Add canonical links for documentation pages

app/Http/Controllers/ShowDocumentationController.php

@@ -2,7 +2,9 @@
 
 namespace App\Http\Controllers;
 
+use App\Services\DocsVersionService;
 use App\Support\CommonMark\CommonMark;
+use Artesaos\SEOTools\Facades\SEOMeta;
 use Artesaos\SEOTools\Facades\SEOTools;
 use Illuminate\Contracts\View\Factory as ViewFactory;
 use Illuminate\Http\RedirectResponse;
@@ -49,6 +51,13 @@ public function __invoke(Request $request, string $platform, string $version, ?s
         $title = $pageProperties['title'].' - NativePHP '.$platform.' v'.$version;
         $description = Arr::exists($pageProperties, 'description') ? $pageProperties['description'] : 'NativePHP documentation for '.$platform.' v'.$version;
 
+        $canonicalUrl = app(DocsVersionService::class)->determineCanonicalUrl(
+            platform: $platform,
+            page: $page,
+        );
+
+        SEOMeta::setCanonical($canonicalUrl);
+
         SEOTools::setTitle($title);
         SEOTools::setDescription($description);
 

app/Services/DocsVersionService.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Services;
+
+class DocsVersionService
+{
+    public function determineCanonicalUrl(string $platform, string $page): string
+    {
+        $latestVersion = $platform === 'mobile' ? config('docs.latest_versions.mobile') : config('docs.latest_versions.desktop');
+
+        $page = $this->resolveOldVersionApisWithPluginsCorePage($platform, $latestVersion, $page);
+
+        $latestPagePath = resource_path("views/docs/{$platform}/{$latestVersion}/{$page}.md");
+
+        $page = file_exists($latestPagePath) ? $page : 'getting-started/introduction';
+
+        return route('docs.show', [
+            'platform' => $platform,
+            'version' => $latestVersion,
+            'page' => $page,
+        ]);
+    }
+
+    /**
+     * Handle renamed paths (e.g., apis/* moved to plugins/core/*)
+     */
+    public function resolveOldVersionApisWithPluginsCorePage(string $platform, string $latestVersion, string $page): string
+    {
+        if (str_starts_with($page, 'apis/')) {
+            $remappedPage = 'plugins/core/'.substr($page, 5);
+            $remappedPath = resource_path("views/docs/{$platform}/{$latestVersion}/{$remappedPage}.md");
+
+            if (file_exists($remappedPath)) {
+                $page = $remappedPage;
+            }
+        }
+
+        return $page;
+    }
+}

tests/Unit/DocsVersionServiceTest.php

@@ -0,0 +1,108 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Services\DocsVersionService;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+class DocsVersionServiceTest extends TestCase
+{
+    use RefreshDatabase;
+
+    protected DocsVersionService $docsVersionService;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->docsVersionService = app(DocsVersionService::class);
+    }
+
+    public static function platformDataProvider(): array
+    {
+        return [
+            'platform=mobile' => ['mobile'],
+            'platform=desktop' => ['desktop'],
+        ];
+    }
+
+    #[Test]
+    #[DataProvider('platformDataProvider')]
+    public function it_points_to_the_latest_version_when_page_exists_in_latest(
+        string $platform,
+    ): void {
+        $latestVersion = $platform === 'mobile' ? config('docs.latest_versions.mobile') : config('docs.latest_versions.desktop');
+
+        $url = $this->docsVersionService->determineCanonicalUrl(
+            platform: $platform,
+            page: 'getting-started/introduction',
+        );
+
+        $expected = route('docs.show', [
+            'platform' => $platform,
+            'version' => $latestVersion,
+            'page' => 'getting-started/introduction',
+        ]);
+
+        $this->assertEquals($expected, $url);
+    }
+
+    #[Test]
+    public function it_remaps_mobile_apis_pages_to_plugins_core_when_the_page_exists_there_in_latest(): void
+    {
+        $url = $this->docsVersionService->determineCanonicalUrl(
+            platform: 'mobile',
+            page: 'apis/camera',
+        );
+
+        $expected = route('docs.show', [
+            'platform' => 'mobile',
+            'version' => config('docs.latest_versions.mobile'),
+            'page' => 'plugins/core/camera',
+        ]);
+
+        $this->assertEquals($expected, $url);
+    }
+
+    #[Test]
+    public function it_points_to_the_latest_version_of_getting_started_introduction_when_page_does_not_exist_in_latest(): void
+    {
+        // concepts/ci-cd only exists in version 1 of mobile documentation
+        $url = $this->docsVersionService->determineCanonicalUrl(
+            platform: 'mobile',
+            page: 'concepts/ci-cd',
+        );
+
+        $expected = route('docs.show', [
+            'platform' => 'mobile',
+            'version' => '3',
+            'page' => 'getting-started/introduction',
+        ]);
+
+        $this->assertEquals($expected, $url);
+    }
+
+    #[Test]
+    #[DataProvider('platformDataProvider')]
+    public function it_points_to_the_latest_version_of_getting_started_introduction_when_page_does_not_exist(
+        string $platform,
+    ): void {
+        $latestVersion = $platform === 'mobile' ? config('docs.latest_versions.mobile') : config('docs.latest_versions.desktop');
+
+        $url = $this->docsVersionService->determineCanonicalUrl(
+            platform: $platform,
+            page: 'non-existent-page',
+        );
+
+        $expected = route('docs.show', [
+            'platform' => $platform,
+            'version' => $latestVersion,
+            'page' => 'getting-started/introduction',
+        ]);
+
+        $this->assertEquals($expected, $url);
+    }
+}