1.2.16: Added nextPost and previousPost to the blog post component.

Fixes #80
Fixes #284

components/Post.php

@@ -69,11 +69,44 @@ protected function loadPost()
          * Add a "url" helper attribute for linking to each category
          */
         if ($post && $post->categories->count()) {
-            $post->categories->each(function($category){
+            $post->categories->each(function($category) {
                 $category->setUrl($this->categoryPage, $this->controller);
             });
         }
 
         return $post;
     }
+
+    public function previousPost()
+    {
+        return $this->getPostSibling(-1);
+    }
+
+    public function nextPost()
+    {
+        return $this->getPostSibling(1);
+    }
+
+    protected function getPostSibling($direction = 1)
+    {
+        if (!$this->post) {
+            return;
+        }
+
+        $method = $direction === -1 ? 'previousPost' : 'nextPost';
+
+        if (!$post = $this->post->$method()) {
+            return;
+        }
+
+        $postPage = $this->getPage()->getBaseFileName();
+
+        $post->setUrl($postPage, $this->controller);
+
+        $post->categories->each(function($category) {
+            $category->setUrl($this->categoryPage, $this->controller);
+        });
+
+        return $post;
+    }
 }

models/Post.php

@@ -342,6 +342,36 @@ public function getSummaryAttribute()
         return Html::limit($this->content_html, 600);
     }
 
+    //
+    // Next / Previous
+    //
+
+    /**
+     * Returns the next post, if available.
+     * @return self
+     */
+    public function nextPost()
+    {
+        return self::isPublished()
+            ->where('id', '>' , $this->id)
+            ->orderBy('id', 'asc')
+            ->first()
+        ;
+    }
+
+    /**
+     * Returns the previous post, if available.
+     * @return self
+     */
+    public function previousPost()
+    {
+        return self::isPublished()
+            ->where('id', '<' , $this->id)
+            ->orderBy('id', 'desc')
+            ->first()
+        ;
+    }
+
     //
     // Menu helpers
     //

updates/version.yaml

@@ -40,3 +40,4 @@
 1.2.13: Improved support for Static Pages menus, added a blog post and all blog posts.
 1.2.14: Added post exception property to the post list component, useful for showing related posts.
 1.2.15: Back-end navigation sort order updated.
+1.2.16: Added `nextPost` and `previousPost` to the blog post component.