ui: Use HTMX to eliminate full page reloads

HTMX implementation is limited to HTML and JS files. No changes to Python files.

Signed-off-by: Joseph Nuthalapati <njoseph@riseup.net>

plinth/templates/base.html

@@ -252,7 +252,11 @@
   </div>
 
   {% block container %}
-    <div class="container content-container">
+    <div id="content-block" class="container content-container"
+         {% if refresh_page_sec %}
+           hx-get="." hx-trigger="load delay:{{ refresh_page_sec }}s"
+           hx-select="#content-block" hx-target="#content-block" hx-swap="outerHTML"
+         {% endif %}>
         {% block content_row %}
             {% include 'messages.html' %}
 

plinth/views.py

@@ -497,9 +497,8 @@ class AppOperationsView(TemplateView):
         context['app_id'] = self.app.app_id
         context['app_info'] = self.app.info
         context['operations'] = operation.manager.filter(self.app.app_id)
-        context['refresh_page_sec'] = 0
-        if context['operations']:
-            context['refresh_page_sec'] = 3
+        # Refresh periodically while operations are running
+        context['refresh_page_sec'] = 3 if context['operations'] else 0
 
         return context
 
@@ -532,10 +531,10 @@ class SetupView(TemplateView):
                                      != app_module.App.SetupState.NEEDS_SETUP)
 
         context['refresh_page_sec'] = None
-        if context['setup_state'] == app_module.App.SetupState.UP_TO_DATE:
-            context['refresh_page_sec'] = 0
-        elif context['operations']:
+        if context['operations']:
             context['refresh_page_sec'] = 3
+        elif context['setup_state'] == app_module.App.SetupState.UP_TO_DATE:
+            context['refresh_page_sec'] = 0
 
         return context
 
@@ -550,10 +549,7 @@ class SetupView(TemplateView):
                 # Give a moment for the setup process to start and show
                 # meaningful status.
                 time.sleep(1)
-                response = self.render_to_response(self.get_context_data())
-                # Post/Response/Get pattern for reloads
-                response.status_code = 303
-                return response
+                return redirect(request.path)
 
         return super().dispatch(request, *args, **kwargs)
 

static/themes/default/js/main.js

@@ -33,24 +33,6 @@ document.addEventListener('DOMContentLoaded', function (event) {
     html.classList.add('js');
 });
 
-/*
- * Refresh page if marked for refresh.
- */
-document.addEventListener('DOMContentLoaded', function () {
-    const body = document.querySelector('body');
-    if (body.hasAttribute('data-refresh-page-sec')) {
-        let seconds = body.getAttribute('data-refresh-page-sec');
-        seconds = parseInt(seconds, 10);
-        if (isNaN(seconds))
-            return;
-
-        window.setTimeout(() => {
-            // Refresh the page without resubmitting the POST data.
-            window.location = window.location.href;
-        }, seconds * 1000);
-    }
-});
-
 /*
  * Return all submit buttons on the page
  */
@@ -303,3 +285,16 @@ document.addEventListener('click', function (event) {
         bsCollapse.hide();
     }
 });
+
+/*
+ * Detect when hx-select element is not found in the response and reload the
+ * page. HTMX unfortunately does not seem to provide a JS event when hx-select
+ * element is not found in the response. However, in htmx:afterSwap event we can
+ * see that the target has no children and choose to refresh the whole page.
+ */
+document.addEventListener('htmx:afterSwap', function (event) {
+    const target = event.detail.target;
+    if (target && target.children.length === 0) {
+        window.location.reload();
+    }
+});