[5.x] Statically cache 404s

config/static_caching.php

@@ -129,4 +129,19 @@
 
     'warm_queue' => null,
 
+    /*
+    |--------------------------------------------------------------------------
+    | Shared Error Pages
+    |--------------------------------------------------------------------------
+    |
+    | You may choose to share the same statically generated error page across
+    | all errors. For example, the first time a 404 is encountered it will
+    | be generated and cached, and then served for all subsequent 404s.
+    |
+    | This is only supported for half measure.
+    |
+    */
+
+    'share_errors' => false,
+
 ];

src/Exceptions/Concerns/RendersHttpExceptions.php

@@ -2,8 +2,12 @@
 
 namespace Statamic\Exceptions\Concerns;
 
+use Illuminate\Http\Request;
+use Illuminate\Http\Response;
 use Statamic\Facades\Cascade;
 use Statamic\Statamic;
+use Statamic\StaticCaching\Cacher;
+use Statamic\StaticCaching\Cachers\ApplicationCacher;
 use Statamic\View\View;
 
 trait RendersHttpExceptions
@@ -18,6 +22,10 @@ public function render()
             return response()->json(['message' => $this->getApiMessage()], $this->getStatusCode());
         }
 
+        if ($cached = $this->getCachedError()) {
+            return $cached;
+        }
+
         if (view()->exists('errors.'.$this->getStatusCode())) {
             return response($this->contents(), $this->getStatusCode());
         }
@@ -53,4 +61,25 @@ public function getApiMessage()
     {
         return $this->getMessage();
     }
+
+    private function getCachedError(): ?Response
+    {
+        $status = $this->getStatusCode();
+
+        if (! config('statamic.static_caching.share_errors')) {
+            return null;
+        }
+
+        $cacher = app(Cacher::class);
+
+        if (! $cacher instanceof ApplicationCacher) {
+            return null;
+        }
+
+        $request = Request::createFrom(request())->fakeStaticCacheStatus($status);
+
+        return $cacher->hasCachedPage($request)
+            ? $cacher->getCachedPage($request)->toResponse($request)
+            : null;
+    }
 }

src/StaticCaching/Cachers/ApplicationCacher.php

@@ -52,6 +52,7 @@ public function cachePage(Request $request, $content)
             $cacheValue = [
                 'content' => $value,
                 'headers' => $headers,
+                'status' => $event->response->getStatusCode(),
             ];
 
             $this->getDefaultExpiration()
@@ -79,7 +80,7 @@ public function getCachedPage(Request $request)
     {
         $cachedPage = $this->cached ?? $this->getFromCache($request);
 
-        return new Page($cachedPage['content'], $cachedPage['headers']);
+        return new Page($cachedPage['content'], $cachedPage['headers'], $cachedPage['status'] ?? 200);
     }
 
     private function getFromCache(Request $request)

src/StaticCaching/Middleware/Cache.php

@@ -10,6 +10,7 @@
 use Statamic\Facades\File;
 use Statamic\Statamic;
 use Statamic\StaticCaching\Cacher;
+use Statamic\StaticCaching\Cachers\ApplicationCacher;
 use Statamic\StaticCaching\Cachers\NullCacher;
 use Statamic\StaticCaching\NoCache\RegionNotFound;
 use Statamic\StaticCaching\NoCache\Session;
@@ -63,6 +64,8 @@ public function handle($request, Closure $next)
         if ($this->shouldBeCached($request, $response)) {
             $lock->acquire(true);
 
+            $this->copyError($request, $response);
+
             $this->makeReplacementsAndCacheResponse($request, $response);
 
             $this->nocache->write();
@@ -73,6 +76,21 @@ public function handle($request, Closure $next)
         return $response;
     }
 
+    private function copyError($request, $response)
+    {
+        $status = $response->getStatusCode();
+
+        if (! config('statamic.static_caching.share_errors')) {
+            return;
+        }
+
+        $request = Request::createFrom($request)->fakeStaticCacheStatus($status);
+
+        if (! $this->cacher->hasCachedPage($request)) {
+            $this->cacher->cachePage($request, $response);
+        }
+    }
+
     private function attemptToGetCachedResponse($request)
     {
         if ($this->canBeCached($request) && $this->cacher->hasCachedPage($request)) {
@@ -139,7 +157,9 @@ private function shouldBeCached($request, $response)
             return false;
         }
 
-        if ($response->getStatusCode() !== 200 || $response->getContent() == '') {
+        $statuses = $this->cacher instanceof ApplicationCacher ? [200, 404] : [200];
+
+        if (! in_array($response->getStatusCode(), $statuses) || $response->getContent() == '') {
             return false;
         }
 

src/StaticCaching/Page.php

@@ -7,12 +7,15 @@
 
 class Page implements Responsable
 {
-    public function __construct(public string $content, public array $headers = [])
-    {
+    public function __construct(
+        public string $content,
+        public array $headers = [],
+        public int $status = 200
+    ) {
     }
 
     public function toResponse($request): Response
     {
-        return new Response($this->content, 200, $this->headers);
+        return new Response($this->content, $this->status, $this->headers);
     }
 }

src/StaticCaching/ServiceProvider.php

@@ -2,6 +2,7 @@
 
 namespace Statamic\StaticCaching;
 
+use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Blade;
 use Illuminate\Support\Facades\Event;
 use Illuminate\Support\ServiceProvider as LaravelServiceProvider;
@@ -78,5 +79,13 @@ public function boot()
         Blade::directive('nocache', function ($exp) {
             return '<?php echo app("Statamic\StaticCaching\NoCache\BladeDirective")->handle('.$exp.', \Illuminate\Support\Arr::except(get_defined_vars(), [\'__data\', \'__path\'])); ?>';
         });
+
+        Request::macro('fakeStaticCacheStatus', function (int $status) {
+            $url = '/__shared-errors/'.$status;
+            $this->pathInfo = $url;
+            $this->requestUri = $url;
+
+            return $this;
+        });
     }
 }

tests/StaticCaching/ApplicationCacherTest.php

@@ -42,6 +42,7 @@ public function gets_cached_page()
         $cachedPage = $cacher->getCachedPage($request);
         $this->assertEquals('html content', $cachedPage->content);
         $this->assertEquals('application/html', $cachedPage->headers['Content-Type']);
+        $this->assertEquals(200, $cachedPage->status);
     }
 
     /** @test */