Add ETag to WebAPI for caching of unchanged resources (#17)

app/Components/Helpers.php

@@ -318,4 +318,17 @@ class Helpers
         return $log->save();
     }
 
+    public static function abortIfNotModified($data): string {
+        $req = request();
+        // Only for "GET" method
+        if (!$req->isMethod('GET')) {
+            return "";
+        }
+
+        $etag = sha1(json_encode($data));
+        if ($etag == $req->header("IF-NONE-MATCH")) {
+            abort(304);
+        }
+        return $etag;
+    }
 }

app/Http/Controllers/Api/WebApi/BaseController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api\WebApi;
 
+use App\Components\Helpers;
 use App\Models\Node;
 use App\Models\NodeHeartBeat;
 use App\Models\NodeOnlineLog;
@@ -53,6 +54,8 @@ class BaseController
         $data = [],
         $addition = []
     ): JsonResponse {
+        $etag = Helpers::abortIfNotModified($data);
+
         $data = [
             'status'  => $status,
             'code'    => $code,
@@ -64,7 +67,7 @@ class BaseController
             $data = array_merge($data, $addition);
         }
 
-        return Response::json($data);
+        return Response::json($data)->header('ETAG', $etag);
     }
 
     // 上报节点在线人数