Add RSS feed for the blog

app/Http/Controllers/ShowBlogController.php

@@ -3,7 +3,9 @@
 namespace App\Http\Controllers;
 
 use App\Models\Article;
+use App\Support\BlogFeed;
 use Artesaos\SEOTools\Facades\SEOTools;
+use Illuminate\Http\Response;
 
 class ShowBlogController extends Controller
 {
@@ -18,6 +20,19 @@ public function index()
         ]);
     }
 
+    public function feed(BlogFeed $feed): Response
+    {
+        $articles = Article::query()
+            ->published()
+            ->with('author')
+            ->limit(20)
+            ->get();
+
+        return response($feed->toRss($articles), 200, [
+            'Content-Type' => 'application/rss+xml; charset=UTF-8',
+        ]);
+    }
+
     public function show(Article $article)
     {
         abort_unless($article->isPublished() || $article->isScheduled() || auth()->user()?->isAdmin(), 404);

app/Support/BlogFeed.php

@@ -0,0 +1,95 @@
+<?php
+
+namespace App\Support;
+
+use App\Models\Article;
+use DOMDocument;
+use DOMElement;
+use Illuminate\Support\Collection;
+
+class BlogFeed
+{
+    private const string ATOM_NAMESPACE = 'http://www.w3.org/2005/Atom';
+
+    private const string DUBLIN_CORE_NAMESPACE = 'http://purl.org/dc/elements/1.1/';
+
+    private const string MEDIA_NAMESPACE = 'http://search.yahoo.com/mrss/';
+
+    /**
+     * @param  Collection<int, Article>  $articles
+     */
+    public function toRss(Collection $articles): string
+    {
+        $document = new DOMDocument('1.0', 'UTF-8');
+        $document->formatOutput = true;
+
+        $rss = $document->createElement('rss');
+        $rss->setAttribute('version', '2.0');
+        $rss->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:atom', self::ATOM_NAMESPACE);
+        $rss->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:dc', self::DUBLIN_CORE_NAMESPACE);
+        $rss->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:media', self::MEDIA_NAMESPACE);
+        $document->appendChild($rss);
+
+        $channel = $document->createElement('channel');
+        $rss->appendChild($channel);
+
+        $this->appendText($document, $channel, 'title', 'NativePHP Blog');
+        $this->appendText($document, $channel, 'link', route('blog'));
+
+        $self = $document->createElementNS(self::ATOM_NAMESPACE, 'atom:link');
+        $self->setAttribute('href', route('blog.feed'));
+        $self->setAttribute('rel', 'self');
+        $self->setAttribute('type', 'application/rss+xml');
+        $channel->appendChild($self);
+
+        $this->appendText($document, $channel, 'description', 'Insights, updates, and stories from the NativePHP community.');
+        $this->appendText($document, $channel, 'language', 'en');
+
+        if ($articles->isNotEmpty()) {
+            $this->appendText($document, $channel, 'lastBuildDate', $articles->max('updated_at')->toRssString());
+        }
+
+        foreach ($articles as $article) {
+            $this->appendItem($document, $channel, $article);
+        }
+
+        return (string) $document->saveXML();
+    }
+
+    private function appendItem(DOMDocument $document, DOMElement $channel, Article $article): void
+    {
+        $item = $document->createElement('item');
+        $channel->appendChild($item);
+
+        $url = route('article', $article);
+
+        $this->appendText($document, $item, 'title', $article->title);
+        $this->appendText($document, $item, 'link', $url);
+        $this->appendText($document, $item, 'guid', $url)->setAttribute('isPermaLink', 'true');
+        $this->appendText($document, $item, 'pubDate', $article->published_at->toRssString());
+
+        if ($article->author?->name) {
+            $creator = $document->createElementNS(self::DUBLIN_CORE_NAMESPACE, 'dc:creator');
+            $creator->appendChild($document->createTextNode($article->author->name));
+            $item->appendChild($creator);
+        }
+
+        $this->appendText($document, $item, 'description', $article->excerpt ?? '');
+
+        if ($article->og_image) {
+            $media = $document->createElementNS(self::MEDIA_NAMESPACE, 'media:content');
+            $media->setAttribute('url', $article->og_image);
+            $media->setAttribute('medium', 'image');
+            $item->appendChild($media);
+        }
+    }
+
+    private function appendText(DOMDocument $document, DOMElement $parent, string $name, string $value): DOMElement
+    {
+        $element = $document->createElement($name);
+        $element->appendChild($document->createTextNode($value));
+        $parent->appendChild($element);
+
+        return $element;
+    }
+}

resources/views/components/layout.blade.php

@@ -66,6 +66,14 @@
             type="image/svg+xml"
         />
 
+        {{-- Blog RSS feed autodiscovery --}}
+        <link
+            rel="alternate"
+            type="application/rss+xml"
+            title="NativePHP Blog"
+            href="{{ route('blog.feed') }}"
+        />
+
         {!! SEOMeta::generate() !!}
         {!! OpenGraph::generate() !!}
         {!! Twitter::generate() !!}

routes/web.php

@@ -196,6 +196,7 @@
 Route::view('vs-flutter', 'vs-flutter')->name('vs-flutter');
 
 Route::get('blog', [ShowBlogController::class, 'index'])->name('blog');
+Route::get('blog/feed', [ShowBlogController::class, 'feed'])->name('blog.feed');
 Route::get('blog/{article}', [ShowBlogController::class, 'show'])->name('article');
 
 Route::get('docs/{platform}/{version}/{page}.md', [ShowDocumentationController::class, 'serveRawMarkdown'])

tests/Feature/BlogFeedTest.php

@@ -0,0 +1,125 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\Article;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+class BlogFeedTest extends TestCase
+{
+    use RefreshDatabase;
+
+    #[Test]
+    public function the_blog_feed_is_served_as_rss_xml()
+    {
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertHeader('Content-Type', 'application/rss+xml; charset=UTF-8')
+            ->assertSee('<rss', false)
+            ->assertSee('<channel>', false);
+    }
+
+    #[Test]
+    public function published_articles_appear_in_the_feed()
+    {
+        $article = Article::factory()->published()->create();
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertSee($article->title, false)
+            ->assertSee(route('article', $article), false)
+            ->assertSee($article->excerpt, false);
+    }
+
+    #[Test]
+    public function articles_expose_their_open_graph_image_in_the_feed()
+    {
+        $article = Article::factory()->published()->create([
+            'og_image' => 'https://example.com/og/cover.png',
+        ]);
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertSee('<media:content', false)
+            ->assertSee('url="https://example.com/og/cover.png"', false)
+            ->assertSee('medium="image"', false);
+    }
+
+    #[Test]
+    public function articles_without_an_open_graph_image_omit_the_media_tag()
+    {
+        Article::factory()->published()->create([
+            'og_image' => null,
+        ]);
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertDontSee('<media:content', false);
+    }
+
+    #[Test]
+    public function the_feed_last_build_date_reflects_the_most_recently_updated_article()
+    {
+        $this->freezeTime();
+
+        Article::factory()->published()->create([
+            'updated_at' => now()->subWeek(),
+        ]);
+
+        $mostRecentlyUpdated = Article::factory()->published()->create([
+            'updated_at' => now()->subDay(),
+        ]);
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertSee('<lastBuildDate>'.$mostRecentlyUpdated->updated_at->toRssString().'</lastBuildDate>', false);
+    }
+
+    #[Test]
+    public function scheduled_articles_do_not_appear_in_the_feed()
+    {
+        $article = Article::factory()->scheduled()->create();
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertDontSee($article->title, false);
+    }
+
+    #[Test]
+    public function draft_articles_do_not_appear_in_the_feed()
+    {
+        $article = Article::factory()->create([
+            'published_at' => null,
+        ]);
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertDontSee($article->title, false);
+    }
+
+    #[Test]
+    public function articles_appear_in_the_feed_in_reverse_chronological_order()
+    {
+        $older = Article::factory()->create([
+            'published_at' => now()->subDays(2),
+        ]);
+
+        $newer = Article::factory()->create([
+            'published_at' => now()->subDay(),
+        ]);
+
+        $this->get(route('blog.feed'))
+            ->assertOk()
+            ->assertSeeInOrder([$newer->title, $older->title], false);
+    }
+
+    #[Test]
+    public function the_blog_page_links_to_the_feed_for_autodiscovery()
+    {
+        $this->get(route('blog'))
+            ->assertOk()
+            ->assertSee(route('blog.feed'), false);
+    }
+}