combo/manager/forms.py

@@ -330,6 +330,12 @@ class PageEditIncludeInNavigationForm(forms.ModelForm):
         return self.instance
 
 
+class PageInspectTemplateTestForm(forms.Form):
+    django_template = forms.CharField(
+        widget=forms.Textarea(attrs={'rows': 5, 'cols': 80}), label=_('Django template')
+    )
+
+
 class CellVisibilityForm(forms.Form):
     visibility = forms.ChoiceField(
         label=_('Visibility'),

combo/manager/templates/combo/page_inspect_fragment.html

@@ -5,6 +5,7 @@
       <button aria-controls="panel-information" aria-selected="true" id="tab-information" role="tab" tabindex="0">{% trans "Information" %}</button>
       <button aria-controls="panel-cells" aria-selected="false" id="tab-cells" role="tab" tabindex="-1">{% trans "Cells" %}</button>
       <button aria-controls="panel-settings" aria-selected="false" id="tab-settings" role="tab" tabindex="-1">{% trans "Settings" %}</button>
+      <button aria-controls="panel-test-template" aria-selected="false" id="tab-test-template" role="tab" tabindex="-1">{% trans "Test template" %}</button>
     </div>
     <div class="pk-tabs--container">
 
@@ -116,6 +117,81 @@
         </div>
       </div>
 
+      <div aria-labelledby="tab-test-template" hidden id="panel-test-template" role="tabpanel" tabindex="0">
+        <form action="{% url 'combo-manager-page-inspect-test-template' pk=object.pk %}" method="post">
+          {% csrf_token %}
+          {{ inspect_form.as_p }}
+          <button id="page-inspect-test-template-submit" class="submit-button submit">
+            {% trans "Test template"%}
+          </button>
+        </form>
+
+        <div>
+          <h3>{% trans "Available context" %}</h3>
+          <dl>
+            <dt><code>page</code></dt>
+            <dd>{% trans "The page object" %}</dd>
+            <dt><code>cells</code></dt>
+            <dd>{% trans "The array of page's cells" %}</dd>
+          </dl>
+        </div>
+
+        <div hidden id="page-inspect-test-template-div">
+          <div class="infonotice">
+            <h3>{% trans "Template result" %}</h3>
+            <div id="page-inspect-test-template-result"></div>
+          </div>
+          <div class="infonotice">
+            <h3>{% trans "HTML sources" %}</h3>
+          <pre id="page-inspect-test-template-result-html"></pre>
+          </div>
+        </div>
+        <div class="errornotice" hidden id="page-inspect-test-template-error-div">
+          <h3>{% trans "Template rendering error" %}</h3>
+          <div id="page-inspect-test-template-error"></div>
+        </div>
+      </div>
     </div>
   </div>
+
+  <script>
+    document.body.onload = function() {
+      function ajax_cllbck() {
+        const res_div = document.getElementById('page-inspect-test-template-div');
+        const res_result = document.getElementById('page-inspect-test-template-result');
+        const res_result_html = document.getElementById('page-inspect-test-template-result-html');
+        const error_div = document.getElementById('page-inspect-test-template-error-div')
+        const error_reason = document.getElementById('page-inspect-test-template-error')
+        const result = JSON.parse(this.responseText)
+
+        if('error' in result) {
+          error_reason.innerHTML = result['error'];
+          res_div.setAttribute('hidden', 'true');
+          error_div.removeAttribute('hidden');
+        } else {
+          res_result.innerHTML = result['result'];
+          res_result_html.textContent = result['result'];
+          error_div.setAttribute('hidden', 'true');
+          res_div.removeAttribute('hidden');
+        }
+      }
+
+      function submit_btn_click() {
+        const csrf_token = document.getElementsByName('csrfmiddlewaretoken')[0].value
+        const django_template = document.getElementsByName('django_template')[0].value
+        const querystring =
+          "csrfmiddlewaretoken="+encodeURIComponent(csrf_token)+"&django_template="+encodeURIComponent(django_template);
+
+        const xhttp = new XMLHttpRequest();
+        xhttp.onload = ajax_cllbck
+        xhttp.open("POST", "{% url 'combo-manager-page-inspect-test-template' pk=object.pk %}", true);
+        xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
+        xhttp.send(querystring);
+        return false;
+      }
+
+      const submit_btn = document.getElementById('page-inspect-test-template-submit')
+      submit_btn.onclick = submit_btn_click
+    }
+  </script>
 {% endwith %}

combo/manager/urls.py

@@ -104,6 +104,11 @@ urlpatterns = [
         name='combo-manager-page-edit-roles',
     ),
     re_path(r'^pages/(?P<pk>\d+)/inspect/$', views.page_inspect, name='combo-manager-page-inspect'),
+    re_path(
+        r'^pages/(?P<pk>\d+)/inspect/test_template$',
+        views.page_inspect_test_template,
+        name='combo-manager-page-inspect-test-template',
+    ),
     re_path(r'^pages/(?P<pk>\d+)/history$', views.page_history, name='combo-manager-page-history'),
     re_path(
         r'^pages/(?P<page_pk>\d+)/history/(?P<pk>\d+)/$',

combo/manager/views.py

@@ -40,7 +40,8 @@ from django.http import (
     JsonResponse,
 )
 from django.shortcuts import get_object_or_404, redirect, render
-from django.template import engines, loader
+from django.template import Context, Template, engines, loader
+from django.template.exceptions import TemplateSyntaxError
 from django.urls import reverse, reverse_lazy
 from django.utils.encoding import force_bytes, force_str
 from django.utils.formats import date_format
@@ -91,6 +92,7 @@ from .forms import (
     PageEditSlugForm,
     PageEditTitleForm,
     PageExportForm,
+    PageInspectTemplateTestForm,
     PageRestrictedAddForm,
     PageSelectTemplateForm,
     PageSnapshotSaveForm,
@@ -659,12 +661,37 @@ class PageInspectView(ManagedPageMixin, DetailView):
             prefetch_groups=True,
             cells_exclude=Q(placeholder__in=['_auto_tile', '_dashboard', '_suggested_tile']),
         )
+
+        kwargs['inspect_form'] = PageInspectTemplateTestForm()
         return super().get_context_data(**kwargs)
 
 
 page_inspect = PageInspectView.as_view()
 
 
+class PageInspectTestTemplateView(ManagedPageMixin, View):
+    model = Page
+
+    def post(self, request, *args, **kwargs):
+        if 'django_template' not in request.POST:
+            return HttpResponseBadRequest()
+
+        response = {}
+        try:
+            template = Template(request.POST['django_template'])
+        except TemplateSyntaxError as expt:
+            response['error'] = str(expt)
+            return JsonResponse(response)
+
+        ctx = {'page': self.page, 'cells': self.page.get_cells()}
+        response['result'] = template.render(Context(ctx))
+
+        return JsonResponse(response)
+
+
+page_inspect_test_template = PageInspectTestTemplateView.as_view()
+
+
 class PageHistoryView(ManagedPageMixin, ListView):
     model = PageSnapshot
     template_name = 'combo/page_history.html'

tests/test_manager.py

@@ -3407,3 +3407,65 @@ def test_manager_inspect_page(settings, app, admin_user):
     app = login(app)
     resp = app.get('/manage/pages/%s/' % page.id)
     resp.click('Inspect')
+
+
+def test_manager_inspect_test_template(app, admin_user):
+    """Testing various template rendering :
+    - checks page & cells basic attribute access
+    - checks no double rendering of templates
+    """
+    page_title = 'TestPage'
+    cell_texts = ['FooBar', 'SecondCell']
+
+    page = Page.objects.create(title=page_title, slug='testslug')
+    for cell_text in cell_texts:
+        TextCell.objects.create(page=page, text=cell_text, order=1)
+
+    app = login(app)
+
+    inspect_page = app.get('/manage/pages/%d/inspect/' % page.pk)
+    form_template = inspect_page.forms[0]
+
+    tests = (
+        ('{{page.title}}', page_title),
+        ('{% for cell in cells %}{{cell.text}}\n{% endfor %}', '%s\n' % ('\n'.join(cell_texts))),
+        ('{% templatetag openvariable%}1|add:1{%templatetag closevariable%}', '{{1|add:1}}'),
+    )
+
+    for template, expected_result in tests:
+        form_template['django_template'] = template
+        resp = form_template.submit()
+        assert resp.status_int == 200
+
+        result = json.loads(resp.text)
+        assert 'error' not in result
+        assert result['result'] == expected_result
+
+
+def test_manager_inspect_test_template_invalid(app, admin_user):
+    app = login(app)
+    page_title = 'TestPage'
+    page = Page.objects.create(title=page_title, slug='testslug')
+
+    invalid_templates = ('{{1|add}}', '{{"foo"|badfilter}}')
+
+    for bad_template in invalid_templates:
+        inspect_page = app.get('/manage/pages/%d/inspect/' % page.pk)
+        form_template = inspect_page.forms[0]
+        form_template['django_template'] = bad_template
+
+        resp = form_template.submit()
+        assert resp.status_int == 200
+
+        result = json.loads(resp.text)
+        assert 'result' not in result
+        assert len(result['error']) > 0
+
+    # testing bad form (missing expected field)
+    inspect_page = app.get('/manage/pages/%d/inspect/' % page.pk)
+    form_template = inspect_page.forms[0]
+
+    csrf = form_template['csrfmiddlewaretoken'].value
+    resp = app.post(
+        '/manage/pages/%d/inspect/test_template' % page.pk, {'csrfmiddlewaretoken': csrf}, status=400
+    )