[13.x] Handle api / json routes with Down (Maintenance) command

src/Illuminate/Foundation/Console/stubs/maintenance-mode.stub

@@ -8,6 +8,21 @@ if (! file_exists($down = __DIR__.'/down')) {
 // Decode the "down" file's JSON...
 $data = json_decode(file_get_contents($down), true);
 
+$expectsJson = (function () {
+    $acceptable = array_map('trim', explode(',', $_SERVER['HTTP_ACCEPT'] ?? ''));
+
+    $firstAcceptable = strtolower(strtok($acceptable[0] ?? '', ';'));
+
+    if (str_contains($firstAcceptable, '/json') || str_contains($firstAcceptable, '+json')) {
+        return true;
+    }
+
+    return isset($_SERVER['HTTP_X_REQUESTED_WITH']) &&
+        strcasecmp($_SERVER['HTTP_X_REQUESTED_WITH'], 'XMLHttpRequest') === 0 &&
+        (! isset($_SERVER['HTTP_X_PJAX']) || strcasecmp($_SERVER['HTTP_X_PJAX'], 'true') !== 0) &&
+        in_array($firstAcceptable, ['', '*/*', '*'], true);
+})();
+
 // Allow framework to handle request if no prerendered template...
 if (! isset($data['template'])) {
     return;
@@ -54,6 +69,11 @@ if (isset($_COOKIE['laravel_maintenance']) && isset($data['secret'])) {
     }
 }
 
+// Allow framework to handle requests expecting a JSON response...
+if ($expectsJson) {
+    return;
+}
+
 // Redirect to the proper path if necessary...
 if (isset($data['redirect']) && $_SERVER['REQUEST_URI'] !== $data['redirect']) {
     http_response_code(302);

src/Illuminate/Foundation/Http/Middleware/PreventRequestsDuringMaintenance.php

@@ -80,7 +80,7 @@ public function handle($request, Closure $next)
                 return $next($request);
             }
 
-            if (isset($data['redirect'])) {
+            if (isset($data['redirect']) && ! $request->expectsJson()) {
                 $path = $data['redirect'] === '/'
                     ? $data['redirect']
                     : trim($data['redirect'], '/');
@@ -90,7 +90,7 @@ public function handle($request, Closure $next)
                 }
             }
 
-            if (isset($data['template'])) {
+            if (isset($data['template']) && ! $request->expectsJson()) {
                 return response(
                     $data['template'],
                     $data['status'] ?? 503,

tests/Integration/Foundation/MaintenanceModeTest.php

@@ -22,6 +22,7 @@ protected function setUp(): void
     {
         $this->beforeApplicationDestroyed(function () {
             @unlink(storage_path('framework/down'));
+            @unlink(storage_path('framework/maintenance.php'));
         });
 
         parent::setUp();
@@ -80,6 +81,67 @@ public function testMaintenanceModeCanHaveCustomTemplate()
         $this->assertSame('Rendered Content', $response->original);
     }
 
+    public function testMaintenanceModeDoesNotUseCustomTemplateForJsonRequests()
+    {
+        file_put_contents(storage_path('framework/down'), json_encode([
+            'retry' => 60,
+            'template' => 'Rendered Content',
+        ]));
+
+        Route::get('/foo', function () {
+            return 'Hello World';
+        })->middleware(PreventRequestsDuringMaintenance::class);
+
+        $response = $this->getJson('/foo');
+
+        $response->assertStatus(503);
+        $response->assertHeader('Retry-After', '60');
+        $response->assertJson(['message' => 'Service Unavailable']);
+    }
+
+    public function testMaintenanceModeDoesNotRedirectJsonRequests()
+    {
+        file_put_contents(storage_path('framework/down'), json_encode([
+            'redirect' => '/maintenance',
+        ]));
+
+        Route::get('/foo', function () {
+            return 'Hello World';
+        })->middleware(PreventRequestsDuringMaintenance::class);
+
+        $response = $this->getJson('/foo');
+
+        $response->assertStatus(503);
+        $response->assertJson(['message' => 'Service Unavailable']);
+    }
+
+    public function testPrerenderedMaintenanceFileAllowsJsonRequestsToReachFramework()
+    {
+        file_put_contents(storage_path('framework/down'), json_encode([
+            'template' => 'Rendered Content',
+        ]));
+
+        file_put_contents(
+            storage_path('framework/maintenance.php'),
+            file_get_contents(__DIR__.'/../../../src/Illuminate/Foundation/Console/stubs/maintenance-mode.stub')
+        );
+
+        $server = $_SERVER;
+
+        try {
+            $_SERVER['REQUEST_URI'] = '/foo';
+            $_SERVER['HTTP_ACCEPT'] = 'application/json';
+
+            ob_start();
+            include storage_path('framework/maintenance.php');
+            $output = ob_get_clean();
+        } finally {
+            $_SERVER = $server;
+        }
+
+        $this->assertSame('', $output);
+    }
+
     public function testMaintenanceModeCanRedirectWithBypassCookie()
     {
         file_put_contents(storage_path('framework/down'), json_encode([