lookup from the token
  bits = token.split_contents()
  tag_name = bits[0]
  arguments = ' '.join(bits[1:]).strip()
 
  # Get config for a specific tag
- tag_config = pattern_config.get('tags', {}).get(tag_name, {})
+ tag_config = tag_overrides.get(tag_name, {})
  if tag_config:
  # Get config for specific arguments
  tag_config = tag_config.get(arguments, {})

pattern_library/urls.py

@@ -1,4 +1,4 @@
-from django.urls import re_path
+from django.urls import re_path, path
 
 from pattern_library import get_pattern_template_suffix, views
 
@@ -22,4 +22,7 @@
  views.RenderPatternView.as_view(),
  name='render_pattern'
  ),
+
+ # API rendering
+ path('api/v1/render-pattern', views.render_pattern_api, name='render_pattern_api'),
 ]

pattern_library/utils.py

@@ -197,12 +197,18 @@ def get_pattern_markdown(template_name):
  return markdown.markdown(f.read())
 
 
-def render_pattern(request, template_name, allow_non_patterns=False):
+def render_pattern(request, template_name, allow_non_patterns=False, config=None):
  if not allow_non_patterns and not is_pattern(template_name):
  raise TemplateIsNotPattern
 
- context = get_pattern_context(template_name)
+ if not config:
+ config = get_pattern_config(template_name)
+
+ context = config.get('context', {})
+ tags = config.get('tags', {})
+ mark_context_strings_safe(context)
  context[get_pattern_context_var_name()] = True
+ context['__pattern_library_tag_overrides'] = tags
  for modifier in registry.get_for_template(template_name):
  modifier(context=context, request=request)
  return render_to_string(template_name, request=request, context=context)

pattern_library/views.py

@@ -1,9 +1,12 @@
+import json
+
 from django.http import Http404, HttpResponse
 from django.template.loader import get_template
 from django.utils.decorators import method_decorator
 from django.utils.html import escape
 from django.views.decorators.clickjacking import xframe_options_sameorigin
-from django.views.generic.base import TemplateView
+from django.views.decorators.csrf import csrf_exempt
+from django.views.generic.base import TemplateView, View
 
 from pattern_library import (
  get_base_template_names, get_pattern_base_template_name
@@ -94,3 +97,17 @@ def get(self, request, pattern_template_name=None):
  return self.render_to_response(context)
 
  return HttpResponse(rendered_pattern)
+
+
+@csrf_exempt
+def render_pattern_api(request):
+ data = json.loads(request.body.decode("utf-8"))
+ template_name = data["template_name"]
+ config = data["config"]
+
+ try:
+ rendered_pattern = render_pattern(request, template_name, allow_non_patterns=False, config=config)
+ except TemplateIsNotPattern:
+ raise Http404
+
+ return HttpResponse(rendered_pattern)

tests/templates/patterns/molecules/button/button.html

@@ -0,0 +1,4 @@
+{% load test_tags %}
+<a href="{% if target_url %}{{ target_url }}{% else %}{% pageurl target_page %}{% endif %}" class="button">
+ {% if label %}{{ label }}{% else %}{{ target_page.title }}{% endif %}
+</a>

tests/templates/patterns/molecules/button/button.yaml

@@ -0,0 +1,7 @@
+context:
+ target_page:
+ title: Get started
+tags:
+ pageurl:
+ target_page:
+ raw: /get-started

tests/templatetags/test_tags.py

@@ -27,6 +27,12 @@ def default_html_tag_falsey(arg=None):
  raise Exception("default_tag raised an exception")
 
 
+@register.simple_tag()
+def pageurl(page):
+ """Approximation of wagtail built-in tag for realistic example."""
+ return "/page/url"
+
+
 # Get widget type of a field
 @register.filter(name="widget_type")
 def widget_type(bound_field):
@@ -36,3 +42,4 @@ def widget_type(bound_field):
 override_tag(register, 'error_tag')
 override_tag(register, 'default_html_tag', default_html="https://potato.com")
 override_tag(register, 'default_html_tag_falsey', default_html=None)
+override_tag(register, 'pageurl')