Add routing templates for Index pages

src/Module.php

@@ -3,6 +3,13 @@
 namespace boilerplate;
 
 use Craft;
+use boilerplate\behaviors\EntryIndexQueryBehavior;
+use boilerplate\behaviors\IndexEntryBehaviors;
+use boilerplate\behaviors\SectionRouterBehavior;
+use craft\base\Element;
+use craft\elements\Entry;
+use craft\elements\db\EntryQuery;
+use craft\events\DefineBehaviorsEvent;
 use craft\web\Response;
 use yii\base\Event;
 
@@ -80,6 +87,39 @@ public function onBeforeSendLivePreview(Event $event)
         }
     }
 
+    // define entry behaviors
+    // - custom index entry properties
+    public function onEntryDefineBehaviors(DefineBehaviorsEvent $event)
+    {
+        $entry = $event->sender;
+        if (
+            $entry->id &&
+            $entry->sectionId &&
+            strpos(
+                $entry->section->handle,
+                IndexEntryBehaviors::$sectionHandlePrefix,
+            ) === 0
+        ) {
+            $event->behaviors[$this->id . 'IndexEntry'] =
+                IndexEntryBehaviors::class;
+        }
+    }
+
+    // define custom index query
+    public function onEntryQueryDefineBehaviors(DefineBehaviorsEvent $event)
+    {
+        $event->behaviors[$this->id . EntryIndexQueryBehavior::class] =
+            EntryIndexQueryBehavior::class;
+    }
+
+    // define custom Section properties
+    public function onSectionDefineBehaviors(DefineBehaviorsEvent $event)
+    {
+        if ($event->sender instanceof Section && $event->sender->id) {
+            $event->behaviors[$this->id] = SectionRouterBehavior::class;
+        }
+    }
+
     // Protected Methods
     // =================
 
@@ -94,5 +134,15 @@ protected function addEventListeners()
             $this,
             'onBeforeSendLivePreview',
         ]);
+
+        Event::on(Entry::class, Element::EVENT_DEFINE_BEHAVIORS, [
+            $this,
+            'onEntryDefineBehaviors',
+        ]);
+
+        Event::on(EntryQuery::class, EntryQuery::EVENT_DEFINE_BEHAVIORS, [
+            $this,
+            'onEntryQueryDefineBehaviors',
+        ]);
     }
 }

src/behaviors/EntryIndexQueryBehavior.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace boilerplate\behaviors;
+
+use Craft;
+use craft\elements\db\EntryQuery;
+use craft\elements\Entry;
+use craft\models\Section;
+use yii\base\Behavior;
+
+/**
+ * Class EntryIndexQueryBehavior
+ *
+ * Adds the ability to query for an entry's Index (single) entry
+ *
+ * @property Entry $owner
+ */
+class EntryIndexQueryBehavior extends Behavior
+{
+    // query for the Index entry of the passed in value
+    public function index_($value): EntryQuery
+    {
+        $sectionHandle = '';
+
+        if ($value instanceof Entry) {
+            $sectionHandle = $value->getSection()->handle;
+        } elseif ($value instanceof Section) {
+            $sectionHandle = $value->handle;
+        } elseif (is_string($value)) {
+            $sectionHandle = $value;
+        }
+
+        if ($sectionHandle !== '') {
+            $this->owner->section('index_' . $sectionHandle)->limit(1);
+        }
+
+        return $this->owner;
+    }
+}

src/behaviors/IndexEntryBehaviors.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace boilerplate\behaviors;
+
+use Craft;
+use craft\models\Section;
+use yii\base\Behavior;
+
+/**
+ * Class IndexEntryBehaviors
+ *
+ * Adds certain behaviors to all Index Single entries
+ *
+ * @property Entry $owner
+ */
+class IndexEntryBehaviors extends Behavior
+{
+    // Sections which the behavior should be attached to
+    public static $sectionHandlePrefix = 'index_';
+
+    // Fetch the section for which this entry serves as the index
+    public function getIndexSection_(): Section|null
+    {
+        $indexSection = $this->owner->getSection()->handle;
+        $indexSection = preg_replace(
+            '/^' . $this::$sectionHandlePrefix . '/',
+            '',
+            $indexSection,
+            1,
+        );
+        $indexSection = Craft::$app->sections->getSectionByHandle(
+            $indexSection,
+        );
+        return $indexSection;
+    }
+}

templates/_routers/index.twig

@@ -0,0 +1,24 @@
+{% minify %}
+  {#
+    Index Router
+
+    @param  section   Section object whose index is being rendered
+                      (auto-set when coming via the router)
+    @param  entry     The section's index page single entry
+                      (auto-set when directly hitting the single)
+    @param  entries   Query object of the index page's contents
+                      (auto-set when coming via the router)
+  #}
+  {% set section = section ?? entry['indexSection_'] ?? entry.section %}
+  {% set entry = entry ?? craft.entries.index_(section).one() %}
+  {% set entries = entries ?? craft.entries.section(section) %}
+
+  {% if not entry %}
+    {% exit 404 %}
+  {% endif %}
+
+  {%- include [
+    '_views/indexes/' ~ section.handle|replace('index_'),
+    '_views/indexes/default',
+  ] -%}
+{% endminify %}

templates/_views/indexes/default.twig

@@ -0,0 +1 @@
+{% extends '_views/detail/default' %}