Merge pull request #443 from shikorism/fix/ignore-resolve-self

Tissue内のURLに対するメタデータ取得は拒否する

app/Http/Controllers/Api/CardController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers\Api;
 
+use App\MetadataResolver\DeniedHostException;
 use App\Services\MetadataResolveService;
 use Illuminate\Http\Request;
 
@@ -13,7 +14,11 @@ class CardController
             'url:required|url'
         ]);
 
-        $metadata = $service->execute($request->input('url'));
+        try {
+            $metadata = $service->execute($request->input('url'));
+        } catch (DeniedHostException $e) {
+            abort(403, $e->getMessage());
+        }
         $metadata->load('tags');
 
         $response = response($metadata);

app/Listeners/LinkCollector.php

@@ -3,6 +3,7 @@
 namespace App\Listeners;
 
 use App\Events\LinkDiscovered;
+use App\MetadataResolver\DeniedHostException;
 use App\Services\MetadataResolveService;
 use Illuminate\Contracts\Queue\ShouldQueue;
 use Illuminate\Queue\InteractsWithQueue;
@@ -32,6 +33,8 @@ class LinkCollector
     {
         try {
             $this->metadataResolveService->execute($event->url);
+        } catch (DeniedHostException $e) {
+            // ignored
         } catch (\Exception $e) {
             // 今のところこのイベントは同期実行されるので、上流をクラッシュさせないために雑catchする
             report($e);

app/MetadataResolver/DeniedHostException.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\MetadataResolver;
+
+use Exception;
+use Throwable;
+
+/**
+ * メタデータの解決を禁止しているホストに対して取得を試み、ブロックされたことを表します。
+ */
+class DeniedHostException extends Exception
+{
+    private $url;
+
+    public function __construct(string $url, Throwable $previous = null)
+    {
+        parent::__construct("Access denied by system policy: $url", 0, $previous);
+        $this->url = $url;
+    }
+
+    public function getUrl(): string
+    {
+        return $this->url;
+    }
+
+    public function getHost(): string
+    {
+        return parse_url($this->url, PHP_URL_HOST);
+    }
+}

app/Services/MetadataResolveService.php

@@ -3,6 +3,7 @@
 namespace App\Services;
 
 use App\Metadata;
+use App\MetadataResolver\DeniedHostException;
 use App\MetadataResolver\MetadataResolver;
 use App\Tag;
 use App\Utilities\Formatter;
@@ -27,6 +28,11 @@ class MetadataResolveService
         // URLの正規化
         $url = $this->formatter->normalizeUrl($url);
 
+        // 自分自身は解決しない
+        if (parse_url($url, PHP_URL_HOST) === parse_url(config('app.url'), PHP_URL_HOST)) {
+            throw new DeniedHostException($url);
+        }
+
         // 無かったら取得
         // TODO: ある程度古かったら再取得とかありだと思う
         $metadata = Metadata::find($url);