[5.x] Cache the isApiRoute results for the request (#9638)

Co-authored-by: Jason Varga <jason@pixelfear.com>

src/Listeners/ClearState.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Statamic\Listeners;
+
+use Statamic\Statamic;
+use Statamic\View\State\StateManager;
+
+class ClearState
+{
+    public function handle()
+    {
+        Statamic::clearApiRouteCache();
+        StateManager::resetState();
+    }
+}

src/Providers/EventServiceProvider.php

@@ -24,10 +24,10 @@ class EventServiceProvider extends ServiceProvider
             \Statamic\Entries\AddSiteColumnToBlueprint::class,
         ],
         \Statamic\Events\ResponseCreated::class => [
-            \Statamic\View\State\ClearState::class,
+            \Statamic\Listeners\ClearState::class,
         ],
         \Illuminate\Foundation\Http\Events\RequestHandled::class => [
-            \Statamic\View\State\ClearState::class,
+            \Statamic\Listeners\ClearState::class,
         ],
     ];
 

src/Statamic.php

@@ -35,6 +35,7 @@ class Statamic
     protected static $jsonVariables = [];
     protected static $bootedCallbacks = [];
     protected static $afterInstalledCallbacks = [];
+    private static $isApiRouteCache;
 
     public static function version()
     {
@@ -211,13 +212,22 @@ public static function cpRoute($route, $params = [])
         return $route;
     }
 
+    public static function clearApiRouteCache()
+    {
+        self::$isApiRouteCache = null;
+    }
+
     public static function isApiRoute()
     {
+        if (self::$isApiRouteCache !== null) {
+            return self::$isApiRouteCache;
+        }
+
         if (! config('statamic.api.enabled') || ! static::pro()) {
-            return false;
+            return self::$isApiRouteCache = false;
         }
 
-        return starts_with(request()->path(), config('statamic.api.route'));
+        return self::$isApiRouteCache = starts_with(request()->path(), config('statamic.api.route'));
     }
 
     public static function apiRoute($route, $params = [])